SEGMENTAL WALL-MOTION ABNORMALITIES ALTER VULNERABILITY TO VENTRICULAR ECTOPIC BEATS ASSOCIATED WITH ACUTE INCREASES IN AORTIC PRESSURE IN PATIENTS WITH UNDERLYING CORONARY-ARTERY DISEASE

Objective-To evaluate whether patients with coronary artery disease ar e susceptible to pressure related ventricular arrhythmias, and if so t o identify possible risk factors. Design-Interventional study. Methods -Metaraminol was given to 43 patients undergoing coronary arteriograph y for ischaemic heart disease to increase their aortic pressure, provi ded their systolic blood pressure was < 160 mm Hg and they mere in sin us rhythm, without any ventricular ectopic activity (or with fewer tha n six ventricular ectopic beats a minute) during a five minute control period. Results-During the metaraminol infusion, systolic aortic pres sure rose from 131 (15) to 199 (12) mm Hg (mean (SD)). Ventricular ect opy appeared (or ventricular ectopic beats increased by > 100%) in 13/ 43 patients. Ventricular ectopy was not related to age, sex, presence of hypertension, history of myocardial infarction, use of beta blocker s, positive exercise test, number of vessels diseased, or heart rate c hange during metaraminol infusion. There was a strong relation between the appearance of ventricular arrhythmia and segmental wall motion ab normalities: 1/19 (5.3%, 95% confidence interval 0.1% to 26.0%) withou t abnormality; 2/12 (16.7%, 2.1% to 48.4%) with hypokinesia; and 10/12 (83.3%, 51.6% to 97.1%) with akinesia or dyskinesia, chi(2) = 22.7, p < 0.001). Ejection fraction was also a significant but not independen t risk factor. Conclusions-Patients with segmental wall motion abnorma lities are predisposed to ventricular ectopic beats during an increase in systolic aortic pressure. This could be explained by associated el ectrophysiological inhomogeneity. The presence of mechanical inhomogen eity, as may occur in postinfarction akinesia or dyskinesia, may affec t the aortic pressure above which ventricular arrhythmias appear.