This ECG was obtained from a 37-year-old male who was complaining of non-radiating substernal chest pain. He offered no significant medical history. He denied taking any medications. He was hypertensive and bradycardic on arrival in the Emergency Dept. He was alert and ambulatory. Approximately 20 minutes after first being seen by paramedics, he suffered an episode of ventricular fibrillation in the E.D. He was resuscitated and sent to the cath lab. His coronary arteries were without lesions. We do not know the results of any lab tests, including troponins.
What does the ECG show? The rhythm is sinus bradycardia at a rate of 48 bpm. The PR, QTc, intervals and QRS duration are normal. The QRS frontal plane axis is normal and there is good R wave progression in the precordial leads. There is ST segment elevation in Leads I, aVL, V2, and V3, with reciprocal ST depression in Leads III and aVF. The ST segments that are elevated retain a relatively “normal” shape, being concave upward. There are no abnormal T wave inversions or pathological Q waves.
Discussion While this ECG is certainly consistent with the diagnosis of anterior-lateral M.I. (STEMI), the patient was found to have “clean” coronary arteries. Any adult presenting with chest pain and ECG abnormalities should be assessed for acute M.I., of course, and that often involves a trip to the cath lab. Most acute M.I.s are caused by a ruptured plaque in a coronary artery that has formed a blood clot and obstructed blood flow through that artery. Other conditions can cause blood flow obstruction, such as coronary artery spasm. An imbalance in supply and demand can also damage the heart muscle, even if not caused by thrombus. A general term for an M.I. (confirmed by troponins, echocardiography, or catheterization) is “MINOCA”, “myocardial infarction with non-obstructive coronary arteries”. It can occur in up to 10% of patients presenting with clinical features that are diagnostic of STEMI. There are many examples of MINOCA, including, but not limited to, spasm, cardiomyopathies, or thrombotic disorders. Because of this patient’s presenting symptoms and subsequent episode of V Fib, we are confident that he received a thorough investigation of possible etiologies, but unfortunately, we have no results.
Please comment below to add to this discussion. We are very interested in your experiences with MINOCA.
Many thanks to Lew Steinberg and the Palm Beach Gardens, FL Fire Rescue Department for donating this ECG.