Kautzner J, St'ovícek P, Anger Z, Savlíková J, Malik M
Department of Cardiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Acta Univ Palacki Olomuc Fac Med. 1998;141:69-73.
Heart rate variability (HRV) computed from 24-hour ECG recording has been associated with an increased risk of malignant arrhythmias after MI. To make HRV analysis more practical, we evaluated prospectively prognostic role of short-term HRV in comparison with other risk stratifiers. Study population consisted of 48 patients with acute MI (mean age 59.6 +/- 10.6 years, 38 males), who were off betablockers. All patients underwent 30-minute ECG recording at supine rest on day 2 and 5 after admission, between 9 and 11 a.m. One ECG channel from a commercial bedside monitor was A/D converted, and subsequently analysed using a purpose-built interactive software. Short-term HRV was computed as the standard deviation of all normal-to-normal RR intervals (SDNN) as well as the square root of the mean of the sum of the squares of differences between adjacent normal RR intervals (rMSSD). Left ventricular ejection fraction (LVEF, in %) was determined using 2D-echocardiography. During one-year follow up, 5 patients (10.4%) died of sudden cardiac death (SCD) and one of non-cardiac death. Subjects who died of SCD presented with significantly lower SDNN parameter on day 5 (28.8 +/- 4.3 vs 39 +/- 18.4, p < 0.006) and similar trend was revealed for rMSSD (12.22.8 vs 24.321, N.S.). Similarly, LVEF was significantly decreased in these patients (35.4 +/- 5.5 vs 49.7 +/- 11.3, p < 0.007). Positive predictive accuracy for prediction of SCD was 17% for rMSSD, 20% for SDNN, 29% for LVEF, and 40% for combination of depressed SDNN (< or = 33 ms) and LVEF (< or = 40). In conclusion, depressed HRV computed from short-term predischarge ECG recordings obtained under standardised conditions is associated with an increased risk of SCD. Such predictive power is substantially increased in combination with depressed LVEF, and this approach seems to be effective as a simple screening method to identify high risk subjects.
从24小时心电图记录计算得出的心率变异性（HRV）与心肌梗死后恶性心律失常风险增加相关。为使HRV分析更具实用性，我们前瞻性地评估了短期HRV与其他风险分层指标相比的预后作用。研究人群包括48例急性心肌梗死患者（平均年龄59.6±10.6岁，男性38例），这些患者未使用β受体阻滞剂。所有患者在入院后第2天和第5天上午9点至11点仰卧休息时进行30分钟心电图记录。将一台商用床边监护仪的一个心电图通道进行A/D转换，随后使用专门构建的交互式软件进行分析。短期HRV计算为所有正常RR间期的标准差（SDNN）以及相邻正常RR间期差值平方和的均值的平方根（rMSSD）。使用二维超声心动图测定左心室射血分数（LVEF，以%表示）。在一年随访期间，5例患者（10.4%）死于心源性猝死（SCD），1例死于非心源性死亡。死于SCD的患者在第5天的SDNN参数显著更低（28.8±4.3对39±18.4，p<0.006），rMSSD也呈现类似趋势（12.2±2.8对24.3±21，无统计学意义）。同样，这些患者的LVEF显著降低（35.4±5.5对49.7±11.3，p<0.007）。rMSSD对SCD预测的阳性预测准确率为17%，SDNN为20%，LVEF为29%，SDNN降低（≤33毫秒）和LVEF降低（≤40）联合预测为40%。总之，在标准化条件下从出院前短期心电图记录计算得出的HRV降低与SCD风险增加相关。与降低的LVEF联合时，这种预测能力显著增强，并且这种方法似乎作为一种识别高危患者的简单筛查方法是有效的。
