title: Coexistence of sick sinus rhythm and atrial flutter-fibrillation.
abstract: A 58-year-old man with hypertensive cardiovascular disease and atrial flutter underwent electrophysiologic studies, including multiple intra-atrial recordings and atrial stimulation. Although the surface ECG suggested the presence of atrial flutter, intra-atrial recordings demonstrated the presence of (1) sinus-like rhythm localized to an area of approximately 5 mm in and around the region of the sinus node, which was protected by entrance block; (2) flutter and/or fibrillation of the remaining parts of the right atrium; (3) fibrillation of the left atrium; and (4) transient degeneration of flutter into fibrillation at right atrial sites, with predominant flutter activity. Although a major part of the right atrium was in flutter and/or fibrillation, we could assess sinus node function by overdrive stimulation of the area of sinus node-activity. Sinus node function studied revealed an underlying sick sinus syndrome.
mesh_terms: D001281:Atrial Fibrillation / Q000150:complications*; D001282:Atrial Flutter / Q000150:complications*; D001285:Atropine / Q000008:administration & dosage; D004562:Electrocardiography; D004594:Electrophysiology; D006333:Heart Failure / Q000150:complications; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D012804:Sick Sinus Syndrome / Q000150:complications* / Q000175:diagnosis
chemical_list: D001285:Atropine