EFFECTS OF REGIONAL SYSTOLIC ASYNCHRONY ON LEFT-VENTRICULAR GLOBAL DIASTOLIC FUNCTION IN PATIENTS WITH CORONARY-ARTERY DISEASE

Patients with coronary artery disease often have impaired left ventricular diastolic filling despite normal global systolic function. The influence of regional systolic asynchrony on diastolic function was assessed by radionuclide angiography in 60 patients with coronary artery disease and normal ejection fraction at rest: group 1 (n = 30) with normal wall motion at rest and group 2 (n = 30) with abnormal wall motion. Data were compared with those obtained from 19 normal volunteers. Age, heart rate, ejection fraction and echocardiographic end-diastolic dimension did not differ among the three groups. Peak filling rate in group 1 and group 2 was similar (2.5 +/- 0.5 and 2.3 +/- 0.6 end-diastolic counts/s, respectively) and significantly lower than that in the normal subjects (2.8 +/- 0.7 end-diastolic counts/s; p < 0.01 vs. group 2, p < 0.05 vs. group 1). Time to peak filling rate was prolonged in group 2 (184 +/- 27 ms) compared with that in normal subjects (162 +/- 19 ms; p < 0.01) and group 1 (172 +/- 15 ms; p < 0.05). Left ventricular end-diastolic pressure was significantly higher in group 2 than in group 1 (14 +/- 7 vs. 10 +/- 5 mm Hg, respectively; p < 0.05). Asynchrony was assessed by sector analysis of the radionuclide left ventricular region of interest. Diastolic asynchrony was similar in the two patient groups (30 +/- 23 ms in group 2, 26 +/- 16 ms in group 1) and was higher in both groups than in the normal subjects (16 +/- 8 ms; p < 0.01). However, systolic asynchrony was higher in group 2 (32 +/- 15 ms) than in both group 1 (14 +/- 6 ms; p < 0.01) and the normal group (9 +/- 6 ms; p < 0.01). In the total group of patients with coronary artery disease, systolic asynchrony correlated with global time to peak filling rate (r = 0.53; p < 0.001). This correlation became stronger when only group 2 was considered (r = 0.62; p < 0.001). Moreover, in group 2 systolic asynchrony correlated with the duration of the isovolumetric relaxation period (r = 0.58; p < 0.001) and the isovolumetric relaxation period, in turn, correlated with global time to peak filling rate (r = 0.72; p < 0.001). Thus, left ventricular systolic asynchrony affects both the relaxation and filling phases of diastole, thereby contributing to the impairment of diastolic function commonly observed in patients with coronary artery disease.