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Left Ventricle Radio-frequency Ablation in the Rat: A New Model of Heart Failure due to Myocardial Infarction Homogeneous in Size and Low in Mortality

2009; Elsevier BV; Volume: 15; Issue: 6 Linguagem: Inglês

10.1016/j.cardfail.2009.01.007

1532-8414

Ednei Luíz Antonio, Alexandra Alberta dos Santos, Sérgio Araújo, Danilo Sales Bocalini, Leonardo dos Santos, Guilherme Fenelon, M.F. Franco, Paulo José Ferreira Tucci,

Cardiac Arrhythmias and Treatments

The purpose of the current study was to create a model of myocardial infarction (MI) that is homogeneous in size with a low immediate (24 hours) mortality.Male and female rats (n = 256) underwent left ventricle (LV) ablation (Ab) by a radiofrequency current (1000 kHz; 12 watts for 12 seconds) to promote a MI. A transmural MI occurred in all rats. Post-Ab complex arrhythmias were frequent (atrioventricular block, ventricular tachycardia, and fibrillation), which rapidly and spontaneously reverted to sinus rhythm. Among 66 male rats, immediate mortality occurred in 7.5%. Small MI size dispersion was characterized by smaller variability following Ab (x +/- SD: 45 +/- 8%) when compared with coronary occlusion (Oc; 40 +/- 19%). The histopathologic evaluations identified lesions similar to those which occurred following Oc, with scarring complete at 4 weeks. The hemodynamic and Doppler echocardiograms showed comparable increases in LV dimension, end-diastolic pressure, and pulmonary water content 1 and 4 weeks post-MI. Papillary muscle mechanics 6 weeks post-MI had matched inotropic and lusitropic dysfunction.LV Ab gave rise to a MI within a narrow size limit and with a low immediate mortality. LV Ab resulted in histopathologic evolution, ventricular dilation, and dysfunction, impairment in myocardial mechanics, and congestive outcome that reproduced a MI from Oc.