Major arrhythmic events
MAE were defined as any of the following: SCD, sudden cardiac arrest, VF, sustained ventricular tachycardia, or implantable cardioverter defibrillator (ICD) appropriate shock. SCD was defined as an unexpected, nontraumatic death that occurred within 60 min from the onset of new or worsening symptoms or within 24 hours of last being observed alive and well (8). Sudden cardiac arrest was defined as a sudden cessation of cardiac activity with hemodynamic collapse for which an intervention or spontaneous reversion restored spontaneous circulation.
VF was defined as documented VF rhythm from standard 12-lead ECG or ECG monitoring, or as defined in each study. Sustained ventricular tachycardia was defined as a sustained organized ventricular rhythm, documented from standard 12-lead ECG or ECG monitoring, faster than 100 beats per minute lasting at least 30 seconds or requiring termination earlier due to hemodynamic instability. Only sustained ventricular tachycardia, VF, and appropriate ICD shocks were counted in this study. Non-sustained ventricular tachycardia and inappropriate shock were not considered an outcome of interest. Ventricular tachyarrhythmias are defined as documented VF rhythm or sustained ventricular tachycardia.