Abstract 2125: Severity of Left Ventricular Dyssynchrony in Patients with Ischemic and Non-Ischemic Cardiomyopathy: a Cardiovascular Magnetic Resonance Tissue Synchronization Mapping Study

Abstract

Aims: Studies on cardiac resynchronization therapy (CRT) for heart failure have shown a differential response in patients with ischemic (ICM) and non-ischemic cardiomyopathy (NICM). Increasing dyssynchrony has been shown to relate to a poor prognosis in patients with heart failure. We hypothesized that ICM and NICM have varying effects on left ventricular (LV) synchrony. Methods: The recently described cardiovascular magnetic resonance tissue synchronization index (CMR-TSI), which predicts benefit from CRT, was quantified in 181 patients (age: 66.4 ± 10.6 yrs, NYHA class III or IV, LVEF: 23.5 ± 10.8%, QRS = 139.8 ± 32.0 ms) with ICM (n=105) or NICM (n=76) and age-matched, healthy controls (n=24). The maximum time-to-peak radial wall motion in a short axis stack of LV images (steady-steady free precession imaging) was fitted to an empirical sine wave [y = a + b * sin (t/RR + c)]. The CMR-TSI was calculated as the SD of all segmental phase shifts of the radial wall motion extracted from this wave (see Figure for bull’s eye maps). Results: CMR-TSI was higher in ICM (105.8 ± 44.2, ANOVA p<0.0001) and in NICM (68.1 ± 30.5, p<0.0001) than in controls (22.5 ± 8.6) (see Figure ). In multivariate analyses including ICM and NICM patients only, ischemic aetiology emerged as a positive predictor of CMR-TSI, independent of QRS duration, LV end-systolic and end-diastolic volumes, and LVEF (all p<0.0001). Conclusions: ICM is associated with a greater degree of dyssynchrony than NICM, independently of QRS duration, LV volumes and LVEF. These findings may account for the differential response to CRT observed with patients with ICM and NICM.