Reduçäo da dispersäo do intervalo QTc: potencial mecanismo de proteçäo cardíaca do brometo de piridostigmina / Reduction of QTc interval dispersion: potential mechanism of cardiac protection of pyridostigmine bromide

ABSTRACT

OBJECTIVE: Parasympathetic dysfunction is an independent risk factor in individuals with coronary artery disease, and cholinergic stimulation is a potential therapeutical option. We determined the effects of pyridostigmine bromide, a reversible anticholinesterase agent, on electrocardiographic variables of healthy individuals. METHODS: We carried out a cross-sectional, double blind, randomized, placebo-controlled study. We obtained electrocardiographic tracings in 12 simultaneous leads of 10 healthy young individuals at rest before and after oral administration of 45 mg of pyridostigmine or placebo. RESULTS: Pyridostigmine increased RR intervals (before 886 + or - 27 ms vs after 1054 + or - 37 ms) and decreased QTc dispersion (before 72 + or - 9ms vs after 45 + or - 3ms), without changing other electrocardiographic variables (PR segment, QT interval, QTc, and QT dispersion). CONCLUSION: Bradycardia and the reduction in QTc dispersion induced by pyridostigmine may effectively represent a protective mechanism if these results can be reproduced in individuals with cardiovascular diseases.