The waves on an ECG include the P wave, Q wave, R wave, S wave, T wave and U wave. Interval: The time between two specific ECG events. The intervals commonly measured on an ECG include the PR ...

to the point where the R wave is larger than the S wave in lead V4. The S wave then becomes quite small in lead V6. Note that an old anterior myocardial infarction can cause poor R wave progression.

pathological Q-waves, left axis deviation and conduction delays and findings suggestive or diagnostic of primary electrical diseases such as long QT syndrome and Wolff-Parkinson-White syndrome. The ...