Impact of transesophageal electrophysiological study on midterm management of pediatric tachyarrhythmias

ABSTRACT

Background:

Transesophageal electrophysiological study (TEEPS) is a minimally invasive procedure that helps in evaluating the risk of recurrence of supraventricular tachycardia based on the inducibility of the tachycardia. The purpose of this study was to evaluate the diagnostic capability, negative predictive value of noninducibility of tachycardia and safety of TEEPS among the Indian pediatric population.

Methods:

It is a retrospective single-center observational study of all patients who underwent TEEPS from January 01, 2014, to December 31, 2020.

Results:

Twenty-two TEEPS procedures were done in eighteen children with three children undergoing more than one procedure. The median duration of follow-up was 42.97 months (8.52–82.12 months). Out of the 22 procedures, four were conducted for acute tachycardia termination, two for tachycardia suppression assessment, and sixteen to assess tachycardia inducibility off medications. Tachycardia was noninducible in nine children and inducible in six children. Two children had clinical recurrence of tachycardia on follow-up. Out of these two children, one had noninducibility of tachycardia on TEEPS. The negative predictive value of TEEPS was 88.89% in this study. None of the children had any postprocedure complication.

Conclusions:

TEEPS is a safe procedure. It is used to assess the efficacy of medication in the suppression of arrhythmia. The noninducibility of tachycardia has a high negative predictive value and is a good indicator of nonrecurrence of clinical tachycardia on midterm follow-up.

INTRODUCTION

Supraventricular tachycardia (SVT) is the most common rhythm disturbance encountered in the pediatric population. Orthodromic atrioventricular reentrant tachycardia is the most frequent cause of SVT in young children. The natural history of Wolff–Parkinson–White Syndrome (WPW) has shown that in the majority of children, SVT disappears with increasing age due to change in conduction properties of the accessory pathway.[1,2] Besides, some of the other causes of SVT occurring in infancy like atrial tachycardia and atrial flutter also disappear as the child gets older.[3,4] Hence, many of the children with documented SVT may become arrhythmia-free as they grow up. However, the risk of SVT recurrence and potential for a malignant arrhythmia with risk of sudden cardiac death cannot be judged solely based on the 12-lead electrocardiogram (ECG).[2]

Transesophageal electrophysiological study (TEEPS), which is a minimally invasive procedure, has a potential role in assessing this risk.[5] It can also be used to assess the efficacy of medication on arrhythmia suppression and acute termination of an incessant tachycardia amenable to atrial overdrive pacing.[6]

This study was performed to evaluate the diagnostic capability, negative predictive value of noninducibility of tachycardia, and safety of TEEPS among the Indian pediatric population presenting to the institution for SVT management.

METHODS

A retrospective observational study was performed. All children who underwent TEEPS from January 01, 2014, to December 31, 2020, in the institution were included in the study. The clinical, demographic, electrocardiographic, echocardiographic, and electrophysiological characteristics of the children were obtained from the hospital inpatient records. Details of any clinical recurrence of tachycardia, medication history, and length of follow-up since the last TEEPS were also obtained from the hospital outpatient records and by telephonic consultation. The study was approved by the institutional research and ethics board.

Transesophageal electrophysiological study procedure

The medications were stopped for a minimum of 5 half-lives before the procedure if the indication was inducibility of tachycardia. Medications were continued if the indications for TEEPS were either to terminate incessant tachycardia or to assess medication efficacy in arrhythmia suppression. After a fasting period of 6 h for solids and 3 h for liquids, the children were taken up for TEEPS. Inhaled desflurane was used to gain intravenous access followed by ketamine or propofol based on the anesthetist’s preference for conscious sedation. Oral sucrose was used to sedate neonates.

An esophageal catheter (Esokid 2S, FIAB, Italy-6 Fr Bipolar catheter) was then introduced through the nostril into the esophagus progressing until a good atrial signal was recorded with the child lying supine. Pacing at 10–20 mA output with a pulse duration of 1 ms until consistent atrial capture is demonstrated was attempted, failing which the pulse duration was progressively increased by 0.5 ms increment until consistent atrial capture was achieved. The child was put in prone position if atrial capture was unsuccessful in supine position at maximal output. Atrial burst and incremental pacing until the atrioventricular Wenckebach point or tachycardia initiation were done initially. This was followed by programmed atrial extrastimuli pacing protocol with up to three extrastimuli till SVT was induced. Isoprenaline was not used for the induction of tachycardia since we felt it would make tachycardia interpretation difficult in infants who already had high basal heart rates.

