Changes of left ventricular filling during the strain phase of Valsalva maneuver in healthy subjects and its mechanism / 中华超声影像学杂志

ABSTRACT

Objective To explore changes of left ventricular filling during the strain phase of Valsalva maneuver (VM) and its mechanism. Methods Thirty healthy volunteers were recruited to perform VM with a load of 40 mmHg. Left ventricular filling parameters (E, A, E/A ratio, e and E/e ratio) were determined by echocardiography at baseline,at the first beat and at the second beat during the strain phase of VM,respectively. Results Compared to those at baseline, E, E/A ratio and E/e ratio increased ( P ＜0.05) while A and e did not change ( P＞0.05) at the first beat during the strain phase. Compared to those at the first beat during the strain phase,E, E/A ratio and E/e ratio decreased ( P ＜0.05) while A and e did not change ( P ＞0. 05) at the second beat during the strain phase. Conclusions Left ventricular filling decreased at the second beat during the strain phase of VM, which is different from the present knowledge that left ventricular filling would begin to decrease 4-5 beats later during the strain phase of VM. Positive intrathoracic pressure decreases left-side heart and pulmonary vessel' transmural pressure while increases the blood resistance, which may be the reason that E, E/A ratio and E/e ratio decreased at the second beat during the strain phase of VM.