正常心室肌复极离散度初步研究

目的

A preliminary study on the dispersion of ventricular repolarization in normal adults

Objective　Values of the ventricular repolarization dispersion in people with normal heart structure were determined to provide a reference for further studies. The mechanisms of electrophysiological stability in normal ventricle were also discussed. Methods　Multipoint endocardium monophasic action potentials (MAP) were recorded in 19 persons without structural heart disease. The activation time (AT), MAP duration at 90% repolarization (APD90) and repolarization time (RT) during sinus rhythm, APD during S1S1 stimulation (APDS1), effective refractory period (ERP) and ERP/APDS1 at every recorded site were measured and their dispersions, defined as the difference between the maximum and minimum of each parameter, were calculated. Results　A close negative correlation between the average AT and APD90 was revealed in this normal group (LV:r=-0.91, RV:r=-0.94, P<0.01). Dispersions of AT(ATd), APD(APDd) and RT (RTd) during sinus rhythm were (28±8) ms, (40±12)ms and (27±6) ms, respectively, without any difference between males and females (P>0.05). RTd was significantly less than APDd(P<0.01). APDd during sinus rhythm was not distinctly different from that during S1S1 pacing (APDS1d) in 10 who received programmed stimulation ［(38±9) ms vs (34±10) ms, P>0.05］. Dispersion of ERP(ERPd), ERP/ APDS1 and dispersion of ERP/ APDS1 (ERP/ APDS1d) were (31±14) ms, 0.89±0.08 and 0.10±0.07, respectively. Conclusions　MAP mapping is a relatively direct method to assess the myocardial repolarization course. Repolarization dispersion and electrophysiological stability exist in normal ventricular myocardia simultaneously.