Tachycardia was considered likely to be reentrant in mechanism if it was repeatedly induced and/or terminated with atrial pacing or intravenous adenosine. Atrioventricular reentrant tachycardia (AVRT) was diagnosed by the presence of preexcitation on the surface ECG, atrial overdrive pacing-induced atrioventricular dissociation with termination of tachycardia, and/or demonstration of cycle length prolongation or shortening during tachycardia attributable to appearance or disappearance of bundle branch block. Tachycardia was considered typical atrioventricular nodal reentrant tachycardia (AVNRT) if it was reentrant with 1:1 ventriculo-atrial (VA) association and VA interval was <70 ms. Atrial tachycardia was considered if it had a warm-up and cool-down phenomenon, P wave configuration of the first beat was identical to subsequent tachycardia beats, tachycardia continued in the atrium despite atrioventricular block, was spontaneously induced and could not be pace terminated. The lab was well equipped with intubation and resuscitation equipment to handle any untoward events. Postprocedure the child was observed for 2 h in the recovery area and then shifted to the ward and discharged from the hospital within 24 h.

Statistical methods

Continuous data were recorded as mean ± standard deviation for normally distributed data or as median (interquartile range) for skewed data. Categorical data were recorded as numbers and percentages. P < 0.05 was considered statistically significant.

Follow-up

The follow-up data were obtained from the hospital outpatient records and by telephonic consultation. The median duration of follow-up was 42.97 months (8.52–82.12 months).

RESULTS

There were eighteen children who underwent transesophageal electrophysiological study from January 01, 2014, to December 31, 2020. All the children had consistent atrial capture making the procedure feasible. Baseline characteristics of the children are shown in Table 1. There were eight males and ten females. Nine children presented in the neonatal period, four at 1–6 months of age, and five were older than 6 months. Of the nine children who presented within 1 month of age, two children had tachyarrhythmia documented in utero, 2 children had orthodromic AVRT, three children had atrial tachycardia, and the mechanism of SVT was unclear in the remaining two children.

Table 1.

Baseline characteristics

Patient number	Sex	Diagnosis	Preexcitation on ECG	ECHO	Weight at 1st TEEPS (kg)	Age at 1st TEEPS (months)	Follow-up (days)
1	Female	Fetal tachyarrhythmia	No	SNH	2.55	0	1913
2	Male	Accessory pathway mediated SVT	Yes	SNH	2.6	0	1385
3	Female	SVT	No	SNH	2.9	0	1617
4	Female	Accessory pathway mediated SVT	No	ASD	3.1	2	963
5	Male	Atrial tachycardia	No	ASD	3.8	3	1044
6	Female	Accessory pathway mediated SVT	Yes	ASD	4	2	657
7	Female	Fetal tachyarrhythmia	No	ASD	4.24	0	2201
8	Male	Atrial flutter	No	SNH	6.4	6	998
9	Male	SVT	No	ASD	8	15	433
10	Female	Accessory pathway mediated SVT	No	SNH	8.2	12	1597
11	Male	Atrial tachycardia	No	SNH	8.8	14	827
12	Female	Accessory pathway mediated SVT	No	SNH	9	14	1082
13	Male	Atrial tachcyardia	No	SNH	9.8	22	172
14	Female	Idiopathic VT-fascicular	No	SNH	10.4	22	758
15	Male	Atrial tachycardia	No	SNH	11.7	15	778
16	Male	Accessory pathway mediated SVT	No	SNH	12	28	1097
17	Female	SVT	No	SNH	12.8	24	1281
18	Female	Accessory pathway mediated SVT	Yes	SNH	13	45	1083

ECHO: Echocardiogram, SNH: Structurally normal heart, VT: Ventricular tachycardia, SVT: Supra VT, ASD: Atrial septal defect, ECG: Electrocardiogram, TEEPS: Transesophageal electrophysiological study

Out of the eighteen children, five had atrial septal defect while the rest had a structurally normal heart (SNH). Of these five, two had orthodromic AVRT, one had fetal tachyarrhythmia, one had atrial tachycardia, and in one child, the diagnosis was not clear. Among those with a SNH, five had orthodromic AVRT, three had atrial tachycardia, one had atrial flutter, one had probable fascicular ventricular tachycardia, one had fetal tachyarrhythmia, and in two children, diagnosis was not clear.

A total number of 22 TEEPS procedures were performed (1.22/person). Three children underwent more than one procedure. Four children underwent their first TEEPS procedure within 1 month of life and between 1 and 6 months of life each, respectively. Ten children underwent their first TEEPS procedure over 6 months of age. Six children weighed between 2.6 and 4 kg while twelve weighed more than 4 kg.

