Relation between exercise-induced ventricular arrhythmias and myocardial perfusion abnormalities in patients with intermediate pretest probability ofcoronary artery disease

The significance of exercise-induced ventricular arrhythmias (VAs) is large ly dependent on the clinical characteristics of the studied population. The relation between exercise-induced VAs and myocardial perfusion abnormaliti es has not yet been evaluated in a homogeneous patient population with inte rmediate probability of coronary artery disease (CAD), We studied 302 patie nts (mean age 54+/-9 years, 152 men and 150 women) with intermediate pretes t probability of CAD (range=0.25-0.80, mean=0.43+/-0.20) by upright bicycle exercise stress test in conjunction with technetium-99m single-photon emis sion tomography (SPET) imaging. Exercise-induced VAs (frequent or complex p remature ventricular contractions or ventricular tachycardia) occurred in 6 5 patients (22%). No significant difference was found between patients with and patient without VAs regarding the pretest probability of CAD (0.45+/-0 .21 vs 0.43+/-0.20). Patients with exercise-induced VAs had a higher preval ence of perfusion abnormalities (52% vs 26%, P=0.002) and ischaemic electro cardiographic changes (31% vs 16%, P<0.05) compared to patients without VAs . A higher prevalence of perfusion abnormalities in patients with VAs was o bserved in both men (67% vs 35%, P<0.01) and women (38% vs 16%, P<0.05). Ho wever, the positive predictive value of exercise-induced VAs for the presen ce of myocardial perfusion abnormalities was higher in men than in women (6 7% vs 38%, P<0.05). The presence of abnormal myocardial perfusion was the o nly independent predictor of exercise-induced VAs (OR 2.2; 95% CI, 1.2-4.2) by multivariate analysis of clinical and stress test variables. It is conc luded that in patients with intermediate pretest probability of CAD, exerci se-induced VAs are predictive of a higher prevalence of myocardial perfusio n abnormalities in both men and women. However, the positive predictive val ue of exercise-induced VAs for perfusion abnormalities is higher in men. Be cause of the underestimation of ischaemia by electrocardiographic changes, exercise-induced VAs should be interpreted as a marker of a higher probabil ity of CAD.