Abnormal heart rate turbulence onset did not significantly predict cardiac events in patients with hypertrophic cardiomyopathy (RR 0.46), whereas abnormal HRT slope remained a significant predictor in patients with myocardial infarction (RR 5.65).
Cohort (n=204)
No
Does abnormal heart rate turbulence (HRT) predict cardiac events in patients with hypertrophic cardiomyopathy compared to those with myocardial infarction?
Heart rate turbulence is a significant predictor of cardiac events in patients with myocardial infarction but remains normal and lacks prognostic value in patients with hypertrophic cardiomyopathy.
Relative Risk: 0.46 (95% CI 0.055–3.86)
p-value: p=0.48
Short-term fluctuations in sinus cycle length after a single ventricular premature complex (VPC) have attracted considerable interest and has been termed heart rate turbulence (HRT). The onset and slope of HRT have each been reported to be independent and powerful predictors of clinical prognosis in patients with myocardial infarction (MI), but there are no data available for patients with hypertrophic cardiomyopathy (HCM). Thus the present study analyzed the 2 HRT variables to determine their prognostic value in HCM patients. Holter monitoring data were obtained from 104 HCM patients, 44 MI patients and 56 normal controls, from which singular VPCs followed by >or=20 normal sinus beats were isolated and the HRT onset and slope were automatically calculated. HRT onset and slope were abnormal in MI patients, but not in HCM patients, as compared with normal control subjects (onset -1.1+/-2.9, -2.1+/-3.4, -1.4+/-5.1%; slope 10.6 +/-8.6, 18.0+/-13.9, 16.6+/-9.7 ms/beat, respectively). During the follow-up period of 27+/-10 months, 7 HCM patients and 10 MI patients either died from cardiac death or were hospitalized for congestive heart failure. In MI patients, HRT onset was higher and the HRT slope was lower in patients with cardiac events than in patients without (onset 1.1+/-2.7 vs -1.7+/-2.7%, p=0.011; slope 5.7+/-4.3 vs 12.0+/-9.0 ms/beat, p=0.028). In HCM patients, however, the HRT onset and slope were similar between patients with and without cardiac events (onset -2.0+/-2.0 vs -2.1 +/-3.5%, p=0.98; slope 18.1+/-10.9 vs 18.0+/-14.0 ms/beat, p=0.68). In conclusion, unlike MI patients, the HRT variables in selected HCM patients were not abnormal and failed to predict the clinical prognosis.
Kawasaki et al. (Wed,) conducted a cohort in Hypertrophic Cardiomyopathy and Myocardial Infarction (n=204). Abnormal heart rate turbulence (HRT) vs. Normal heart rate turbulence was evaluated on Cardiac events (cardiac death or heart failure) in HCM patients with abnormal HRT onset (RR 0.46, 95% CI 0.055-3.86, p=0.48). Abnormal heart rate turbulence onset did not significantly predict cardiac events in patients with hypertrophic cardiomyopathy (RR 0.46), whereas abnormal HRT slope remained a significant predictor in patients with myocardial infarction (RR 5.65).