ABSTRACT
In the present study we standardized an experimental model of parabiotic circulation of isolated pig heart. The isolated heart was perfused with arterial blood from a second animal as support and submitted to regional ischemia for 30 min, followed by total ischemia for 90 min and reperfusion for 90 min. Parameters for measurement of ventricular performance using different indices measured directly or indirectly from intraventricular pressure were defined as: maximum peak pressure, final diastolic pressure, pressure developed, first derivative of maximum pressure (dP/dt max), first derivative of minimum pressure (dP/dt min), systolic stress of the left ventricle (sigmas), and maximum elastance of the left ventricle. Isolated hearts subjected to regional and global ischemia presented significant worsening of all measured parameters. Less discriminative parameters were dP/dt max and dP/dt min. Elastance was the most sensitive parameter during the reperfusion period, demonstrating an early loss of ventricular function during reperfusion. The model proved to be stable and reproducible and permitted the study of several variables in the isolated heart, such as ischemia and reperfusion phenomena, the effects of different drugs, surgical interventions, etc. The model introduces an advantage over the classical models which use crystalloid solutions as perfusate, because parabiotic circulation mimics heart surgery with extracorporeal circulation
Subject(s)
Animals , Cross Circulation , Myocardial Reperfusion , Analysis of Variance , Blood Pressure , Heart Rate , Myocardial Reperfusion , Swine , Ventricular Function, LeftABSTRACT
Os marcapassos responsivos foram um grande avanço na estimulaçäo cardíaca, contudo, a escolha de um biossensor fisiológico adequado é objeto de muito estudo. Mulher de 35 anos com marcapasso responsivo devido a bloqueio atrioventricular total (BAVT) secundário a correçäo de comunicaçäo interventricular deu entrada com insuficiência cardíaca (IC) e estimulaçäo peitoral importante na loja do marcapasso, que levou a interpretaçäo errônea, causando IC. Uma soluçäo paliativa foi tomada até o fim da gestäo, dimunuindo-se a sensibilidade do biossensor.