Increased nocturnal heart rate and wave reflection are early markers of cardiovascular disease in Williams-Beurensyndrome children.

J Hypertens. 2015 Apr;33(4):804-9. doi: 10.1097/HJH.0000000000000454.

Increased nocturnal heart rate and wave reflection are early markers of  cardiovascular disease in Williams-Beurensyndrome children.

Maloberti A1Cesana FHametner BDozio DVilla PHulpke-Wette MSchwarz ASelicorni AWassertheurer SMancia GGiannattasio C.

Comment: Systemic hypertension develops in as many as 50% of adults with Williams syndrome (7q11.23 deletion).  It is generally perceived that hemizygous deletion of elastin results in abnormal structure and vascular function of the distal arteries, but the exact mechanisms are not defined.  Using an ambulatory heart rate and blood pressure monitoring system, Maloberti and colleagues have compared vascular function parameters between 19 patients with Williams syndrome (13±4 years) and 23 control patients (10±4 years).  Cases and controls were matched for age, sex, height, weight, and blood pressure.  The significant findings in this study were that patients with Williams syndrome had higher night time augmentation index and reflection magnitude than controls, indicating higher arterial resistance.  The patients with Williams syndrome also had higher night time heart rate than controls and less oscillation in heart rate over 24 hours, suggesting that autonomic function may be altered in Williams syndrome.  These observations provide further insight into the physiological mechanisms of hypertension in patients with Williams syndrome.  Increased peripheral arterial resistance may be related to higher arterial wall stiffness due to elastin deficiency, but autonomic dysregulation may also contribute to risk for hypertension.  The ambulatory parameters used in this study may be useful to detect vascular dysfunction at a young age.