Timing and Velocity of Ejection as Major Determinants of End‐Systolic Pressure in Isolated Rabbit Hearts
作者:
Abdellatif Ezzaher,
Taïb El Ouazzani,
Bertrand Crozatier,
期刊:
Circulation
(OVID Available online 1994)
卷期:
Volume 90,
issue 6
页码: 3055-3062
ISSN:0009-7322
年代: 1994
出版商: OVID
关键词: systole;pressure-volume relation;pressure;hypertrophy
数据来源: OVID
摘要:
BackgroundSystolic shortening is known to produce muscle deactivation. The present study was designed to analyze whether the velocity and the timing of ejection play a role on end-systolic pressure-volume relations (ESPVR).Methods and ResultsIn isolated rabbit hearts, left ventricular pressure and volume were recorded and digitized, and left ventricular volume was controlled by a servosystem (4-millisecond cycles) to alter the timing of ejection. A significant deficit in end-systolic pressure was observed when ejection was late in systole with respect to earlier ejection. This was associated with a significantly reduced end-systolic elastance. End-systolic pressure of beats with slow ejection was intermediate between that of the beats with early ejection and that of beats with late ejection with a significantly increased end-systolic volume compared with beats with early rapid ejection. The same results were obtained with hypertrophied hearts (abdominal aortic stenosis). Pressure-volume loop areas were significantly increased in beats with slow ejections and with rapid delayed ejections versus early rapid ejections. No change in the positive peak of dP/dt was observed when the timing and the velocity of ejection were modified.ConclusionsESPVR is modified by the ejection profile, with a decreased end-systolic pressure and an increased pressure-volume loop area related to the velocity and the amount of shortening during the end-systolic phase. These indices of ventricular function thus must be used with caution when the timing of ejection is altered, and the end-diastolic volume-peak dP/dt relation may be a better index of ventricular function.
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