What is indicated by the presence of RR' in V1, V2, V3?

The presence of RR' in the leads V1, V2, and V3 is indicative of a Right Bundle Branch Block (RBBB). This characteristic pattern arises when there is a delay in the conduction along the right bundle branch of the heart's conduction system.

In RBBB, the electrical impulse that normally travels down the right bundle branch is slowed or blocked, causing the right ventricle to activate later than the left ventricle. This leads to a characteristic electrocardiographic appearance where you see a double peaked R wave (RR') in the V1, V2, and V3 leads. The presence of this pattern clearly distinguishes RBBB from other potential arrhythmias or conduction issues.

While Left Bundle Branch Block (LBBB) would typically present with a broader and monophasic R wave in the lateral leads (often V5, V6, or I, aVL), sinus bradycardia and normal sinus rhythm have different presentations. Sinus bradycardia presents as a slower heart rate with a normal P wave configuration and QRS complex, while normal sinus rhythm shows a consistent P-QRS-T pattern without any unusual features like RR' in V1, V2, or V3.

Therefore, the