EFFERENT VAGAL STIMULATION INCREASES INFARCT SIZE IN ACUTE MYOCARDIAL INFARCTION IN RABBITS

BUCHHOLZ B; RODRÍGUEZ JM; IVALDE FC; DONATO M; GELPI RJ

Buenos Aires

Congreso; XVII Reunion Anual de la Seccion Latino Americana de la International Society for Heart Research (ISHR); 2009

Seccion Latino Americana de la International Society for Heart Research (ISHR)

Vagal stimulation (VS) induces cardioprotective protein expression, attenuates arrythmias, and improves survival in the settings of myocardial infarction and heart failure. Despite these benefits, there are no conclusive data regarding the effects of VS on infarct size in acute myocardial infarction with reperfusion (R). The aim of our study was to evaluate the effect of VS on infarct size in two settings: when the VS was carried out either prior to the onset of ischemia or at the beggining of R. Methods: Open-chest rabbits were subjected to 45 min of regional ischemia followed by 4 hs of R, with or without efferent right VS. VS was performed during 10 min before ischemia or during the first 10 min of R. Risk area was measured by Evans blue stain and infarct size was assessed by triphenyltetrazolium chloride. Infarct size was expressed as percentage of risk area. Results: VS performed before ischemia or during R increased infarct size from 39.9+- 2.9% (n=7) to 57.8+- 5.7% (n= 6) (p<0.05) and 60.2+- 4.7% (n=5) (p<0.05); respectively. Conclusion: Our results clearly demostrate the effect of VS on infarct size in acute myocardial infarction. Contrary to some evidence showing beneficial effects of VS, vagal nerve stimulation performed either before ischemia or at the onset of reperfusion significantly increased the ischemia/reperfusion injury.