Myocardial injury in the mouse induced by transthoracic cauterization

A simplified transthoracic procedure using electrocauterization was used to induce myocardial injury in mice. After a single small incision through the skin and dissection of the underlying musculature, a modified electrocautery probe consisting of an insulated 20-gauge blunt needle with a polyethylene sleeve was inserted through the interior intercostal muscle at the fourth intercostal space and positioned on the anterior surface of the heart. The placement of the probe on the heart was indicated by mechanical motion of the exterior section of the needle. Electrocautery was applied to the distal exposed end of the probe. Of 10 mice that underwent this procedure, nine survived. After 10 days, myocardial damage was assessed by visual and histologic examination of the heart. In eight of nine surviving mice, transmural injury was induced in the left ventricle. The region of myocardial tissue damage on the surface of the left ventricle was 4.6 +/- 0.5 mm in diameter. This method provides a simple, noninvasive technique using a transthoracic electrocautery procedure to induce myocardial injury in the mouse heart with a low incidence of postoperative mortality.