title: Methodology and instrumentation for the in vitro sinus node recovery time determination.
abstract: In the present work we describe a methodology and a low-cost instrument to determine the sinus node recovery time (SNRT) in the isolated rat right atrium. The instrumentation measures the SNRT using the continuous pacing method and the method of stimulation with premature pulses. When these methods were compared, we observed that the corrected SNRT (CSNRT = SNRT - the mean spontaneous cycle length, MCL) significantly (p less than 0.001) depended on the method used. The effects of norepinephrine (NE) and acetylcholine (ACh) on MCL and CSNRT were also analyzed. Although both neurotransmitters affected MCL (p less than 0.001), only in the presence of ACh a significant (p less than 0.05) correlation between CSNRT and MCL was found. In both methods, the CSNRT values were quite reproducible. The agreement between the data obtained and the predictions of the theoretical models for in vivo SNRT determination suggests that the present methodology may be useful for studies concerning physical and chemical influences on SNRT, as well as for the development of new stimulation tests.
authors.affiliation: Department of Biomedical Engineering, Universidade Estadual de Campinas, Sao Paulo, Brazil.
authors.forename: J L
authors.initials: JL
authors.lastname: Marques
authors.forename: R A
authors.initials: RA
authors.lastname: Bassani
authors.forename: J W
authors.initials: JW
authors.lastname: Bassani
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000465:Algorithms; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D004558:Electric Stimulation; D004594:Electrophysiology; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012849:Sinoatrial Node / Q000502:physiology*; D012984:Software
chemical_list: D000109:Acetylcholine; D009638:Norepinephrine