Key result
Hypertrophic cardiomyopathy is linked to ~39% lower 24-hour HRV variance versus controls.
Why the study?
Do patients with hypertrophic cardiomyopathy without heart failure have altered cardiac autonomic function compared to healthy controls?
Case-Control (n=36)
Do patients with hypertrophic cardiomyopathy without heart failure have altered cardiac autonomic function compared to healthy controls?
Absolute Event Rate: 15000% vs 24720%
p-value: p=< 0.05
Patients with hypertrophic cardiomyopathy exhibit altered neural modulation of the heart, characterized by reduced 24-hour heart rate variability and blunted circadian rhythms, even in the absence of heart failure.
Suggests autonomic dysfunction in non-HF HCM; hypothesis-generating for prognostic or therapeutic roles of HRV.
Background: It has been hypothesized that an interaction between sympathetic nervous activity and an abnormal myocardium plays a role in the development and progression of hypertrophic cardiomyopathy (HCM). Methods: In the present study we investigated cardiac autonomic function by 24‐hour spectral analysis of heart rate variability (HRV) in 18 patients with HCM, without evidence of heart failure, and 18 controls of similar age. Results: We found a significant reduction of 24 hour variance in HCM patients relative to controls (15,000 ± 9480 ms2 vs 24,720 ± 12,450 ms2 respectively; p < 0.05). Moreover, a loss of the expected day‐night changes in the low frequency (LF) spectral component (expressed in normalized units), and LF/HF ratio (HF; high frequency component) were observed in HCM patients. Decreased day‐night changes in LF/HF ratio were previously reported in patients with mild hypertension, uncomplicated coronary disease, and after myocardial infarction, conditions in which it seems to exist a higher than normal sympathetic activity. No significant correlations were found between HRV indices and echocardiographic standard measures of systolic and diastolic function parameters. Conclusions: These data are consistent with the presence of an alteration in neural modulation of heart period in HCM patients, noninvasively detectable by continuous 24 hour HRV analysis.
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Guzzetti et al. (1996) conducted a case-control in Hypertrophic Cardiomyopathy (n=36). Hypertrophic cardiomyopathy vs. Controls of similar age was evaluated on 24-hour variance of heart rate variability (p=< 0.05). Hypertrophic cardiomyopathy was associated with a significant reduction in 24-hour heart rate variability variance compared to controls (15,000 vs 24,720 ms2; p < 0.05).
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