Ischemic Heart Disease and Angina

• When the heart does not get enough oxygen and nutrients from the blood to meet its needs, the heart muscle experiences discomfort.

Ischemia and Ischemic Heart Disease

• Ischemia refers to a reduced blood supply to an organ.
• Ischemic heart disease occurs when there is poor blood supply to the heart muscle.
• Atherosclerosis, or coronary artery disease, is a common cause of reduced blood flow to the heart.

Myocardial Infarction

• Myocardial infarction involves the necrosis, or death, of cardiac tissue.
• It can be disabling or fatal.

Types of Angina

• Chronic stable angina (classic or effort angina).
• Unstable angina (preinfarction angina).
• Vasospastic angina (Prinzmetal or variant angina).

Therapeutic Objectives for Angina

• Minimize the frequency, duration, and intensity of anginal pain.
• Improve the patient’s functional capacity while minimizing adverse effects.
• Prevent or delay myocardial infarction.

Drugs for Angina

• Nitrates and nitrites.
• Beta-blockers.
• Calcium channel blockers.

Forms of Nitrates and Nitrites

• Sublingual: Bypasses the liver and the first-pass effect.
• Chewable tablets.
• Oral capsules/tablets.
• Intravenous solutions: Bypasses the liver and the first-pass effect.
• Transdermal patches: Bypasses the liver and the first-pass effect.
• Ointments.
• Translingual sprays: Bypasses the liver and the first-pass effect.

Mechanism of Action and Drug Effects of Nitrates and Nitrites

• Causes vasodilation due to relaxation of smooth muscles.
• Has a potent dilating effect on coronary arteries.
• Increases oxygen supply to ischemic myocardial tissue.
• Used for both prevention and treatment of angina.

Rapid- and Long-Acting Nitrates and Nitrites

• Rapid-acting forms are for treating acute anginal attacks using sublingual tablets or spray; or IV infusion.
• Long-acting forms are for preventing anginal episodes.

Specific Nitrates and Nitrites

• nitroglycerin (both rapid and long acting).
• isosorbide dinitrate (both rapid and long acting).
• isosorbide mononitrate (primarily long acting).

Nitroglycerin

• Prototypical nitrate.
• Used for symptomatic treatment of ischemic heart conditions like angina.
• Administered orally, sublingually, via metered-dose aerosol sprayed under the tongue, intravenously, and topically.

Nitrates: Adverse Effects

• Headaches, which usually decrease with continued use.
• Reflex tachycardia.
• Postural hypotension.
• Tolerance may develop.

Tolerance of Nitrates

• Occurs in patients taking nitrates around the clock or with long-acting forms.
• Prevented by allowing a regular nitrate-free period for enzyme pathways to replenish.
• Transdermal forms: remove patch at bedtime for 8 hours, then apply a new patch in the morning.

isosorbide dinitrate

• Available in rapid-acting sublingual tablets and long-acting oral dosage forms.

Nitrates: Contraindications

• Known drug allergy.
• Severe anemia.
• Closed-angle glaucoma.
• Hypotension.
• Severe head injury.
• Use of erectile dysfunction drugs like sildenafil citrate (Viagra), tadalafil (Cialis), and vardenafil hydrochloride (Levitra).

Beta-Blockers

• Mainstay in treating several cardiovascular diseases.
• Used to treat angina, myocardial infarction, hypertension, and dysrhythmias.

Beta-Blockers: Mechanism of Action

• Block β1-receptors on the heart.
• Decrease heart rate, resulting in decreased myocardial oxygen demand and increased oxygen delivery to the heart.
• Decrease myocardial contractility, helping to conserve energy or decrease demand.
• Block the harmful effects of catecholamines, improving survival after a myocardial infarction.

Beta-Blockers: Indications

• Angina.
• Hypertension.
• Cardiac dysrhythmias.
• myocardial infarction.
• Migraine headaches, essential tremors, and stage fright.

Antianginal Beta-Blockers

• atenolol.
• metoprolol.
• propranolol hydrochloride.
• nadolol.

Beta-Blockers: Contraindications

• Systolic heart failure.
• Serious conduction disturbances.
• Caution in patients with bronchial asthma, because any level of blockade of β2-receptors can promote bronchoconstriction.
• Diabetes mellitus: can mask hypoglycemia-induced tachycardia.
• Peripheral vascular disease: may further compromise cerebral or peripheral blood flow.

