title: Electrophysiologic mechanisms: sinus node dysfunction.
mesh_terms: D001341:Autonomic Nervous System / Q000503:physiopathology; D004594:Electrophysiology / Q000379:methods; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D011930:Reaction Time; D012804:Sick Sinus Syndrome / Q000503:physiopathology*