-year-old boy was admitted for cardiac catheterization because of mitral
regurgitation. The family history was noncontributory. He is the second
twin, delivered after normal pregnancy without maternal illness,
infection, or medication. He showed normal development and weight gain.
At the age of 2 years, a heart murmur was first noted;
echocardiographically, a small (2.5-mm) ventricular septal defect
(VSD) was found. This closed spontaneously 3 years later, but
mitral valve prolapse accompanied by mild mitral incompetence was
noticed. During the next 2 years, mitral regurgitation became more
severe. At the age of 10 years, mitral insufficiency was treated
surgically because of the clinical signs of congestive heart failure.
Afterwards, mild mitral regurgitation was still noticed in
echocardiography. Clinically, the boy did well during the next 3 years,
but at echocardiography, the left atrium as well as the left ventricle
were found to be progressively enlarged, probably caused by mitral
regurgitation. The boy again was admitted to the hospital for