P319 SOMETHING MORE OF SIMPLE CARDIAC CONDUCTION DISORDERS

Abstract

Abstract Background Cardiac amyloidosis (CA) is an infiltrative disease caused by extracellular deposition of amyloid fibrils. Possible cardiac manifestations include heart failure with preserved ejection fraction (EF), aortic valve stenosis, microvascular coronary artery disease, atrial fibrillation (AF), ventricular arrhythmias, and cardiac conduction disorders (CCD). We report a case of advanced CCD in a patient first diagnosed with wild–type transthyretin amyloidosis (ATTRwt). Case Report An 88–year–old man went to Emergency Room for chest pain with minimal elevation of troponin I and increase in NTproBNP. The patient reported a recent syncope with ribs fractures. The medical history showed hypertension, paroxysmal AF, carotid atherosclerosis, vascular encephalopathy and prostate cancer. Troponin I monitoring showed plateau values and there were no clinical signs of heart failure. ECG showed regular sinus rhythm with marked first degree atrioventricular block, right bundle branch block and left anterior fascicular block (Fig. 1A). Cardiac telemetry recorded brief phases of atrioventricular dissociation (AVD). Transthoracic echocardiography showed severe left ventricular concentric hypertrophy (LVCH) with granular–sparkling appearance and preserved EF, reduced global longitudinal strain with apical sparing (Fig. 1B), mitral–aortic valve degeneration and dilation of the ascending aorta. Given the advanced CCD with AVD and the recent syncope, the patient underwent a dual–chamber pacemaker implantation. In consideration of the echocardiographic suspicion of CA, following Gillmore’s diagnostic algorithm (GDA), serum electrophoresis and assay of serum free light chains were performed and resulted normal, while 99mTc–DPD bone scintigraphy was positive for significant radiotracer cardiac uptake (Perugini grade 3) (Fig. 1C). Based on this result, we carried out the search for transthyretin gene mutations which resulted negative, and therefore the diagnosis of ATTRwt was made. Discussion Advanced CCD in patients with transthyretin CA are present in about 9.5% of cases at the time of diagnosis, especially in older patients. It is therefore essential, in case of concomitant LVCH, to suspect the presence of CA as the cause of CCD by searching for the disease red flags and following the GDA to non–invasively confirm or exclude the diagnosis of CA. A correct and timely diagnosis of CA makes it possible to treat the disease and its complications, improving the prognosis.