EXERCISE INTOLERANCE IN PATIENTS WITH HEART-FAILURE AND PRESERVED LEFT-VENTRICULAR SYSTOLIC FUNCTION - FAILURE OF THE FRANK-STARLING MECHANISM
EXERCISE INTOLERANCE IN PATIENTS WITH HEART-FAILURE AND PRESERVED LEFT-VENTRICULAR SYSTOLIC FUNCTION - FAILURE OF THE FRANK-STARLING MECHANISM
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DOI：
10.1016/0735-1097(91)90832-t
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发表时间：
1991-04-01
影响因子：
24
通讯作者：
SULLIVAN, MJ
中科院分区：
文献类型：
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作者：
KITZMAN, DW;HIGGINBOTHAM, MB;SULLIVAN, MJ
对7例充血性心力衰竭、左心室射血分数正常、无明显冠脉或瓣膜疾病的患者和10例年龄匹配的正常人进行有创心肺运动试验。与正常受试者相比，患者表现出严重的运动耐量，峰值耗氧量下降48%(11.6±-4.0vs22.7+/-6.1ml/kg/min；p<；0.001)，主要是由于心脏峰值指数下降了41%(4.2ml.4vs7.1+/-1.1L/min/m2；p<；0.001)。舒张期末容量指数(每平方米56+/-14对68+/-12ml/min；P<；0.08)降低，而峰值射血分数和收缩末期容量指数无明显变化。在患者中，运动时舒张末容量指数的变化与每搏输出量指数(r=0.97p<；0.0001)和心脏指数(r=0.80p<；0.03)的变化密切相关。在运动高峰时，患者的肺楔压显著高于正常人(25.7±9.1vs7.1±4.4 mm Hg；p<；0.0001)。患者表现为静息时左室舒张末压-容量关系向上和向左移动。运动过程中左心室充盈压力的增加并不伴随着舒张末容量的增加，这表明左心室充盈受限。这些数据表明，左室舒张功能异常限制了患者通过Frank-Starling机制增加每搏量的能力，导致严重的运动耐量。这些发现为慢性疲劳和劳力性呼吸困难的症状提供了病理生理学基础，这些症状通常出现在有充血性心力衰竭病史和收缩功能保留的患者中。
Invasive cardiopulmonary exercise testing was performed in 7 patients who presented with congestive heart failure, normal left ventricular ejection fraction and no significant coronary or valvular heart disease and in 10 age-matched normal subjects. Compared with the normal subjects, patients demonstrated severe exercise intolerance with a 48% reduction in peak oxygen consumption (11.6 +/- 4.0 versus 22.7 +/- 6.1 ml/kg per min; p < 0.001), primarily due to a 41% reduction in peak cardiac index (4.2 +/- 1.4 versus 7.1 +/- 1.1 liters/min per m2; p < 0.001).In patients compared with normal subjects, peak left ventricular stroke volume index (34 +/- 9 versus 46 +/- 7 ml/min per m2; p < 0.01) and end-diastolic volume index (56 +/- 14 versus 68 +/- 12 ml/min per m2; p < 0.08) were reduced, whereas peak ejection fraction and end-systolic volume index were not different. In patients, the change in end-diastolic volume index during exercise correlated strongly with the change in stroke volume index (r = 0.97; p < 0.0001) and cardiac index (r = 0.80; p < 0.03). Pulmonary wedge pressure was markedly increased at peak exercise in patients compared with normal subjects (25.7 +/- 9.1 versus 7.1 +/- 4.4 mm Hg; p < 0.0001). Patients demonstrated a shift of the left ventricular end-diastolic pressure-volume relation upward and to the left at rest. Increases in left ventricular filling pressure during exercise were not accompanied by increases in end-diastolic volume, indicating a limitation to left ventricular filling.These data suggest that abnormalities in left ventricular diastolic function limited the patients' ability to augment stroke volume by means of the Frank-Starling mechanism, resulting in severe exercise intolerance. These findings provide a pathophysiologic rationale for symptoms of chronic fatigue and dyspnea on exertion, which are often present in patients with a history of congestive heart failure and preserved systolic function.