Article date: June 2013
By: Agnieszka Katarzynska‐Szymanska, Romuald Ochotny, Zofia Oko‐Sarnowska, Hanna Wachowiak‐Baszynska, Tomasz Krauze, Jaroslaw Piskorski, Adrian Gwizdala, Przemyslaw Mitkowski, Przemyslaw Guzik, in Volume 75, Issue 6, pages 1516-1524
Aims
Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and impaired diastolic and systolic function. Abnormal sympathetic–parasympathetic balance is a potential stimulus for left ventricular hypertrophy in HCM patients. β‐Blockers are routinely used in HCM for their strong negative inotropic effect; however, these drugs also influence the sympathetic–parasympathetic balance. This study aimed to determine the autonomic control of the cardiovascular system and the autonomic effects of β‐blockers in HCM patients treated or untreated with β‐blockers.
Methods
Among 51 HCM outpatients (18–70 years old; 29 men) there were 19 individuals with no medication and 32 subjects treated with a β‐blocker. Fourteen age‐ and gender‐matched (23–70 years old; nine men) healthy volunteers were enrolled in the control group. Continuous, non‐invasive finger blood pressure was recorded during supine rest for 30 min. Autonomic regulation of the cardiovascular system was measured by heart rate variability and spontaneous baroreflex function (cross‐correlation sequence method).
Results
The mean pulse interval, time domain and spectral measures of heart rate variability and baroreflex sensitivity were comparable between HCM patients, treated or not with β‐blockers, and the control group. However, the delay of the baroreflex was significantly longer in HCM patients who were not treated with β‐blockers [2.0 (1.6–2.3) s] in comparison with HCM patients receiving β‐blockers [1.4 (1.1–1.8) s; P = 0.0072] or control subjects [1.2 (0.8–1.8) s; P = 0.0025]. This delay did not differ between HCM patients treated with β‐blockers and the control group.
Conclusions
Hypertrophic cardiomyopathy not treated with β‐blockers is accompanied by prolonged baroreflex delay. The use of β‐blockers normalizes this delay.
DOI: 10.1111/bcp.12027
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