Plehn Gunnar, Vormbrock Julia, Machnick Sebastian, Meissner Axel, Trappe Hans-Joachim
Department of Cardiology and Angiology, Marienhospital Herne, University of Bochum, Germany.
J Heart Valve Dis. 2009 Jan;18(1):9-17.
Exercise-induced abnormalities of the systolic-diastolic phase proportion and their impact on hemodynamic variables have been investigated only minimally in asymptomatic patients with chronic aortic regurgitation (AR).
A group of 33 asymptomatic patients with severe AR and preserved left ventricular (LV) systolic function was studied during incremental exercise, using a combined hemodynamic-radionuclide angiographic approach. The phases of the cardiac cycle were derived with high temporal resolution from the LV time-activity curve. The loss of diastolic time per beat (LDT) was quantified using a regression equation obtained from a healthy control group (n=26). Based on the median LDT at peak exercise, patients were allocated to two groups with LDT < or = 12.4 ms (group A) and LDT > 12.4 ms (group B).
At peak exercise the relative duration of LV diastole was significantly shorter in AR patients than in controls (31.4 +/- 3.0 versus 33.1 +/- 2.4 s/min; p = 0.02) and a significant LDT (12.1 +/- 19 ms; p = 0.003) was observed. Group A patients had a higher peak cardiac output (9.2 +/- 2.0 versus 7.4 +/- 2 l/min/m2; p < 0.03), a longer exercise duration (18 +/- 5 min versus 13 +/- 6 min; p < 0.02) and a lesser extent of mean pulmonary artery pressure rise (27 +/- 10 versus 34 +/- 12 mmHg; p = 0.03) than group B patients.
Cardiac exercise performance in asymptomatic patients with AR is influenced not only by the ability of the cardiovascular system to favorably redistribute total stroke volume, but also to handle volume overload without changing the systole and diastole phase proportions.
在无症状的慢性主动脉瓣反流（AR）患者中，运动诱发的收缩 - 舒张期比例异常及其对血流动力学变量的影响仅得到了极少的研究。
采用血流动力学 - 放射性核素血管造影联合方法，对一组33例无症状的重度AR且左心室（LV）收缩功能保留的患者进行递增运动研究。从LV时间 - 活动曲线以高时间分辨率得出心动周期各阶段。使用从健康对照组（n = 26）获得的回归方程对每搏舒张期时间损失（LDT）进行量化。根据运动峰值时的LDT中位数，将患者分为两组，LDT≤12.4毫秒（A组）和LDT＞12.4毫秒（B组）。
运动峰值时，AR患者的LV舒张期相对持续时间显著短于对照组（31.4±3.0对33.1±2.4秒/分钟；p = 0.02），并且观察到显著的LDT（12.1±19毫秒；p = 0.003）。与B组患者相比，A组患者的峰值心输出量更高（9.2±2.0对7.4±2升/分钟/平方米；p＜0.03），运动持续时间更长（18±5分钟对13±6分钟；p＜0.02），平均肺动脉压升高程度更小（27±10对34±12毫米汞柱；p = 0.03）。
无症状AR患者的心脏运动表现不仅受心血管系统有利地重新分配总心搏量能力的影响，还受在不改变收缩期和舒张期比例的情况下处理容量超负荷能力的影响。
