Turbulence slope after atrial premature complexes is an independent predictor of mortality in survivors of acute myocardial infarction.
BACKGROUND
Heart rate turbulence is a potent postinfarction risk predictor that originally was investigated when it was triggered by ventricular premature complexes. Similar heart rate response is present after atrial premature complexes. "Atrial" turbulence slope (TSA) moderately correlates with "ventricular" turbulence slope (TSV). This study investigated the value of TSA assessed in 24-hour Holter recordings for postinfarction risk stratification.


RESULTS
Predictive power of TSA was investigated in the placebo arm of the European Myocardial Infarction Amiodarone Trial, which enrolled patients surviving acute myocardial infarction with left ventricular ejection fraction (LVEF) < or =40%. Of 633 patients with available 24-hour Holter recordings, 87 died during the follow-up period of 662 +/- 105 days. The same methodology was used to calculate TSA and TSV. TSA was significantly lower in nonsurvivors compared to survivors (2.0 +/- 2.7 vs 3.0 +/- 3.3 msec/RR, P = 0.014). TSA< or =0.8 msec/RR was associated with relative risk all-cause mortality of 2.5 (95% confidence interval 1.6-3.9, P = 0.000046). In a multivariate Cox regression model including age, LVEF, QRS duration, mean RR interval, heart rate variability index, presence of nonsustained ventricular tachycardia, and TSV, TSA remained a significant predictor of total mortality with relative risk of 2.0 (95% confidence interval 1.2-3.4, P = 0.014).


CONCLUSIONS
TSA is a significant and independent predictor of all-cause mortality in postinfarction patients with left ventricular dysfunction.
Wichterle
Dan
D
Department of Cardiac and Vascular Sciences, St. George's Hospital Medical School, London, United Kingdom. wichterle@hotmail.com
Camm
A John
AJ
Malik
Marek
M
D000368:Aged; D018880:Atrial Premature Complexes / Q000503:physiopathology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis