Abstracts: Transesophageal Electrophysiolology: Diagnosis and Treatment of Arrhythmias Clinical Abstracts on Transesophageal Electrophysiology For more information See: http://www.cardiocommand.com/research_electrophysiology.html

A gastroesophageal electrode for electrophysiological studies. McEneaney DJ, Escalona O, Anderson JA, Adgey AA. Regional Medical Cardiology Centre, Royal Victoria Hospital, Belfast. Pacing Clin Electrophysiol 1999 Mar;22(3):487-99. A novel gastroesophageal electrode has been developed capable of atrial and ventricular pacing. We performed electrophysiological studies using the gastroesophageal electrode (Esothoracic) and compared the results with the standard endocardial approach. The flexible polythene gastroesophageal electrode was passed into the stomach under light sedation. Five ring electrodes, now positioned in the lower esophagus were used for bipolar atrial pacing and recording. Ventricular pacing was performed using a cathodic point source on the gastroesophageal electrode tip; the indifferent electrode (anode) was a high impedance chest pad. Parameters of sinus and AV nodal function were obtained by atrial pacing. Programmed ventricular stimulation was performed using a standard protocol. These electrophysiological parameters were subsequently determined using the endocardial approach. There was close correlation between measurements of sinus and AV node function using the two approaches in 48 subjects: sinus node recovery time (SNRT) r2 = 0.70, corrected sinus node recovery time (CSNRT) r2 = 0.87, AV Wenckebach cycle length (AVWCL) r2 = 0.97. The degree of agreement between the two approaches was estimated by the mean difference delta and standard deviation of the difference sigma (SNRT delta = 40 ms, sigma = 257 ms; CSNRT sigma = 14 ms, delta = 164 ms; AVWCL sigma = 7 ms, delta = 16 ms). Programmed ventricular stimulation was performed in 15 of 48 subjects with known or suspected ventricular tachyarrhythmias. Seven had ventricular tachycardia induced using both esothoracic and endocardial programmed ventricular stimulation. One subject was noninducible using esothoracic programmed ventricular stimulation, but inducible at endocardial electrophysiological studies. Another subject was inducible at esothoracic electrophysiological studies, but noninducible using endocardial programmed ventricular stimulation. Six subjects were noninducible using both endocardial and esothoracic programmed ventricular stimulation. The gastroesophageal electrode permits reliable atrial and ventricular pacing without transvenous catheterization or fluoroscopy. Electrophysiological parameters determined using this electrode are similar to those obtained using endocardial stimulation.

Supraventricular paroxysmal reentry tachycardia. Empirical and guided therapy. Piccolo E, Bonso A, Raviele A, Delise P. Divisione di Cardiologia, Ospedale Umberto I, Mestre-Venezia. Cardiologia 1991 Aug;36(8 Suppl):87-97. The empirical therapy of reentrant supraventricular tachycardias (A-V and junctional tachycardia) is based on a preliminary diagnosis through standard ECG to evaluate, whenever possible, the relationship between P wave and QRS. In order to distinguish atrial tachycardias from other types, we must employ vagal manoeuvres or drugs. Often we use methods of recording and stimulation such as Holter monitoring and transesophageal technique which can provide useful information about the electrophysiological mechanisms and therefore can better guide our choice of drugs. The decision of undertaking pharmacologic treatment takes into account frequency, duration and tolerability of the crises and the patient's compliance. The most commonly used drugs are verapamil, diltiazem, propafenone, flecainide, sotalol and amiodarone. The percentage of success at 1 year ranges from 30 to 60%. Particularly in the Wolff-Parkinson-White (WPW) therapy must follow an accurate evaluation of the electrophysiological pattern through effort test, drugs test, transesophageal (ETS) or endocavitary (EPS) electrophysiological study. Indeed therapy aims not only at reducing arrhythmic relapses, but also preventing the potential risk of either death or severe damage. The useful drugs must have the property of acting at the same time upon at least one branch of the A-V circuit, on the atrium reducing its vulnerability and finally modifying the conductive anterograde capacity of the Kent bundle. They are quinidine, procainamide, propafenone (group I) sotalol and amiodarone (group III). The limitations of the empirical therapy are a high percentage of relapses and the difficulty in foreseeing the pro-arrhythmic effects. The guided by serial electrophysiologic testing implies artificial induction of spontaneous arrhythmia by repeating the test after acute or chronic assumption of drugs. Is this way it can be evaluated the efficacy as well as the tolerability of an antiarrhythmic drug which later will be taken for chronic prophylaxis. The percentage of inducibility of clinical arrhythmias is next to 100% both for EPS and TES. The number of patients for whom we can find an effective pharmacologic regimen through acute testing ranges from 30 to 100%, but is influenced by several factors such as aggressiveness of therapeutic protocol and type and dosage of drugs. The predictive value is high as it approaches 100% for a positive acute test. The elective indications for serial electrophysiologic study are: failure of empirical therapy; disabling and very frequent arrhythmias; arrhythmias provoking major disturbances (lipothymia, syncope, hypotension, shock); symptomatic WPW.

Comparative study of auricular stimulation by transesophageal and endocavitary approach for evaluating sinus and atrioventricular node function. Cebron JP, Brugada J, Gallay P, Puech P. Arch Mal Coeur Vaiss 1987 Feb;80(2):170-5. The purpose of this study was to find out whether non-invasive transoesophageal pacing could effectively replace right intra-atrial pacing for the indirect evaluation of sinus node and atrioventricular (AV) node function. In a population of 17 patients the corrected sinus node recovery time (CSRT), the atrio-sinu-atrial conduction time (ASACT) and Wenckebach's point (W) were calculated by intracavitary pacing, then by transoesophageal pacing. There was no significant difference between the two methods in pre-pacing sinus cycle. With right intra-atrial pacing, mean CSRT value was 365 +/- 54 ms (with 5 values greater than 520 ms), mean ASACT value was 229 +/- 29 ms (with 8 values greater than 220 ms), and W occurred at a mean cycle length of 425 +/- 29 ms. With transoesophageal pacing, mean CSRT value was 406 +/- 87 ms (with 5 values greater than 520 ms), mean ASACT value was 222 +/- 17 ms (with 8 values greater than 220 ms), and W occurred at a mean cycle length of 408 +/- 26 ms. The two methods correlated very closely for CSRT and W (r = 0.97) and relatively well for ASACT (r = 0.84). The number of CSRT and ASACT values regarded as prolonged was the same with the two methods; 4% of recorded (i.e. maximal) CSRT values occurred with the same length of pacing cycle. There was no statistically significant difference between the two methods in the calculation of CSRT and ASACT, but W occurred at a slightly shorter cycle (p less than 0.05) with transoesophageal pacing. Thus, transoesophageal pacing is a non-invasive, easy to perform method for indirect exploration of sinus node and AV node function in patients who do not require subnodal conduction studies.

