From the Guidelines
Biphasic T waves are a significant electrocardiogram (ECG) abnormality that requires prompt cardiac evaluation, especially when associated with cardiac symptoms, as they may indicate myocardial ischemia or infarction, and are often seen in the early stages of myocardial infarction, particularly in the precordial leads V2-V4, representing Wellens' syndrome. This finding can be associated with critical stenosis of the left anterior descending coronary artery, and when identified, especially in the context of chest pain that has resolved, urgent cardiac evaluation is necessary as these patients are at high risk for anterior wall myocardial infarction 1. Other causes of biphasic T waves include electrolyte abnormalities (particularly hypokalemia), bundle branch blocks, ventricular hypertrophy, and the effects of certain medications. The underlying mechanism involves altered ventricular repolarization sequences.
Key Considerations
- Biphasic T waves can indicate myocardial ischemia, particularly when newly developed in a patient with cardiac symptoms.
- The presence of biphasic T waves in the precordial leads V2-V4 may represent Wellens' syndrome, a pattern associated with critical stenosis of the left anterior descending coronary artery.
- Any patient with new biphasic T waves should undergo prompt cardiac assessment including cardiac biomarkers, additional ECG monitoring, and consideration for coronary angiography, particularly if Wellens' pattern is present, as this may prevent progression to a full-thickness myocardial infarction.
- Electrolyte abnormalities, such as hypokalemia, should be considered as potential causes of biphasic T waves, and corrected if present.
- The T-wave amplitude and morphology can vary by age, gender, and race, and should be interpreted in the context of the individual patient's clinical presentation and ECG findings 1.
Clinical Implications
- Biphasic T waves are a significant ECG abnormality that requires prompt evaluation and management.
- The presence of biphasic T waves in the context of cardiac symptoms, such as chest pain, should prompt urgent cardiac evaluation, including cardiac biomarkers, ECG monitoring, and consideration for coronary angiography.
- The identification of biphasic T waves in asymptomatic patients should also prompt further evaluation, including ECG monitoring and consideration for cardiac stress testing or coronary angiography, as indicated by the patient's individual risk factors and clinical presentation.
From the Research
Biphasic T Wave Overview
- A biphasic T wave is an electrocardiogram (ECG) abnormality that can be associated with various cardiac conditions, including unstable angina and the long QT syndrome 2, 3.
- The presence of biphasic T waves in precordial leads, also known as Wellens syndrome, is a significant indicator of critical stenosis in the left anterior descending coronary artery (LAD) 2, 4.
Clinical Significance
- Biphasic T waves are often seen in patients with coronary artery disease, particularly those with LAD stenosis, and can be a marker of increased risk for sudden cardiac death 5, 4.
- The presence of biphasic T waves in patients with the long QT syndrome is associated with a higher risk of syncope or cardiac arrest 3.
- T-wave changes in patients with Wellens syndrome are associated with increased myocardial mechanical and electrical dispersion, which can contribute to the development of life-threatening arrhythmias 4.
Diagnostic and Prognostic Value
- The diagnostic and prognostic value of biphasic T waves can be assessed using various methods, including ECG, angiography, and echocardiography 2, 3, 4.
- Stress echocardiography can be used to assess coronary artery disease and guide revascularization in patients with known ischemic heart disease 6.
- The analysis of T-wave abnormalities, including biphasic T waves, can contribute to the diagnosis and risk stratification of patients with cardiac conditions, such as the long QT syndrome and coronary artery disease 5, 3, 4.