Objective: To investigate the relationship between the chronotropic incompetence and angiographic severity in patients with coronary artery disease (CAD).
Methods: Coronary angiography was performed in 130 patients suspected for CAD and angiographic severity of coronary artery was quantitated by Duke score and Gensini score. Patients were divided to 4 groups: non-CAD group (39 patients), CAD group with one coronary artery involved (CHD1 group, 30 patients), CHD group with two coronary arteries involved (CHD2 group, 31 patients) and CAD group with three coronary arteries involved (CHD3 group, 30 patients). One month before coronary angiography, symptom-limited exercise treadmill tests were made and the ratio of heart rate reserve (HRR) and the percent maximal age-predicted heart rate achieved (rHR) were measured.
Results: rHR and HRR were significantly lower in CHD2 group (rHR 0.79+/-0.08, HRR 0.63+/-0.11) and CHD3 (rHR 0.78+/-0.07, HRR 0.59+/-0.12) than that in non-CHD group (rHR 0.89+/-0.06, HRR 0.80+/-0.10) and CHD1 group (rHR 0.86+/-0.08, HRR 0.74+/-0.15, all P<0.05). rHR and HRR also significantly correlated with Duke score (r=-0.554, -0.578, all P<0.01) and Gennisi score (r=-0.453, -0.467, all P<0.01). CHD incidence rate was 75% in patients with positive rHR (or HRR) but without ST lowering during exercise.
Conclusion: Chronotropic incompetence are negatively related to angiographic coronary severities and thus predict angiographic coronary severities. There is a high CAD incidence in patients with positive rHR (or HRR) but no ST lowering during symptom-limited exercise treadmill tests.