Clinical implications of early ST-segment variability. A report from the ASSENT 2 ST-monitoring sub-study.
OBJECTIVE
Evolution of the ST-segment during acute myocardial infarction has been shown to yield more information on prognosis than invasive measurements. By continuous ST-monitoring even very occasional dynamic changes can be analysed. We have recently suggested these variations to be of prognostic importance and possibly reflect individual abilities to deal with a vascular event. We wanted to confirm these findings.


METHODS
Four hundred and forty-eight patients were included in the vectorcardiographic sub-study of the second Assessment of Safety and Efficacy of a New Thrombolytic (ASSENT 2) trial. Patients underwent 24 h of ST-monitoring. ST-trend curves were blindly analysed by two independent observers.


RESULTS
ST-variability, defined as an increase of the ST-segment shift of > or = 25 microV for 2 min or more, was found to predict death, reinfarction at 30 days or urgent revascularization. By combining variability with resolution of the ST-segment elevation we could identify a high-risk group with 9.9%, and a low-risk group with only 0.8% 30-day mortality. Hypertensive patients, suggested to have an impaired secretion of endogenous t-PA, expressed significantly more ST-variability, possibly a non-invasive marker of impaired capability of dissolving and preventing thrombi.


CONCLUSIONS
Small variations in ST-segment shift during the first 4 h of acute myocardial infarction predict worse outcome.
Johanson
P
P
Clinical Experimental Research Laboratory, Sahlgrenska University Hospital/Ostra, Göteborg, Sweden. pj@hjl.gu.se
Svensson
A M
AM
Dellborg
M
M
D000368:Aged; D000465:Algorithms; D002940:Circadian Rhythm; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D009203:Myocardial Infarction / Q000401:mortality / Q000503:physiopathology*; D012008:Recurrence