QUAN Xin, ZHU Tian-gang, GUO Shi, MA Jian-xin, WANG Xin , GUO Ji-hong

Background  Mechanical asynchrony is an important parameter in predicting the response to cardiac resynchronization therapy, but detailed knowledge about cardiac timing in healthy persons is scarce. Therefore, in the current study, we sought to investigate the physiological status of interventricular synchronicity using pulse wave flow and tissue Doppler imaging in a healthy Chinese population.
Methods  Eighty-eight healthy volunteers underwent standard flow and tissue Doppler echocardiographic examinations. Ventricular inflow and outflow pulse wave flow Doppler patterns were recorded together with annulus pulse tissue Doppler imaging. Time intervals from the beginning of the QRS complex to the onset, peak and end of each wave were measured.
Results  The onsets of systole between left and right ventricles were highly synchronized by both imaging modalities. However, the left ventricle reached the peak flow ejection and peak mechanical contraction earlier than the right ventricle, (165.61±26.23) ms vs. (204.3±34.55) ms (P <0.01) and (133.62±26.19) ms vs. (191.25±38.47) ms (P <0.01). Time to peak early diastolic relaxation was earlier in the left ventricle than in the right heart, (500.23±56.52) ms vs. (524.94±47.42) ms (P <0.01).
Conclusions  Left and right ventricles were well synchronized at the onsets of systole and diastole even though interventricular peak systolic and peak early diastolic dyssynchrony was observed in healthy people by pulse wave Doppler imaging. In addition, diastolic timing events were slightly affected by age and gender.