Bonow R O
Cardiology Branch, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Herz. 1991 Feb;16(1):13-21.
Impaired diastolic function of the hypertrophied and stiffened left ventricle is a characteristic feature of hypertrophic cardiomyopathy (Figure 1). Altered left ventricular filling dynamics and reduced left ventricular distensibility or increased left ventricular diastolic chamber stiffness are associated with reduced left ventricular stroke volume, increased left ventricular filling pressures and compressive effects on the coronary microcirculation. These factors contribute importantly to the clinical presentation of many patients, including symptoms of fatigue, dyspnea and angina pectoris. Reduced distensibility results both from factors determining the passive elastic properties of the ventricular chamber (including severity of hypertrophy, fibrosis and cellular disarray) and from factors influencing the rate and extent of active left ventricular relaxation (Figure 2). The factors contributing to impaired relaxation in hypertrophic cardiomyopathy are mediated via either inactivation dependent or load-dependent mechanisms. In laboratory animals, compromise of myocardial inactivation results in a persistent increase in intracellular calcium concentration and in prolonged interaction of the contractile proteins. Additionally, there is evidence for an increased number of active receptors for calcium antagonists and, lastly, for myocardial ischemia (Figure 3). Load-dependent mechanisms include diminished wall tension at the opening of the mitral valve, changes in afterload, contractility and coronary flow. Other factors are nonuniform and asynchronous regional ventricular function due to differing increases in thickness of the ventricular walls and ischemia (Figure 4). Calcium channel blockers exert a favorable influence on left ventricular relaxation and filling (Figure 5); verapamil and diltiazem are preferable to nifedipine. Verapamil increases left ventricular stroke volume without an increase in the end-diastolic pressure (Figure 6), reduces regional asynchrony if present, and leads to a more homogeneous regional diastolic filling (Figure 4).(ABSTRACT TRUNCATED AT 250 WORDS)
肥厚且僵硬的左心室舒张功能受损是肥厚型心肌病的一个特征性表现（图1）。左心室充盈动力学改变、左心室扩张性降低或左心室舒张期腔室僵硬度增加与左心室每搏输出量减少、左心室充盈压升高以及对冠状动脉微循环的压迫作用相关。这些因素在许多患者的临床表现中起重要作用，包括疲劳、呼吸困难和心绞痛症状。扩张性降低既源于决定心室腔室被动弹性特性的因素（包括肥厚程度、纤维化和细胞排列紊乱），也源于影响左心室主动舒张速率和程度的因素（图2）。导致肥厚型心肌病舒张功能受损的因素通过失活依赖性或负荷依赖性机制介导。在实验动物中，心肌失活受损会导致细胞内钙浓度持续升高以及收缩蛋白相互作用时间延长。此外，有证据表明钙拮抗剂的活性受体数量增加，最后还有心肌缺血（图3）。负荷依赖性机制包括二尖瓣开放时壁张力降低、后负荷、收缩力和冠状动脉血流的变化。其他因素是由于心室壁厚度不同增加和缺血导致的不均匀且不同步的局部心室功能（图4）。钙通道阻滞剂对左心室舒张和充盈有有利影响（图5）；维拉帕米和地尔硫䓬比硝苯地平更可取。维拉帕米增加左心室每搏输出量而不增加舒张末期压力（图6），减少存在的局部不同步性，并导致更均匀的局部舒张期充盈（图4）。（摘要截断于250字）
