Abstract 15854: Prediction of Arrhythmic Events in Ischemic and Non-Ischemic Cardiomyopathy Patients Referred for Implantable Cardioverter-Defibrillator Therapy: Evaluation of Resting Perfusion Defects by SPECT-Myocardial Perfusion Imaging

Abstract

Background Myocardial scar identifies patients at higher risk for ventricular arrhythmias among patients with left ventricular dysfunction. However, the ability of scar identification by SPECT-myocardial perfusion imaging (MPI) to predict events in such patients is not known

MethodsWe identified 509 patients who underwent SPECT-MPI prior to ICD implantation with a follow-up of 958 ± 757 days at a single institution. Subjects with a mild to moderate [summed rest score (SRS) 1-8, mean 5±2, n=150)] or severe (SRS>8, mean 19±8, n=287) resting perfusion defect were compared to those with normal perfusion (SRS=0, n=72) on the outcome of ICD therapy for VT/VF (anti-tachycardia pacing or shock therapy) and analyzed by the Kaplan Meier and Cox proportional hazards analyses

Results Overall the mean age was 66 ± 12 years, mean EF 29 ± 14%, 78% male, 73% with an ischemic cardiomyopathy (ICM), 59% with primary prevention indications, mean summed stress score 14±10 and a mean SRS 12±10. Compared to subjects with a SRS=0, an increased incidence of ICD therapy for VT/VF was observed among subjects with a SRS 1-8 (10% vs 27% p<0.001) and SRS>8 (10% vs 63% p<0.001, figure). Upon multivariable analyses a 1-point increase in SRS was associated with a 9% increased probability of ICD therapy for VT/VF [AHR 1.09 (95% CI 1.03 -1.14), p<0.001]. Among patients with an ICM (N=372, mean SRS 14±10) no patient had a normal perfusion result and 100% of patients receiving ICD therapy had myocardial scar. Among patients with a non-ischemic cardiomyopathy (N=137, mean SRS 6±7), the presence of normal perfusion result was associated with a markedly lower incidence of ICD therapy compared to a patients with a resting perfusion defect (18% vs 82%, p<0.001)

Conclusion The presence of myocardial scar by SPECT-MPI predicts arrhythmic events both among patients with an ischemic and non-ischemic cardiomyopathy referred for ICD-based therapy. Patients with a NICM and no scar demonstrate a very low arrhythmia risk