Diagnostic and therapeutic use of transesophageal atrial pacing in children. Janousek J. Center of Pediatric Cardiology and Cardiac Surgery, Prague. Int J Cardiol 1989 Oct;25(1):7-14. Transesophageal atrial pacing was used in 29 consecutive patients aged 1 day to 16.5 years (mean 8.04 years) to replace the following procedures: intracardiac electrophysiologic study in patients with selected arrhythmias (21 patients), intracardiac overdrive or synchronized direct current cardioversion of supraventricular tachyarrhythmias or drug administration in patients with acute reciprocating supraventricular tachycardia (9 patients). Atrial capture was achieved without discomfort in 27 patients (93.1%). The diagnostic or therapeutic goal of the procedure was achieved in 26 children (89.7%). Transesophageal atrial pacing may replace intracardiac pacing procedures, direct current cardioversion and drug administration in patients with selected cardiac arrhythmias and has proved appropriate as a first diagnostic or therapeutic step.

The study of acute clinical electrophysiological effects of propafenone on paroxysmal supraventricular tachycardia using transesophageal atrial pacing technique. Li Q, Wang Z, Peng D. Department of Cardiology, Second Affiliated Hospital, Hunan Medical University, Changsha. Hunan I Ko Ta Hsueh Hsueh Pao 1997;22(2):123-6. Trans-esophagus atrial pacing (TEAP) was employed to evaluate the acute electrophysiological effects of propafenone administrated intravenously in 50 patients with SVT. Forty three of the subjects are patients with atrial ventricular reciprocating tachycardia (AVRT). Seven of them were involved in atrioventricular nodal reentry tachycardia (AVNRT). The results indicate that propafenone exerts an obvious inhibitory effect on both the dual atrioventricular node pathways and the accessory pathways, with the latter one being markedly affected. In addition, propafenone can deter the antegrade and retrograde conduction and prolong the refractory period of the accessory pathways. Still more, it results in preceding of the Wenchebach and 2 to 1 block point of the atrioventricular node conduction. All these promise the potential terminating effect on tachycardia. Propafenone has little effects on sinus node. Prolongation of sinus node recovery time (SNRT) to 3600 ms following drug administration was observed in only one patient who has a history of sinus bradycardia. 

The role of an electropharmacological transesophageal test in the prevention of paroxysmal atrial fibrillation. Experience with flecainide. De Sisti A, Matteucci C, Patrissi T, Accogli S, Di Lorenzo M, Sasdelli M, Ciolli A, Lo Sardo G, Palamara A. Divisione di Cardiologia, Ospedale Sandro Pertini, Roma. G Ital Cardiol 1998 Dec;28(12):1391-9. BACKGROUND: The management of patients with paroxysmal atrial fibrillation (AF) is unsuccessful, because AF recurs in about 50% of patients despite an antiarrhythmic treatment. Usefulness of non-pharmacological strategies is available in a limited subset of patients and it does not present a global solution to the problem. At present, treatment with antiarrhythmic agents is the only available tool in patients with AF recurrence. The aim of this study was to assess the predictive value of the electropharmacological transesophageal (TE) test in the management of patients with paroxysmal AF treated by flecainide. METHODS: In 32 patients, ranging in age from 38 to 70 years (mean: 59 +/- 12 years), with documented episodes of paroxysmal AF (mean: 5.6 +/- 3.7 episodes/last year), we performed an electrophysiological transesophageal (TE) test following pharmacological wash-out. An aggressive protocol was used: step A: 10 sec atrial burst at Wenckebach point + 10 bpm, 200 and 250 bpm; step B: 10 sec atrial bursts at 300, 400, 500 and 600 bpm; step C: 8 sec increasing rate burst from 200 to 800 bpm. Induction of sustained AF (> 1 min) was considered the end-point. Patients were treated with flecainide 100 mg bid and a second TE test was performed at the steady-state, with an identical induction protocol and end-point. Based on the response of the second test, patients were divided into responders (R Group: non-inducible AF) and non-responders (NR Group: inducible, sustained AF). Patients were followed-up by periodical controls and contacted by telephone to confirm their clinical status. RESULTS: Sustained AF was induced in 30 patients (94%) at the first TE study. Eight of them dropped-out at the time of the second TE test (6 patients for lack of consent, 1 patient for side-effects and another one for proarrhythmic effects). In the mean follow-up of 15 +/- 6 months, among patients who underwent a second TE test, AF recurrence was documented in 2 out of 14 patients from the R Group and in 7 out of 10 patients from the NR Group (p < 0.01). There were 4 AF episodes in the R Group and 19 in the NR Group (p < 0.001). We did not find significant statistical differences between the two groups in terms of age, sex, body weight, AF episodes/past year, P-wave duration, left atrial dimension, structural heart disease, AF duration at the first TE test and follow-up duration. In five patients from the NR Group with induced AF lasting > 5 min, the percentage of recurrence was 100% and there were 16 AF episodes. Global percentage of patients with recurrence was 37%. CONCLUSIONS: Flecainide is effective in reducing the incidence of AF and results are similar to other antiarrhythmic agents generally used. The electropharmacological TE test might be a useful tool to predict the response to an antiarrhythmic treatment. 

Study of sinus function and nodal conduction using transesophageal recordings. Le Heuzey JY, Khaznadar G, Guize L, Carcone P, Weissenburger J, Lavergne T, Ourbak P, Valty J. Arch Mal Coeur Vaiss 1987 Jan;80(1):28-35. Transoesophageal pacing is mainly used for treatment of supraventricular tachycardias and assessment of refractory periods of accessory pathways. It has been proposed for the study of sinus node function and A-V nodal conduction. The aim of this study was to know if transoesophageal pacing could modify the vago-sympathetic tone, therefore the results of the tests, knowing it can be discomfortable and that endodigestive procedures can induce vagal responses. Furthermore, the stimulation is elicited near the left atrium, and not in the right atrium as during endocavitary tests. We have compared in 20 patients (age 68 +/- 12) the results obtained by both endocavitary and transoesophageal pacing (tension 21.2 +/- 4.5 V, duration 16 msec, interelectrode spacing 30 mm). We measured sino-atrial conduction time (SACT), sinus node recovery time (SNRT), Wenckebach's point and nodal refractory periods. After introduction of the oesophageal lead we observed a significant (p < 0.01) but slight and transitory tachycardia. The results of A-V nodal conduction parameters were not significantly different and were significantly correlated (r = 0.94 for Wenckebach's point and effective refractory period). For the sinus node function, there was no significant difference between the parameters if the oesophago-atrial delay (mean 104.4 +/- 25.9 msec) is taken into account. The correlation is poor for sino-atrial conduction time (corrected SACT, r = 0.55), tighter for sinus node recovery time (maximal corrected SNRT, r = 0.92).

