Temporal variations in microvolt T-wave alternans testing after acute myocardial infarction
Mário Martins Oliveira1, António Fiarresga, Nuno Pelicano
1Cardiology Department, Santa Marta Hospital, Lisbon, Portugal. mmoliveira@clix.pt
Summary
Microvolt T-wave alternans (TWA) measurements frequently change in the first six months after acute myocardial infarction (AMI). These temporal variations in TWA are important for risk stratification after AMI.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Microvolt T-wave alternans (TWA) is established for assessing ventricular tachyarrhythmia risk.
- Prospective data on TWA temporal variations post-acute myocardial infarction (AMI) is limited.
Purpose of the Study:
- To analyze temporal patterns of TWA measurements in patients following AMI.
- To investigate TWA changes within the first six months post-AMI.
Main Methods:
- 51 post-AMI patients underwent TWA testing early (<1 month) and late (6 months) after percutaneous coronary intervention (PCI).
- TWA was measured using a treadmill exercise protocol.
- Patients were categorized based on TWA results (negative, positive, indeterminate) and test concordance.
Main Results:
- TWA abnormality rates increased from 25.4% early to 41.1% late post-AMI.
- 19.6% of patients shifted from TWA-negative to TWA-abnormal, and 7.8% from TWA-abnormal to TWA-negative.
- 45% of patients had at least one abnormal TWA test; abnormal TWA late correlated with reduced left ventricular ejection fraction.
Conclusions:
- Temporal changes in TWA are common in the first six months post-AMI.
- These dynamic TWA patterns necessitate consideration in post-AMI risk stratification strategies.
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