Combined papillary muscle and left ventricular wall infarction produced mitral insufficiency in 14 of 16 dogs (87.5%), whereas isolated infarction of either structure did not.
Does combined papillary muscle and left ventricular wall infarction cause mitral regurgitation in a canine model compared to isolated infarction of either structure?
Papillary muscle infarction alone does not lead to mitral regurgitation; it requires concurrent left ventricular wall dyskinesia or dilatation to produce mitral valve incompetency.
Absolute Event Rate: 87.5% vs 0%
Papillary muscle infarction was produced in 16 mongrel dogs by placing sutures around the base of one of the papillary muscles. In addition, patchy infarction of the adjacent left ventricular wall was produced by placing an Ameroid constrictor around the appropriate coronary artery. Mitral insufficiency developed in 14 of these animals; it was severe in four and mild to moderate in ten. Mitral insufficiency was not produced by isolated infarction of a papillary muscle or by isolated infarction of the left ventricular wall. It is concluded that papillary muscle infarction alone does not lead to mitral regurgitation, but that papillary; muscle dysfunction acts in concert with left ventricular wall dyskinesia or dilatation to produce mitral valve incompetency.
Mittal et al. (Sun,) conducted a other in Mitral Regurgitation (n=16). Combined papillary muscle and left ventricular wall infarction vs. Isolated infarction of a papillary muscle or left ventricular wall was evaluated on Development of mitral insufficiency. Combined papillary muscle and left ventricular wall infarction produced mitral insufficiency in 14 of 16 dogs (87.5%), whereas isolated infarction of either structure did not.