On-line vectorcardiography in ischemic heart disease

ON-LINE VECTORCARDIOGRAPHY IN ISCHEMIC HEART DISEASEPeter Lundin, KAROLINSKA INSTITUTET, DANDERYD HOSPITAL, Division of IntemalMedicine, S-182 88, Danderyd, Sweden The clinical usefulness of continuous on-line vectorcardiography (VCG) was assessed in 435patients, admitted to the coronary care unit. The ability of 24-hour VCG monitoring todifferentiate patients with or without ischemic heart disease (IHD), to provide long-temmprognostic information and to predict results from a predischarge exercise test in patients withunstable angina pectoris or acute myocardial infarction (MI) was evaluated. Findings fromdobutamine stress echocardiography during simultaneous VCG monitoring and the inter- andintra-observer variations of 24-hour VCG measurements were also evaluated. Patients with low probability of IHD (n=15) had significantly lower QRS-VD end values andfewer transient VCG changes (QRS-VD, ST-VM and STC-VM episodes) than patients withIHD. Patients with unstable angina pectoris (n=15) had a higher number of transient VCGchanges but lower QRS-VD end values than patients with acute MI (n=31). In 100 patients with unstable angina pectoris, followed for 343±77 days, 7 died from cardiaccauses and 8 suffered a non-fatal MI. Univariate predictors of cardiac death or non-fatal MIincluded higher age, rest pain during hospitalization, diabetes mellitus and high incidence oftransient VCG changes. Multivariate analysis showed that high incidence of STC-VM episodes(p