Normal and noninfarct Q waves.

Pseudo-infarct Q waves occur in a number of conditions, related to physiologic or positional variants, altered ventricular conduction, ventricular enlargement, and non-coronary myocardial damage. Prominent Q waves in asymptomatic individuals may be due to previous "silent" myocardial infarction, normal variants, or some pathologic but non-coronary cause. Differential diagnosis may be aided by echocardiography (normal variants, cardiomyopathies, left or right ventricular enlargement, amyloid deposition, and so on). Failure to recognize pseudo-infarct patterns may result in "electrocardiographogenic disease" if the Q wave is a normal variant, or in missing a critical clue to some important pathology such as hypertrophic cardiomyopathy or pulmonary embolism that has very different therapeutic implications from coronary disease.