The clinical significance of exercise-induced left ventricular wall motion abnormality occurring at a low heart rate.

Abstract We studied the relationship between the heart rate at the time of onset of exercise-induced wall motion abnormality and the severity of coronary artery disease in 89 patients who underwent exercise oquilibrium radionuclide ventriculography as part of their svaluation for coronary artery disease. Segmental wall motion was scored with a five-point system (3 = normal; −1 = dyskinesis); a decrease of one score defined the onset of wall motion abnormality. The onset of wall motion abnormality at ≤70% of maximal predicted heart rate had 100% predictive accuracy for coronary artery disease and higher sensitivity than the onset of ischemic ST segment depression at similar heart rate during exercise: 36% (25 of 69 patients with coronary disease) vs 19% (13 of 69 pationts), p = 0.01. Wall motion abnormality occurring at ≤70% of maximal predicted heart rate was present in 49% of patients (23 of 47) with critical stenosis (≥90% luminal diameter narrowing), and in only 5% of patients (2 of 42) without such severe stenosis, p p p