Azarbal Babak, Hayes Sean W, Lewin Howard C, Hachamovitch Rory, Cohen Ishac, Berman Daniel S
Department of Medicine (Division of Cardiology), University of California, Los Angeles, School of Medicine, Los Angeles, California, USA.
J Am Coll Cardiol. 2004 Jul 21;44(2):423-30. doi: 10.1016/j.jacc.2004.02.060.
We sought to determine whether chronotropic incompetence (CI) adds incremental value in predicting cardiac death (CD) and all-cause mortality and to determine which marker of CI is superior.
Chronotropic incompetence, defined by either a low percent heart rate (HR) reserve achieved or failure to achieve 85% maximal age-predicted heart rate (MA-PHR), is a predictor of mortality. These variables have not been examined together in a comprehensive myocardial perfusion single-photon emission computed tomographic (SPECT), or MPS, model.
A total of 10,021 patients who underwent exercise MPS, evaluated by a summed stress score (SSS), were followed up for 719 +/- 252 days. Percent HR reserve = (peak HR - rest HR)/(220 - age - rest HR) x 100, with <80% considered abnormal.
A total of 2,956 patients (29.5%) had low %HR reserve; 1,331 (13.3%) achieved <85% MA-PHR; and 1,296 (13.0%) had both. There were 234 deaths (93 CDs). On multivariate analysis, the SSS, %HR reserve, and inability to achieve 85% MA-PHR were predictors of all-cause mortality and CD (all p < 0.01). Myocardial perfusion SPECT was the most powerful predictor of CD (chi-square = 50). When the %HR reserve and ability to achieve 85% MA-PHR were considered, only the former remained a predictor of CD (p = 0.006 vs. p = 0.59).
In a comprehensive MPS model, CI was an important predictor of CD and all-cause mortality. Percent HR reserve was superior to the ability to achieve 85% MA-PHR in predicting CD; MPS was superior to both. Combined with previous studies, the findings suggest that %HR reserve should become the standard for assessing the adequacy of HR response during exercise testing, and that it should be routinely incorporated in risk stratification algorithms.
我们试图确定变时性功能不全（CI）在预测心源性死亡（CD）和全因死亡率方面是否具有额外价值，并确定CI的哪种标志物更具优势。
变时性功能不全定义为达到的心率储备百分比低或未达到最大年龄预测心率（MA-PHR）的85%，是死亡率的一个预测指标。这些变量尚未在综合心肌灌注单光子发射计算机断层扫描（SPECT）或心肌灌注显像（MPS）模型中一起进行研究。
总共10021例接受运动MPS检查的患者，通过总应力评分（SSS）进行评估，随访719±252天。心率储备百分比=（峰值心率-静息心率）/（220-年龄-静息心率）×100，<80%被认为异常。
总共2956例患者（29.5%）心率储备百分比低；1331例（13.3%）未达到MA-PHR的85%；1296例（13.0%）两者都有。有234例死亡（93例心源性死亡）。多因素分析显示，SSS、心率储备百分比和未达到MA-PHR的85%是全因死亡率和心源性死亡的预测指标（所有p<0.01）。心肌灌注SPECT是心源性死亡最有力的预测指标（卡方=50）。当考虑心率储备百分比和达到MA-PHR的85%的能力时，只有前者仍然是心源性死亡的预测指标（p=0.006对比p=0.59）。
在综合MPS模型中，CI是心源性死亡和全因死亡率的重要预测指标。在预测心源性死亡方面，心率储备百分比优于达到MA-PHR的85%的能力；MPS两者都优于。结合先前的研究，研究结果表明心率储备百分比应成为运动试验期间评估心率反应充分性的标准，并应常规纳入风险分层算法中。
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