Patient History: An 83-old-female patient presents with a history of syncope. It has occurred three times in the last few months and there were no specific triggers. She is otherwise feeling well, has no other complaints and does not have any relevant medical history. Physical examination reveals no abnormalities except for a relatively slow heart rate (45 beats/min).

Her ECG is presented in the attached image. What is your diagnosis and what would you consider the most likely cause of her complaints? *This patient case is from Docplexus Editorial Team for educative purpose only. Source: ECGpedia The answers are posted in the comments section click here .