Pathologic Q wave

Abnormally deep and/or wide Q wave on ECG, typically ≥0.03–0.04 seconds in duration and ≥1–2 mm in depth in at least two contiguous leads, reflecting loss of electrically active myocardium or altered ventricular depolarization.

Causes

• Prior transmural myocardial infarction with myocardial scar formation

• Cardiomyopathic causes

  • Hypertrophic cardiomyopathy

  • Left ventricular hypertrophy

  • Cardiac amyloidosis

  • Myocarditis with myocardial fibrosis

  • Congenital cardiac conditions affecting ventricular activation

• Conduction abnormalities

  • Left bundle branch block

  • Ventricular conduction delay

• Technical and positional causes

  • ECG electrode misplacement

  • Normal anatomical or positional Q-wave variants