哈尔滨医科大学_药理学_抗心绞痛药.ppt

抗心绞痛药Antianginal Drugs Factors affecting myocardial oxygen demand and oxygen supply * * Oxygen demand Oxygen supply = Coronary blood flow Regional myocardial distribution Ventricular volume LV pressure Wall tension Heart rate Contractile state Aortic pressure Coronary vascular resistance Chemical structures of two nitrates Nitroglycerine Isosorbide dinitrate -O-NO2 Reflex increase in contractility Decreased myocardial perfusion Decreased diastolic perfusion time due to tachycardia Increased myocardial oxygen requirement Potential deleterious effects Reflex tachycardia Improved subendocardial perfusion Decreased left ventricular diastolic pressure Improved perfusion to ischemic myocardium Increased collateral flow Relief of coronary artery spasm Vasodilation of epicardial coronary arteries Decreased ejection time Decreased arterial pressure Decreased myocardial oxygen requirement Potential beneficial effects Decreased ventricular volume Result Effect Beneficial and deleterious effects of nitrates in the treatment of angina ? Nitrates alone β-blockers Combined nitrates with β-blockers Heart rate Reflex increase Decrease Decrease Arterial pressure Decrease Decrease Decrease* End-diastolic volume Decrease Increase None or decrease Contractility Reflex increase Decrease None Ejection time Decrease Increase None Effects of nitrates alone and with β-blockers in angina pectoris