Recent developments in reperfusion therapy for acute myocardial infarction.

The efficacy, and mechanisms of benefit, of thrombolytic therapy in reducing mortality following myocardial infarction are time-dependent. Early treatment results in myocardial salvage and preservation of left ventricular function, mediated through prompt restoration of normal antegrade infarct artery perfusion. Later treatment exerts favourable effects on electrical stability of the myocardium and may attenuate progressive left ventricular dilation independent of myocardial salvage. Tissue plasminogen activator, administered using an accelerated, front loaded dosing regimen, affords early infarct artery patency which is superior to that achieved with streptokinase and is associated with a small, but significant, further reduction in mortality. The implications for choice of thrombolytic agent in a cost-contained health care system are examined, as is the importance of minimizing in-hospital delay in administering thrombolytic agents in the setting of acute myocardial infarction (AMI). Recognition of the pivotal role of patency and the shortcomings of thrombolytic agents in achieving optimal reperfusion has lead to renewed interest in percutaneous transluminal coronary angioplasty (PTCA) as primary therapy for AMI, Preliminary results are promising but must be confirmed in larger studies. Primary PTCA should be considered for patients with AMI and contraindications to thrombolytic therapy.