Relationship between R-R interval and left ventricular systolic synchrony in subjects with coronary artery disease determined using angiography.

The aim of this study was to assess the relationship between R-R interval and left ventricular systolic synchrony in subjects with coronary artery disease determined using angiography. A total of 277 subjects who underwent coronary angiography for suspected CAD were recruited in this study. For all subjects, the R-R interval was quantified using simultaneous ECG, and the times to peak systolic longitudinal strain (Tssl) on 17 LV segments were quantified using four-dimensional (4D) speckle tracking echocardiography (STE) and manually measured. The independent predictors of R-R interval using multiple linear regression analyses were the time to peak systolic longitudinal strain in the apical-septal segment (Tssl-Apical-S) (β=0.325, P=0.000), smoking status (β=0.141, P=0.013), and the time to peak systolic longitudinal strain in the basal-anterolateral segment (Tssl-Basal-AL) (β=0.151, P=0.014), which were significantly independently associated with the R-R interval. In multiple regression analyses, smoking status (OR, 1.943; 95% CI, 1.119-3.375, P=0.018), Tssl-Basal-AL (OR, 1.002; 95% CI, 1.000-1.004, P=0.043), the time to peak systolic longitudinal strain in the mid-inferoseptal segment (Tssl-Mid-IS) (OR, 1.008; 95% CI, 1.003-1.013, P=0.004), and Tssl-Apical-S (OR, 1.010; 95% CI, 1.004-1.016, P=0.002) remained independently associated with the risk of a longer R-R interval (the median 849.49 ms was set as the cutoff value) in the population. Our findings may provide the basis for future investigations of LV systolic synchrony and cardiac resynchronization therapy.