What is R wave transition?

As a domain expert in cardiology, I can explain the concept of R wave transition. The R wave in an electrocardiogram (ECG) represents the depolarization of the ventricles during a heartbeat. The R wave transition specifically refers to the change in the size and shape of the R wave as you move from one ECG lead to another, particularly across the chest leads (V1 to V6). The transition is considered early when it occurs in lead V1 or V2. This might suggest a condition where the electrical impulse is transitioning to the ventricles sooner than expected, which can be seen in certain congenital heart diseases or other conditions affecting the electrical conduction system of the heart. Conversely, a late transition is when the change in the R wave occurs in leads V4, V5, or V6. A late transition might indicate a problem with the left ventricular conduction or hypertrophy (enlargement of the heart muscle). Additionally, there should be a gradual increase in the amplitude of the R wave between leads V1-V4. This gradual increase is known as R wave progression. It reflects the normal spread of electrical activity across the ventricular wall. In summary, the R wave transition is an important aspect of ECG interpretation that can provide insights into the heart's electrical activity and potential abnormalities.

When the transition happens in lead V1 or V2 it is referred to as an early transition. When it happens in leads V4, V5, or V6 it is referred to as a late transition. In addition, there should be a gradual increase in the amplitude of the R-wave between leads V1-V4. This is referred to as R-wave progression.