Left heart bypass without thoracotomy.
An effective, simple and rapidly installed temporary mechanical assistance to the heart is needed. It should be capable of sustaining adequate circulation for several weeks. Patients with extensive myocardial infarctions, complicated by cardiogenic shock, or in end-stage heart failure, and who are candidates for heart replacement by transplantation or by a mechanical device, would benefit from such circulatory assistance. A mediastinal route was developed in human cadavers and in dogs institute left heart bypass without thoracotomy. Anatomical studies demonstrated the accessibility of the left atrium via the anterior mediastinum. A silastic cannula was made that can be inserted, with the help of a stylet, in the left atrium, via a mediastinoscopy. Two balloons attached to the cannula secure it onto the atrial wall and prevent hemorrhage. The cannula is connected to an extracorporeal circuit that is able to pump up to 90% of the cardiac output back into a femoral artery. The insertion of the atrial cannula proved to be simple, and the system very effective.