Statin restores cardiac autonomic response to acute hypoxia in hypercholesterolaemia.

BACKGROUND

Hypercholesterolaemia may alter cardiovascular autonomic function. We investigated the autonomic cardiovascular regulation during normoxia and hypoxia in familial isolated HC patients with or without statin treatment.

MATERIALS AND METHODS

Low (LF-RR) and high (HF-RR) components of spectral analysis of RR interval and systolic arterial pressure (LF-SAP) were obtained during 5 min of normoxia and isocapnic hypoxia (10% O(2) ) in 10 normotensive familial HC patients without medication, in seven HC patients after a 12-week treatment period with 40 mg of simvastatin (HC + SVT) and in eight matched normal volunteers (CO).

RESULTS

The HC patients had significant impairment of cardiac autonomic modulation parameters compared with CO at normoxia, which was maintained or even accentuated during hypoxia; these parameters included lower total variance of RR, increased normalized LF-RR, decreased normalized HF-RR, increased LF-RR/HF-RR ratio, higher LF-SAP component and reduced α index. However, the HC + SVT group had a significant improvement in all parameters: the LF-RR and LF-SAP decreased (indicating a decrease in cardiac and vascular sympathetic activity), the HF-RR increased (indicating an increase in parasympathetic activity) and the spontaneous baroreflex sensitivity improved. These changes were detected at normoxia and were maintained during hypoxia.

CONCLUSIONS

Our data are the first to show that isolated HC is characterized by an increase in cardiac and vasomotor sympathetic drive, a decrease in cardiac vagal modulation and baroreflex impairment during normoxia and hypoxia. In addition, our data suggest that statin treatment has a potential role in restoring the physiological cardiovascular autonomic control at baseline and during cardiovascular challenge.