Impaired circadian rhythm of blood pressure in normotensive patients with rheumatic mitral valve stenosis

Abstract

The aim of the present cross-sectional study was to evaluate either non-dipper-type or dipper-type circadian rhythm of blood pressure (BP) in normotensive rheumatic mitral stenosis (MS) patients. Eighty-eight normotensive rheumatic mitral valve disease (RMVD) patients and 41 normal participants were enrolled in the study. All participants underwent ambulatory blood pressure monitoring. Nocturnal BP dipping was calculated as follows: (awake BP-asleep BP)×100/awake BP. Patients with a nocturnal reduction in average daytime systolic BP and diastolic BP of less than 10% were classified as nondippers. Patients with RMVD were divided into two groups with respect to the top and bottom 1.5 cm of the mitral valve area (MVA). There was a highly significant relationship between the two groups with control in the frequency of a nondipping status (χ=22.721; d.f.=2; P<0.001). Afterwards, the Mann-Whitney U-test was used to compare the two groups and the control group. There was no difference in the frequency of nondipping between patients with an MVA of greater than 1.5 cm and the control group (P>0.05). However, the nondipping level was higher in patients with an MVA of less than 1.5 cm than in the control group and in patients with RMVD with an MVA of greater than 1.5 cm (P<0.001 and <0.001, respectively). The circadian BP rhythm is impaired and the incidence of nondipping BP is higher in patients with MS than in normal patients. Moreover, we believe that autonomic nervous system dysfunction in patients with MS may be detected efficiently using ambulatory blood pressure monitoring.