From the Guidelines
A prolonged T wave on an electrocardiogram (ECG) is a significant finding that requires further evaluation to determine the underlying cause, which may include electrolyte disturbances, medication effects, ischemic heart disease, or cardiomyopathies. This finding may indicate an abnormality in cardiac repolarization, which is the recovery phase of the heart's electrical cycle. The management of a prolonged T wave should prioritize the identification and correction of the underlying cause, as this can impact morbidity, mortality, and quality of life.
Key Considerations
- Checking serum electrolytes (potassium, calcium, magnesium) is essential, as electrolyte imbalances can cause T wave prolongation 1.
- Reviewing the patient's medication list for QT-prolonging drugs is crucial, as these medications can contribute to T wave prolongation and increase the risk of arrhythmias 1.
- Assessing for symptoms of cardiac ischemia is necessary, as ischemic heart disease can cause T wave changes 1.
Management
- In asymptomatic patients with isolated T wave prolongation, correction of electrolyte abnormalities may be sufficient 1.
- For patients taking QT-prolonging medications, dose adjustment or medication substitution may be required to prevent further prolongation of the T wave and reduce the risk of arrhythmias 1.
- The prolongation occurs because the heart muscle cells take longer than normal to reset their electrical properties after contraction, which can potentially lead to dangerous arrhythmias in some cases, particularly when combined with other factors that further affect cardiac electrical stability 1.
Prioritization
- The most recent and highest quality study, which is the 2009 study by the American Heart Association 1, provides the most relevant guidance on the management of T wave prolongation.
- This study emphasizes the importance of distinguishing between primary and secondary repolarization abnormalities, which can help guide the management of T wave prolongation.
From the Research
Prolonged T Wave
- A prolonged T wave can be associated with various electrocardiographic manifestations, including those related to electrolyte disturbances such as hypokalemia 2 and hyperkalemia 3.
- The T-wave of the electrocardiogram (ECG) is generated both from the left and the right ventricles of the heart, and the observed T-wave in the clinical ECG is the summation of the left and right ventricular T waves, and is thus biventricular 4.
- Electrocardiographic alterations, including T wave changes, are common in patients with hyperkalemia, but the presence of peaked T waves is a poor predictor of serum potassium levels and hyperkalemia in patients with acute kidney injury 3.
- T-wave inversion (TWI) can be associated with both benign and pathological conditions, and its interpretation is complex, particularly in athletes, where it may represent an early sign of an underlying structural heart disease or life-threatening arrhythmogenic cardiomyopathies 5.
Related Conditions
- Hypokalemia: can cause dynamic changes in T-wave morphology, ST-segment depression, and U waves, which are often best seen in the mid-precordial leads (V2–V4) 2.
- Hyperkalemia: can cause electrocardiographic alterations, including peaked T waves, but these changes are poor predictors of serum potassium levels and hyperkalemia in patients with acute kidney injury 3.
- Cardiomyopathies: T-wave inversion (TWI) can be an early sign of underlying structural heart disease or life-threatening arrhythmogenic cardiomyopathies, particularly in athletes 5.
Electrocardiographic Characteristics
- T-wave morphology: can be affected by various conditions, including hypokalemia and hyperkalemia 2, 3.
- ST-segment depression: can be associated with hypokalemia 2.
- U waves: can be associated with hypokalemia 2.
- Peaked T waves: are a common electrocardiographic alteration in hyperkalemic patients, but are poor predictors of serum potassium levels and hyperkalemia 3.