Pediatric ECG and Right Ventricular Hypertrophy

How to interpret the R(V1), R:S(V1), and S(V5) triad without overdiagnosing right ventricular hypertrophy.

Scope

This page addresses the pediatric ECG patterns often summarized as “RSS criteria” for right ventricular hypertrophy (RVH). It does not replace a pediatric cardiology review, age-specific ECG reference values, or imaging when right ventricular disease is suspected.

The RSS triad is a memory aid, not a stand-alone diagnosis

A common teaching slide lists three findings:

Teaching shorthand	Displayed threshold
R(V1)	at least 0.5 mV (5 mm at standard calibration)
R/S(V1)	at least 1
S(V5)	at least 0.5 mV (5 mm at standard calibration)

These values are reproduced only to explain the shorthand; they are not age-specific diagnostic limits (Lambrechts 2020).

Those fixed values are not universal diagnostic thresholds across childhood. Right ventricular dominance is normal in infants and can persist to about age 3, normal R-wave and S-wave amplitudes change substantially with age, and pediatric ECG interpretation requires age-specific limits (Lambrechts 2020; Saarel 2018). A positive triad alone therefore does not establish RVH.

Use an age-specific approach

Confirm the patient’s age, lead placement, and calibration, then compare the tracing with age-specific normal limits rather than adult cutoffs (Lambrechts 2020; Saarel 2018).
Look for features that support RVH beyond isolated voltage, including right axis deviation, a prominent R wave in V1, a deep S wave in V6, an upright T wave in V1 after the first week of life, and a qR pattern in V1 (Lambrechts 2020).
Interpret voltage in the clinical context. In children evaluated for pulmonary hypertension, ECG voltage criteria had limited sensitivity (69%) and positive predictive value (67%) for echocardiography-documented RVH (Puchalski 2006).
Obtain pediatric cardiology input or echocardiography when RVH, pulmonary hypertension, or right ventricular disease is clinically suspected; ECG alone is not a reliable screening test for RVH (Puchalski 2006).

What changed in the evidence

The 2025 CHILDHEART study developed an age-specific ECG score for right ventricular disease in children. In a retrospective case-control cohort of 246 children with confirmed right ventricular disease and 1,391 age-matched controls, right bundle branch block and RV1 + SV6 at least 18 mm were significant predictors. The score’s area under the curve was 0.84 under age 3 years and 0.81 at age 3 years or older (CHILDHEART 2025).

This is promising but not yet a stand-alone bedside rule: the study was retrospective, had potential selection bias, and requires prospective validation (CHILDHEART 2025).

Bottom line

Use the RSS triad as a prompt to look closely at an age-specific ECG and the whole clinical picture. Do not label a child as having RVH from the fixed R(V1), R/S(V1), and S(V5) values alone (Lambrechts 2020; Puchalski 2006).