A 73-year-old woman had an episode a week ago in which she became disoriented, had difficulty speaking, and had persisting weakness on the right side of her body. On physical examination, she is now afebrile with pulse of 68/min, respirations of 15/min, and blood pressure of 130/85 mm Hg. On auscultation, the lungs are clear, the heart rate is irregular, and there is a midsystolic click. A chest CT scan shows a focus of bright attenuation within the heart. An echocardiogram shows that one valvular leaflet appears to balloon upward. The ejection fraction is estimated to be 55%. Laboratory findings show serum creatine kinase (CK), 100 U/L; glucose, 77 mg/dL; creatinine, 0.8 mg/dL; calcium, 8.1 mg/dL; and phosphorus, 3.5 mg/dL. Which of the following is the most likely diagnosis? Carcinoid heart disease

**Core Concept**
The patient's presentation of a midsystolic click, a focus of bright attenuation within the heart on chest CT, and a valvular leaflet ballooning upward on echocardiogram suggests a condition affecting the heart valves. The laboratory findings of elevated serum CK and the patient's history of persistent weakness on the right side of her body hint at a possible cardiac cause of embolic stroke or cardiac dysfunction.

**Why the Correct Answer is Right**
The presence of a midsystolic click, a focus of bright attenuation within the heart, and a valvular leaflet ballooning upward on echocardiogram are characteristic of mitral valve prolapse (MVP). The elevated serum CK levels may be due to rhabdomyolysis secondary to cardiac dysfunction. MVP is often associated with a midsystolic click due to the mitral leaflet prolapsing into the left atrium. The echocardiogram findings are consistent with MVP, and the patient's symptoms and laboratory findings support this diagnosis.

**Why Each Wrong Option is Incorrect**
**Option A:** Carcinoid heart disease typically presents with fibrosis and thickening of the tricuspid and pulmonary valves, which is not consistent with the patient's echocardiogram findings.
**Option B:** Hypertrophic cardiomyopathy (HCM) may present with left ventricular outflow tract obstruction, but it would not typically produce a midsystolic click or a ballooning valvular leaflet on echocardiogram.
**Option C:** Cardiac amyloidosis may present with diastolic dysfunction and a restrictive filling pattern, but it would not typically produce a midsystolic click or a ballooning valvular leaflet on echocardiogram.
**Option D:** There is no mention of a cardiac tumor, which would be an alternative diagnosis for the patient's symptoms and echocardiogram findings.

**Clinical Pearl / High-Yield Fact**
MVP is a common valvular heart disease that can be associated with embolic stroke, cardiac dysfunction, and arrhythmias. The classic auscultatory finding of a midsystolic click followed by a late systolic murmur is a key diagnostic feature.

**Correct Answer:** B. Hypertrophic cardiomyopathy

✓ Correct Answer: D. Rheumatic heart disease