Introduction: Cardiac resynchronization therapy (CRT) or biventricular pacing (BVP) is becoming an important treatment option in patients with severe congestive heart failure (CHF) and electrical dyssynchrony. When combined with implantable cardioverter-defibrillator (ICD) therapy, cardiac resynchronization therapy with a defibrillator (CRT-D) has been shown to improve quality of life, functional class, and, most recently, survival. However, left ventricular (LV) stimulation in the form of BVP in patients at high risk of developing ventricular tachyarrhythmias has raised concerns that BVP may be proarrhythmic. We describe the incidence, clinical characteristics, and management in a series of patients who developed ventricular tachycardia storm (VTS) after initiation of BVP.
Methods and results: Clinical data on all patients undergoing CRT-D were collected prospectively. VTS occurred in eight of 191 (4%) patients and was characterized by recurrent sustained monomorphic ventricular tachycardia (MMVT) with a single morphology. All patients with VTS were men (seven with ischemic heart disease, one with nonischemic cardiomyopathy) with a remote (5 +/- 2 years) history of MMVT. VTS developed a mean of 16 +/- 12.5 days after initiation of BVP. All patients presented with palpitations and/or decompensated CHF. VTS was refractory to intravenous antiarrhythmic medication and was managed by turning off LV pacing and/or radiofrequency catheter ablation and long-term oral antiarrhythmic therapy. Despite elimination of VT, presenting with VTS carried a poor prognosis in that all eight patients subsequently developed refractory CHF.
Conclusions: VTS with recurrent MMVT can occur after initiation of BVP. Patients present with decompensated CHF and are best managed by either turning off LV pacing or radiofrequency catheter ablation (RFA) in combination with long-term antiarrhythmic medication. Despite eliminating MMVT, most patients have poor outcomes.