Isolated infundibular pulmonary stenosis

Abstract

A case of isolated infundibular pulmonary stenosis is reported and literature is reviewed. Infundibular pulmonary stenosis is usually a part of tetralogy of Fallot or is associated with ventricular septal defect. Isolated infundibular pulmonary stenosis is rare. Patients may be asymptomatic in spite of significant stenosis. Dyspnea, chest pain, and presyncope or syncope on effort are common symptoms in significant obstruction. Ejection systolic murmur is best audible in the left 3rd intercostal space and increases on inspiration. Additional murmur of tricuspid regurgitation may appear if there is right ventricular failure. Absence of pulmonary valvular click and normal intensity and splitting of the second sound differentiate it from pulmonary valve stenosis. Electrocardiogram shows right ventricular overload. Two-dimensional (2D) echocardiography shows right ventricular hypertrophy with narrowing of infundibulum, normal pulmonary valve, main pulmonary artery, and branch pulmonary arteries. Right ventricle and right atrium may dilate if there is right-sided failure with significant tricuspid regurgitation. Doppler evaluation reveals systolic gradient in the region of infundibulum with no additional gradient at the level of pulmonary valve, main pulmonary artery, or branch pulmonary arteries. Tricuspid regurgitation may be present. 2D echocardiography with Doppler evaluation also excludes other lesions. Angiography is usually not required. Surgery is safe and effective in relieving obstruction. Stent implantation is safe and effective in highly selected patients with discretely narrow circumferential stenotic segment and near-normal-sized peristenotic segment between the pulmonary and tricuspid valves.

Keywords

• Congenital heart disease
• echocardiography
• ejection systolic murmur
• electrocardiography
• right ventricular hypertrophy
• right ventricular outflow obstruction
• sudden death