Prediction of Outcome of Patients With Life-Threatening Ventricular Arrhythmias Treated With Automatic Implantable Cardioverter-Defibrillators Using SPECT Perfusion Imaging

Abstract

Background In the present study, we examined the predictors of outcome of 103 patients with coronary artery disease and left ventricular dysfunction who had life-threatening ventricular arrhythmias and were treated with implantable cardioverter-defibrillators with the use of single-photon emission computed tomography (SPECT). Methods and Results During a mean follow-up of 29 months, there were 29 cardiac deaths. In comparison with patients who died, survivors had less diabetes mellitus (45% versus 19%, P <.007), higher left ventricular ejection fraction (23±9% versus 27±11%, P =.04), and fewer perfusion defects as determined with stress SPECT (15±5 versus 12±5, P <.004). Most of the perfusion defects were fixed, indicative of scarring; the extent of reversible defects did not differ (2±3 in survivors and 3±4 in nonsurvivors). Multivariate Cox survival analysis identified the number of fixed defects as the only independent predictor of death (χ 2 =10, P =.002). There were six deaths among 42 patients (14%) with <8 fixed defects compared with 23 deaths among 61 patients (38%) with ≥8 defects ( P =.005). The 4-year survival was better in patients with <8 segmental fixed defects than in those with ≥8 fixed defects (80% versus 36%) (χ 2 =8, P =.005). Conclusions The myocardial perfusion pattern is an important determinant of outcome in patients with life-threatening ventricular arrhythmias who are treated with a implantable cardioverter-defibrillator. The extent of scarring separates patients into high- and low-risk groups with a 2.7-fold difference in death rate.