Abstract 16928: Impact of Statin Therapy on Dynamic and Static Measures of Autonomic Tone in Patients with Hypertrophic Cardiomyopathy
Background: Heart rate turbulence (HRT) measures dynamic changes in the autonomic nervous system, while the Standard Deviation of NN intervals (SDNN) reflects resting autonomic tone. The pleiotropic effects of statins include altered vascular reactivity. The impact of statins on autonomic tone in patients with hypertrophic cardiomyopathy (HCM) has not been previously reported. Aims: To assess the effect of atorvastatin on temporal changes in HRT and SDNN.
Methods: The Statin Induced Regression of Cardiomyopathy Trial (SIRCAT) was a randomized comparison of atorvastatin 80 mg daily versus matching placebo in 22 patients with HCM. As previously reported, no significant difference in LV mass over 12 months was found with atorvastatin versus placebo treatment. Changes in HRT and SDNN were assessed in 21 (of 22; 95%) SIRCAT subjects with analyzable 24-hour ambulatory ECG (Holter) data. LV mass / scar was measured at baseline and after 6 and 12 months of therapy via late enhancement (LE) cardiac magnetic resonance (CMR) imaging. HRT and SDNN were assessed at these same time points using commercial Holters (SEER) and software (CardioDay). Holters data was assessed in duplicate, blinded to both randomization assignment and the CMR data.
Results: The average age of the 21 patients was 46 years, 30% were female, mean LV mass was 199 ± 81 g, and mean LE was 6.9 ± 10.0%. Mean HRT slope was 9.8 ± 8.1 ms/RR, and mean SDNN was 146 ± 41 ms at baseline. Ten patients were assigned to atorvastatin and 11 to placebo. LV mass and percentage scar were stable over time and not altered by atorvastatin therapy (p-values > 0.2). Patients assigned to atorvastatin had stable HRT and SDNN values, while patients receiving placebo had a significant decline in HRT slope (p = 0.03) and a trend towards a decline in SDNN (p = 0.1) over time. No temporal differences in heart rate (p = 0.8) or the frequency of premature ventricular complexes (p = 0.8) were observed with atorvastatin versus placebo therapy.
Conclusions: Atorvastatin therapy was significantly associated with normalization of HRT, a dynamic marker of autonomic tone, and a trend toward normalization of SDNN, a static measure of autonomic nervous system function. No significant relationship between atorvastatin therapy with LV mass or scar were observed.
- Heart rate/Heart rate variability
- Hypertrophic cardiomyopathy
- Magnetic resonance imaging
- Autonomic nervous system
- © 2012 by American Heart Association, Inc.