Circulatory and Catecholamine Responses to Mental Stress Test in Subjects with Mitral Valve Prolapse

Abstract

Mitral valve prolapse (MYP) is frequently associated with multiple symptoms such as anxiety, palpitations and chest pain that may be related to an imbalance of autonomic tone. In this study, 10 asymptomatic subjects with and 11 subjects without MYP shown by echocardiography underwent the Stroop mental stress test. The resting heart rate of 68 ± 16/min increased to 76 ± 19/min in subjects without MVP during mental stress (p < 0.05), while in subjects with MVP the resting heart rate increased from 76 ± 14/min to 82 ± 13/min (p < 0.05). Resting systolic blood pressure of 109 ± 13 mm Hg in subjects without MVP increased to 122 ± 13 mm Hg during mental stress (p < 0.05). Subjects with MVP had a resting systolic blood pressure of 121 ± 12 mm Hg which increased to 137 ± 13 mm Hg (p < 0.05). The resting diastolic blood pressure of 69 ± 9 mm Hg increased to 76 ± 11 mm Hg (p < 0.05) in subjects with MVP during mental stress. Subjects with MVP increased the resting diastolic blood pressure to 89 ± 8 mm Hg from a resting level of 79 ± 8 mm Hg (p < 0.05). Subjects with MVP had significantly higher heart rates, systolic and diastolic blood pressure than the normal subjects before, during and after mental stress. The magnitude of these increases was similar in both groups. Epinephrine and norepinephrine levels in venous blood before, immediately after mental stress and 1,5, and 10 min after mental stress did not change significantly in either group. The data suggest a different autonomic tone in subjects with MVP without differences in the level of circulating catecholamines. This may reflect a difference in ß-receptors or parasympathetic activity in subjects with MVP.