A 30-year-old woman presents with a hea murmur. There is a history of recurrent episodes of ahritis, skin rash and glomerulonephritis. Blood cultures are negative. Laboratory tests for antinuclear antibodies (ANA) and anti-double-stranded DNA are positive. Which of the following is the most likely cause of hea murmur in this patient?
Libman-Sacks endocarditis Mitral valve prolapse Myocardial infarct Rheumatic fever