Malik M, Camm A J
Department of Cardiological Sciences, St George's Hospital Medical School, London.
Cardiovasc Res. 1990 Oct;24(10):793-803. doi: 10.1093/cvr/24.10.793.
The study examined heart rate variability to find out whether shorter ECG records can predict long term mortality following acute myocardial infarction as efficiently as 24 h recordings.
Heart rate variability was assessed in 24 h electrocardiograms recorded during the first 2 weeks following acute myocardial infarction and in separate 1 h portions of the complete recording. The spectral analysis of complete 24 h records was performed and different short and long term components of heart rate variability were used to distinguish between patients with and without later complications.
20 patients who initially survived acute myocardial infarction but later experienced serious events (death or symptomatic sustained ventricular tachycardia) during a 6 month follow up (group I) were compared with 20 patients (group II) who remained free of complications for more than 6 months after discharge and who were matched with group I for age, gender, infarct site, ejection fraction, and beta blocker treatment.
The distinction based on components limited to changes of heart rate within periods less than or equal to 1 h was as significant (p less than 0.001, paired t test) as when using the components limited to changes of periods less than or equal to 10 h. However, heart rate variability of separate 1 h portions of the complete 24 h records differed between the groups significantly only for certain 1 h intervals of the day (the p values varied from 0.2 to 0.0005).
Whilst the maximum value of short term heart rate variability is sufficient for stratification of the high risk post-myocardial infarction patients, an arbitrarily selected short term ECG recording is unlikely to register the maximum heart rate variability. It is concluded that the heart rate variability assessed from arbitrary 1 h electrocardiographic records is not as prognostically important as the variability estimated from 24 h recordings.
本研究检测心率变异性，以确定较短的心电图记录能否像24小时记录一样有效地预测急性心肌梗死后的长期死亡率。
在急性心肌梗死后的前2周记录的24小时心电图以及完整记录中单独的1小时部分中评估心率变异性。对完整的24小时记录进行频谱分析，并使用心率变异性的不同短期和长期成分来区分有和没有后期并发症的患者。
将20例最初在急性心肌梗死中存活但在6个月随访期间后来发生严重事件（死亡或症状性持续性室性心动过速）的患者（第一组）与20例出院后6个月以上无并发症且在年龄、性别、梗死部位、射血分数和β受体阻滞剂治疗方面与第一组匹配的患者（第二组）进行比较。
基于限于小于或等于1小时期间内心率变化的成分进行的区分与使用限于小于或等于10小时期间变化的成分时一样显著（配对t检验，p<0.001）。然而，完整24小时记录中单独1小时部分的心率变异性仅在一天中的某些1小时间隔内两组之间存在显著差异（p值从0.2到0.0005不等）。
虽然短期心率变异性的最大值足以对心肌梗死后的高危患者进行分层，但任意选择的短期心电图记录不太可能记录到最大心率变异性。得出的结论是，从任意1小时心电图记录评估的心率变异性在预后方面不如从24小时记录估计的变异性重要。
