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Multi-scale heart rate dynamics detected by phase-rectified signal averaging predicts mortality after acute
Masaya Kisohara1, Phyllis K Stein, Yutaka Yoshida
1Center for Medical Education Research and Development, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
Insights
Reduced deceleration capacity (DC) in long-term heart rate dynamics predicts mortality after acute myocardial infarction (AMI). This finding is independent of short-term heart rate variability measures, offering new prognostic insights for AMI patients.
Area of Science:
- Cardiology
- Biomedical Engineering
- Data Science
Background:
- Short-term heart rate dynamics, specifically acceleration capacity (AC) and deceleration capacity (DC), are established predictors of mortality post-acute myocardial infarction (AMI).
- The prognostic value of these measures over longer, minute-order time scales remains less understood.
Purpose of the Study:
- To investigate whether AC and DC, calculated over minute-order time scales, possess independent predictive value for mortality in patients following AMI.
- To compare the predictive power of long-term AC and DC with conventional short-term measures.
Main Methods:
- Analysis of 24-hour Holter electrocardiograms from 708 post-AMI patients with up to 30 months of follow-up.
- Calculation of AC and DC using wavelet analysis across various time scales (1-500 seconds).
- Comparison of prognostic values using C statistics, including conventional short-term measures (AC(conv), DC(conv)).
Main Results:
- Both increased AC(conv) and decreased DC(conv) predicted mortality (C-statistic: 0.792 and 0.797).
- Long-term AC and DC showed peak predictive power around 30-60 second time scales (C-statistic: 0.783 and 0.796).
- Deceleration capacity at the 30-60 second scale was a significant independent predictor of mortality (P=0.028), outperforming AC at the same scale.
Conclusions:
- Decreased deceleration capacity (DC) over minute-order time scales is a robust predictor of post-AMI mortality.
- The prognostic value of long-term DC is independent of conventional short-term AC and DC measures.
- Minute-order heart rate dynamics offer valuable, independent prognostic information in post-AMI patients.
Aims:
Acceleration and deceleration capacity (AC and DC) for beat-to-beat short-term heart rate dynamics are powerful predictors of mortality after acute myocardial infarction (AMI). We examined if AC and DC for minute-order long-term heart rate dynamics also have independent predictive value.
Methods And Results:
We studied 24-hr Holter electrcardiograms in 708 post-AMI patients who were followed up for up to 30 months thereafter. Acceleration capacity and DC was calculated with the time scales of T (window size defining heart rate) and s (wavelet scale) from 1 to 500 s and compared their prognostic values with conventional measures (AC(conv) and DC(conv)) that were calculated with (T,s) = [1,2 (beat)]. During the follow-up, 47 patients died. Both increased AC(conv) and decreased DC(conv) predicted mortality (C statistic, 0.792 and 0.797). Concordantly, sharp peaks of C statistics were observed at (T,s) = [2,7 (sec)] for both increased AC and decreased DC (0.762 and 0.768), but there were larger peaks of C statistics at around [30,60 (sec)] for both (0.783 and 0.796). The C statistic was greater for DC than AC at (30,60) (P = 0.0012). Deceleration capacity at (30,60) was a significant predictor even after adjusted for AC(conv) (P = 0.020) and DC(conv) (P = 0.028), but the predictive power of AC at (30,60) was no longer significant.
Conclusion:
A decrease in DC for minute-order long-term heart rate dynamics is a strong predictor for post-AMI mortality and the predictive power is independent of AC(conv) and DC(conv) for beat-to-beat short-term heart rate dynamics.
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