Electrocardiographic changes following diaphragmatic inspiration

Spiked helmet sign: An under-recognized electrocardiogram finding in critically ill patients

A 77-year-old male patient presented with rhabdomyolysis. He developed progressive respiratory failure and acute respiratory distress syndrome during his hospital stay requiring mechanical ventilation. An electrocardiogram during mechanical ventilation showed findings suggestive of ST elevation myocardial infarction. Closer review showed dome and spike findings that have been likened to a “spiked helmet.” This finding has been associated with significant mortality. We discuss this under-recognized finding and the potential contributing mechanisms.

Labile T-wave changes caused by respiratory variation in a patient with unstable angina

We describe an unusual case of asymptomatic T-wave inversion induced by respiration in a patient with coronary artery disease.