Key result
The integration at 30 msec (A30) of the signal-averaged QRS complex correlated significantly with ejection fraction (r=0.73) and total creatine kinase release (r=-0.78, p<0.001) in RMI patients.
Why the study?
Does the initial portion of the signal-averaged QRS complex correlate with cardiac function and infarct size in patients with recent myocardial infarction?
Observational (n=70)
Does the initial portion of the signal-averaged QRS complex correlate with cardiac function and infarct size in patients with recent myocardial infarction?
The integration of the first 30 msec of the signal-averaged QRS complex (A30) may serve as an important predictor of ventricular dysfunction and infarct size in patients with recent myocardial infarction.
We analyzed signal-averaged electrocardiograms (ECG) obtained in 50 patients with recent myocardial infarction (RMI: 25 anterior and 25 inferior) and 20 normal subjects to determine the relationship between the initial portion of the signal-averaged QRS complex and cardiac function and infarct size. We examined (1) the root mean square voltage (RMS10-40, microV), (2) the integration (A10-40, microV.msec) at 10-msec intervals over the first 40 msec of the signal-averaged QRS complex, and (3) the intervals (T) of the magnitude of the signal-averaged ECG achieved at 10-microV intervals over the first 40 microV (T10-40, msec). The mean RMS10-40 (p < 0.01) and A10-40 (A10, p < 0.05; A20-40, p < 0.01) were significantly lower and the T10-40 (p < 0.01) was significantly longer in RMI patients than in normal subjects. The RMS10-40 (p < 0.01) and A10-40 (p < 0.05) were significantly lower and the T10-40 (T10.20, p < 0.01; T30.40, p < 0.05) was significantly longer in patients with anterior RMI patients than in patients with inferior RMI. The A30 was correlated with the ejection fraction and total creatine kinase (CK) release in all patients (r = 0.73, and -0.78, respectively, p < 0.001). These results suggest that the A30 may be an important predictor of ventricular dysfunction and infarct size in patients with RMI.
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Kobayashi et al. (1997) conducted an observational in Recent myocardial infarction (n=70). Signal-averaged electrocardiogram vs. Normal subjects was evaluated on Relationship between the initial portion of the signal-averaged QRS complex and cardiac function and infarct size (r = 0.73 (EF), r = -0.78 (CK), p=<0.001). The integration at 30 msec (A30) of the signal-averaged QRS complex correlated significantly with ejection fraction (r=0.73) and total creatine kinase release (r=-0.78, p<0.001) in RMI patients.
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