P182 A STRANGE ELECTROCARDIOGRAM RECORDED AFTER A FALL TO THE GROUND

Abstract

Abstract An 84–year–old man was found unconscious on the ground by his daughter. The patient had a medical history of arterial hypertension, dyslipidemia and type II diabetes mellitus complicated by peripheral neuropathy and has been experiencing frequent falls. The emergency services were alerted, and the man was taken to the emergency room. In the ER, an abnormal electrocardiogram was recorded, and an urgent cardiological consultation was requested. Upon reading the ECG, the cardiologist ordered the patient‘s body temperature to be measured, which was found to be 29.7°C. The recorded ECG showed signs of severe hypothermia, including an advanced atrioventricular block (in this case, III–degree AV block), a widening of the QRS complex with the appearance of the Osborn wave, and a prolonged QT interval. The Osborn wave is a positive deflection visible at the J point and it is an uncommon electrocardiographic finding that immediately suggests hypothermia, although it is not pathognomonic (it can also be found in acute myocardial ischemia, hypercalcemia, sepsis, and other non–hypothermic conditions). The electrophysiological basis of the Osborn wave lies in the Ito current, a transient current caused by the release of potassium ions from the ventricular myocardiocyte, which is responsible for a brief partial repolarization during phase 1 of the action potential. Hypothermia increases the amplitude and width of the action potential notch due to the Ito current in the epicardium much more than in the endocardium, creating a transmural voltage gradient that manifests on the surface ECG as the Osborn wave. The Osborn wave is initially more evident in the inferolateral leads; as the body temperature decreases, the wave gradually becomes visible in all 12 leads and, when the body temperature returns to normal, the wave progressively disappears. This potential difference also correlates with possible proarrhythmic effects and, when linked to acute myocardial ischemia, the Osborn wave is an adverse prognostic factor as it is associated with a higher risk of ventricular fibrillation. In this case, the patient had fallen during the night and remained on the ground for hours. He was hospitalized for short intensive observation, warmed up, and hydrated, with a rapid and complete resolution of the clinical and electrocardiographic abnormalities