Transesophageal stimulation in the treatment of atrial flutter and tachysystole. Factor influencing immediate results.Girardot C, Diebold H, Morelon P, Dentan G, Fraison M, Eicher JC, Bouhey J, Louis P. Hopital du Bocage, Dijon. Arch Mal Coeur Vaiss 1988 Nov;81(11):1379-84. The effectiveness and safety of transoesophageal atrial pacing in the treatment of atrial flutter and tachycardia have been well demonstrated. The purpose of this study was to determine the factors that could influence the results of this method at the end of the procedure. Seventy-seven transoesophageal atrial pacings were performed in 62 unselected consecutive patients with either flutter or atrial tachycardia. The following parameters could be evaluated in 55 patients: date of onset of the arrhythmia, echocardiographic diameter of the left atrium, maximum amplitude of oesophageal atrial potentials, voltage and frequency of stimuli in the last stage of pacing. Our results can be summarized as follows: In both flutter and atrial tachycardia taken globally, conversion to sinus rhythm was obtained in 37% of the cases, and conversion to atrial fibrillation in 46.7% of the cases. The failure rate was 19.4%; all failures were due to lack of atrial capture during pacing. The main factor or transoesophageal atrial capture is voltage. Patients must be able to tolerate the voltage needed for capture. In the case of flutter, when capture was achieved a normal-sized left atrium and a high maximum amplitude of oesophageal atrial potentials were factors indicating that conversion to sinus rhythm could be expected. This, however, did not apply to atrial tachycardia. -- Whatever the type of tachyarrhythmia, the more recent its onset the easier its reduction.

Diagnostic transesophageal atrial stimulation as a sinus node function test. I. Normal values and comparison with right atrial stimulation. Volkmann H, Paliege R. Z Gesamte Inn Med 1981 May 1;36(9):287-94. For the non-invasive functional analysis of the sinus node diagnostic transoesophageal atrial stimulations were performed. By means of transoesophageal premature individual stimulation we succeeded in a calculation of the so-called sinuatrial conduction time in 112 of 118 normal persons (ESACT = 103 +/- 23.5 ms). In comparison to the results in right-atrial stimulation the transoesophageally established times were 20 to 30 ms longer. By means of transoesophageal atrial stimulation with higher frequency in 64 healthy test persons the recreation time of the sinus node was determined in 64 healthy test persons (ESNRT = 968 +/- 218 ms). Taking into consideration the double standard deviation in an upper limit of 1,400 ms was the result which corresponds to the limit in intraatrial stimulation. In the direct comparison of the transoesophageal and right-atrial stimulation technique in patients with and without syndrome of the sinus node for the sinuatrial conduction time (r = 0.81, n = 51) as well as for the recreation time of the sinus node (r = 0.90, n = 36) relatively good correspondences were found. In the transoesophageal stimulation, however, the larger distance of the place of stimulation from the marginal area of the sinus node, the conduction of the impulse over the left to the right atrium as well as a possible vagal irritation are to be taken into consideration.

Diagnostic transesophageal atrial stimulation for sinus node function testing. II. Results in patients with and without sinus node syndrome. Volkmann H, Paliege R. Z Gesamte Inn Med 1981 Feb 15;36(4):93-102. By means of transoesophageal atrial stimulation of higher frequency in patients with sinus node syndromes (n = 78) in about 60% of the cases a prolonged sinus node recovery time could be proved. After the end of the stimulation secondary stops appeared in about half of the patients, so that in 81% of the cases at least one pathological result was established. By means of premature individual transoesophageal stimulation (n = 99) in 2/3 of the patients with sinus node syndrome we contrived to perform a calculation of the sinuatrial conduction time. Half of all calculable values were above the normal. In 1/3 of the examined persons pathological stimulation patterns were found. Altogether 90% of the patients showed at least one pathological result, when apart from prolonged sinus node recovery times and sinuatrial conduction times at the same time secondary stops after serial stimulation with higher frequency and abnormal behaviour patterns of the post-extrasystolic stops after individual stimulation were taken into consideration. In patients with different cardiovascular diseases without clinical or electrocardiographic reference to a sinus node dysfunction in 25% of the cases at least one pathological result was found, in which case cannot be clarified, whether latent functional sinus node disturbances or falsely positive results are in question or not. Altogether the non-invasive transoesophageal stimulation technique leads to on principle diagnostic evidences of the same value as the up to now usual stimulation of the right atrium. Methodical problems which arise from the stimulation of the right atrium in transoesophageal approach are to be taken into consideration in the interpretation of the results.

Esophageal approach in rythmology. Diagnostic and therapeutic applications. Moustaghfir A, van de Walle JP, Deharo JC, Djiane P, Touze JE. Service de Pathologie Cardio-vasculaire, HIA Laveran, Marseille Armees. Ann Cardiol Angeiol (Paris) 1996 Nov;45(9):539-44. The oesophageal route is a simple technique, which is easy to perform. It allows precise assessment of supraventricular arrhythmias without using the endocavitary route. There is a perfect correlation between the two methods for the study of sinus function and the Wenckebach point. This technique makes a considerable contribution to the diagnosis of junctional tachycardia and the evaluation of Wolff-Parkinson-White syndrome. It can reduce approximately 65% of flutters and 50% of atrial tachyarrythmias. It can also be used to monitor antiarrhythmic treatment or in the assessment of radiofrequency resection, especially in nodal tachycardias and left atrioventricular accessory pathways. Its limitations concern the sometimes painful nature of the investigation and the impossibility of recording the electrical activity of the His bundle.

Programmed atrial stimulation via the esophagus for management of supraventricular arrhythmias in infants and children. Rhodes LA, Walsh EP, Saul JP. Children's Hospital, Harvard Medical School. Am J Cardiol 1994 Aug 15;74(4):353-6.  This report describes the use of programmed atrial stimulation via the esophagus to predict the clinical efficacy of various management strategies for supraventricular arrhythmias in infants and children. A total of 203 transesophageal electrophysiologic studies were performed in 132 patients. Therapies evaluated included medications from each antiarrhythmic class, the Valsalva maneuver, follow-up of radiofrequency ablation, and no therapy. The transesophageal technique appeared to be adequate for inducing tachycardia, yielding a low false-negative rate. Overall, the predictive value of a negative study was high (89%), and increased to 96% when stimulation was performed in the presence of isoproterenol. However, the positive predictive value was significantly lower both with (72%, p < 0.00001) and without (60%, p < 0.0001) isoproterenol. These results were due in part to a very low positive predictive value when evaluating either digoxin and/or beta-blocker therapy, 62% vs 82% for the remaining studies. When clinical tachycardia cannot be induced with therapy, transesophageal techniques can be used to predict freedom from many supraventricular tachycardias for most therapies in children. However, induction of tachycardia may not predict treatment failure. Transesophageal pacing to evaluate arrhythmia therapy may be most useful when managing either severe symptoms, multiple recurrences, or the results of radiofrequency ablation.

