Nitroglycerin in acute myocardial infarction.

Nitroglycerin is an effective agent for reducing preload and afterload in acute myocardial infarction. Until two decades ago, it was considered to be contra-indicated in acute myocardial infarction because of fear of hypotension and reflex tachycardia. Recent animal studies indicated that prolonged low dose infusion during early stages of acute infarction, titrated to decrease mean arterial pressure by 10% but not below 80 mmHg, produced marked increase in collateral blood flow and decrease in infarct size. However, higher doses to further decrease blood pressure offset the beneficial effect on collateral flow and infarct size. More importantly, clinical studies have confirmed that low dose intravenous nitroglycerin is safe therapy during acute myocardial infarction for improving left ventricular performance, limiting infarct size and reducing infarct related complications.