Effect of Nicorandil on Cardiac Sympathetic Nerve for the Patients of Acute ST Segment Elevation Myocardial Infarction

Effects of Nicorandil on Cardiac Sympathetic Nerve Activity and Distribution in Patients With Acute Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

The investigators evaluate the effects of intracoronary and intravenous administration of nicorandil on cardiac sympathetic nerve activity and distribution in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention

Reperfusion injury might occur in patients with acute ST segment elevation myocardial infarction undergoing the primary percutaneous coronary intervention(P-PCI),characterized by myocardial stunning, reperfusion-induced arrhythmia, microvascular dysfunction and injury of cardiac sympathetic nerve, etc.

Nicorandil is an antianginal agent with a dual mechanism of action: nitrate and K+ATP channel opener. The nitrate action causes vasodilation of systemic veins and epicardial coronary arteries, while the adenosine triphosphate (ATP)-sensitive potassium channel opener action causes vasodilation of peripheral and coronary resistance arterioles. Nicorandil not only decreases preload and afterload but also increases coronary blood flow.

The study will compare the effectiveness between nicorandil and placebo of preventing the reperfusion injury especially injury of cardiac sympathetic nerve in patients with acute ST segment elevation myocardial infarction undergoing the P-PCI.It is intended that before reperfusion injury ,nicorandil which was early used by intracoronary injection could prevent and release the microcirculatory spasm, release the coronary microvascular endothelial swelling,decrease embolism of atherosclerotic debris and thrombus formation,moreover,it could reduces the release of norepinephrine from sympathetic endings of the heart directly.So,it could decrease the phenomenon of no-reflow/slow reflow,reperfusion-induced arrhythmia and injury of cardiac sympathetic nerve.

Inclusion Criteria:

1. acute ST-segment elevation myocardial infarction within 12 hours of symptom onset;
2. Age20-80,All genders
3. anterior myocardial infarction
4. The first myocardial infarction
5. The infarct-related artery(IRA) is totally occlusive
6. Blood pressure is higher than 90/60 millimeters of mercury（mmHg）
7. The time from myocardial infarction onset to reach the hospital is less than 12 hs

Exclusion Criteria:

1. kidney dysfunction (creatinine >2 mg/dl),
2. History of previous liver disease,
3. Cardiogenic shock,
4. History of myocardial infarction (MI)
5. History of coronary artery bypass grafting
6. History of allergic response to drugs
7. Severe hypovolemia