title: Multi-scale heart rate dynamics detected by phase-rectified signal averaging predicts mortality after acute myocardial infarction.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Center for Medical Education Research and Development,  Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya 467-8601,  Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Kisohara
authors.forename: Phyllis K
authors.initials: PK
authors.lastname: Stein
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Mari
authors.initials: M
authors.lastname: Suzuki
authors.forename: Narushi
authors.initials: N
authors.lastname: Iizuka
authors.forename: Robert M
authors.initials: RM
authors.lastname: Carney
authors.forename: Lana L
authors.initials: LL
authors.lastname: Watkins
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Freedland
authors.forename: James A
authors.initials: JA
authors.lastname: Blumenthal
authors.forename: Junichiro
authors.initials: J
authors.lastname: Hayano
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors