Qual o diagnóstico? Qual o Diagnóstico?

A female 82-year-old Caucasian patient with a history of paroxysmal atrial fibrillation (AF) for several years, with palpitation crises of varying duration between a few minutes and several hours, without clinical control, using beta-blockers and diltiazem. The patient presented complaints of fatigue on moderate efforts, without precordial pain or syncope, with progressive asthenia and indisposition. She informed three previous hospitalizations for chemical cardioversion of AF.