Notched R Waves on ECG: Clinical Significance and Management

Differential Diagnosis by Lead Location

The American College of Cardiology and the American Heart Association recommend that complete Right Bundle Branch Block (RBBB) be diagnosed with QRS duration ≥120 ms in adults with rsR', rSR', or RSR' pattern in V1 or V2, where the R' deflection is typically wider than the initial R wave 1, 2
Incomplete RBBB is characterized by the same morphology but QRS duration 110-119 ms in adults, according to the American College of Cardiology 3, 4
The American College of Cardiology states that additional supporting criteria for RBBB include S wave duration >40 ms in leads I and V6, and R peak time >50 ms in V1 1, 2
The American Heart Association recommends that in children, an rsR' pattern in V1-V2 with normal QRS duration (<120 ms) is a normal variant and requires no further evaluation 2, 3
The European Society of Cardiology notes that in athletes, isolated rsR' pattern with normal QRS duration is part of the normal ECG spectrum 3
Right Ventricular Hypertrophy can present with notched R waves in V1-V2, particularly when associated with right axis deviation, according to the American College of Cardiology 3, 5

The American College of Cardiology recommends that if QRS ≥120 ms, apply complete bundle branch block criteria, and consider echocardiography to assess ventricular function and structural disease 1, 2
The American Heart Association states that if QRS <120 ms, proceed to pattern recognition, and consider fragmented QRS pattern as a marker of myocardial scar 3
The European Society of Cardiology recommends that in patients with hypertension, assess for left ventricular hypertrophy using voltage criteria, and consider echocardiography for definitive assessment 5

The American College of Cardiology warns against dismissing rsR' pattern in V1-V2 as "incomplete RBBB" without measuring QRS duration, as normal QRS duration indicates a benign variant in most cases 2, 3
The American Heart Association advises against relying solely on Q waves to detect prior MI, as fragmented QRS has 2.4-fold higher sensitivity, although the exact sensitivity value is not provided in the cited references 1, 2