Emergence and resolution of the electrocardiographic spiked helmet sign in acute noncardiac conditions.

Patients with acute abdominal or acute thoracic events occasionally develop a curious electrocardiographic ST-segment elevation, where the upward shift of the baseline starts before the onset of the QRS complex. The shape of the complexes resembles a German military spiked helmet. It has been previously postulated that the “spiked helmet” sign is the result of an acute rise in intraabdominal or intrathoracic pressure causing pulsatile epidermal stretch that is in concert with the cardiac cycle. Here, we present 2 cases, where recognition of the spiked helmet sign led to immediate discovery of the underlying pathology. Removal of a large epigastric content resulted in the prompt resolution of the spiked helmet sign in the inferior leads, whereas suctioning of a large pneumothorax lead to the gradual disappearance of the spiked helmet sign in the chest leads. These cases provide the first definitive proof of a mechanical, noncardiac etiology of the spiked helmet sign.