Abstract
Introduction
Endocarditis complicating hypertrophic cardiomyopathy (HCM) is not commonly reported but occurs almost universally in patients showing evidence of outflow tract obstruction. The estimated cumulative 10 year probability of developing endocarditis in obstructive HCM is < 5%. We report a rare case of mitral valve endocarditis in a young man with hypertrophic obstructive cardiomyopathy.
Case report
A 45 years old man was admitted to the emergency room after a 7 days history of weakness, thoracic discomfort, short of breath, cough and temperature up to 40 °C. He was treated with oral antibiotics in ambulatory setting, but symptoms persisted. He had no previous history of hypertension or known heart disease, family history of coronary heart disease and excessive smoker. On clinical examination, the patient was afebrile with a harsh systolic murmur. Initial blood tests showed normal inflammatory markers (C reactive protein 0.2 mg/l and fibrinogen 202 mg/dL) and normal blood sample. An ECG showed major left ventricular hypertrophy and abnormal lateral repolarisation. Transthoracic echocardiography showed localized septal hypertrophy (2.4 cm) and systolic anterior motion of the anterior mitral leaflet. Continuous wave Doppler ultrasound in the left ventricular cavity and outflow tract, had given a maximal predicted gradient of 73 mmHg. There was suspicion of vegetation on the anterior mitral valve leaflet and mitral regurgitation was quantified as moderate. Transoesophageal echocardiography confirmed the presence of vegetation on the anterior mitral valve leaflet, posterior leaflet prolapse and moderate mitral regurgitation. We found normal coronary arteries on coronary angio-CT. Treatment with intravenous antibiotics was initiated and the case was discussed with a microbiologist and a cardiothoracic surgeon.
Discussion
Infective endocarditis is a rare complication of hypertrophic cardiomyopathy (HCM). It is clear from morphological studies that systolic anterior motion of the anterior mitral valve leaflet is relevant to the pathogenesis of endocarditis. Pathogenesis of infective endocarditis in obstructive HCM can be explained by endocardium damage of the mitral or aortic valve, consequence of turbulence of blood flow during ejection and of the contact between the mitral anterior leaflet and the septum during systole as well as mitral regurgitation. Antibiotic therapy is the mainstay of the treatment. Surgery should be considered promptly whenever there is traditional indication (haemodynamic, emboli, persistent fever, abscess). Surgical procedure may consist of valve replacement or repair, and some authors reported relieve of outflow tract obstruction after mitral valve replacement which may be explained by the removal of systolic anterior motion of the mitral valve. Valve surgery combined with septal myectomy seems logical but requires great expertise and carries a higher operative mortality
Abstract P1698 Figure.
Combined anterior mitral valve leaflet retention plasty and septal myectomy in patients with hypertrophic obstructive cardiomyopathy