The ECG shown here is from a 21 year old patient with severestenosis of the pulmonary valve and a right ventricular pressure of 128/12 (the normal is 25/5). The only differences between this tracing and the one from the patient with pulmonary hypertension shown on the preceding pages are the slightly wider QRS complex, which measures 0.11 seconds, and the more marked ST segment and T wave changes.