title: Heart rate and the PR interval.
mesh_terms: D000328:Adult; D000368:Aged; D003936:Diagnosis, Computer-Assisted; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors