title: 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.
abstract: 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.
authors: Department of Physiology, Cardiovascular Division, Federal University of São Paulo (UNIFESP), Brazil.
authors: Ednei L
authors: EL
authors: Antonio
authors: Alexandra A
authors: AA
authors: Dos Santos
authors: Sérgio R R
authors: SR
authors: Araujo
authors: Danilo S
authors: DS
authors: Bocalini
authors: Leonardo
authors: L
authors: Dos Santos
authors: Guilherme
authors: G
authors: Fenelon
authors: Marcelo F
authors: MF
authors: Franco
authors: Paulo J F
authors: PJ
authors: Tucci
mesh_terms: 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