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Eur Heart J Case Rep
Eur Heart J Case Rep
ehjcr
European Heart Journal. Case Reports
2514-2119
Oxford University Press UK

10.1093/ehjcr/ytae472
ytae472
ECG Challenge
AcademicSubjects/MED00200
Eurheartj/1
Eurheartj/2
Eurheartj/5
An electrical swinging!
https://orcid.org/0000-0001-9715-0141
Kumar Swasthi S Department of Cardiology, Electrophysiology Division, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala PIN 695011, India

https://orcid.org/0009-0000-1901-5665
Mondal Sudipta Department of Cardiology, Electrophysiology Division, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala PIN 695011, India

Vijay Jyothi Department of Cardiology, Electrophysiology Division, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala PIN 695011, India

Gajendragadkar Parag Ravindra Handling Editor
Corresponding author. Tel: +91-7686906481, Email: sudiptamondalnrs@gmail.com
Conflict of interest: None declared.

9 2024
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© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.
2024
https://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
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pmcCase

A 35-year-old patient with a perimembranous ventricular septal defect was electively planned for intracardiac repair. Following surgery, he required inotropes for haemodynamic support. However, the post-operative electrocardiogram showed a wide complex tachycardia (Figure 1, Supplementary material online, Figure S1). Despite amiodarone infusion and electrical cardioversion, the patient remained in tachycardia and there was no termination and re-initiation as well.

Figure 1 Twelve-lead electrocardiogram of the patient during tachycardia (see text for explanation).

Question 1

Which of the diagnoses is possible in this case?

Atrioventricular nodal re-entrant tachycardia (AVNRT)

Orthodromic atrioventricular reciprocating tachycardia (AVRT)

Antidromic AVRT

Junctional ectopic tachycardia (JET) or Ventricular tachycardia (VT) with electrical alternans

JET or VT with cycle length alternans

Answer: D

This electrocardiogram of regular wide complex tachycardia (WCT) with a QRS duration of 120 ms with atrioventricular dissociation (Figure 1, Supplementary material online, Figure S1) rules out all AV node-dependent regular tachycardia like AVNRT, AVRT, and atrial tachycardia or atrial flutter. There were no cycle length variations. The QRS complex exhibited alternating morphology, consistent with variable degrees of left bundle branch block patterns. This finding suggests the potential presence of underlying distal conduction system disease. Electrical alternans can also be observed in the mechanical swinging of the heart within the pericardial cavity. However, in such cases, the QRS complex morphology remains unchanged with a reduction in amplitude, unlike the presented case. Although the first differential diagnosis of WCT in structural heart disease is VT, a typical post-operative state, refractoriness to medical treatment and instant resumption of tachycardia following electrical cardioversion (suggesting automaticity rather than re-entry), all pointed towards a JET with electrical alternans rather than a VT. Given the absence of dropped QRS and constant R–R intervals, the possibility of ectopic atrial tachycardia with AV Wenckebach is also unlikely.

Question 2

Which electrocardiographic presentation is extremely unlikely in JET?

Narrow complex tachycardia (NCT) with 1:1 VA relation

NCT with VA dissociation

Wide complex tachycardia (WCT) with VA dissociation

WCT with bigeminy

Irregularly irregular NCT with VA dissociation

Answer: E

Junctional ectopic tachycardia is a well-recognized complication following congenital heart surgery, particularly arising within the initial 72 post-operative hours. This arrhythmia is most frequently observed after procedures involving perinodal tissues.1 Potential contributing factors include direct mechanical trauma or indirect stretch injury to perinodal tissues. ECG manifestations typically include narrow complex tachycardia with AV dissociation, although occasional cases of 1:1 VA conduction may also be observed. In less frequent presentations, JET may manifest with right bundle branch block (RBBB) (post-operative RBBB in Tetralogy of Fallot repair) or VA Wenckebach. Junctional ectopic tachycardia presenting as WCT with echo-bigeminy has also been reported in infants.2 Overdrive pacing or administration of Adenosine may help in confirming the diagnosis.

Question 3

Which of the following is unlikely to be effective in post-operative JET?

Therapeutic cooling

Amiodarone

Ivabradine

Beta-blockers

Nifekalant

Answer: D

Junctional ectopic tachycardia typically demonstrates refractoriness to medical therapy and electrical cardioversion. Fortunately, the majority of JET episodes are self-limiting. Therapeutic hypothermia with a target core temperature range of 32–34°C, atrial overdrive pacing to maintain AV synchrony, amiodarone, and ivabradine are treatment options that may be employed for JET.3 In rare instances and based on limited case reports, alpha-2 adrenergic agonists, flecainide, propafenone, procainamide, sotalol, or nifekalant, may be considered. Digoxin, beta-blockers (except sotalol), and calcium channel blockers are unlikely to be effective. Catheter ablation is reserved as a last resort for patients with JET who experience haemodynamic compromise despite maximal medical therapy.

Supplementary Material

ytae472_Supplementary_Data

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports online.

Consent: Obtained from the patient in line with COPE guidance.

Funding: None declared.

Data availability

Data are available on request from authors.
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References

1 Paluszek C , BrennerP, PichlmaierM, HaasNA, Dalla-PozzaR, HaglC, et al Risk factors and outcome of post Fallot repair junctional ectopic tachycardia (JET). World J Pediatr Congenit Heart Surg 2019;10 :50–57.30799715
2 Mondal S , DharanBS, NamboodiriN. A wide complex tachycardia in bigeminy. Pacing Clin Electrophysiol 2024;47 :1032–1034.38953492
3 Kylat RI , SamsonRA. Junctional ectopic tachycardia in infants and children. J Arrhythm 2019;36 :59–66.32071621
