0176 : LV diastolic function and mechanics adaptation during the transition from rest to exercise

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• 作者：Omar Izem¹ ; ^{omizem@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Claire Maufrais¹ ; Thomas Rupp² ; Iris Shuster³ ; Sté ; phane Nottin¹
• 刊名：Archives of Cardiovascular Diseases Supplements
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：8
• 期：3
• 页码：264
• 全文大小：49 K

文摘

During the transition from rest to exercise, heart rate (HR) immediately increase to provide a sufficient O2 delivery to active muscle. This adaptation of HR induces a dramatically decrease of left ventricular (LV) filling time, that requires a very fast adaptation of the LV diastolic function to maintain LV filling. Diastolic function depends on many factors including intrinsic cardiomyocytes relaxation, LV filling pressure and also LV untwisting that occurs very early in diastole. However, the kinetics of these underlying mechanisms of LV diastolic function during the transition from rest to exercise remain to be explore. 25 young males (23±4 years) were recruited. Each subject performed 5 similar 4-min constant load exercises on a dedicated ergometer in a semi-supine position. 2D cine loops were recorded every 15s from different echocardiographic views. LV longitudinal diastolic strain rate (SrL_diast), an index of LV relaxation, and LV end-diastolic volume (LV-EDV) were assessed from an apical 4-chamber view. LV rotations, twist and its subsequent untwist were assessed from basal and apical short-axis views. The global strain imaging diastolic index was used as a sensitive index of LV filling pressures. At the onset of exercise, LV-EDV increased during the first 60s despite rapid increase of HR. This adaptation was firstly driven by rapid increase of LV filling pressure in the first 15s, probably due to venous return induced by the pedaling. LV filling was also facilitated by a rapid increase of cardiomyocyte relaxation as evidenced by the increase of SrL_diast. Moreover, the increase in LV twist and its subsequent untwist was major during the first min of exercise and increase of the untwisting rate/twist ratio until 90s underlined an improvement in elastic recoil very early in diastole. These findings bring new and original data regarding the adaptation of the LV diastolic function and mechanics during the transient from rest to exercise in healthy subjects.

The author hereby declares no conflict of interest