Electrocardiographic and atrial sensibility analysis in rats treated with transcutaneous electrical diaphragmatic stimulation

[Abstract] Objective The objective was to carry out an electrocardiographic evaluation and determine the atrial sensibility to catecholamines in rats submitted to a protocol of transcutaneous electrical diaphragmatic stimulation (TEDS).Methods Twenty唱four male Wistar rats(3 ~4 months) were divided into two experimental groups(n = 12/group):control(C) and treated with TEDS( f=50 Hz,TON =2 s,TO FF =2 s,I =5 mA with an increase of 1 mA every 3 minutes,T=0.4 ms,t=20 minutes) for 7 days.After the experimental period,the animals were anaesthe唱 tized for the electrocardiographic analysis(n=6/group),or sacrificed to evaluate the sensibility of the isolated right atrium to noradrenalin in vitro ( n =6/group).The statistical analysis consisted of a test for normality and the Student,t唱test( P <0畅05).Results TEDS promoted no alterations in the electrocardiographic analysis,including the heart rate,amplitudes of the PR,QR,QT,QTc and the electric axis.In addition,no significant differences were observed between the two experimental groups in the basal heart beat rate,maximum response or sensibility to nora唱 drenalin of the isolated right atrium, or in the activity of the catecholamine metabolising system in this tissue. Conclusion The lack of alteration in the electrical activity of the heart tissue after the TEDS protocol showed its applicability and safety for use in studies with laboratory rats.