Atrial systole enhances intraventricular filling flow propagation during increasing heart rate

JOURNAL OF BIOMECHANICS

卷:49

Article

Santhanakrishnan, Arvind^1,4,5  Okafor, Ikechukwu²  Kumar, Gautam³  Yoganathan, Ajit P.^2,4,5 

[1] Oklahoma State Univ, Sch Mech & Aerosp Engn, 218 Engn North, Stillwater, OK 74078 USA

[2] Georgia Inst Technol, Sch Chem & Biomol Engn, Atlanta, GA 30332 USA

[3] Emory Univ, Sch Med, Div Cardiol, Atlanta, GA 30322 USA

[4] Georgia Inst Technol, Wallace H Coulter Dept Biomed Engn, 315 Ferst Dr, Atlanta, GA 30332 USA

[5] Emory Univ, 315 Ferst Dr, Atlanta, GA 30332 USA

关键词: Intraventricular flow;    Left ventricle;    Heart rate;    Atrial systole;    Flow phantom;   

DOI  :  10.1016/j.jbiomech.2016.01.026

来源: Elsevier

【 摘 要 】

Diastolic fluid dynamics in the left ventricle (LV) has been examined in multiple clinical studies for understanding cardiac function in healthy humans and developing diagnostic measures in disease conditions. The question of how intraventricular filling vortex flow pattern is affected by increasing heart rate (HR) is still unanswered. Previous studies on healthy subjects have shown a correlation between increasing HR and diminished E/A ratio of transmitral peak velocities during early filling (E-wave) to atrial systole (A-wave). We hypothesize that with increasing HR under constant E/A ratio, E-wave contribution to intraventricular vortex propagation is diminished. A physiologic in vitro flow phantom consisting of a LV physical model was used for this study. HR was varied across 70,100 and 120 beats per minute (bpm) with E/A of 1.1-1.2. Intraventricular flow patterns were characterized using 2D particle image velocimetry measured across three parallel longitudinal (apical-basal) planes in the LV. A pair of counter-rotating vortices was observed during E-wave across all HRs. With increasing HR, diminished vortex propagation occurred during E-wave and atrial systole was found to amplify secondary vorticity production. The diastolic time point where peak vortex circulation occurred was delayed with increasing HR, with peak circulation for 120 bpm occurring as late as 90% into diastole near the end of A-wave. The role of atrial systole is elevated for higher HR due to the limited time available for filling. Our baseline findings and analysis approach can be applied to studies of clinical conditions where impaired exercise tolerance is observed. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

Free