EMS 353. Lectures 6 Dr. Maha Khalid physiology of pharmacology cardiovascular system

3.Coronary Heart Diseases

Coronary Heart Diseaseatherosclerosis. angina pectoris myocardia l infarction

Coronary Heart Disease atherosclerosis. The major underlying cause is atherosclerosis. Atherosclerosis Atherosclerosis is a slow, progressive disease which begins in childhood and takes decades to advance

Coronary Heart Disease injury Plaque (the build-up of lipid/cholesterol) in the artery wall forms as a response to injury to the endothelium in the artery wall.

Coronary Artery Diseases Due to arterio- and atherosclerosis of the coronary arteries Fatty plaques cause blockage and decreased blood flow to the myocardium Main symptom is angina pectoris or chest pain, caused by lack of blood and oxygen Myocardial infarction (MI) occurs when an artery is totally blocked

atherosclerosis Atheroma Artery wall Blood within the artery Atheroma (fatty deposits) building up Fat deposits develop, restricting blood flow through the artery

coronary artery with atheroma Atheroma Coronary Artery with atherosclerosis Coronary Artery

atheroma Atheroma (fatty layer) Cross SectionLongitudinal Section

Angina Pectoris Chest pain due to coronary artery disease (CAD) and myocardial ischemia 1.Exertional angina (pain) usually occurs during physical exertion or stress 2.Vasospastic angina may occur at any time and is due to coronary artery vasospasm Untreated CAD and angina pectoris may lead to myocardial infarction and death

angina and heart attack angina ◦ narrowed coronary artery ◦ tightness or ache in the chest, breathlessness, sick feeling, dizziness ◦ comes on with exertion or emotion ◦ goes away with rest - usually 2-10 mins heart attack ◦ due to sudden blockage of the coronary artery ◦ chest pain “like a band”, indigestion, breathlessness, sickness, looking pale ◦ comes on at any time ◦ doesn’t go away - if still there in 15 minutes call for emergency

Drugs Used to Treat CAD Nitrites and nitrates Beta adrenergic blocking drugs Calcium antagonists, also referred to as calcium channel blockers

Nitrites and Nitrates Drugs stimulate the formation of nitric oxide, a potent vasodilator of blood vessels Vasodilation of veins and arteries decreases cardiac work and cardiac oxygen consumption to relieve the pain of myocardial ischemia Nitrites and nitrates may cause a drop in blood pressure and reflex tachycardia These drugs can be used to treat acute attacks of angina or to prevent anginal attacks

Drugs Used to Relieve Acute Attacks of Angina Amyl nitrite is administered by inhalation from a glass ampule, it has a sudden onset and duration of action of 5–10 minutes Nitroglycerin is administered as sublingual tablets which require a few minutes for onset and may last 30–45 minutes Nitroglycerin may also be administered intravenously in more severe cases

Drugs Used Prophylactically to Prevent Angina Pectoris Nitroglycerin can be administered as an ointment, as extended release tablets or capsules, or by transdermal patch Isosorbide and pentaerythritol nitrates are usually administered orally 3–4 times/day depending on the frequency of anginal attacks

Adverse Effects of Nitrites and Nitrates Vasomotor flushing, dizziness, and headache are common due to vasodilation When administered for acute angina, the sudden onset of vasodilation may cause hypotension, fainting, and tachycardia Patients should be seated when inhaling or taking these drugs sublingually

Beta Adrenergic Blockers As mention before

Calcium Antagonists As mention before

Myocardial Infarction (MI ) Caused by complete blockage of one of the coronary arteries Heart cells deprived of blood/oxygen become ischemic, die, and form an infarct MI may result in sudden death, or the infarct undergoes a healing process and is replaced with connective tissue After an MI the heart may be weakened and develop congestive failure or cardiac arrhythmias