Ventricular tachycardia in nonischemic heart failure (HF) initiates by a nonreentrant
mechanism that appears to be due to triggered activity primarily from delayed
afterdepolarizations that arise from altered cellular Ca handling and ionic currents. In HF,
factors that conspire to enhance triggered arrhythmias include upregulated Na/Ca
exchange, preserved β-adrenergic responsiveness, and decreased IK1. Overall, the further
delineation of key factors that underlie triggered arrhythmias in HF will provide the basis for …