The diagnosis and management of supraventricular tachycardia by transesophageal cardiac stimulation and recording. Harte MT, Teo KK, Horgan JH. Saint Laurence's Hospital, Dublin, Ireland. Chest 1988; 93(2):339-44. Twenty-two consecutive patients underwent esophageal stimulation and recording for the diagnosis and management of supraventricular tachycardia. In 13 of these patients, the resting electrocardiogram was normal and in nine it showed pre-excitation. Of the 13 patients with a normal resting electrocardiogram, supraventricular tachycardia was initiated in all. Seven patients had a ventricular-to-atrial interval greater than 70 ms during supraventricular tachycardia suggesting the presence of a concealed accessory pathway, and six patients had a ventricular-to-atrial interval less than 70 ms during supraventricular tachycardia suggesting reentry within the atrioventricular node. Supraventricular tachycardia was initiated in four of nine patients with pre-excitation on the resting electrocardiogram and the accessory pathway was confirmed by a ventricular-to-atrial interval of greater than 70 ms during supraventricular tachycardia in these four patients. Atrial fibrillation was initiated in eight of the nine patients with pre-excitation on the resting electrocardiogram and the shortest R-R interval during atrial fibrillation was measured. The response to therapy was assessed in seven of these nine patients by further measurement of the shortest R-R interval during atrial fibrillation following treatment. Esophageal stimulation and recording provides a simple noninvasive procedure which can be utilized as a screening technique to identify patients with intranodal reentry and those with reentry utilizing an accessory pathway. Sequential assessment of the response to therapy, especially in those patients with pre-excitation, is of considerable value in treatment.

Role of transesophageal pacing in evaluation of palpitations in children and adolescents. Pongiglione G, Saul JP, Dunnigan A, Strasburger JF, Benson DW Jr. Children's Memorial Hospital, Chicago. Am J Cardiol 1988 Sep 15;62(9):566-70. Transesophageal atrial pacing was used to evaluate the cause of palpitations in 28 patients ages 3 to 18 years (mean 11). Palpitations were defined as the sustained (seconds to minutes) sensation of rapid heart beating. Each patient had had greater than 2 episodes of palpitations. No patient had other evidence of heart disease. Standard electrocardiogram was normal (23 of 28 patients), demonstrated ventricular preexcitation (3 of 28 patients) or demonstrated short PR interval (2 of 28 patients). In selected patients, ambulatory monitoring (11 patients) or exercise testing (3 patients) was performed but failed to demonstrate a cause of palpitations. In an effort to initiate tachycardia, a similar transesophageal atrial pacing protocol was performed in each patient. The protocol consisted of: (1) single extrastimuli at progressively closer intervals during sinus rhythm and after an 8-beat pacing train at greater than or equal to 1 cycle lengths and (2) incremental atrial pacing to the point of second-degree atrioventricular block. If this pacing regimen failed to initiate tachycardia, it was repeated during isoproterenol infusion (0.02, 0.05 and 0.1 micrograms/kg/min) and then following intravenous atropine (0.04 mg/kg) administration. During the study, tachycardia was initiated in 20 of 28 patients (71%) (14 of 15 patients greater than 10 years, 6 of 13 patients less than or equal to 10 years; p < 0.01, Fisher's exact test). Electrophysiologic characteristics of induced tachycardia suggested reentry within the atrioventricular node (8 of 20 patients) or orthodromic reciprocating tachycardia (12 of 20 patients). In 3 of 12 patients with orthodromic reciprocating tachycardia, a transition to atrial fibrillation was observed.

Clinical value of transesophageal atrial stimulation and recording in patients with arrhythmia-related symptoms or documented supraventricular tachycardia--correlation to clinical history and invasive studies. Pehrson SM, Blomstrom-Lundqvist C, Ljungstrom E, Blomstrom P. University Hospital, Lund, Sweden. Clin Cardiol 1994 Oct;17(10):528-34. The main objective of the present study was to evaluate the clinical applicability of transesophageal atrial stimulation (TAS) and recording with regard to inducibility of supraventricular tachycardia (SVT) in patients with either an ECG-documented paroxysmal SVT or a clinical history of palpitations suggesting this disease. A further objective was to assess the inducibility of SVT and to compare the inducibility by TAS with that obtained by an invasive electrophysiologic study (EPS). A total of 64 patients (aged 13-74 years) with ECG-documented paroxysmal SVT (n = 50) or only a history of palpitations (n = 14) was referred for TAS. Preexcitation was present in 35 patients. The study protocol included single and double extrastimuli delivered at a basic paced interval of 500 ms, and incremental atrial stimulation until a cycle length of 275 ms or a second-degree AV block appeared. In 10 patients atropine intravenously was required for induction. The same protocol was used in 34 of the patients who also underwent invasive EPS. TAS was completed in 56 of 64 patients (88%). In this group SVT was induced during TAS in 84% (47/56). Of patients with ECG-documented tachycardia, clinical tachycardia was induced in 90% (35/39) with ECG-documented regular paroxysmal SVT and in 67% of patients (4/6) with ECG-documented atrial fibrillation. In patients without ECG-documented tachycardia, clinically relevant arrhythmia was induced in 73% (8/11). In 30 of 32 patients (94%) with an inducible tachycardia during invasive EPS, it was also possible to induce the tachycardia by TAS.

Transesophageal study of infant supraventricular tachycardia: electrophysiologic characteristics. Benson DW Jr, Dunnigan A, Benditt DG, Pritzker MR, Thompson TR. Am J Cardiol 1983 Nov 1;52(8):1002-6. Programmed electrical stimulation of the heart to initiate and terminate tachycardia and analysis of the temporal relation between ventricular and atrial activation during tachycardia have been useful in the evaluation of supraventricular tachycardia (SVT). Such techniques have rarely been applied to evaluate infants with SVT. We used a silicone rubber-coated bipolar electrode catheter (15 or 22 mm interelectrode spacing), positioned in the esophagus, for electrical stimulation of the heart and recording of electrograms for the evaluation of 14 infants aged 1 to 84 days with SVT. Three infants had electrocardiographic features of Wolff-Parkinson-White syndrome, and no infant had other manifestations of congenital heart disease. Tachycardia cycle lengths ranged from 180 to 295 ms and ventriculoatrial intervals recorded from the esophagus were 80 to 220 ms. In 12 infants, transesophageal atrial stimulation was used to terminate and initiate SVT using stimuli of 9.9 ms and 10 to 20 mA. Initiation and termination of SVT by electrical stimulation suggest that SVT in infants is due to reentry, and the presence of ventriculoatrial intervals greater than 70 ms further suggests that accessory atrioventricular connections (usually concealed) constitute a portion of the reentry circuit.

Evaluation of electrophysiological diagnosis of concealed accessory pathway (CAP) during transesophageal atrial pacing. Li Q, Wang Z, Zhou S. Cardiology Division, Second Affiliated Hospital, Hunan Medical University, Changsha. Hunan I Ko Ta Hsueh Hsueh Pao 1997;22(1):49-52. CAP were diagnosed by TEAP using RPE intervals in 55 cases of paroxysmal supraventricular tachycardia (PSVT). There were no obvious CAP manifestations of ECG in those cases, the mean RPE interval during tachycardia was 140 +/- 29 ms, and the lower limit of x +/- 2 s was 82 ms. Among them, the VA intervals were measured by electrocardiophysiological examination in 21 cases. The mean value was 130 +/- 25 ms, and the lower limit of x +/- 2 s was 80 ms. The results suggest that RPE over 82 ms may be an important diagnostic threshold cut off point of atrioventricular reciprocation. 

