Heart Rate Recovery in Coronary Artery Disease and the Changes of Exercise Parameters after Coronary Stenting

ABSTRACT

BACKGROUND AND OBJECTIVES: The recovery of the normal heart rate immediately after exercise is a function of vagal reactivation. An attenuated heart rate recovery during the first minute after graded exercise is believed to be a marker of reduced parasympathetic activity and has been proven to be an independent predictor of overall mortality. However, the clinical significance of an abnormal heart rate recovery in coronary artery disease and the changes in the exercise parameters after coronary stenting have not been fully evaluated. Subjects and Methods: The study population included 53 patients with a significant coronary artery stenosis and 25 subjects with a normal coronary artery. All underwent a treadmill exercise test prior to coronary angiography. The differences in the heart rate recovery and the Duke treadmill score between two groups were investigated. After coronary stenting, changes in the exercise parameters were evaluated during the follow-up treadmill exercise test in 22 coronary artery disease patients. RESULTS: The frequencies of abnormal heart rate recovery (12% vs 38.3%, p=0.014) and a moderate to high risk Duke treadmill score (4% vs 21.3%, p=0.034) were significantly higher in the coronary artery disease group. The frequencies of these parameters were also significantly higher in the multivessel disease group than the single vessel disease group. After coronary stenting, most of the exercise parameters showed no significant changes but the Duke treadmill score improved significantly (p=0.038). CONCLUSION: The frequency of abnormal heart rate recovery was significantly higher in the coronary artery disease group. The Duke treadmill score was significantly improved and is thought to be a useful follow up parameter after coronary stenting.