The sick sinus syndrome.
D001146:Arrhythmia, Sinus / Q000150:complications* / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D001919:Bradycardia / Q000150:complications; D006339:Heart Rate; D006801:Humans; D013577:Syndrome; D013610:Tachycardia / Q000150:complications