Standard of transesophageal atrial pacing to diagnose dual atrioventricular node pathway. Fu H, Lang EP. Hua Hsi I Ko Ta Hsueh Hsueh Pao 1989 Mar;20(1):99-102. In order to assess the diagnostic methods of dual atrioventricular node pathway (DAVNP), we performed transesophageal atrial pacing in 58 patients with palpitation. These patients were classified into two groups, group A comprising 40 patients without broken A-V conduction curve during pacing, compared with group B of 18 patients with broken A-V conduction curve. In our study, both atypical Wenckebach cycle and 3:2 A-V conduction during the increment atrial pacing (IAP) had no significant difference between the two groups (P greater than 0.05). The maximum increments of SR interval in Wenckebach cycle of group A and B during pacing (Wenckebach delta SRmax) were 83.59 +/- 20.92 ms and 125.00 +/- 32.52 ms respectively (P less than 0.001) and at the cut-off point of Wenckebach delta SRmax at 120 ms the specificity and positive predicative value were very high (96.88% and 90.91%), but sensitivity was not so high (71.43%). The minimum increments of RS interval (delta RSmin) in a greater change of SR interval showed a significant difference between the two groups and the specificity and positive predicative value were also high, but the sensitivity was not so high, either (78.57%). We conclude that the diagnostic value of both Wenckebach delta SRmax and delta RSmin, when the SR interval is of greater change during pacing to the DAVNP, is rather significant. As the sensitivity is very low, isolated atypical Wenckebach phenomenon is not as reliable a diagnostic criterion to the DAVNP as previously supposed.  

Transesophageal versus intracardiac atrial stimulation in assessing anterograde conduction properties of the accessory pathway in Wolff-Parkinson-White syndrome. Favale S, Minafra F, Massari V, Tritto M, Rizzon P.Univ of Bari, Italy. Int J Cardiol 1991 Feb;30(2):209-14. Electrophysiologic intracardiac and noninvasive transesophageal testing, used to evaluate parameters of anterograde conduction across the accessory pathway, the refractory period and shortest atrial cycle length with 1:1 conduction over the pathway, were compared to assess the reliability of the noninvasive technique in identifying patients with Wolff-Parkinson-White syndrome, at risk of rapid ventricular response during atrial fibrillation when this arrhythmia is not inducible. Sixteen patients with Wolff-Parkinson-White syndrome were submitted both to invasive and transesophageal atrial stimulation. We evaluated both the functional and effective refractory periods of the accessory pathway, using the same drive cycle length, and the shortest cycle length with 1:1 atrioventricular conduction over the accessory pathway. There were no differences between the parameters obtained by intracardiac atrial stimulation and by transesophageal atrial stimulation. The two approaches correlated well: mean functional refractory periods of the accessory pathway were 285 +/- 42 msec and 289 +/- 32 msec, respectively (NS, r = 0.88); mean effective refractory periods of the accessory pathway were 267 +/- 41 msec and 271 +/- 32 msec, respectively (NS, r = 0.89); mean shortest cycle lengths with 1:1 conduction over the accessory pathway were 255 +/- 48 msec and 255 +/- 44 msec, respectively (NS, r = 0.94). These data demonstrate the reliability of transesophageal atrial stimulation in estimating the parameters for anterograde conduction across an accessory pathway. These results, and the already documented ability of transesophageal atrial stimulation to induce atrial fibrillation, suggest this noninvasive technique should be taken as a first approach in screening patients with Wolff-Parkinson-White syndrome.

Transesophageal versus intracardiac atrial stimulation in assessing electrophysiologic parameters of the sinus and AV nodes and of the atrial myocardium. Blomstrom-Lundqvist C, Edvardsson N. Sahlgren's Hospital, Gothenburg, Sweden. Pacing Clin Electrophysiol 1987 Sep;10(5):1081-95. Electrophysiological parameters of the sinus and AV nodes and of the atrial myocardium were assessed with both transesophageal atrial stimulation (TAS) and intracardiac atrial stimulation (ICS) in the same patient during the same study. The study group was comprised of nine men and seven women, aged 45 to 79 years, referred for the evaluation of syncope of possible arrhythmogenic origin. Twelve patients were included for analysis. Autonomic inhibition (AI) was obtained in five patients. The most striking result was the significantly longer AERP with TAS (mean 286 +/- 9 ms) than with ICS (mean 244 +/- 12 ms; p than 0.02). After AI, the AERP was even more prolonged with TAS (mean 332 +/- 20 ms) than with ICS (mean 237 +/- 8 ms; p less than 0.01). Intraatrial and AV nodal conduction times assessed at multiple paced cycle lengths were significantly shorter with TAS than with ICS. There was no difference between TAS and ICS with regard to AVERP, Wenckebach periodicity and H-V intervals. Although a tendency towards shorter sinus node recovery time (SNRT) and sinoatrial conduction time (SACT) was observed with TAS, the difference was not statistically significant. Possible mechanisms of the differences are discussed. It seemed clear that the site of origin of an atrial impulse can have definite effects upon excitability and conduction properties of atrial and AV nodal fibers. Enhanced sympathetic activity during TAS was also suggested. The electrophysiological properties inherent in the TAS technique warrant further elucidation.

Transesophageal electrocardiography and atrial pacing in acute cardiac care: diagnostic and therapeutic value. Twidale N, Roberts-Thomson P, Tonkin AM. Department of Medicine, Flinders Medical Centre, Bedford Park, SA. Aust N Z J Med 1989 Feb;19(1):11-5. The utility of transesophageal electrocardiography using a bipolar 'pill electrode' was assessed in 17 consecutive patients with tachycardia presenting to our casualty department. Standard 12-lead electrocardiography showed regular narrow QRS tachycardia in 12 patients, and five patients had wide QRS tachycardia. Esophageal atrial electrogram recordings were obtained in 14 patients (82%), and these were helpful in determining the mechanism of tachycardia in 11 patients (78%). Of these 11, seven patients fulfilled criteria for atrioventricular junctional (AVJ) tachycardia based on measurement of the minimum interval between the onset of ventricular depolarisation and earliest atrial (esophageal) activity. One of these patients had presented with a wide QRS tachycardia. The other four patients were diagnosed as having ventricular tachycardia (VT) following diagnosis of AV dissociation. Atrial overdrive pacing, via the pill electrode, successfully reverted four of the nine patients (44%) with narrow QRS tachycardia but no patient with VT. Esophageal recording during tachycardia is a simple, relatively non-invasive technique which is helpful in suggesting the mechanism of tachycardia both in patients with narrow and wide QRS tachycardia, and may have a therapeutic role in patients with AVJ tachycardia. 

