English Reading Materials Chapter 21:Vasodilators the Treatment of Angina Pectoris INTRODUCTION Angina pectoris is the most common condition involving tissue ischemia in which vasodilator drugs are used.The name denotes chest pain caused by accumulation of metabolites resulting from myocardial ischemia.The organic nitrates,eg, nitroglycerin,are the mainstay of therapy for the immediate relief of angina.Another group of vasodilators,the calcium channel blockers,is also important,especially for prophylaxis,and the blockers,which are not vasodilators,are also useful in prophylaxis.New groups of drugs under investigation include fatty acid oxidation inhibitors and selective cardiac rate inhibitors. Ischemic heart disease is the most common serious health problem in many Western societies.By far the most frequent cause of angina is atheromatous obstruction of the large coronary vessels (atherosclerotic angina,classic angina).However,transient spasm of localized portions of these vessels,which is usually associated with underlying atheromas,can also cause significant myocardial ischemia and pain (vasospastic or variant angina). The primary cause of angina pectoris is an imbalance between the oxygen requirement of the heart and the oxygen supplied to it via the coronary vessels.In classic angina,the imbalance occurs when the myocardial oxygen requirement increases,as during exercise,and coronary blood flow does not increase proportionately.The resulting ischemia usually leads to pain.Classic angina is therefore "angina of effort."(In some individuals,the ischemia is not always accompanied by pain,resulting in "silent"or "ambulatory"ischemia.)In variant angina,oxygen delivery decreases as a result of reversible coronary vasospasm. Variant angina is also called Prinzmetal's angina. In theory,the imbalance between oxygen delivery and myocardial oxygen demand can be corrected by decreasing oxygen demand or by increasing delivery (by increasing coronary flow).In effort angina,oxygen demand can be reduced by decreasing cardiac work or,according to recent studies,by shifting myocardial metabolism to substrates that require less oxygen per unit of ATP produced.In variant angina,on the other hand,spasm of coronary vessels can be reversed by nitrates or calcium channel blockers.Lipid-lowering drugs,especially the "statins,"have become extremely important in the long-term treatment of atherosclerotic disease. 11 English Reading Materials Chapter 21: Vasodilators  the Treatment of Angina Pectoris INTRODUCTION Angina pectoris is the most common condition involving tissue ischemia in which vasodilator drugs are used. The name denotes chest pain caused by accumulation of metabolites resulting from myocardial ischemia. The organic nitrates, eg, nitroglycerin, are the mainstay of therapy for the immediate relief of angina. Another group of vasodilators, the calcium channel blockers, is also important, especially for prophylaxis, and the blockers, which are not vasodilators, are also useful in prophylaxis. New groups of drugs under investigation include fatty acid oxidation inhibitors and selective cardiac rate inhibitors. Ischemic heart disease is the most common serious health problem in many Western societies. By far the most frequent cause of angina is atheromatous obstruction of the large coronary vessels (atherosclerotic angina, classic angina). However, transient spasm of localized portions of these vessels, which is usually associated with underlying atheromas, can also cause significant myocardial ischemia and pain (vasospastic or variant angina). The primary cause of angina pectoris is an imbalance between the oxygen requirement of the heart and the oxygen supplied to it via the coronary vessels. In classic angina, the imbalance occurs when the myocardial oxygen requirement increases, as during exercise, and coronary blood flow does not increase proportionately. The resulting ischemia usually leads to pain. Classic angina is therefore "angina of effort." (In some individuals, the ischemia is not always accompanied by pain, resulting in "silent" or "ambulatory" ischemia.) In variant angina, oxygen delivery decreases as a result of reversible coronary vasospasm. Variant angina is also called Prinzmetal's angina. In theory, the imbalance between oxygen delivery and myocardial oxygen demand can be corrected by decreasing oxygen demand or by increasing delivery (by increasing coronary flow). In effort angina, oxygen demand can be reduced by decreasing cardiac work or, according to recent studies, by shifting myocardial metabolism to substrates that require less oxygen per unit of ATP produced. In variant angina, on the other hand, spasm of coronary vessels can be reversed by nitrates or calcium channel blockers. Lipid-lowering drugs, especially the "statins," have become extremely important in the long-term treatment of atherosclerotic disease