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Abnormal heart rate response to exercise in vasospastic angina: pathophysiologic mechanism in the provocation of
Abstract:
To examine the alteration in control function of the heart, which may account for the pathophysiologic condition precipitating coronary arterial spasm, the dynamic property of heart rate response to exercise in vasospastic angina was evaluated by using our previously developed frequency analytic procedure. We studied 21 patients with vasospastic angina, divided into two groups (active angina and inactive angina) and 12 normal control subjects. When compared with the transfer function of the heart rate control system in normal control subjects, the transfer function in patients with active vasospastic angina showed moderately lower gain, especially in the middle frequency range, and significantly delayed phase angle over the whole frequency range, especially in the middle and high frequency ranges. These abnormalities were not observed in inactive vasospastic angina. The present exercise test to detect abnormal heart rate control can feasibly be used in the detection and management of vasospastic angina.