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

EMS 353. EMS 353. Lectures 6 Lectures 6 Dr . Maha KhalidDr . Maha Khalid

physiology of pharmacology cardiovascular system

33..Coronary Heart DiseasesCoronary Heart Diseases

Coronary Heart DiseaseCoronary Heart DiseaseThe major underlying

cause is atherosclerosisatherosclerosis..AtherosclerosisAtherosclerosis is a

slow, progressive disease which begins in childhood and takes decades to advance

Coronary Heart DiseaseCoronary Heart DiseasePlaque (the build-up of

lipid/cholesterol) in the artery wall forms as a response to injuryinjury to the endothelium in the artery wall.

Coronary Artery Coronary Artery DiseasesDiseases

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 Section Longitudinal Section

Angina PectorisAngina PectorisChest 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 attackangina and heart attackangina

◦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 Drugs Used to Treat CADCAD

Nitrites and nitratesBeta adrenergic blocking drugs

Calcium antagonists, also referred to as calcium channel blockers

Nitrites and NitratesNitrites and NitratesDrugs 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 Drugs Used to Relieve Acute Attacks of AnginaAcute 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 Drugs Used Prophylactically to Prophylactically to Prevent Angina PectorisPrevent 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 Adverse Effects of Nitrites and NitratesNitrites 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 Beta Adrenergic BlockersBlockers

As mention before

Calcium AntagonistsCalcium AntagonistsAs mention before

Myocardial Infarction Myocardial Infarction (MI )(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