Beta-Blockers: Adverse Effects

• Cardiovascular: Bradycardia, hypotension, atrioventricular block.
• Metabolic: Hyperglycemia, hypoglycemia, hyperlipidemia.
• Central nervous system: Dizziness, fatigue, depression, lethargy.
• Other: Erectile dysfunction, wheezing, dyspnea.

atenolol (Tenormin)

• Cardioselective β1-adrenergic receptor blocker.
• Indicated for prophylactic treatment of angina pectoris.
• Use of atenolol after myocardial infarction has been shown to decrease mortality.
• Oral dosage form.

metoprolol tartrate (Lopresor, Betaloc)

• Cardioselective β1-adrenergic receptor blocker.
• Indicated for prophylactic treatment of angina.
• Reduces mortality rate in patients after myocardial infarction and in treating angina.
• Forms: oral (immediate release and long acting) and parenteral (injectable) forms.

Calcium Channel Blockers for Chronic Stable Angina

• amlodipine.
• diltiazem.
• nifedipine.
• verapamil hydrochloride.

Calcium Channel Blockers: Mechanism of Action

• Cause coronary artery vasodilation.
• Cause peripheral arterial vasodilation, decreasing systemic vascular resistance.
• Reduce the workload of the heart.
• Decrease myocardial oxygen demand.
• Dysrhythmias: depression of the automaticity of and conduction through the sinoatrial and atrioventricular nodes.

Calcium Channel Blockers: Indications

• Angina.
• Hypertension.
• Supraventricular tachycardia.
• Coronary artery spasms (Prinzmetal angina).
• Short-term management of atrial fibrillation and flutter.
• Migraine headaches.
• Raynaud’s disease.
• dihydropyridine nimodipine: cerebral artery spasms associated with aneurysm rupture.

Calcium Channel Blockers: Contraindications

• Known drug allergy.
• Acute myocardial Infarction.
• Second- or third-degree atrioventricular block (unless the patient has a pacemaker).
• Hypotension.

Calcium Channel Blockers: Adverse Effects

• Hypotension, palpitations, tachycardia or bradycardia, constipation, nausea, dyspnea, other adverse effects.

diltiazem hydrochloride (Cardizem, Tiazac)

• Very effective for the treatment of angina pectoris resulting from coronary insufficiency and hypertension.
• Also used in the treatment of atrial fibrillation and flutter along with paroxysmal supraventricular tachycardia.

amlodipine besylate (Norvasc)

• Most popular calcium channel blocker of the dihydropyridine subclass.
• Indicated for both angina and hypertension.
• Available only for oral use.

Nursing Implications

• Before administering, perform a complete health history to determine contraindications for use or those that may call for cautious us.
• Obtain baseline vital signs, including respiratory patterns and rate.
• Assess for drug interactions.

Nursing Implications: Patient Education

• Report blurred vision, persistent headache, dry mouth, edema, fainting episodes, weight gain of 1 kg in 24 hours or 2.3 kg in 1 week, pulse rate less than 60 beats/min, or dyspnea.
• Avoid alcohol consumption and spending time in hot environments as it results in vasodilation, hypotension, and the possibility of fainting.
• Teach patients to change positions slowly to avoid postural changes in blood pressure.
• Encourage patients to keep a record of their anginal attacks, including precipitating factors, number of pills taken, and therapeutic effects.

Nursing Implications: Nitroglycerin

• Instruct patients in proper technique and guidelines for taking sublingual nitroglycerin for anginal pain, and to never chew or swallow the sublingual form.
• A burning sensation felt with sublingual forms indicates that the drug is still potent.
• Keep a fresh supply of sublingual medication on hand; potency is good for about 3 to 6 months, and store in an airtight, dark glass bottle with a metal cap and no cotton filler.
• Instruct patients in the proper application of nitrate topical ointments and transdermal forms, including site rotation and removal of old medication: remove topical forms at bedtime and apply new doses in the morning, allowing for a nitrate-free period to reduce tolerance.
• Instruct patients to take as-needed nitrates at the first hint of anginal pain.
• Monitor vital signs frequently during acute exacerbations of angina and during intravenous administration.
• If experiencing chest pain, the patient taking sublingual nitroglycerin should lie down to prevent or decrease dizziness and fainting that may occur because of hypotension.
• The patient should stop activity and sit or lie down and take a sublingual tablet, call 911 or emergency services immediately and take a second sublingual tablet if there is no relief in 5 minutes, and take a third sublingual tablet if there is no relief in 5 minutes.
• Intravenous forms of nitroglycerin must be given with special non–polyvinyl chloride tubing and bags: discard parenteral solutions that are not clear and are discoloured.

Nursing Implications: Beta-Blockers

• Patients should monitor their pulse rates daily and report any rate lower than 60 beats/min or symptoms of relative bradycardia, dizziness or fainting, and never abruptly discontinue these medications.
• Inform patients that these medications are for long-term prevention of angina, not for immediate relief.

Nursing implications: Calcium Channel Blockers

• Constipation is a common problem; instruct patients to take in adequate fluids and eat high-fiber foods.

Applying Transdermal Nitroglycerin

• Apply the patch to hairless areas of the body.