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W at is angina pectoris?y Anginal pain is a sudden retro-sternal/ sub-sternal pain/discomfort due to transient myocardial

ischaemia due to narrowing or constriction of smooth muscles in the coronary arteries reduces theamount of blood carried to the heart when there is lack of blood supply to bring oxygen and

nutrients to the heart, the pain of angina is felt. Commonly, the pain radiates to the left arm,occasionally to right or both arms. Usually there is an exersional or emotional component to help indiagnosis. The pain is characterized by a tightness, an ache, a pressure, a heavy feeling, constrictionor frequently breathless feeling. Describing the pain with a clenched fist is a helpful sign (seefigure).

y Some experience the pain when lying f lat (decubitus angina), and some are awakened by it(nocturnal angina)

y The most convincing ECG evidence of myocardial ischaemia is obtained by reversible ST segmentdepression or elevation, with or with out T wave inversion at the time of pain induced by exercisetesting

y Angina may also occur as a result of coronary arterial spasm accompanied by transient ST elevationon ECG (Prinz metals or variant angina).

y Preinfarction angina or unstable angina is an acute coronary insufficiency characterized by

worsening angina or angina at rest . Though the pain occurs at rest it is still relieved by sublingualnitrates.

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Site And Radiation Of Anginal Pain

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Precipitating Causes O AnginaCoronary artery fill in diastole, when supply and demand problem

occur secondary to coronary artery disease, any factor increasing

heart rate and demand at the expense of supply will induce pain.

Pain therefore follows exertion, emotion, a large meal andtemperature change. Typically, the pain is present on walking,specially up hill or up stairs and is worse in cold or windy weather

or soon after a meal.The amount of exercise needed to bring on the pain can vary a lot,

emotional background (dream induced angina) sexual intercourseand emotion can induce angina

A slowing of heart rate by rest and relaxation will reduce demand.This means walking slowly, sitting down or using GTN will relieve

the pain of angina

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Medical managementy Four groups of drugs are used to help relieve or prevent the pain of angina:- Nitrates, beta

blockers, calcium antagonists and potassium channel activators

y

Nitrates and nitrites act directly on smooth muscles to produce venous and arteriolardilatation causing reduction in myocardial oxygen demand (lower preload and after load) andan increase in myocardial oxygen supply (coronary vasodilatation)

y Rapidly acting preparations for the treatment of acute angina:-

1. Sublingual glyceryl trinitrate :(GTN) administered from a metered- dose aerosol (400mcg per spray) or as a tablet (300 or 5000 mcg) to dissolve under the tongue will usuallyrelieve an attack of angina in 2-3 minutes.

2. Amyl nitrite:Volatile liquid given by inhalation3. Isosorbide dinitrate: Given as sublingual tablet similar to GTN, but has a long duration of

action

y GTNis subject to extensive first-pass metabolism in the liver and is there fore ineffectivewhen swallowed

y Topical nitrates also avoid liver metabolism. GTN ointment 2% (Percutol) will last upto 8

hours. The ointment begins at 1/2 inch tds doses. Dosage can be increased at 1 inchincrements tds and used as sweat band around the wrist. Topical nitrates are of great valuefor nocturnal pain. Continuous nitrate therapy often causes pharmacological tolerancewhich can be avoided by using by a variety of once- daily preparations with a built innitrate-free period and given at night when the patient is inactive.

y I.V nitrates (GTN 0.6mg/hr or isosorbide dinitrate 1mg/hr) are useful in the treatment ofunstable angina

y Side effects: The main side effects are flushing, throbbing head ache and postralhypotension.

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Management (cont)Beta blockers: Lower myocardial oxygen demand by reducing

heart rate, blood pressure and myocardial contractility.Nonselective beta blockers may aggravate coronary spasm byblocking the coronary artery B2- adrenoceptors and is usuallyadvisable to use a once-daily cardio selective preparation (e.g.atenolol 50-100 mg daily, SR metoprolol 200mg daily, besoprolol

5-10 mg daily).Beta blockers shouldnt be with drawn abruptly because of danger

of arrhythmias, worsening angina or MI

Side effects Are bronchospasm which aggravate asthma andheart failure and peripheral vascular disease (cold hands, feet and

heavy legs) present the major problems. These symptoms reflect afall in cardiac output. CNS side effects include night mares,drowsiness and depression

Atenolol and besoprolol are water soluble and largely excretedunchanged through the kidneys and there fore useful in the

treatment of angina

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Management (cont)y Calcium antagonists: Inhibit the slow inward current

caused by the entry of extra cellular calcium through the cellmembrane of cardiac arteriolar smooth muscle, and lowermyocardial oxygen demand by reducing blood pressure andmyocardial contractility and there fore useful in themanagement of angina pectoris.

yNifedipine (Adalat) nicardipine and amlodipine often causereflex tachycardia there fore best to use in combination withbeta blockers. Verapamil and diltiazem are suitable forpatients not receiving a beta blocker because they inhibit AVnode conduction and tend to cause bradycardia. It is of great

value in patients with COPD or peripheral artery diseasewhere beta blockers are contraindicated.

y Toxicity: excessive inhibition of calcium influx can causeserious cardiac depression, including cardiac arrest,

bradycardia AV block and heart failure.

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Anti AnginalMedications

1: Baroreceptor reflex

Note: Undesirable effects are shown in ITALICS

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Calcium antagonists used for treatment of angina

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Summary (cont)

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Newer Investigational Drugs

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Invasive Treatment Of Angina

y Invasive treatment of ischemic heart disease include coronary

angioplasty called PTCA (percutaneous transluminal coronaryangioplasty), reversed sapheanous vein bypass grafting andinternal memory artery grafting called CABG (coronary arterybypass grafting)

y

Coronary angioplasty (PTCA) is an invasive technique which canbe used to provide complete or partial revascularization inpatients with stable and unstable angina and MI

y Coronary angioplasty is an effective symptomatic treatment forchronic stable angina and is mainly used in single or 2 vessel

disease, and the procedure is often used to provide palliativetherapy for patients with recurrent angina after CABG

y Coronary angiography is essential before performing PTCA inpatients when non invasive tests fail to diagnose the cause of

atypical chest pain (See diagram)

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Coronary Angiograp y An PTCA