Induction of supraventricular tachycardia (paroxysmal junctional tachycardia and atrial tachycardia) by esophageal stimulation. Brembilla-Perrot B, Spatz F, Khaldi E, Terrier de la Chaise A, Suty-Selton C, Le Van D, Cherrier F, Pernot C. CHU Brabois, Vandoeuvre. Arch Mal Coeur Vaiss 1998;83(11):1695-702. Transesophageal stimulation is tending to replace endocavitary electrophysiological studies in the investigation and treatment of supraventricular tachyarrhythmias. The aim of this study was to determine the sensitivity of this technique in the evaluation of paroxysmal junctional tachycardia (PJT) and atrial tachycardia (AT). Fifty-eight patients with these arrhythmias (PJT, n = 23; AT, n = 35) were investigated under basal conditions and then during Isoproterenol infusions with a protocol using incremental atrial stimulation and programmed atrial stimulation delivering one and two extra-stimuli on two paced rhythms (400-600 ms). It was possible to induce the arrhythmia in the 23 patients with PJT either under basal conditions (n = 16) or during Isoproterenol (n = 7). A reentrant mechanism was suggested in 22 patients by the following findings: position of the auriculogramme with respect to the ventriculogramme, presence or absence of a delaying branch block, situation and morphology of the P wave in lead V1 compared with atrial activation recorded by the esophageal catheter. Atrial tachycardia was induced in 26 patients (74 %), 19 under basal conditions, 6 with Isoproterenol and once after carotid sinus massage. As a conclusion, we can say that the sensitivity of transesophageal stimulation is the same as for endocavitary stimulation.

Transesophageal study in the diagnostic evaluation of pre-excitation. Favale S, Pitzalis MV, Totaro P, Di Biase M, Rizzon P. Universita degli Studi, Bari. Cardiologia 1991 Aug;36(8 Suppl):75-80. Electrophysiologic non-invasive transesophageal testing is compared to intracardiac study in the management of patients with Wolff-Parkinson-White (WPW) syndrome. Transesophageal study can be reliably used to identify the participation of the accessory pathway in reciprocating supraventricular tachycardia and to determine the anterograde conduction properties of the accessory pathway. Using the shortest pre-excited interval during induced atrial fibrillation, or programmed and continuous atrial transesophageal stimulation can markedly reduce the need of intracardiac evaluation. The greater safety and economy of transesophageal compared to the intracardiac technique justify its wider use in preliminary screening of all WPW patients, unless ablative treatment has been clinically indicated, and in evaluating long-term drug protection against a potential deleterious ventricular response during atrial tachyarrhythmias.

Evaluation of the informative value and safety of the transesophageal atrial electric stimulation test in patients with unstable stenocardia and myocardial infarction (data of 24-hour ECG monitoring). Merkulova IN, Khakimov AG, Chikvashvili DI, Karpov I. Kardiologiia 1987 Oct;27(10):69-74. Kardiologiia 1987 Oct;27(10):69-74. The effect of the transesophageal pacing test (TEPT) on the occurrence of ventricular arrhythmias and ischemic episodes was examined on the basis of 24-hour ECG monitoring in patients with unstable angina (UA) and myocardial infarction (MI). It is demonstrated that TEPT is a relatively safe test for UA and MI patients (to be performed on day 10-14), which does not provoke severe arrhythmias during and after the testing, but for short paroxysms of ventricular tachycardia seen in 2-4% of the cases. Both painful and painless ST displacements were recorded during the test; ST elevation was only noted in MI patients. The time of ECG baseline recovery was longer in painful ischemic episodes, as compared to painless ones. The TEPT test is a valuable instrument for detecting latent atrioventricular conductivity disorders in UA and MI patients.

Use of esophageal investigation in the mid-term outcome after radiofrequency ablation of intranodal reentrant tachycardia. Deharo JC, Moustaghfir A, Macaluso G, Le Tallec L, Djiane P. Service de cardiologie, hopital Sainte-Marguerite, CHU Marseille. Arch Mal Coeur Vaiss 1996 Nov;89(11):1375-9. The aim of this prospective study was to assess the medium term results of radio-frequency ablation of intranodal tachycardias by transoesophageal stimulation and recordings. Transoesophageal stimulation was performed on average 9 months after ablation. The anterograde Wenckebach point, the presence of dual nodal conduction and inducibility of nodal tachycardias were determined under basal conditions and after isoproterenol. The follow-up period after ablation was 16.1 +/- 10.2 months. At the time of the oesophageal investigation 25 patients were asymptomatic and 5 had a recurrence of palpitations. The investigation was carried out without complications in all patients and lasted 34.8 +/- 14 minutes. The anterograde Wenckebach point was 340 +/- 78.2 ms and was unchanged compared with the value recorded by endocavitary left atrial stimulation before ablation (332 +/- 63.2 ms). Dual nodal conduction was observed in 19 patients. Nodal tachycardia was inducible in only 2 of the 5 patients with palpitations. Of the asymptomatic patients, 3 had inducible nodal tachycardias after isoproterenol. The authors conclude that oesophageal electrophysiological studies are a simple means of assessing the medium-term results of radiofrequency ablation of intranodal tachycardias. In those patients with a recurrence of symptoms but without documented arrhythmias, failure of radiofrequency ablation may be identified. In addition, the possibility of inducing nodal tachycardias in asymptomatic patients may be detected.

The diagnostic and treatment characteristics of cardiac arrhythmias in patients with the premature ventricular excitation syndrome. Lipnitskii TN, Otkalenko IuK, Randin AG, Stepaniuk AV. Vrach Delo 1991 Oct;(10):83-6. Studied were 24 patients with the syndrome of premature excitation of the ventricles. In 18 of them transesophageal electrophysiological examination was carried out. Reciprocal paroxysmal tachycardia was revealed in 16 patients (orthodromic form--in 14, antidromic--in 2 patients). Cardiac fibrillation with a cardiac contraction rate of 320-340 per minute was noted in 2 patients. Difficulties are noted in the differential diagnosis of antidromic form with ventricular paroxysmal tachycardia and risk of development of ventricular fibrillation in auricular fibrillation. The authors propose a method of diagnosis of latent forms of the syndrome of premature excitation of the ventricles using short-term pharmacological block of atrioventricular conduction in intravenous administration of ATP.

Transesophageal atrial stimulation in 168 patients.Arribada A; Alfaro M; Kuhne W; Valdivia L. Hospital Clinico San Borja-Arriaran. Rev Med Chil (Chile), Apr 1992, 120(4) p383-9. Transesophageal atrial stimulation was performed in 168 patients, 95 males and 73 males, 20 to 81 years of age. The indication for atrial stimulation was the study of some bradyarrhythmia in 109 and ischemic heart disease in 59. An esophageal catheter was introduced through the nose and placed at a spot where a bimodal P wave was obtained. Stimulation was performed using a baby Medtronic stimulator coupled to a Vygon amplifier delivering an output of 30 volt. Sinus node recovery time was measured after 2 to 3 min of stimulation at different rates. Wenckebach and 2:1 A-V block as well as ST deviation were determined. Sick sinus syndrome was diagnosed in 41 cases through altered sinus node recovery time and/or secondary pauses; 35 patients showed Wenckebach rhythm at a stimulation rate over 120 per min; 2: 1 A-V block appeared in 22. Ischemic ST-T changes were produced in 20 subjects. No complications were observed, confirming this approach as a simple and effective way to achieve atrial stimulation for diagnostic purposes.

