(1183) The Silent Disturbance: Exploring ECG Changes in Spontaneous Pneumomediastinum

Introduction: Spontaneous pneumomediastinum describes the presence of air in the mediastinum, not attributed to trauma, surgery, or any medical procedure. This condition has been associated with a variety of electrocardiographic (EKG) abnormalities, mimicking pericarditis and acute myocardial infarction. The following report describes one such case.

Description: A 21 year old Afroamerican male with well controlled asthma presented with sudden onset dyspnea and diaphoresis, 3 hours after smoking marijuana. There was no wheezing, chest pain or palpitations. He was tachycardic (120), tachypneic (22) and had a low grade fever. Labs were unremarkable, including serial troponins. The initial EKG showed sinus tachyardia. Chest X-ray revealed pneumomediastinum in the region of the superior mediastinum with gas extending into the lower neck, which was confirmed by the CT chest, showing diffuse pneumomediastinum with no evidence of esophageal perforation or pneumothorax. He was admitted to the ICU for observation.
The next day, although asymptomatic, there were acute ST-T changes on the telemetry. The EKG showed widespread ST elevation in the inferior and anterolateral leads. An ECHO performed was unremarkable. CT coronaries ruled out coronary atherosclerosis. He was ultimately discharged with colchicine and ibuprofen to cover for probable pericarditis with a repeat EKG to ensure resolution.

Discussion: Smoking marijuana in asthmatics can cause bronchoconstriction and increase intrathoracic pressure can further result in spontaneous pneumomediastinum as the mediastinum has negative pressure at baseline(1). The potential reason behind EKG simulating that of myocardial infarction or ischemia in pneumomediastinum, is the displacement of the tense heart due to the presence of air in the chest cavity between the heart and lungs, leading to alterations in electrical conductance(2). Our patient exhibited widespread ST elevation in the inferior and anterolateral leads. Since there was no actual injury to the myocardial cells, the troponin levels remained unaltered. Other EKG changes could be low voltage QRS, electrical alternans or just T wave inversion. It is crucial to consider various potential causes of significant ST-T wave changes before proceeding with any interventional procedure.