Grimm Wolfram
Department of Cardiology, Hospital of the Philipps-University of Marburg, Germany.
Card Electrophysiol Rev. 2003 Dec;7(4):463-7. doi: 10.1023/B:CEPR.0000023152.66316.8f.
Several randomized clinical trials have been designed to evaluate the usefulness of prophylactic implantable cardioverter defibrillator (ICD) therapy in patients with nonischemic cardiomyopathy. In 2 trials, CAT and AMIOVIRT, no survival benefit was reported for patients with dilated cardiomyopathy and prophylactic ICD therapy. The major limitation of both trials is the small sample size of 104 patients in CAT and 103 patients in AMIOVIRT. Another limitation of both trials is the lack of a run-in phase on optimized medical therapy. Since LV function may improve considerably on optimized medical therapy, LV function should be reevaluated 3 to 4 months after initiation of ACE inhibitors, ss-blockers and aldosterone antagonists before prophylactic ICD therapy is considered. Two additional trials, DEFINITE and SCD-HEFT, are still ongoing. Particularly SCD-HEFT will follow a sufficient number of patients with nonischemic cardiomyopathy to give a more definitive answer with regard to the clinical usefulness of prophylactic ICDs in patients with nonischemic cardiomyopathy. Recently, the Marburg Cardiomyopathy study (MACAS) was finished. The results of MACAS strongly suggest that reduced LV ejection fraction is the most important arrhythmia risk predictor in idiopathic dilated cardiomyopathy, whereas signal-averaged ECG, baroreflex sensitivity, heart rate variability and T wave alternans do not appear to be helpful for arrhythmia risk stratification. In addition, MACAS showed that total mortality in patients with idiopathic dilated cardiomyopathy and an ejection fraction <30% is only about 5% per year on optimized medical therapy after exclusion of patients with end stage heart failure and after exclusion of patients with sustained ventricular arrhythmias. Thus, any future study designed to demonstrate a mortality benefit by prophylactic ICD therapy with an 80% power in this patient population needs to enroll more than 1000 patients.
已经设计了多项随机临床试验来评估预防性植入式心脏复律除颤器（ICD）治疗对非缺血性心肌病患者的有效性。在两项试验CAT和AMIOVIRT中，未报告扩张型心肌病患者接受预防性ICD治疗有生存获益。这两项试验的主要局限性在于样本量较小，CAT试验中有104例患者，AMIOVIRT试验中有103例患者。这两项试验的另一个局限性是缺乏优化药物治疗的导入期。由于优化药物治疗可能会使左心室功能显著改善，因此在考虑预防性ICD治疗之前，应在开始使用血管紧张素转换酶抑制剂、β受体阻滞剂和醛固酮拮抗剂3至4个月后重新评估左心室功能。另外两项试验DEFINITE和SCD-HEFT仍在进行中。特别是SCD-HEFT将跟踪足够数量的非缺血性心肌病患者，以便就预防性ICD在非缺血性心肌病患者中的临床有效性给出更明确的答案。最近，马尔堡心肌病研究（MACAS）已经完成。MACAS的结果强烈表明，左心室射血分数降低是特发性扩张型心肌病中最重要的心律失常风险预测指标，而信号平均心电图、压力反射敏感性、心率变异性和T波交替似乎无助于心律失常风险分层。此外，MACAS表明特发性扩张型心肌病且射血分数<30%的患者，在排除终末期心力衰竭患者和持续性室性心律失常患者后，接受优化药物治疗时每年的总死亡率仅约为5%。因此，未来任何旨在证明在该患者群体中预防性ICD治疗有死亡率获益且检验效能为80%的研究都需要纳入超过1000例患者。
