Q wave on the electrocardiogram (ECG) is an initially negative deflection of the QRS complex. Technically, a Q wave indicates that the net direction of early ventricular depolarization (QRS) electrical forces projects toward the negative pole of the lead axis in question.

    A non-Q wave myocardial infarction refers to a myocardial infarction that does not result in a Q wave on the 12-lead ECG once the infarction is completed. ... Instead, acute coronary syndromes are classified as unstable angina, non-ST elevation myocardial infarction and ST elevation myocardial infarction.