A previously healthy 36-year-old man comes to the physician for a 2-month history of worsening shortness of breath, fatigue, and intermittent palpitations. Vitals are normal. The lungs are clear to auscultation. S2 is widely split and fixed. A 2/6 systolic ejection murmur is heard at the apex. Chest x-ray shows right ventricular enlargement and increased pulmonary vascularity. ECG shows a right bundle branch block. Which of the following is the most likely explanation for these findings?
Chronic pressure overload on right ventricle
Chronic volume overload on right ventricle
Paradoxical pulse with right ventricular decompensation
Primary pulmonary hypertension
Reversal of shunt
