Diagnosis of Pulmonic Stenosis Echocardiography Diagnosis of pulmonic stenosis is confirmed by Doppler echocardiography, which can characterize the severity as Mild: Peak gradient < 36 mm Hg (peak velocity < 3 m / second) Moderate: Peak gradient 36 to 64 mm Hg (peak velocity 3 to 4 m / second) Severe: Peak gradient > 64 mm Hg (peak velocity > 4 m / second) ECG may be normal or show RV hypertrophy or right bundle branch block.