Cholinesterase inhibition reduces arrhythmias in asymptomatic Chagas disease.

INTRODUCTION: Parasympathetic dysfunction may play a role in the genesis of arrhythmias in Chagas disease. AIM: This study evaluates the acute effects of pyridostigmine (PYR), a reversible cholinesterase inhibitor, on the occurrence of arrhythmias in patients with Chagas cardiac disease. METHOD: Following a double-blind, randomized, placebo-controlled, cross-over protocol, 17 patients (age 50±2 years) with Chagas cardiac disease type B underwent 24-hour Holter recordings after oral administration of either pyridostigmine bromide (45 mg, 3 times/day) or placebo (PLA). RESULTS: Pyridostigmine reduced the 24-hours incidence (median [25%-75%]) of premature ventricular beats-PLA: 2998 (1920-4870), PYR: 2359 (940-3253), P=.044; ventricular couplets-PLA: 84 (15-159), PYR: 33 (6-94), P=.046. Although the total number of nonsustained ventricular tachycardia in the entire group was not different (P=.19) between PLA (1 [0-8]) and PYR (0 [0-4]), there were fewer episodes under PYR in 72% of the patients presenting this type of arrhythmia (P=.033). CONCLUSION: Acute administration of pyridostigmine reduced the incidence of nonsustained ventricular arrhythmias in patients with Chagas cardiac disease. Further studies that address the use of pyridostigmine by patients with Chagas cardiac disease under a more prolonged follow-up are warranted.

Pyridostigmine reduces QTc interval during recovery from maximal exercise in ischemic heart disease.

Following a randomized, cross-over, and double-blind design, 14 patients with coronary heart disease were submitted, to maximal cardiopulmonary exercise tests on a treadmill, 2 h after the oral administration of either placebo or pyridostigmine bromide (45 mg), a reversible cholinesterase inhibitor. One observer, who was blind to the experimental condition, measured RR and QT intervals over the 12 electrocardiographic leads in the first and third minute of active recovery from exercise. Paired t test was used to compare each variable measured in the same moment after placebo and pyridostigmine. Pyridostigmine reduced the QTc interval in the first minute of active recovery when compared to placebo (P=0.004). Two patients, whose heart rate recovery (1st minute) was below normal values (patient 1=4 bpm; patient 2=7 bpm; i.e. <12 bpm) presented with correction of this variable after pyridostigmine ingestion (patient 1=22 bpm; patient 2=36 bpm). Prospective trials should evaluate the impact of cholinergic stimulation with pyridostigmine on mortality.

Estimulação colinérgica com peridostigmina em coronariopatas durante o exercício diâmico / Cholinergic stimulation with peridostigmina during exercise in patients with coronary diâmico

A disfunção parassimpática correlaciopna-se com pior prognóstico após infarto agudo do miocárdio e na insuficiência cardíaca, independente da presença de outros fatores de risco. A atualização de uma droga que atue aumentando a ação colinérgica, tem potencial efeito benéfico em portadores de cardiopatias. O objetivo foi estudar o efeito do brometo de piridostigmina(PIR). um inibidor reversível da atividade colinesterásica, portanto um parassimpaticomimético indireto, sobre as respostas cardiorespiratórias no teste cardioplumunar de exercício (TCPE) em portadores de doença coronariana estável. PIR inibiu FC no exercício submáxino, aumentou a intensidade na qual a isquemia miocárdica ocorreu e melhorou a tolerância ao exercício. Estas alterações sugerem que PYR pode apresentar potencial efeito cardioprotetor em pacientes com doença arterial coronária que apresentem isquemia miocárdica induzida pelo esforço.