title: ECG of the month. Normal and long P-R intervals. Sinus arrhythmia and a P-R interval that abruptly changes due to conduction down the fast atrioventricular (A-V) nodal pathway on some complexes and down the slow A-V nodal pathway on others.
authors.affiliation: Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, USA.
authors.forename: D Luke
authors.initials: DL
authors.lastname: Glancy
mesh_terms: D000328:Adult; D001146:Arrhythmia, Sinus / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006801:Humans; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology