Anderson J L
University of Utah School of Medicine, Salt Lake City.
Postgrad Med. 1988 Feb 29;Spec No:104-12.
The increase in sympathetic nervous system activity noted in heart failure of several etiologies has beneficial effects in the short term; in the long term, though, it may be detrimental. This provides a rationale for use of beta-blocker therapy in patients with cardiac myopathies of various etiologies. Postinfarction trials in patients with ischemic heart disease have suggested that beta blockade provides a substantial mortality benefit, and beta blockers are accepted as first-line therapy for hypertrophic cardiomyopathy. The use of beta-blocking drugs for dilated cardiomyopathy (DCM), however, is currently investigational. Early trials reporting benefits in functional class, exercise capacity, and myocardial function stimulated further interest in this application of beta blockade. Recent studies comparing metoprolol with placebo or standard treatment have shown promising improvements in functional class and exercise capacity. The patients who will benefit most from beta-blocker therapy in DCM may be those with a high resting heart rate and a short duration of symptoms and, perhaps, feminine gender. Marked structural abnormality on cardiac biopsy (eg, fibrosis) may suggest a poor response to treatment. A multicenter controlled study of metoprolol in dilated cardiomyopathy is in progress. If the outcome is favorable, beta-blocker therapy in DCM may become an accepted, rather than an experimental, treatment.
在几种病因所致的心力衰竭中所观察到的交感神经系统活性增加，在短期内具有有益作用；然而，从长期来看，它可能是有害的。这为在各种病因的心肌病患者中使用β受体阻滞剂治疗提供了理论依据。对缺血性心脏病患者进行的心肌梗死后试验表明，β受体阻滞剂可带来显著的死亡率获益，并且β受体阻滞剂被公认为肥厚型心肌病的一线治疗药物。然而，β受体阻滞剂在扩张型心肌病（DCM）中的应用目前仍处于研究阶段。早期试验报告了其在功能分级、运动能力和心肌功能方面的获益，这进一步激发了人们对β受体阻滞剂在这一应用中的兴趣。最近比较美托洛尔与安慰剂或标准治疗的研究显示，在功能分级和运动能力方面有令人鼓舞的改善。在DCM中最可能从β受体阻滞剂治疗中获益的患者可能是静息心率高、症状持续时间短以及可能为女性的患者。心脏活检显示明显的结构异常（如纤维化）可能提示对治疗反应不佳。一项关于美托洛尔治疗扩张型心肌病的多中心对照研究正在进行中。如果结果是有利的，β受体阻滞剂在DCM中的治疗可能会成为一种被认可的治疗方法，而不再是试验性治疗。
