Key result
Acute myocardial infarction was associated with abnormal repolarization alternans outside the physiological region in 32.6% of patients, compared to 0% in healthy controls.
Why the study?
Can characterization of repolarization alternans (RA) heterogeneity using a heart-rate adaptive match filter method discriminate abnormal RA cases in AMI patients compared to healthy subjects?
Case-Control (n=94)
Can characterization of repolarization alternans (RA) heterogeneity using a heart-rate adaptive match filter method discriminate abnormal RA cases in AMI patients compared to healthy subjects?
Absolute Event Rate: 53.5% vs 74.5%
p-value: p=<0.05
Myocardial infarction is associated with abnormal repolarization alternans occurring early or late along the JT segment, or with abnormally high amplitude, which may help identify patients at risk for arrhythmic events.
Abnormal RA may aid arrhythmic risk assessment in AMI; cross-sectional data leave open prospective validation before clinical use.
An association between heterogeneity of repolarization alternans (RA) and cardiac electrical instability has been reported. Characterization of RA in health and identification of physiological RA heterogeneity may help discrimination of abnormal RA cases more likely associated to arrhythmic events. Thus, aim of the present study was the identification of a physiological RA region in terms of mean temporal location (MRAD) with respect to the T apex, and mean amplitude (MRAA), by application of our heart-rate adaptive match filter method to clinical ECG recordings from 51 control healthy (CH) subjects and 43 acute myocardial infarction (AMI) patients. Results indicate that RA occurring within the first half of the T wave is dominant in both CH and AMI populations (74.5% and 53.5% of cases, respectively; P<0.05). Definition of physiological RA region in the MRAD vs. MRAA plane (-83 ms ≤ MRAD ≤ 23 ms, 0≤ MRAA ≤ 30 μV) provided 0% and 32.6% abnormal RA cases among the CH subjects and AMI patients, respectively. We conclude that myocardial infarction may associate with an RA occurring early (MRAD<-83 ms) or late (MRAD >23 ms) along the JT segment, in addition or in alternative to an abnormally high RA amplitude (MRAA >30 μV).
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Burattini et al. (2011) conducted a case-control in Acute myocardial infarction (n=94). Acute myocardial infarction vs. Healthy controls was evaluated on Repolarization alternans occurring within the first half of the T wave (p=<0.05). Acute myocardial infarction was associated with abnormal repolarization alternans outside the physiological region in 32.6% of patients, compared to 0% in healthy controls.
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