Esophageal pacing in children. 38 consecutive cases. Lucet V, Do Ngoc D, Denjoy I, Saby MA, Toumieux MC, Batisse A. Centre de Cardiologie Infantile. Arch Fr Pediatr 1990 Mar;47(3):185-9. On the occasion of a preliminary series of 38 cases, the authors review the esophageal pacing technique and its main indications. On the therapeutic level, the esophageal lead may be successfully used to decrease supraventricular tachycardias due to reentry (typical or atypical flutter, reciprocating nodal tachycardia with or without WPW). As a means of investigation, esophageal pacing is overall useful to diagnose undocumented paroxysmal tachycardia fits (palpitations), to evaluate the refractory stage of an accessory pathway (WPW) or to assess the refractory stage of antiarrhythmia medications. This investigation may also be used to assess the sinusal function, the atrioventricular conduction (Wenckebach point) and the spontaneous rhythm of atrioventricular blocks after pacemaker insertion. Due to the technical improvements achieved, esophageal pacing may be used presently in pediatric units taking care of children with arrhythmias.

Efficacy and risks of medical therapy for supraventricular tachycardia in neonates and infants. Weindling SN, Saul JP, Walsh EP. Children's Hospital, Boston, Mass., USA. Am Heart J 1996 Jan;131(1):66-72. To assess the efficacy and safety of current pharmacologic therapy for supraventricular tachycardia (SVT) in infants, we reviewed 112 infants treated between July 1985 and March 1993. The SVT mechanism was determined by esophageal electrophysiologic study and involved an accessory pathway in 86, atrioventricular (AV) node reentry in 10, atrial muscle reentry in 11, and an ectopic atrial tachycardia in 5 patients. Of six infants not treated, none had clinical recurrences of SVT. Of the 106 patients treated, 70% remained free of tachycardia while receiving digoxin, propranolol, or both. Class I antiarrhythmic agents were necessary for 13 patients, and class III agents were required for another 13 infants. Verapamil was used in one infant with AV node reentry tachycardia. Nine infants with complex clinical presentations were believed to have failed medical management and underwent radiofrequency ablation. Five patients died, four of complications related to structural heart disease and one shortly after radiofrequency ablation was performed. No deaths appeared to be related to antiarrhythmic medications. No drug-related side effects requiring medication change occurred, and no proarrhythmia was observed. Thus medical therapy appears to be effective and safe in infants with SVT. Radiofrequency ablation should be reserved for rare infants who fail aggressive medical regimens or when the situation is complicated by ventricular dysfunction, severe symptoms, or complex congenital heart disease.

Transesophageal electropharmacologic test in a newborn with familial Wolff-Parkinson-White syndrome. Colloridi V, Boscioni M, Patruno N, Pulignano G, Critelli G. University of Rome La Sapienza, Italy. Pediatr Cardiol 1990 Oct;11(4):213-5. A newborn infant with familial Wolff-Parkinson-White (WPW) syndrome presented with a supraventricular tachycardia of 300 beats/min, refractory to digoxin and flecainide administration. Serial electropharmacologic tests were performed via the esophagus before and during oral therapy with verapamil at 40, 80, and 60 mg daily. Before treatment, tachycardia could be induced with programmed stimulation. A regimen of verapamil at 60 mg daily, which resulted in the initiation of nonsustained (less than 10 s) reciprocating tachycardia only, without clinical recurrences, was identified as suitable long-term oral therapy. The efficacy of this drug regimen in preventing episodes of tachycardia was confirmed during a 1-month follow-up period. It is concluded that transesophageal atrial pacing is a useful, noninvasive means of selecting treatment in neonates with supraventricular tachycardia, when nonconventional drugs are considered for prophylaxis.

The esophageal approach in rhythmology. Mabo P, Gras D, Leclercq C, Daubert C. CHRU, 2, Rennes. Arch Mal Coeur Vaiss 1995 Dec;88 Spec No 5:43-7. The possibility of detecting the electrical activity of the heart from the oesophageus has been recognised for nearly a century. On the other hand, transesophageal pacing has only been really developped in the last fifteen years, which explains the recent interest for this technique in clinical practice. Easily put into practice, but not always well tolerated, the oesophageal approach has many uses in rhythmology. The principal diagnostic applications are in unlabelled tachycardias whether with narrow or wide QRS complexes, the evaluation of the Wolff-Parkinson-White syndrome, the study of sinus node function or nodal conduction. The therapeutic applications are dominated by the reduction of supraventricular tachycardias especially atrial flutter, with a success rate similar to that of endocavitary stimulation. The facility of realisation, especially at the patient's bedside, without need for fluoroscopie control, makes it a useful tool in emergencies, especially if the endocavitary approach cannot be used. The only reserve is the painful character of pacing in some patients.

The diagnostic value of esophageal ECG and transesophageal atrial stimulation in paroxysmal supraventricular tachycardia. Pehrson SM, Blomstrom P.Kardiologkliniken, Lunds Lasarett, Sverige. Ugeskr Laeger 1991 Nov 25;153(48):3403-7. Paroxysmal supraventricular tachycardia (PSVT) includes a group of common arrhythmias. The diagnosis should be based on 12-lead ECG. Oesophageal ECG, which registers mainly left-sided posterior atrial activity may be of value for further assessment of the arrhythmic mechanism in determination of the time relationship between atrial and ventricular signals. A ventriculoatrial interval during PSVT measured by oesophageal ECG of under 70 ms is evidence of atrioventricular nodal re-entry tachycardia while an interval of over 70 ms suggests orthodromic reciprocating tachycardia with participation of an accessory atrioventricular pathway. Transoesophageal atrial stimulation (TAS) via an electrode catheter is possible in approximately 90% of the patients with PSVT. TAS requires greater quantities of energy than endocardial stimulation and is associated with slight to moderate retrosternal discomfort. The method renders possible both programmed stimulation with the object of inducing arrhythmia and in stopping the majority of cases PSVT, with the exception of atrial fibrillation. The method is relatively simple, non-invasive, requires few resources and can be carried out on outpatients.

Transesophageal electric heart stimulation in the diagnosis of paroxysmal supraventricular tachycardias. Smetnev AS, Grosu AA, Sokolov SF, Golitsyn SP. Kardiologiia 1983 Nov;23(11):13-8. Thirty-one patients with paroxysms of supraventricular tachycardia (SVT) were examined using trans-esophagus electrical stimulation of the left atrium. SVT paroxysms were provoked in 23 patients. An analysis of the esophagus electrogram recorded revealed SVT paroxysms in the presence of the latent Wolff-Parkinson-White (WPW) syndrome in 12 patients, orthodromic SVT in the presence of the WPW syndrome in seven, and paroxysmal reciprocal atrioventricular node tachycardia in four patients. Paroxysms were also induced in three out of 8 patients with atrial fibrillation. Two patients displayed a fall in the ST segment.

