The ultrasonic research of left ventricular systolic volume and pressure in different electro-mechanical patterns:a canine model

Objeetive To evaluate the changes of left ventricular(LV) global and segmental volume, LV outlet pressure and their co-relationship, and to access LV global and segmental systolic function and mechanical asynchrony in different LV electro-mechanical patterns using full volume three-dimensional echocardiography(3DE). Methods Nineteen open-chest canine models were employed for the acquirement of LV full volume dynamic 3DE imaging during right atrial appendage (RAA), right ventricular apical (RVA), LV lateral wall(LVL) and LV apical(LVA). LV outlet end-systolic pressure(ESP) was recorded simultaneously. End-systolic volume (ESV), end-diastolic volume (EDV), global and segmental ejection fraction(EF) and systolic dyssynchrony index(SDI) of LV were measured and calculated using a dedicated workstation. The average ascending rate of LV pressure during systole(+ dp/dt) and the average descending systolic pressure(ESP), + dp/dt and - dp/dt during RVA pacing were lower than those during RAA pacing (P <0.05). SDI during RVA pacing was higher than that during RAA pacing(P<0.05). ESP, + dp/dtand - dp/dt during LVL and LVA pacing were lower than those during RAA pacing (P <0.05). There and LVA pacing was higher than that during RVA pacing (P <0.05),SD1 during LVL pacing was lower than that during RVA pacing (P <0.05), there was no significant difference of SDI between RVA and LVA and LVL pacing. Segmental EF of septum and apex during LVI. pacing were higher than those during LVA pacing (P <0.05). @Segmental EF of anterior and post septum and all apical segments (except lateral wall) during RVA pacing were lower than those during RAA pacing (P <0.05). Segmental EF of lateral and anterior wall during I.VI. pacing were lower than those during RAA pacing (P <0.05). Segmental EF of anterior wall and anterior septum during LVA pacing were lower than those during RAA parameters. Conclusions The global and minority segmental systolic function of LV during RAA pacing could be reduced compared with normal sinus rhythm. All the ventricular pacing worsen LV systolic and diastolic function compared with RAA pacing. LV systolic function during LVL pacing was superior to RVA pacing. During ventricular pacing,the systolic function at nearby segments of the pacing site was depressed. Key words: Echocardiography; Cardiac pacing,artificial; Ventricular function,left