title: Seemingly complex QRS alternation: what is the mechanism?
authors.affiliation: Department of Internal Medicine, Carolinas Medical Center, Charlotte, North Carolina 28203, USA. LLittmann@carolinas.org
authors.forename: L
authors.initials: L
authors.lastname: Littmann
authors.forename: M H
authors.initials: MH
authors.lastname: Monroe
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000503:physiopathology; D002317:Cardiovascular Agents / Q000008:administration & dosage; D003937:Diagnosis, Differential; D004110:Diltiazem / Q000008:administration & dosage; D004562:Electrocardiography; D006329:Heart Conduction System / Q000187:drug effects / Q000503:physiopathology; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis* / Q000503:physiopathology; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis* / Q000503:physiopathology; D013686:Telemetry
chemical_list: D002317:Cardiovascular Agents; D004110:Diltiazem