Electrophysiological characteristics of the TEEPS procedure are shown in Table 2. Three patients underwent urgent TEEPS toward terminating incessant tachycardia in hospital that was unresponsive to antiarrhythmic medications. The remaining 15 children underwent elective TEEPS to assess medication efficacy, arrhythmia inducibility, and mechanism. Out of the 22 TEEPS procedures, four procedures were conducted for acute tachycardia termination, two procedures were conducted for tachycardia suppression assessment, and sixteen procedures were done to assess tachycardia inducibility off medications [Figure 1]. The time interval from the initial diagnosis to the first TEEPS procedure varied from 1 day to 651 days (median of 70 days). Prior to the first TEEPS procedure, thirteen children were on beta-blockers (propranolol), three children were on propranolol and flecainide combination, and two children were not on any medications.

Table 2.

Transesophageal electrophysiological study characteristics

Patient number	Number of procedures	Indication for TEEPS	Tachycardia inducible	Advice	GA effect	Recurrence of clinical tachycardia
1	1	Inducibility	No	Stop medications	No	No
2	2	1st-tachycardia termination	NA	Continue medications	No	No
		2nd-medication efficacy	NA
3	1	Inducibility	No	Stop medications	No	No
4	1	1st-inducibility	Yes	Continue medications	No	No
		2nd-inducibility	Yes
5	3	1st-tachycardia termination	NA	Stop medications	No	No
		2nd-tachycardia termination	NA
		3rd TEEPS-inducibility	No
6	1	Medication efficacy	No	Continue medications	No	No
7	1	Inducibility	No	Stop medications	No	No
8	1	Tachycardia termination	NA	Continue medications	Yes	No
9	1	Inducibility	No	Stop medications	No	No
10	1	Inducibility	Yes	Continue medications	No	No
11	1	Inducibility	No	Stop medications	No	No
12	1	Inducibility	Yes	Continue medications	No	No
13	1	Inducibility	Yes	Continue medications	No	No
14	1	Inducibility	No	Continue medications	Yes	Yes
15	1	Inducibility	No	Stop medications	No	No
16	1	Inducibility	Yes	Continue medications	No	No
17	1	Inducibility	No	Stop medications	No	No
18	1	Inducibility	Yes	Continue medications	Yes	Yes

GA: General anesthesia, NA: Not applicable, TEEPS: Transesophageal electrophysiological study

Figure 1.

Flow chart, TEEPS: Transeophageal electrophysiological study

Out of the sixteen procedures which were done to assess the inducibility of tachycardia, it was inducible in six children (seven procedures) and noninducible in nine children (nine procedures). The six children with inducible tachycardia were advised to continue medications and one of them had a clinical recurrence despite medication warranting a drug uptitration [Figure 1]. Of the nine children with noninducible tachycardia, the effect of sedation could not be ruled out in one case. The ECG taken during tachycardia in this child was suggestive of fascicular ventricular tachycardia and the child was advised to continue medications. This child subsequently had a clinical recurrence of the arrhythmia despite medication warranting a drug uptitration [Figure 2]. Thus, the negative predictive value of the TEEPS procedure in the present study is 88.89%.

Figure 2.

Bar chart showing clinical recurrence of tachycardia in relation to inducibility of tachycardia during TEEPSL: Transeophageal electrophysiological study

Out of the four TEEPS procedures for incessant tachycardia, one of them resulted in termination with sedation and a second incessant tachycardia terminated with iv adenosine. The third case did not terminate despite overdrive esophageal pacing and 24 h of beta-blocker therapy. This child was thereafter taken up for a repeat TEEPS after 24 h as beta-blocker therapy was unsuccessful and Direct current (DC) cardioversion was required.

In our study, there were seven patients with orthodromic AVRT. Five patients had inducible tachycardia, of which one patient had incessant tachycardia which was terminated with intravenous adenosine and another patient was tested for medication efficacy. All these seven patients were discharged on medications to suppress the tachycardia. One of these patients had clinical tachycardia despite medication warranting a drug uptitration. There was no complication noted in the study population. The median duration of follow-up was 42.97 months (8.52–82.12 months). At the time of last follow-up, nine children were on medications with eight of them on propranolol and one child was on a combination of propranolol and amiodarone.

DISCUSSION

The placement of an esophageal lead to record activity from the atrium was first reported by Cremer in 1906.[7] The esophageal lead records the activity in the left atrium which is in its proximity. Pacing through this lead could help capture the atrium and be used to perform an electrophysiologic study. The various indications for TEEPS in pediatric population are acute termination of tachycardia, assessment of tachycardia mechanism, efficacy of medication in tachycardia suppression, and tachycardia induction off medications, all of which help in the medical management.[2,8,9] The present study confirms that TEEPS is a safe procedure and that it can be used to assess the efficacy of medication for arrhythmia suppression. The noninducibility of tachycardia in the absence of pathway conduction is a good indicator of the clinical tachycardia nonrecurrence over midterm, at least until the child is old enough to report symptoms on his or her own and can undergo a regular EP study.

