OS 37-04 EFFECTS OF WHITE COAT HYPERTENSION ON HEART RATE RECOVERY AND BLOOD PRESSURE RESPONSE DURING EXERCISE TESTING.

OBJECTIVE: Increased sympathetic activity is one of the proposed mechanisms underlying exaggerated blood pressure (BP) response to exercise (EBPR). Heart rate recovery (HRR) is a simple non-invasive measurement analyzing autonomic nervous dysfunction, and has been shown to predict cardiovascular disease mortality. We aimed to the association between HRR and EBPR in patients with hypertension according to the circadian pattern and white coat hypertension.

DESIGN AND METHOD: A total of 409 consecutive patients who simultaneously underwent Treadmill test and 24-hours ambulatory BP monitoring (ABPM) were included to this cross-sectional case-control study. Patients were classified according to the ABPM; 147 patients with hypertension with dipper pattern (dipper), 140 patients with hypertension with non-dipper pattern (non-dipper) and 71 normotensive controls. EBPR was defined as a peak exercise systolic BP ≥ 210 mmHg in men and ≥ 190 mmHg in women. HRR was defined as peak heart rate minus heart rate after a 1-minute recovery; abnormal HRR was defined as ≤ 12 beats/min. These parameters were compared with respect to occurrence of EBPR.

RESULTS: HRR values were significantly lower (p < 0.001) in subjects with white coat hypertension and both hypertensive groups when compared with normotensive subjects, especially in non-dipper. In patients with white coat hypertension, there was a significant negative correlation between the decrease in systolic BP during the recovery and degree of HRR (r = -0.292, p = 0.044). The percentages of blunted HRR and EBPR were significantly highest in patients with white coat hypertension (35.3% and 33.3%, respectively). In multivariate logistic regression analyses, HRR and resting systolic BP were the only determinants associated with the occurrence of EBPR.

CONCLUSIONS: Blunted HRR indicating impaired parasympathetic reactivation and higher prevalence of EBPR indicating increased sympathetic activation suggest that these autonomic dysfunctions could be the important future cardiovascular risk factors in subjects with white coat hypertension.