Non-Q-wave myocardial infarction: comprehensive analysis of electrocardiogram, pathophysiology, and therapeutics

Since the invention of electrocardiogram (ECG or EKG), its significance in the diagnosis of acute ischemic disease, chronic ischemic disease, and its contribution to cardiology has been no less than remarkable. The pathophysiology of acute coronary syndromes in most cases correlates with the clinical outcomes, biochemical findings (cardiac biomarkers), and electrocardiographic patterns. Electric activity in the myocardium is registered in the ECG describing positive deflections when the depolarization potential orientates positive charges to the recording electrode (approaches to it) and negative deflections when the depolarization potential orientates negative charges to the recording electrode and gets away from it. The abnormal Q-wave is the cornerstone of the myocardial infarction diagnosis after several days of the ischemic event. Findings in the ECG suggestive of ischemia and necrosis are ST elevation/depression and deep Q-waves, respectively, and the presence of a deep abnormal Q-wave in the ECG is evidence of necrotic areas and an inert myocardium, which is not capable to depolarize. Non-Q-wave myocardial infarction has been defined as acute myocardial infarction without a new-onset deep Q-wave on the ECG after day(s) of evolution, and because of the anatomopathological concept of infarction is usually related to necrosis, it results paradoxical to consider this widely known clinical and biochemical entity as a myocardial infarction when there is no evidence of necrosis in the ECG.