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Relation between the initial portion of the signal-averaged QRS complex and cardiac function and infarct size in
N Kobayashi1, S Horinaka, A Machiyama
1Department of Medicine, Dokkyo University School of Medicine, Tochigi, Japan.
Insights
Signal-averaged electrocardiograms (ECG) reveal altered QRS complex parameters in recent myocardial infarction (RMI) patients. The integration (A30) of the signal-averaged QRS complex shows promise as a predictor of cardiac dysfunction and infarct size.
Area of Science:
- Cardiology
- Biomedical Engineering
- Signal Processing
Background:
- Recent myocardial infarction (RMI) can lead to significant cardiac dysfunction and altered ventricular electrical activity.
- Signal-averaged electrocardiograms (ECG) provide detailed information about the terminal QRS complex, reflecting myocardial electrical properties.
- Identifying reliable predictors of ventricular dysfunction and infarct size is crucial for patient management after RMI.
Purpose of the Study:
- To investigate the relationship between specific parameters of the initial portion of the signal-averaged QRS complex and cardiac function and infarct size in patients with RMI.
- To compare these parameters between patients with anterior and inferior RMI and normal subjects.
- To assess the predictive value of signal-averaged ECG parameters for ventricular dysfunction and infarct size.
Main Methods:
- Analysis of signal-averaged ECGs in 50 RMI patients (25 anterior, 25 inferior) and 20 normal subjects.
- Measurement of root mean square voltage (RMS10-40), integration (A10-40), and interval (T10-40) of the signal-averaged QRS complex.
- Correlation analysis between signal-averaged ECG parameters, ejection fraction, and total creatine kinase (CK) release.
Main Results:
- RMI patients exhibited significantly lower RMS10-40 and A10-40, and longer T10-40 compared to normal subjects (p < 0.01).
- Anterior RMI patients showed significantly lower RMS10-40 and A10-40, and longer T10-40 compared to inferior RMI patients (p < 0.05).
- The integration parameter A30 demonstrated a significant correlation with ejection fraction (r = 0.73) and total CK release (r = -0.78, p < 0.001).
Conclusions:
- Specific parameters of the signal-averaged QRS complex are significantly altered in patients with RMI.
- These alterations differ between anterior and inferior RMI.
- The integration parameter A30 shows potential as a valuable predictor of ventricular dysfunction and infarct size in RMI patients.
Abstract:
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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