ASSOCIATION OF VENTRICULAR ECTOPY WITH NUCLEAR SCINTIGRAPHIC PERFUSION DEFECTS DURING DIPYRIDAMOLE STRESS-TESTING

Background and hypothesis: No information is available regarding the s ignificance of ventricular ectopic activity induced during dipyridamol e nuclear scintigraphic stress testing. This study tested the hypothes is that dipyridamole-induced ventricular ectopy predicts a thallium-20 1 or technetium-99m sestamibi perfusion defect. Methods: A group of 18 6 consecutive patients with premature ventricular contractions and/or couplets occurring juring dipyridamole stress testing (ventricular tac hycardia did not occur) was compared with a control group of 194 patie nts without ventricular ectopy during dipyridamole stress testing. Res ults: The results indicated that ventricular ectopy induced during dip yridamole infusion occurred more frequently in patients demonstrating either a fixed or reversible perfusion defect on scintigraphic imaging (p < 0.01). The higher frequency of perfusion defects in this group o f patients was attributable to a higher frequency of ''fixed'' compare d with ''reversible'' defects (p < 0.05). This finding is consistent w ith the additional observation that ventricular ectopy induced by dipy ridamole was associated with the presence of Q waves on the resting EC G (p < 0.05). The positive and negative predictive values of the prese nce of ventricular ectopy in predicting a fixed myocardial perfusion d efect were 59 and 54%, respectively. Conclusions: Ventricular ectopy i nduced during dipyridamole infusion suggests the presence of a fu;ed m yocardial perfusion defect.