Complete Atrioventricular Block Complicating Mitral Infective Endocarditis Caused by Streptococcus Agalactiae.

BACKGROUND Infective endocarditis (IE) involving the mitral valve can but rarely lead to complete atrioventricular block (CAVB). CASE REPORT A 74-year-old man with a history of infective endocarditis caused by Streptococcus gordonii (S. gordonii) presented to our emergency room with fever and loss of appetite, which had lasted for 5 days. On admission, results of serologic tests pointed to severe infection. Electrocardiography showed normal sinus rhythm with first-degree atrioventricular block and incomplete right bundle branch block, and transthoracic echocardiography and transesophageal echocardiography revealed severe mitral regurgitation caused by posterior leaflet perforation and 2 vegetations (5 mm and 6 mm) on the tricuspid valve. The patient was initially treated with ceftriaxone and gentamycin because blood and cutaneous ulcer cultures yielded S. agalactiae. On hospital day 2, however, sudden CAVB requiring transvenous pacing occurred, and the patient's heart failure and infection worsened. Although an emergent surgery is strongly recommended, even in patients with uncontrolled heart failure or infection, surgery was not performed because of the Child-Pugh class B liver cirrhosis. Despite intensive therapy, the patient's condition further deteriorated, and he died on hospital day 16. On postmortem examination, a 2×1-cm vegetation was seen on the perforated posterior mitral leaflet, and the infection had extended to the interventricular septum. Histologic examination revealed extensive necrosis of the AV node. CONCLUSIONS This rare case of CAVB resulting from S. agalactiae IE points to the fact that in monitoring patients with IE involving the mitral valve, clinicians should be aware of the potential for perivalvular extension of the infection, which can lead to fatal heart block.

Spontaneous Remission in a Case of Giant Cell Myocarditis with Preserved Left Ventricular Ejection Fraction.

BACKGROUND: Giant cell myocarditis (GCM) is rapidly progressive fulminant myocarditis causing death or requiring cardiac transplantation despite various immunosuppression therapies. CASE REPORT: A 28-year-old woman with progressive shortness of breath and palpitation following an upper respiratory infection was referred to our institution. On admission, transthoracic echocardiography (TTE) revealed a preserved left ventricular ejection fraction (LVEF) with mildly impaired LV diastolic function despite extensive ECG abnormalities, a mildly elevated troponin I concentration, and moderately elevated N-terminal pro-brain natriuretic peptide (NT-pro-BNP) concentration. The diagnosis of GCM was made by endomyocardial biopsy (EMB), which revealed extensive fibrosis and inflammatory infiltration with multinucleated giant cells, as well as scattered eosinophils and lymphocytes in the absence of granuloma formation. However, the patient's symptoms began to improve without any specific therapy within 2 weeks, followed by the normalization of the ECG abnormalities, TTE-determined diastolic function, and troponin I and NT-pro-BNP concentrations. In sub-acute phase, 18F-fluorodeoxyglucose positron emission tomography showed no evidence of inflammation, and repeat EMB showed a significant decrease in the inflammatory infiltration and fibrosis, including absence of giant cells. Given the favorable clinical course, the patient was discharged without medications. At the 6-month follow-up, the patient had no LV functional impairment, cardiovascular events, or arrhythmia. CONCLUSIONS: We encountered a rare case of atypical GCM in which clinical and histologic remission was achieved without immunosuppression therapy. There seems to be a population of GCM patients who improve without immunosuppression therapy. In monitoring GCM patients, clinicians should be aware of the possibility of spontaneous remission.