Deceleration capacity of heart rate as a predictor of mortality after myocardial infarction: cohort study.
BACKGROUND
Decreased vagal activity after myocardial infarction results in reduced heart-rate variability and increased risk of death. To distinguish between vagal and sympathetic factors that affect heart-rate variability, we used a signal-processing algorithm to separately characterise deceleration and acceleration of heart rate. We postulated that diminished deceleration-related modulation of heart rate is an important prognostic marker. Our prospective hypotheses were that deceleration capacity is a better predictor of risk than left-ventricular ejection fraction (LVEF) and standard deviation of normal-to-normal intervals (SDNN).


METHODS
We quantified heart rate deceleration capacity by assessing 24-h Holter recordings from a post-infarction cohort in Munich (n=1455). We blindly validated the prognostic power of deceleration capacity in post-infarction populations in London, UK (n=656), and Oulu, Finland (n=600). We tested our hypotheses by assessment of the area under the receiver-operator characteristics curve (AUC).


RESULTS
During a median follow-up of 24 months, 70 people died in the Munich cohort and 66 in the London cohort. The Oulu cohort was followed-up for 38 months and 77 people died. In the London cohort, mean AUC of deceleration capacity was 0.80 (SD 0.03) compared with 0.67 (0.04) for LVEF and 0.69 (0.04) for SDNN. In the Oulu cohort, mean AUC of deceleration capacity was 0.74 (0.03) compared with 0.60 (0.04) for LVEF and 0.64 (0.03) for SDNN (p<0.0001 for all comparisons). Stratification by dichotomised deceleration capacity was especially powerful in patients with preserved LVEF (p<0.0001 in all cohorts).


CONCLUSIONS
Impaired heart rate deceleration capacity is a powerful predictor of mortality after myocardial infarction and is more accurate than LVEF and the conventional measures of heart-rate variability.
Bauer
Axel
A
Deutsches Herzzentrum München, Klinikum rechts der Isar, Technische Universität München, Germany.
Kantelhardt
Jan W
JW
Barthel
Petra
P
Schneider
Raphael
R
Mäkikallio
Timo
T
Ulm
Kurt
K
Hnatkova
Katerina
K
Schömig
Albert
A
Huikuri
Heikki
H
Bunde
Armin
A
Malik
Marek
M
Schmidt
Georg
G
D000368:Aged; D002316:Cardiotonic Agents / Q000627:therapeutic use; D015331:Cohort Studies; D003654:Deceleration; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000401:mortality*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors; D013318:Stroke Volume
D002316:Cardiotonic Agents