Question

What is the criteria for normal (physiologic) Q waves?

1) Less than 0.04 sec
2) Less than 0.3 sec
3) Less than 1/3 the height of R wave in that lead
4) More than 0.04 sec

Answer 1

Normal (physiologic) Q waves on an ECG are less than 0.04 seconds in duration and less than 1/3 the height of the R wave in the corresponding lead, reflecting the early phase of ventricular depolarization.

Step-by-step explanation:

The criteria for normal (physiologic) Q waves on an electrocardiogram (ECG) are as follows: Q waves should be less than 0.04 seconds in duration and less than 1/3 the height of the R wave in the lead in which they are observed. The presence of Q waves within these parameters is considered normal and is a reflection of the early phase of ventricular depolarization in the cardiac cycle. Normal Q waves are a part of the QRS complex, which represents ventricular depolarization, and the complexities of this can be observed in the detailed features of the ECG, including the PR interval, QT interval, and other components of the waveform.