Consideration of the total ST-segment deviation on the initial electrocardiogram for predicting final acute posterior myocardial infarct size in patients with maximum ST-segment deviation as depression in leads V1 through V3. A FRISC II substudy.
BACKGROUND
Because patients with acute left circumflex occlusion are typically characterized primarily on the standard 12-lead electrocardiogram (ECG) by ST depression, they do not qualify to receive reperfusion therapy. Documentation of a relationship between the quantities of acute ST change and final QRS estimated acute myocardial infarction (AMI) size could form the basis for clinical trials to determine the value of reperfusion therapy.


METHODS
The Fragmin and Fast Revascularization during Instability in Coronary artery disease trial included 3214 patients with unstable coronary artery disease. Two percent of the patients (n = 69) had maximum ST-segment depression in leads V 1 through V 3 and were selected for this study. Initial ECG changes were compared to final myocardial infarction size, using the Selvester QRS score as the end point.


RESULTS
The quantity of initial ST-segment deviation correlated with the final AMI size (r = 0.43, P < .0005). The formula 3[0.22 (SigmaST downward arrow + SigmaST upward arrow) -0.02], where downward arrow indicates depression and upward arrow elevation, derived from measurements on the initial ECG, predicted the size of the AMI in percentage of the left ventricle as estimated on the final ECG. The study population had a large proportion of AMI (73%) indicated to be in or adjacent to the posterior left ventricular wall.


CONCLUSIONS
The quantitative initial ST-segment deviation correlates linearly to the final AMI size in patients with maximum ST-segment depression in leads V 1 through V 3. The formula derived could be valuable for selecting patients who fail to meet strict ST-elevation AMI criteria for emergency intravenous or intracoronary reperfusion therapy.
Division of Cardiology, Duke University Medical Center, Durham, NC 27705, USA.
Rasmus S
RS
Ripa
Lene
L
Holmvang
Charles
C
Maynard
Maria
M
Sejersten
Peter
P
Clemmensen
Peer
P
Grande
Bertil
B
Lindahl
Bo
B
Lagerqvist
Lars
L
Wallentin
Galen S
GS
Wagner
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000627:therapeutic use; D003327:Coronary Disease / Q000503:physiopathology; D017985:Dalteparin / Q000627:therapeutic use; D004562:Electrocardiography / Q000145:classification* / Q000295:instrumentation / Q000379:methods; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D005500:Follow-Up Studies; D005544:Forecasting; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology* / Q000628:therapy; D015425:Myocardial Reperfusion; D010919:Placebos; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011446:Prospective Studies
D005343:Fibrinolytic Agents; D010919:Placebos; D010975:Platelet Aggregation Inhibitors; D001241:Aspirin; D017985:Dalteparin