The anterior position of the aortic valve in that condition would have produced the loud and palpable second heart sound
the splitting of a strand of DNA than that of the second heart sound, the key to differentiating many innocent murmurs from such serious conditions as atrial septal defect, aortic stenosis, pulmonic stenosis, pulmonary hypertension, and left bundle branch block.
Splitting of the second heart sound (the audible separation of aortic and pulmonic valve closure) is not a rare, esoteric finding; it can be detected in almost 80% of all normal individuals from 6 to 74 years of age (8).
Cardiac auscultation demonstrated a regular rate and rhythm with a normal first and second heart sound
Auscultation revealed a loud, single second heart sound and a prominent systolic ejection click.
Thus, in our patient, increasing cyanosis, a diminishing murmur, a loud, single second heart sound, and an ejection click indicate Eisenmenger physiology with severe pulmonary hypertension and right-to-left or bidirectional shunting (2).
The second heart sound
was moderately and fixedly split with a loud second component.
The second heart sound was of normal intensity, was persistently split, and moved physiologically with respiration.
The normal electrocardiogram, the inequality of the a and v waves in the jugular pulse, the respiratory movement of the second heart sound, the absence of a systolic ejection murmur, and the size of the defect measured echocardiographically all suggested that the defect was restrictive and the left-to-right shunt smaller than usual.