Clinical Values Of Chronotropic Incompetence During Treadmill Exercise Test In Patients With Coronary Heart Disease

Objective: To evaluate the clinical significance of chronotropic incompetence during Treadmill exercise test in patients with coronary heart disease(CHD).Methods: We investigated 147 patients who were suspected to CHD from October, 2003 to December, 2005 in our hospital. Exclusion criteria included heart valve disease, history of NYHA II-IV, history of coronary angiography , history of implanting pacemaker, invasive procedures, cardiac surgery, pre-excitation syndrome, congenital heart disease and the use of digoxin. We did Treadmill exercise test (before test, the patients had stopped taking these drugs impacting automatic system for more than three days) and coronary angiography (CAG). According to the results of CAG , all these patients were divided into control Group (n= 83) and CHD Group (n=64), the latter being subdivided into single-vessel disease group (n=35), double-vessel disease group (n=14) and triple-vessel disease group (n=7). Then, we analyzed and compared the ability of heart rate response (HRR) between the control group and CHD group and among each group of CHD. Two indexes were considered: failing to achieve 85% of the maximal age-predicted heart rate(HR), and low chronotropic response index (CRI<0.8). We used the way of Variance Analysis to compare the average among each group, Grouped t-test to compare the average between two group, Chi-square test to compare the Categorical data and linear regression to compare the average between...