Introduction: Although atherosclerosis represents the most frequent cause of acute myocardial infarction (AMI), searching for other etiologies is necessary in patients with no evidence of obstructive coronary artery disease. Identifying an embolic cause can be difficult in patients with multiple comorbidities.
Case presentation: We present the case of a 56 year-old ex-smoker man admitted to the hospital due to a ST elevation myocardial infarction of the inferior wall, at 4 hours after pain onset. Of note, the patient was recently investigated in another hospital for a respiratory event associated with fever and treated with antibiotics. On same occasion, he was diagnosed with new onset atrial fibrillation and anticoagulant treatment with acenocumarol was started. On examination, he presented with no fever, but a systolic murmur radiating to the axilla and another continuous murmur radiating to the ca-rotid arteries could be heard. Biomarkers compatible with cardiomyocite injury were positive, INR was 1.9 and no leukocytosis was noticed. Emergent coronary angiography revealed an embolic occlusion of the distal segment of the left anterior descending artery, without further lesions of the coronary arteries. Therefore, the mechanism of the AMI was considered embolic, re-lated to atrial fibrillation, in a recently anticoagulated patient. Medical treatment (with triple therapy, statin, angiotensin enzyme inhibitor and beta-blocker) was started, with favorable evolution. Transthoracic echo-cardiography showed hypokinesia of the apex, mild left ventricular systolic dysfunction and severe valvular heart disease (VHD) (moderate aortic stenosis and mo-derate-severe aortic regurgitation, large mitral stenosis and moderate-severe mitral regurgitation), probably of rheumatic origin. Considering the severity of the VHD with indication for surgery, the patient was reevaluated by means of trans-esophageal echocardiography at one month after the acute event. This evaluation revealed a bicuspid aortic valve due to the fusion of the right and left coronary cusps, complicated with pseudo-aneurysm of the aortic ring and subsequent aortic regurgitation, as well as a mobile vegetation attached to the A1 leaflet of the mitral valve, with leaflet flail and subsequent severe mitral regurgitation Carpentier type 1. In this context, the patient was diagnosed with infective endocarditis and this disease was regarded as the cause of the embolic myocardial infarction. The patient was transferred to an infectious disease unit, where he was investigated by means of blood cultures (repeatedly ne-gative for common bacteria) and was treated with antibiotics (cefoperazone and gentamycin). The patient was afterwards referred to a cardiac surgery unit.
Particularity of the case: The particularity of the case is that the acute myocardial infarction was the first manifestation of an infective endocarditis with atrial and mitral valve involvement. The patient was olygosimptomatic from an infectious point of view.
Discussions: Embolic myocardial infarction is an uncommon complication of infective endocarditis (incidence ranges between 1 and 10%) associated with a high mortality risk. The diagnosis requires a high index of suspicion in patients presenting with angina and fever. Transesophageal echocardiography is usually the diagnostic tool for this disease.