Reduction in Ventricular Tachyarrhythmia Burden in Patients Enrolled in the RAIDTrial.

Abstract

The RAID (Ranolazine Implantable Cardioverter-Defibrillator) randomized placebo-controlled trial showed that ranolazine treatment was associated with reduction in recurrent ventricular tachycardia (VT) requiring appropriate implantable cardioverter-defibrillator (ICD) therapy. This study aimed to identify groups of patients in whom ranolazine treatment would result in the highest reduction of ventricular tachyarrhythmia (VTA) burden. Andersen-Gill analyses were performed to identify variables associated with risk for VTA burden among 1,012 patients enrolled in RAID. The primary endpoint was VTA burden defined as VTA episodes requiring appropriate treatment. Multivariate analysis identified 7 factors associated with increased VTA burden: history of VTA, age≥65 years, New York Heart Association functional class≥III, QRS complex (≥130ms), low ejection fraction (<30%), atrial fibrillation (AF), and concomitant antiarrhythmic drug (AAD) therapy. The effect of ranolazine on VTA burden was seen among patients without concomitant AAD therapy (HR [HR]: 0.68; 95%CI: 0.55-0.84; P< 0.001), whereas no effect was seen among those who are concomitantly treated with other AADs (HR: 1.33; 95%CI: 0.90-1.96; P = 0.16); P = 0.003 for interaction. In patients with cardiac resynchronization therapy (CRT) ICDs, ranolazine treatment was associated with a 36% risk reduction for VTA recurrence (HR: 0.64; 95%CI: 0.47-0.86; P< 0.001), whereas among patients with ICDs without CRT no significant effect was noted (HR: 0.94; 95%CI: 0.74-1.18; P = 0.57); P = 0.047 for interaction. In patients with high risk for VTA, ranolazine is effective in reducing VTA burden, with significantly greater effect in CRT-treated patients, those without AF, and those not treated with concomitant AADs. In patients already on AADs or those with AF, the addition of ranolazine did not affect VTA burden. (Ranolazine Implantable Cardioverter-Defibrillator Trial [RAID]; NCT01215253).