"Stable" ventricular tachycardia is not a benign rhythm - Insights from the antiarrhythmics versus implantable defibrillators (AVID) registry

Background-Sustained ventricular tachycardia (VT) can be unstable, can be a ssociated with serious symptoms, or can be stable and relatively free of sy mptoms. Patients with unstable VT are at high risk for sudden death and are best treated with an implantable defibrillator. The prognosis of patients with stable VT is controversial, and it is unknown whether implantable card ioverter-defibrillator therapy is beneficial. Methods and Results-Screening for the Antiarrhythmics Versus Implantable De fibrillators (AVID) trial identified patients with both stable and unstable VT. Both groups were included in a registry, and their clinical characteri stics and discharge treatments were recorded. Mortality data were obtained through the National Death Index. The mortality in 440 patients with stable VT tended to be greater than that observed in 1029 patients presenting wit h unstable VT (33.6% versus 27.6% at 3 years; relative risk [RR]=1.22; P=0. 07). After adjustment for baseline and treatment differences, the RR was li ttle changed (RR=1.25, P=0.06). Conclusions-Sustained VT without serious symptoms or hemodynamic compromise is associated with a high mortality rate and may be a marker for a substra te capable of producing a more malignant arrhythmia. Implantable cardiovert er-defibrillator therapy may be indicated in patients presenting with stabl e VT.