Electrocardiographic measurement of infarct size after thrombolytic therapy.
OBJECTIVE
We examined the utility of the 32-point QRS score from the 12-lead electrocardiogram (ECG) for measurement of the ischemic risk region and infarct size in patients receiving thrombolytic therapy.


BACKGROUND
The QRS score offers a means of evaluating the therapeutic benefit of thrombolytic therapy by comparing final infarct size with the initial extent of ischemic myocardium.


METHODS
The study included 38 patients (34 men, 4 women; mean [+/-SD] age 54 +/- 10 years) with a first infarction (18 anterior, 20 inferior). The maximal potential QRS score (QRS0) was assigned to all leads with >/= 100-microV ST elevation on the initial ECG. The QRS scores were calculated at 7 and 30 days after infarction. Left ventricular ejection fraction was measured by radionuclide ventriculography at 1 month. Twenty-eight patients had thallium (Tl)-201 and technetium (Tc)-99m pyrophosphate tomographic measurement of the ischemic region and infarct size.


RESULTS
The QRS0 was 10.3 +/- 3.1 (mean +/- SD) for anterior and 10.4 +/- 3.5 for inferior infarcts. The QRS scores were similar at 7 and 30 days for both anterior (5.6 +/- 3.4 vs. 5.5 +/- 3.4) and inferior infarcts (3.7 +/- 2.6 vs. 2.9 +/- 2.2). The day 7 QRS score and ejection fraction at 1 month were inversely correlated (r = -0.74, p < 0.01). The Tl-201 perfusion defect was 34 +/- 11% of the left ventricle for anterior and 32 +/- 7% for inferior infarcts. Subsequent Tc-99m pyrophosphate infarct size was 15 +/- 9% of the left ventricle for anterior and 17 +/- 9% for inferior infarcts. The QRS0 was correlated with the extent of the Tl-201 perfusion defect (r = 0.79, p < 0.001), and the day 7 QRS score was correlated with Tc-99m pyrophosphate infarct size (r = 0.79, p < 0.005).


CONCLUSIONS
The 32-point QRS score can provide useful immediate measurements of the ischemic risk region and subsequent infarct size.
Juergens
C P
CP
Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia.
Fernandes
C
C
Hasche
E T
ET
Meikle
S
S
Bautovich
G
G
Currie
C A
CA
Freedman
S B
SB
Jeremy
R W
RW
D000368:Aged; D016903:Drug Monitoring; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000188:drug therapy*; D011379:Prognosis; D011446:Prospective Studies; D015635:Radionuclide Ventriculography; D015203:Reproducibility of Results; D012307:Risk Factors; D012720:Severity of Illness Index; D013318:Stroke Volume; D015912:Thrombolytic Therapy; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon