Premature ventricular beats initiate recurrent ventricular fibrillation in early repolarization syndrome

Abstract

An early repolarization (ER) pattern on electrocardiography was historically considered a benign finding; however, this finding in the inferior and lateral leads has recently been associated with idiopathic ventricular fibrillation (VF). Here we describe a case of a 29-year-old man with an ER pattern, who experienced recurrent implantable cardioverter-defibrillator (ICD) shocks for ventricular tachycardia (VT) and VF. An ICD interrogation demonstrated how VF and VT were repeatedly initiated by closely coupled premature ventricular beats.

1. Case report

A 29-year-old man was referred to our institution with recurrent implantable cardioverter-defibrillator (ICD) shocks (<3 shocks over 24 h) for ventricular tachycardia (VT) and ventricular fibrillation (VF) that were repeatedly initiated by closely coupled premature ventricular beats (Fig. 1). He had experienced 18 appropriate shocks since the ICD implantation. He had suffered an out-of-hospital cardiac arrest 5 years previously. No cardiac risk factors or family history of sudden cardiac death was found. Echocardiography and cardiac magnetic resonance findings were normal. Coronary angiography demonstrated normal coronary arteries. Ajmaline and adrenaline provocation test findings were unremarkable. A secondary prevention single-chamber ICD device was implanted at a local district general hospital (Atlas model V-168; St. Jude Medical, Inc., St. Paul, MN, USA). Resting 12-lead electrocardiography (ECG) revealed a clear ER pattern described as J point elevation in inferolateral leads (Fig. 2). Ambulatory 12-lead ECG monitoring was arranged to guide future catheter ablation but was unable to capture any triggering premature ventricular beats. He then underwent an electrophysiology study, which was unable to initiate any clinical ectopics or VT. The patient was started on oral quinidine in addition to beta-blockers to reduce the risk of recurrent VF and ICD shocks.

Fig. 1.

Implanted cardioverter-defibrillator (ICD) interrogation demonstrating closely coupled ventricular premature beats triggering ventricular fibrillation (VF) with a coupling interval of 240 ms. The arrows show the premature ventricular beat initiating VF that was not sensed by the ICD.

Fig. 2.

Early repolarization is evident in the varying patterns of QRS slurring or notching in the inferolateral leads.

2. Discussion

Debate persists about how to best define the ER ECG pattern. There is consensus regarding definition of the malignant form of ER as a J-point elevation that could be (or not) associated with ST elevation [1]. In this case, a clear J-point elevation was seen, particularly in lead III (Fig. 2).

The incidence of an ER pattern on surface ECG is reportedly up to 13%, and is higher in more recent studies [2–5]. It is more common in physically active young males and athletes [3]. Transient changes in the presence of J-point elevation poses a higher risk for VF [4], and J-point elevation amplitude has been associated with an elevated risk of these life-threatening arrhythmias [5].

The clinical presentation of ER syndrome is often unexpected malignant arrhythmias at first presentation [4]. In this case, the clinical VT/VF episode (Fig. 1) was initiated by closely coupled ventricular premature beats as previously described [2]. Acute suppression of the premature beat can be achieved with isoproterenol with oral quinidine for long-term control [5]. Catheter ablation has also been successfully performed [5].

Conflict of interest

None.