title: Age-related effects of ischemia, lidocaine and verapamil on overdrive-induced suppression of ventricular pacemakers in isolated rat heart.
abstract: The effect of age on ventricular automaticity in the isolated perfused rat heart was determined under different conditions. When the ventricle is electrically stimulated at a faster rate, drive cessation is followed by a temporary suppression of ventricular automaticity (overdrive suppression). The effects of ischemia, lidocaine and verapamil on overdrive suppression were studied in isolated perfused adult and senescent rat hearts with complete atrio-ventricular block, by monitoring ventricular escape rate and escape rhythm recovery time after 1 minute of overdrive at a constant multiple (x3) of the spontaneous rate. The results demonstrated that: 1) lidocaine decreases ventricular automaticity especially in senescent hearts; 2) verapamil does not modify ventricular automaticity in basal conditions in either adult or senescent hearts; 3) myocardial ischemia causes a reduction in ventricular automaticity and more markedly in senescent hearts; and 4) lidocaine exaggerates the effect of ischemia, while verapamil seems to antagonize its depressant effect more in adult than in senescent hearts.
authors.affiliation: Institute of Internal Medicine, Cardiology and Cardiovascular Surgery, University of Napoli, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Abete
authors.forename: N
authors.initials: N
authors.lastname: Ferrara
authors.forename: D
authors.initials: D
authors.lastname: Leosco
authors.forename: P
authors.initials: P
authors.lastname: Caccese
authors.forename: P
authors.initials: P
authors.lastname: Landino
authors.forename: S
authors.initials: S
authors.lastname: Sederino
authors.forename: R
authors.initials: R
authors.lastname: Balbi
authors.forename: F
authors.initials: F
authors.lastname: Rengo
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D003327:Coronary Disease / Q000503:physiopathology*; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D016276:Ventricular Function / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D008012:Lidocaine; D014700:Verapamil