The sick sinus syndrome.
D001146:Arrhythmia, Sinus / Q000209:etiology* / Q000628:therapy; D001919:Bradycardia / Q000209:etiology* / Q000628:therapy; D006801:Humans; D013577:Syndrome; D013614:Tachycardia, Paroxysmal / Q000209:etiology* / Q000628:therapy