exercise-induced T-wave alternans
Alternating morphology of T-waves during exercise that may indicate electrical instability and increased risk of ventricular arrhythmias in athletes.
Full Definition
Exercise-induced T-wave alternans is a subtle electrocardiographic phenomenon characterized by beat-to-beat alternation in T-wave morphology, amplitude, or polarity that becomes apparent during exercise stress testing. This finding represents underlying electrical instability of the ventricular myocardium that may not be evident at rest but emerges during the physiological stress of exercise. T-wave alternans can be either visible to the naked eye (macroscopic) or detectable only through specialized computer analysis (microscopic). In athletes, exercise-induced T-wave alternans may indicate increased susceptibility to ventricular arrhythmias and sudden cardiac death, particularly in the presence of underlying structural heart disease or channelopathies. The detection of this phenomenon during sports-related activities or exercise testing typically warrants comprehensive cardiac evaluation and consideration of activity restriction pending risk stratification.
Usage
Usage note: May abbreviate as TWA after first use; hyphenate when used as compound modifier; distinguish from technical artifact.
In Context
- "Microvolt T-wave alternans analysis revealed exercise-induced T-wave alternans that was not visible on standard ECG monitoring." — Electrophysiology study report
- "The presence of exercise-induced T-wave alternans prompted immediate cessation of competitive swimming pending arrhythmia evaluation." — Sports cardiology consultation