Induction of ventricular tachycardia by esophageal stimulation. Apropos of 2 cases. Kieny JR, Roul G, Sachs D, Mossard JM, Bareiss P, Sacrez A/ CHU Hautepierre, Strasbourg. Arch Mal Coeur Vaiss 1991, 84(11):1587-90. The utility of transesophageal atrial pacing in sustained left ventricular tachycardia is reported in two cases. A 46 year old man without any apparent cardiac disease presented with invalidating but undocumented palpitations. Transesophageal atrial pacing with isoproterenol infusion induced wide complex tachycardia with a right bundle branch block morphology and left axis deviation. Atrio-ventricular dissociation was observed and it was possible to reduce the ventricular complex width by rapid transesophageal atrial pacing: the tachycardia was terminated by an injection of verapamil. It was not possible to reinduce the tachycardia after treatment with atenolol 100 mg/day, introduced because of the catecholinergic nature of the arrhythmia. The patient is symptom free after 2 years of treatment with this drug. Regular wide complex tachycardia with right bundle branch block and left axis deviation without any detectable atrial activity was recorded in a 50 year old man without known cardiac disease. Transesophageal atrial pacing with isoproterenol infusion induced an identical tachycardia. The tachycardia started after a normally conducted atrial extrastimulus followed by ventriculo-atrial dissociation and it was possible to overdrive with atrial pacing. The tachycardia could not be reinduced after treatment with atenolol and the patient is asymptomatic 12 months later. These reports show that it is possible to study certain ventricular tachycardias by transesophageal atrial pacing. The efficacy of antiarrhythmic therapy can be controlled simply by this non-invasive technique.

Diagnostic and therapeutic potential of transesophageal cardiac pacing in the management of patients with arrhythmias. Behulova R; Margitfalvi P; Hatala R. Bratisl Lek Listy (Slovakia), Nov 1997, 98(11) p589-93 BACKGROUND: Transoesophageal cardiostimulation is a semiinvasive method of stimulation of atrii enabling the performance of the programmed atrial stimulation without the inevitability of an invasive vascular approach. This method was used in 124 patients with the following indication spectrum. Diagnostic indications: total 82%, paroxysmal supraventricular tachycardia (SVT), and WPW sy-22%, tachycardia with wide QRS-complex-8%. SSS syndrome and bradycardia-20%, sycopes and collapses with unclear etiology-13%, palpitations-11%, control of antiarrhythmic therapy-4%, and other states-6%. Therapeutic indications: total-18%, versions of paroxysmal SVT and flutter of atrii. RESULTS: The patients with SVT were assumed to develop the arrhythmogenic mechanism--AV nodal re-entry tachycardia in 80%, orthodrome AV-re-entry tachycardia in 30%, and flutter of atrii in 20%. All patients with WPW-syndrome were stratified by the use of this method. The origin of this state from ventricular arrhythmia was verified in 40% of patients with tachycardia with a wide QRS complex. In coincidence with other indications, the diagnostic benefit of transoesophageal cardiostimulation was evaluated as follows: syncopes-68%, palpitations-64%, syndrome SSS and bradycardia-48%. The therapeutic indication of SVT version and flutter of atrii, was totally successful in 40%, partly successful in 45% and unsuccessful in 15% of patients. CONCLUSION: Transoesophageal cardiostimulation has contributed to the assessment of the diagnosis in 69% of patients and has acutely managed arrhythmia in 85% of cases. According to our experience, this method is effective in the initial management of patients with arrhythmia. Its low technical and economic demands make its wider utilisation appropriate in clinical practice of internal medicine.

Transesophageal atrial stimulation. Origgi MS, Gallo Junior L, Godoy RA, Marin-Neto JA, Maciel BC. Universidad de Sao Paulo, Brasil. Arch Inst Cardiol Mex 1990;60(3):241-51. (Published erratum appears in Arch Inst Cardiol Mex 1991;61(1):91). Considering that catheterization of the esophagus is a relatively easy procedure, we studied the electrical transesophageal atrial stimulation in ninety patients (age range 15 to 75 years (mean 42 +/- 9 years). A multipolar electrode catheter was introduced through the nose into the esophagus of each patient and fixed in position at a site where the simultaneous recording of intraesophageal unipolar electrocardiographic derivations showed the greatest P wave potentials. Electrical atrial capture through the esophagus was obtained at frequency values higher than that of the heart, with lower voltages needed for atrial stimulation at the site in which the unipolar recording of the intraesophageal P wave was of highest amplitude. The difference of potential used was between 6 and 30 volts, with the highest values corresponding to patients with megaesophagus, whereas values below 15 volts were tolerated without major discomfort. Electric pulses of more than 10 ms duration did not significantly reduce the intensity of electric current needed to produce the atrial command. The stimulation bipole (area to be stimulated per pole, 0.72 cm2) had an interpolar distance of 22 or 30 mm, our overall experience showing that distances up to 44 mm did not require higher voltages. No cases of esophageal damage or severe arrhythmia were reported due to stimulation. In the present study, programmed transesophageal stimulation proved to be a good option for the evaluation of sinus node function and for the study and reversal of paroxysmal supraventricular tachycardia attacks by a reentry mechanism, representing in some cases an alternative approach for the study of atrioventricular conduction.

Clinical and prognostic value of evaluation of atrial vulnerability in an electrophysiological endocavitary and transesophageal study. Delise P, Bonso A, Allibardi P, Millosevich P, Zerio C, D'Este D, Rigo F, Gasparini G, Coro L, Raviele A.G Ital Cardiol 1990 Jun;20(6):533-42. Atrial fibrillation or flutter is frequently inducible during endocavitary or transesophageal electrophysiologic study. However, its clinic and prognostic significance has not yet been clarified. We studied 443 patients: 276 underwent endocavitary electrophysiologic study, 228 underwent transesophageal electrophysiologic study and 61 underwent both methods. In 343 of them a satisfactory echocardiogram was obtained. Patients were divided in three groups: gr. I, 93 patients with documented episodes of paroxysmal atrial fibrillation or flutter; gr. II, 257 patients with or without heart disease without clinical atrial fibrillation or flutter; gr. III, 93 symptomatic or asymptomatic Wolff-Parkinson-White patients without clinical atrial fibrillation or flutter. Gr. I included patients without overt heart disease (20), with WPW (11), mitral valve prolapse (4), and miscellaneous (58). Gr. II included patients without overt heart disease (49), with concealed Kent bundles (7), Mahaim (1) or James fibers (1) mitral valve prolapse (6), sick sinus syndrome (40), miscellaneous (91), or syncope of an unknown origin (62). Atrial vulnerability was evaluated both by endocavitary and transesophageal electrophysiologic study using two different protocols; the first protocol was moderately aggressive (prot. A), while the second was aggressive (prot. B). Endocavitary electrophysiologic study. Prot. A: single and double extrastimuli at the three heart rates (sinus, 100 and 150/m'), 10/m' incremental atrial pacing from 160 to 250/m; prot. B: prot. A + incremental atrial pacing from 260/m' up to 2:1 St-A block. Transesophageal electrophy