Final answer:
A normal split S2 heart sound is a key indicator for excluding severe pulmonary hypertension since it suggests that there is no significant delay in the closure of the pulmonary valve which can be caused by conditions like severe pulmonary hypertension. Pulmonary infundibular stenosis, as seen in Tetralogy of Fallot, is one such condition that could affect the S2 sound but would typically present with other symptoms and confirmed by echocardiography.
Step-by-step explanation:
The presence of a normal split S2 is the most reliable examination finding for excluding severe pulmonary hypertension. In a healthy heart, there are two audible heart sounds: S1 and S2. S1 represents the closing of the atrioventricular valves, which is the "lub" sound during ventricular contraction, and S2 is the "dub" sound created by the closing of the semilunar valves during ventricular diastole. These sounds can be altered in various cardiac conditions, such as Tetralogy of Fallot or hypertrophic cardiomyopathy.
Tetralogy of Fallot is a congenital heart defect consisting of four abnormalities: pulmonary infundibular stenosis, overriding aorta, ventricular septal defect, and right ventricular hypertrophy. This condition leads to a mixing of deoxygenated and oxygenated blood, causing cyanosis after birth and other symptoms like heart murmur and difficulty in breathing. The diagnosis is confirmed with echocardiography, and treatment often involves surgical intervention.
Normally, S2 can be split into two distinct sounds due to the aortic valve closing slightly before the pulmonary valve. The absence of a normal split S2 can indicate several conditions, but a normal split is a strong indicator that there is no severe blockage in the pulmonary trunk, such as that seen in severe pulmonary hypertension. This is because severe pulmonary hypertension would lead to a delay in the closure of the pulmonary valve, affecting the normal S2 sound. Therefore, hearing a normal split S2 through auscultation can help in excluding the possibility of severe pulmonary hypertension in a patient.