ISCHEMIA MONITORING WITH ONLINE VECTORCARDIOGRAPHY COMPARED WITH RESULTS FROM A PREDISCHARGE EXERCISE TEST IN PATIENTS WITH ACUTE ISCHEMIC-HEART-DISEASE
P. Lundin et al., ISCHEMIA MONITORING WITH ONLINE VECTORCARDIOGRAPHY COMPARED WITH RESULTS FROM A PREDISCHARGE EXERCISE TEST IN PATIENTS WITH ACUTE ISCHEMIC-HEART-DISEASE, Journal of electrocardiology, 28(4), 1995, pp. 277-285
Information from 24-hour monitoring with on-line vectorcardiography, s
tarting immediately after admission, was compared with results from a
predischarge exercise test 3-13 days after admission. A total of 169 p
atients with acute myocardial infarction and 73 patients with unstable
angina pectoris were investigated. Patients were followed for 487 +/-
135 days. During the follow-up period, 19 patients (8%) died from car
diac causes and 34 (14%) were hospitalized for a myocardial infarction
. The QRS vector difference (QRS-VD), ST change vector magnitude (STC-
VM), ST vector magnitude (ST-VM), and ST vector leads X, Y, Z were mon
itored. Patients with ST depression on the exercise test showed higher
occurrence of transient, supposedly ischemic, episodes of QRS-VD, STC
-VM, and ST-VM than patients without ST depression. The sensitivity an
d specificity of identifying patients with ST depression at the exerci
se test were respectively, 71 and 47% for QRS-VD episodes, 58 and 56%
for ST-VM episodes, and 55 and 65% for STC-VM episodes. The maximum ST
depression at the exercise test was related to the maximum ST depress
ion in vector lead X (r = .44, P < .001) the number of STC-VM (r = .40
, P < .001), ST-VM (r = .37, P < .001), and QRS-VD (r = .33, P < .001)
episodes on the VCG. In multivariate analysis, maximum ST depression
in vector lead X and STC-VM episodes were the best determinants for ST
depression at the exercise test. in a Cox regression model, the optim
al combination of exercise test data in patients who died from cardiac
causes exhibited a global chi-square value of 20.0. The combination o
f these data and the number of STC-VM episodes increased the global ch
i-square value to 30.6. This study indicates that in patients with acu
te ischemic heart disease, early continuous vectorcardiographic monito
ring may predict the results from a predischarge exercise test and als
o contributes independent prognostic information beyond that of exerci
se test data.