Author:
Wang Zhibin,Jalali Fereshteh,Sun Yi-Hui,Wang Jiun-Jr,Parker Kim H.,Tyberg John V.
Abstract
Two apparently different types of mechanisms have emerged to explain diastolic suction (DS), that property of the left ventricle (LV) that tends to cause it to refill itself during early diastole independent of any force from the left atrium (LA). By means of the first mechanism, DS depends on decreased elastance [e.g., the relaxation time constant (τ)] and, by the second, end-systolic volume (VLVES). We used wave-intensity analysis (WIA) to measure the total energy transported by the backward expansion wave ( IW−) during LV relaxation in an attempt to reconcile these mechanisms. In six anesthetized, open-chest dogs, we measured aortic, LV (PLV), LA (PLA), and pericardial pressures and LV volume by orthogonal ultrasonic crystals. Mitral velocity was measured by Doppler echocardiography, and aortic velocity was measured by an ultrasonic flow probe. Heart rate was controlled by pacing, VLVES by volume loading, and τ by isoproterenol or esmolol administration. IW− was found to be inversely related to τ and VLVES. Our measure of DS, the energy remaining after mitral valve opening, IW−DS, was also found to be inversely related to τ and VLVES and was ∼10% of the total “aspirating” energy generated by LV relaxation (i.e., IW−). The size of the Doppler (early filling) E wave depended on IW−DS in addition to IW+, the energy associated with LA decompression. We conclude that the energy of the backward-going wave generated by the LV during relaxation depends on both the rate at which elastance decreases (i.e., τ) and VLVES. WIA provides a new approach for assessing DS and reconciles those two previously proposed mechanisms. The E wave depends on DS in addition to LA decompression.
Publisher
American Physiological Society
Subject
Physiology (medical),Cardiology and Cardiovascular Medicine,Physiology
Cited by
53 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献