What is a common ECG finding for right bundle branch block (RBBB)?

A common finding in right bundle branch block (RBBB) on an electrocardiogram (ECG) is the presence of a wide QRS complex accompanied by an rSR' pattern, specifically noted in the right precordial leads (V1 and V2). The rSR' pattern results from delayed conduction through the right bundle branch, leading to a characteristic "bunny ears" appearance, where the first R wave is followed by a downward deflection (the S wave) and then a second R wave (R').

The widening of the QRS complex occurs because the electrical impulse takes longer than normal to travel through the right bundle branch, which is why it exceeds 120 milliseconds. Additionally, this pattern can be contrasted with the normal QRS complex seen in healthy individuals, which is narrow and does not exhibit symmetrical changes. The other options provided do not reflect the hallmark of RBBB; for instance, a normal QRS and T wave or specific Q waves are indicative of other heart conditions, while ST elevation may point towards acute myocardial infarction or other cardiac issues unrelated to bundle branch blocks. Understanding these distinctions is crucial for proper ECG interpretation and diagnosing underlying heart conditions.