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.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Antonio
Ednei L
EL
Department of Physiology, Cardiovascular Division, Federal University of São Paulo (UNIFESP), Brazil.
Dos Santos
Alexandra A
AA
Araujo
Sérgio R R
SR
Bocalini
Danilo S
DS
Dos Santos
Leonardo
L
Fenelon
Guilherme
G
Franco
Marcelo F
MF
Tucci
Paulo J F
PJ
D000818:Animals; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D004195:Disease Models, Animal; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000401:mortality* / Q000473:pathology*; D006352:Heart Ventricles / Q000601:surgery; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000401:mortality* / Q000473:pathology*; D051381:Rats