is defined as R in V₄ < R in V_{3 or R in V₃ < R in V_{2 or R in V₂ < R in V_{1, or any combination of these. Poor R wave progression is commonly attributed to anterior myocardial infarction, but it may also be caused by left bundle branch block, Wolff-Parkinson-White syndrome, right and left ventricular hypertrophy, or a faulty ECG recording technique.}}}