Circulatory assistance for the failing heart.

Although coronary care units have been successful in reducing the in-hospital mortality after acute myocardial infarction, this is largely a result ofpreventing and treating dysrhythmias. Thefailing myocardium remains a therapeutic challenge and current medical therapy disappointing. Methods ofproviding the heart with mechanical support are described and indications and contraindications to their use are detailed. The results of clinical trials are reported, including the use of bypass pumps and especially the intra-aortic balloon. A recent advance has been the availability of noninvasive support techniques, and results using external synchronous compression are detailed. All methods of circulatory support require careful documentation of claims of their effectiveness. Emphasis should be placed on demonstrating improved myocardial perfusion, preservation of myocardial cells, and reduction in size of the infarct since mortality rates continue to be unacceptably high despite initial haenodynamic improvement even when circulatory support is combined with emergency selective coronary arteriography and direct coronary arterial surgery.