Mechanical cardiac assistance: historical perspectives

Cardiac transplantation remains the therapeutic option of choice for treating patients with chronic, progressive, end-stage heart failure. However, over the past 40 years, a number of mechanical assist systems have been developed with the goal of treating and rehabilitating patients with severe circulatory compromise. Today, a wide array of devices is available to provide increasing levels of circulatory support. When used as bridges to heart transplantation, long-term circulatory support systems are a reliable means of keeping heart-failure patients alive as they await suitable donor hearts. Initially, transplant candidates who were receiving this type of support were unable to leave the hospital; today, however, because of advances in mechanical support technology and the portability of the current systems, these patients may return to their homes and even to their jobs while awaiting transplantation. Although heart transplantation may now be considered a routine procedure, the demand for donor hearts will always outweigh the supply, creating a definite need for long-term mechanical circulatory support. Already, clinical trials are underway to test the effectiveness of left ventricular assist devices as long-term support. As smaller, more effective cardiac assist devices become available, they should benefit even more the number of patients who may need permanent circulatory support. The fact that myocardial function can improve enough with chronic ventricular unloading to allow removal of the device may further broaden the use of this technology.