Respiratory T-Wave Inversion in a Patient With Chest Pain

T-wave inversion on electrocardiogram (ECG) is always a concerning finding as it is often associated with myocardial ischemia or ventricular strain. Respiratory variation in the T-wave morphology has been reported in the literature; however, the frequency of this observation remains unknown as this is not routinely evaluated. Although the exact physiological mechanisms underlying this ECG change are unclear, it is proposed to be due to the respiratory variation of the heart position resulting in an alteration in T-wave polarity. We describe a case of a patient who presented with chest pain with T-wave inversions in inferior and lateral ECG leads. On repeating ECG with breath held in end inspiration, the T waves became positive. The pain was found to be musculoskeletal in origin. This case is a reminder of an under-recognized physiological phenomenon involving the cardiac conduction. Variation of T-wave morphology with respiration may suggest a noncardiac cause of chest pain.