Electrical Storm Induced by Cardiac Resynchronization Therapy Is Determined by Pacing on Epicardial Scar and Can be Successfully Managed by Catheter Ablation

Abstract

Background-The mechanism of cardiac resynchronization therapy (CRT)-induced proarrhythmia remains unknown. We postulated that pacing from a left ventricular (LV) lead positioned on epicardial scar can facilitate re-entrant ventricular tachycardia. The aim of this study was to investigate the relationship between CRT-induced proarrhythmia and LV lead location within scar. Methods and Results-Twenty-eight epicardial and 63 endocardial maps, obtained from 64 CRT patients undergoing ventricular tachycardia ablation, were analyzed. A positive LV lead/scar relationship, defined as a lead tip positioned on scar/border zone, was determined by overlaying fluoroscopic projections with LV electroanatomical maps. CRTinduced proarrhythmia occurred in 8 patients (12.5%). They all presented early with electrical storm (100% versus 39% of patients with no proarrhythmia; P<0.01), requiring temporary biventricular pacing discontinuation in half of cases. They more frequently presented with heart failure/cardiogenic shock (50% versus 7%; P<0.01), requiring intensive care management. Ventricular tachycardia was re-entrant in all. The LV lead location within epicardial scar was significantly more frequent in the proarrhythmia group (60% versus 9% P=0.03 on epicardial bipolar scar, 80% versus 17% P=0.02 on epicardial unipolar scar, and 80% versus 17% P=0.02 on any-epicardial scar). Ablation was performed within epicardial scar, close to the LV lead, and allowed CRT reactivation in all patients. Conclusions-CRT-induced proarrhythmia presented early with electrical storm and was associated with an LV lead positioning within epicardial scar. Catheter ablation allowed for resumption of biventricular stimulation in all patients. (Circ Arrhythm Electrophysiol. 2014;7:1064-1069.)

Myocardial infarction induces structural and functional remodelling of the intrinsic cardiac nervous system

“…Pacing in the presence of an infarct scar has also been reported to cause an electrical storm (Roque et al . ). Further, it can accelerate the progression of heart failure and increase mortality (Wilkoff et al .…”

Fragmented QRS Is a Novel Risk Factor for Ventricular Arrhythmic Events After Receiving Cardiac Resynchronization Therapy in Nonischemic Cardiomyopathy

“…However, it has been reported that pacing in myocardial scar leads to a prolonged and fQRS . Furthermore, electrical storms, which are related to pacing on epicardial scar, also have been reported . Therefore, the LV lead on the lateral wall might have been on an LV free wall scar in those patients.…”

Cardiac Resynchronization Therapy–Induced Proarrhythmia

“…In the current study, Roque et al 1 present their data on CRT-induced proarrhythmia because of pacing from within, or adjacent to, an epicardial scar demonstrated on cardiac MRI (cMRI). The authors demonstrate that this phenomenon can be successfully managed with catheter ablation and that in most cases CRT can be restored after ablation.…”