Diagnosis and Management of Rsr' Pattern in V1
Diagnostic Criteria
- The American College of Cardiology recommends that a QRS duration of ≥120 ms in adults is indicative of complete right bundle branch block (RBBB), while a duration of <110 ms is considered a normal variant 1, 2
- In children, a QRS duration of >100 ms (ages 4-16 years) or >90 ms (<4 years) is indicative of complete RBBB, while a duration of 110-119 ms in adults (90-100 ms in children 4-16 years, 86-90 ms in children <8 years) suggests incomplete RBBB 1, 2
- The presence of an Rsr' pattern in V1 and V2, with a QRS duration <110 ms, is considered a normal variant in children and young adults 1, 3
Clinical Context and Management
- The American College of Cardiology suggests that children or young adults with an Rsr' pattern in V1-V2 and a normal QRS duration (<110 ms) do not require further workup 1, 3, 4
- New-onset complete or incomplete RBBB warrants echocardiography to assess for structural heart disease, right ventricular pressure/volume overload, or conduction system disease, according to the American College of Cardiology 2
Common Pitfalls to Avoid
- The American College of Cardiology advises against using the terms "Rsr'" or "normal Rsr'" interchangeably, as they can be variously interpreted and lead to confusion 1, 3
- Incorrect lead placement (V1 recorded too high or too far right) can create a false Rsr' pattern, as noted by the American College of Cardiology 1
RSR' Pattern in Lead V1: Diagnostic Approach and Management
Diagnostic Criteria
- The American College of Cardiology recommends that complete RBBB is diagnosed when QRS duration is ≥120 ms in adults, with an RSR', rsR', rSR', or rarely qR pattern in leads V1 or V2, and an S wave of greater duration than R wave or >40 ms in leads I and V6 5
- The American College of Cardiology also recommends that normal R peak time in leads V5 and V6 but >50 ms in lead V1 is a criterion for complete RBBB 5
Management Algorithm
- The American College of Cardiology suggests that for asymptomatic patients with RSR' in V1, measuring QRS duration precisely is the first step in management, and if QRS ≥120 ms, obtaining an echocardiogram to evaluate for structural disease is recommended 5
Interpretation of an rSR′ Pattern in Lead V1 According to QRS Duration
Normal Variant (QRS < 110 ms)
Incomplete Right Bundle Branch Block (IRBBB) (QRS 110–119 ms)
Complete Right Bundle Branch Block (CRBBB) (QRS ≥ 120 ms)
- S‑wave duration longer than the R‑wave or > 40 ms in leads I and V6, and
- R‑peak time > 50 ms in lead V1.