493 A CASE REPORT OF SUBACUTE INFLAMMATORY HEART DISEASE WITH AN ATYPICAL ONSET

Abstract

Abstract Background Inflammatory heart disease is a heterogeneous process with variegate clinical manifestations. The acute phase is characterized by a sudden injury involving cardiomyocytes, cardiac conduction system and/or pericardium, with different pathophysiological implications. Case Summary A 26-year-old previously healthy woman presented for worsening fatigue and bradycardia. The ECG at admission showed total heart block with infra-Hisian escape rhythm, heart rate was 36 bpm. She reported no history of tick bite or recent inflammatory event; body temperature was 36,8 °C. Laboratory assessment showed persistently raised troponin (28943 -> 32632 ng/l), C-reactive protein was 0,70 mg/l, white blood cells 4,86×10^3/µl, procalcitonin 0,03 µg/l, interleukin-6 was 60,5 pg/ml (n.v. <28,0) and NT-pro-BNP was 312 pg/ml. Borrelia, Salmonella, Ricketsiae, Toxoplasma screening was negative for acute infection as well as any other viral serology. Comprehensive laboratory autoimmunity assessment was negative. Echocardiography revealed normal biventricular volume and kinetics, no valvulopathies and no pericardial effusion. Coronary angiogram was normal. The cardiac magnetic resonance showed extensive oedema and contextual late gadolinium enhancement predominantly in the interventricular septum and mid segment of the anterior wall. Serum angiotensin-converting enzyme concentration was normal. Due to persistent heart block, after 5 days the patient underwent endomyocardial biopsy that showed slight oedema and mild fibrosis without lymphocytic infiltration nor histochemical findings suggestive of active myocarditis. Granulomas were absent. Viral analysis on myocardium was negative. An intermediate dose of steroids was started with a progressive restoration of 1:1 atrioventricular conduction and shortening of QRS up to incomplete right bundle branch block, hence the patient was discharged without pacemaker implantation. Discussion In heart inflammatory diseases with bradyarrhythmic onset, atrioventricular conduction may be restored with targeted therapy. Multimodality assessment is crucial in the diagnostic and therapeutic work-up of these cases.