The natural history of infants presenting with WPW syndrome and narrow QRS tachycardia has shown that the tachycardia disappeared in significant proportion of patients at 1 year of age (36%–93%).[1,2] However, one-third of these patients may have recurrence of SVT at a later age.[1,2] Hence, these accessory pathway-mediated tachycardias that present in early infancy may become silent by 1 year of age and medications can be safely discontinued, provided there is no inducibility of tachycardia on TEEPS. Other causes of SVT such as atrial tachycardia too disappear with increasing age and do not require continuation of medications. Once a child is started on medications for SVT, they are continued till the child is fit for an invasive electrophysiological procedure through the femoral venous route with three or four catheters. The average age at which this is performed is around 7 years. Until such a time, the child is exposed potentially to the significant side effects of these medications which are usually antiarrhythmic drugs of class Ic, II, or class III of Vaughan Williams classification. It is in this subset of patients that TEEPS will guide decision-making regarding the continuation of such potent medications based on the inducibility of tachycardia.

Out of the nine children who had no inducible tachycardia, one child had a clinical recurrence of tachycardia. The ECG during clinical tachycardia was suggestive of fascicular ventricular tachycardia which is notorious for noninducibility in the catheterization laboratory.[10] The negative predictive value of the TEEPS procedure in the present study is 88.89%. It could have been higher if drugs were used for arrhythmia induction. Rhodes et al. reported a negative predictive value of 96% when isoprenaline was used for arrhythmia induction.[6]

The positive predictive value cannot be calculated in the present study as all the patients who had inducible tachycardia on TEEPS were started on medications. TEEPS is most helpful in patients with tachyarrhythmias diagnosed in utero or in infancy where a definitive diagnosis was not possible. In this situation, noninducibility on TEEPS gives the physician confidence to stop medications. The utility of TEEPS in guiding decision-making should be weighed against the risk involved with the procedure. The added information obtained by TEEPS outweighs the negligible risk associated with intraprocedural sedation.

Four procedures were performed for termination of incessant tachycardia. However, overdrive pacing to suppress the tachycardia was unsuccessful in all. Even though these incessant tachycardias tend to terminate and reinitiate spontaneously making TEEPS ineffective, overdrive suppression was attempted to provide brief periods of respite which would be beneficial in children with ventricular dysfunction. It would also help buy time until the drugs administered acted to suppress the tachycardia.

Two patients in this study underwent TEEPS to look for medication (beta-blockers) effectiveness in the suppression of tachyarrhythmia as both had incessant tachycardia before therapy. In both these patients, the beta-blocker was effective in the suppression of tachycardia and the medication was continued with no clinical recurrence of tachycardia on follow-up.

TEEPS also has a definite role in documenting (shortest preexcited RR interval) and risk-stratifying accessory pathways. However, this role is more relevant in patients with incidentally detected preexcitation. It then helps decide whether these hitherto asymptomatic pathways have a lethal potential thereby warranting treatment. Brembilla-Perrot et al. in their paper looking at SVT in children with no preexcitation on ECG (140 patients) at baseline found 19 patients (13.5%) with demonstrable preexcitation during TEEPS and of these two patients (1.4%) had a malignant form of the preexcitation syndrome.[11] None of the procedures in our study were performed solely for risk stratification as there was no patients referred for incidentally detected preexcitation. In our study, there were two children with antegrade accessory pathway conduction and the electrophysiological properties of both these pathways were benign.

Limitations

This is a retrospective study. The number of children evaluated in the study is small. Isoprenaline was not used in cases where tachycardia was noninducible on TEEPS. Since most of our TEEPS were done in neonates and infants, it was felt that isoprenaline-induced rapid sinus rates may confound and make it difficult to identify an induced arrhythmia. The use of isoprenaline could have negated the effect of sedation and antiarrhythmic medication thereby increasing the negative predictive value. Automatic ectopic atrial tachycardia is unlikely to be inducible with pacing maneuvers. Hence, they can have clinical recurrence on follow-up making the utility of TEEPS in this scenario uncertain. Discrimination between AVNRT and AVRT by the esophageal study is not always possible and can require ventricular pacing maneuvers performed during tachycardia to make the correct diagnosis. Even though we did not have any patients with a diagnosis of AVNRT, some of the tachycardias could have been misdiagnosed.

CONCLUSION

TEEPS is a daycare procedure that can be performed safely even in children who weigh <4 kg. The risk of arrhythmia recurrence, its potential lethality, and the efficacy of medications in its suppression are assessable by this procedure. The noninducibility of tachycardia on TEEPS has a high negative predictive value and is a good indicator of arrhythmia nonrecurrence on midterm follow-up.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.