Momentary giant T‐waves hint the genesis of the electrocardiographic T‐wave in human

T‐wave morphology changes are linked to dispersion of ventricular repolarization. I encountered an 80‐year‐old man on hemodialysis manifesting momentary giant T‐waves and QT prolongation on the 12‐lead electrocardiogram, soon after initiating mechanical ventilation because of hypercapnic respiratory failure. A computed tomography of the brain showed no acute cerebrovascular accidents. An echocardiogram showed no left ventricular asynergy. Mechanisms that may be responsible for this phenomenon are discussed. Interpreting the giant T‐waves with the concept of the three bipolar limb lead vectors, the Einthoven's triangle leads to recognize origin of the electrocardiographic T‐wave.