Myocardial Infarction

• Introduction

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• ST Elevation Infarction
• Thrombolytic Therapy- Reducing Mortality
• Thrombolytic Therapy- Additional Benefits

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• Assessing Extent of Infarction
• ECG and Q Waves

Thrombolytic Therapy for ST-segment Elevation Myocardial Infarction

Benefits in Addition to Reducing Mortality Rates

The benefits of thrombolytic therapy extend beyond mortality reduction.

In the early days of thrombolytic therapy, the group from Green Lane Hospital randomised patients with ST-elevation infarction, presenting early, to receive streptokinase or placebo.

They found that patients with first infarctions treated with streptokinase, left ventricular ejection fraction was 6% higher than placebo treated patients (59 vs 53%) with much greater benefit to those with anterior infarction (57 vs 49%) compared with inferior infarction (60 vs 55%).

Significant mitral regurgitation after infarction is being recognised as an adverse prognostic indicator. An interesting study examined the occurence of significant mitral regurgitation after inferior myocardial infarction. This study found that thrombolytic therapy after inferior ST elevation infarction reduced hypokinesis of the posterobasal segment and this meant less mitral regurgitation.

References:

• Effect of intravenous streptokinase on left ventricular function and early survival after myocardial infarction, NEJM 1987;317:850-855
  
• Improved posterobasal segment function after thrombolysis is associated with decreased incidence of signifiacnt mitral regurgitation in a first inferior myocardial infarction, J Am Coll Cardiol 1995;25:1558-63