Left ventricular systolic dyssynchrony is associated with pulmonary arterial hypertension in patients with coronary artery disease

Abstract

BACKGROUND: Left ventricular (LV) systolic dyssynchrony is an important pathologic mechanism in patients (pts) with coronary artery disease (CAD), however, its impact on the occurrence of pulmonary arterial hypertension (PAH) remains unclear. METHODS: We studied the impact of inter- or intra-ventricular mechanical dyssynchrony on the development of PAH in 148 consecutive pts (mean age 68±10 years, 82% M) with CAD. Detailed echocardiographic studies, including pulse Doppler and Tissue Doppler imaging (TDI) were performed to measure inter-ventricular dyssynchrony (Ts-RL=time difference between basal lateral and right free wall; and IVD=time interval between left and right outflow pre-ejection time), intra-LV dyssynchrony (Ts-SD=standard deviation of time to peak systolic velocity of 12 LV segments; and Ts-SL= time difference between basal septal and lateral wall), and pulmonary artery systolic pressure (PASP). RESULTS: 38 pts had PAH defined by PASP>35mmHg. There were no significant differences in age (71±9 vs. 68±10 yrs), prevalence of myocardial infarction (23 vs. 16%), hypertension (76 vs. 64%), and diabetes (45 vs. 30%), left ventricular ejection fraction (55±14 vs. 56±13%) between pts with or without PAH (all P>0.05). However, pts with PAH had significantly high prevalence of diastolic dysfunction (abnormal relaxation: 68 vs. 82%; pseudonormal: 24 vs. 17%; restrictive: 8 vs. 1%, P=0.042), greater Ts-SD (48.2±20.3 vs. 38.3±20.4ms, P=0.011) and Ts-SL (72.2±51.8 vs 49.6±42.5ms, P=0.008) compared with pts without PAH, without any difference in Ts-RL (75.5±47.8 vs. 65.8±49.3 ms, P=0.294) or IVD (16.1±9.9 vs. 16.7±13.8ms, P=0.796). Furthermore, PASP was significantly correlated with LV dyssynchrony index (Ts-SD: r=0.19, P=0.012; Ts-SL:r=0.22, P=0.004) and diastolic dysfunction (E/e', r=0.28, P< 0.001). CONCLUSIONS: Our results demonstrate that intra- but not inter-ventricular dyssynchrony is associated with PAH in CAD pts, independent of LV systolic function, providing further insight on the potential impact of LV dysschrony on exercise capacity in CAD pts.