A 50-year-old man presents to the emergency department with chest pain. He states that the pain is dull in quality, started 30 minutes ago, has been gradually worsening, and is worse with exertion. He also endorses some shortness of breath. He also believes the pain is worse when leaning back and improved when leaning forward. His wife noticed he fainted after the pain started but regained consciousness shortly after. He has a medical history of diabetes and hypertension for which he is on metformin and losartan. His temperature is 99.2°F (37.3°C), blood pressure is 130/87 mmHg, pulse is 99/min, respirations are 22/min, and oxygen saturation is 100% on room air. Physical exam reveals an overweight man. A normal S1 and S2 are auscultated with clear breath sounds. An ECG is performed as seen in Figure A. Which of the following is the most likely diagnosis?
Hypertrophic obstructive cardiomyopathy
Hypokalemia
Myocardial infarction
Hyperkalemia
Myocardial infarction
This patient is presenting with chest pain and an ECG demonstrating hyperacute T waves (leads V2-V6) which is an early finding concerning for a myocardial infarction.

A myocardial infarction occurs when an atherosclerotic plaque ruptures causing occlusion of a coronary artery. Patients classically present with chest pain, dyspnea, and diaphoresis. Atypical manifestations of an acute myocardial infarction may include abdominal pain, nausea, reflux symptoms, and dizziness. The most important initial step in management is to administer aspirin as it lowers mortality and carries minimal risk. An ECG should then be performed. Classically, an ST-elevation myocardial infarction (STEMI) will demonstrate ST elevations in a vascular distribution. However, the progression to a STEMI is usually stepwise and may present with ST depressions, hyperacute T waves, pseudonormalization of the ST segment (a normal ST segment after a depression as it elevates), ST elevations, and finally tombstoning (a concave down wave that looks like a tombstone). If a STEMI is suspected after an ECG is performed, the patient should be started on a second antiplatelet agent (e.g., ticagrelor), heparin, and sent immediately to the cardiac catheterization laboratory.

Nable et al. review the typical electrophysiologic changes found in STEMI. The authors note that T-wave inversions and ST-segment depression can before, during, or after the STEMI event. The authors recommend obtaining serial ECGs in patients with suspected STEMI.

Figure/Illustration A demonstrates hyperacute T waves (blue arrows) that are only occurring in a vascular distribution (V2-V6).

Incorrect Answers:
Answer A: Hyperkalemia can present with peaked T waves; however, peaked T waves would be demonstrated in all leads. Other findings of hyperkalemia can include QRS widening. Immediate management of hyperkalemia with ECG changes should include calcium administration followed by drugs that shift potassium intracellularly such as insulin, albuterol, or sodium bicarbonate. Further management may include diuresis and/or dialysis.

Answer B: Hypertrophic obstructive cardiomyopathy may demonstrate increased voltages throughout the ECG, in particular, in leads V2-V6 with deep Q waves in the septal leads. It may present with syncope upon exertion in a young patient (and in rare cases, sudden cardiac death). Ultrasound would show hypertrophy and left ventricular outflow tract obstruction. Management involves staying hydrated, avoiding strenuous activities, and beta blockers.

Answer C: Hypokalemia can present initially on ECG with U waves and may progress to cardiac dysrhythmias. Repletion with potassium is the preferred treatment, and the magnesium level should be checked as low magnesium can lead to potassium wasting in the kidneys.

Answer E: Pericarditis presents with chest pain worse by laying back and relieved by leaning forward. ECG may demonstrate diffuse ST elevations with PR depressions, and echocardiography may demonstrate a pericardial effusion. Management involves the administration of ibuprofen or colchicine and steroids in refractory cases. However, these therapies should not be used after myocardial infarction.

Bullet Summary:
Hyperacute T waves are an early finding that is concerning for myocardial infarction.