Yield of left ventricular dyssynchrony by gated SPECT MPI in patients with heart failure prior to implantable cardioverter-defibrillator or cardiac resynchronization therapy with a defibrillator: Characteristics and prediction of cardiac outcome

Mechanical left ventricular dyssynchrony (MLVD) might contribute in the therapeutic decision-making in patients with heart failure (HF) prior to cardiac resynchronization therapy (CRT). Our aim was to assess MLVD in patients with HF prior to implantable cardioverter-defibrillator (ICD) compared to patients with CRT-D. In a prospective study, patients with LVEF <= 35% who were scheduled for ICD or CRT-D, underwent gated SPECT myocardial perfusion imaging with technetium 99m sestamibi within 3 months prior procedure. MLVD was measured by phase analysis. The study cohort consisted of 143 patients, 71 with ICD and 72 with CRT-D. Age 68.3 +/- 11 and LVEF 24 +/- 6%. Phase standard deviation (SD) was 62.5 +/- 18 and 59.7 +/- 20 (P = NS), respectively. During follow-up of 23.7 +/- 12.1 months, there were 10 vs 14 cardiac death in ICD and CRT-D, respectively (P = NS), hospitalization for HF, in 34 vs 53 (P < .001). In multivariate analysis, Phase SD was the independent predictor for cardiac death [HR 2.66 (95% CI 1.046-6.768), P = .04]. Kaplan-Meier curves of phase SD of 60A degrees significantly identified ICD patients with and without cardiac deaths and hospitalization for HF exacerbation. MLVD by phase SD can identify patients with cardiac events and predict cardiac death in patients treated with ICD.