stability in cyclic epidemic models a general formulation for a family of cyclic epidemic models with densitydependent feedback mechanisms and removed classes is presented a parameter lambda related to the basic reproductive rate determines the asymptotic behaviour of solutions of the model it is shown that if lambda less than 1 the trivial solution is globally stable and if lambda greater than 1 it is conditionally stable the results are applied to a set of differential equations that has been used to model the life cycle of a parasite that has two hosts transventricular mitral valve replacement in a patient with a left ventricular aneurysm report of a case postinfarct left ventricular aneurysm associated with mitral valve regurgitation is resistant to medical treatment and often requires surgical repair a transventricular approach to the mitral valve in such a patient can enable the surgeon to avoid incision of the right or left atrium and can provide for safe and reliable surgical intervention we report herein the case of a patient in whom left ventricular aneurysmectomy and concomitant mitral valve replacement were successfully performed using a transventricular approach via aneurysmectomy