Angina and Heart Failure Overview

Angina and Heart Failure

• Angina is chest pain caused by reduced blood flow to the heart muscle.
• Ischemia is a deficiency of blood flow.
• Atherosclerosis is a disease where plaque builds up in the arteries.
• Negative inotropic effect decreases the force of cardiac contraction.
• Negative chronotropic effect decreases the heart rate.
• Dysrhythmia is an abnormal heart rhythm.
• Heart failure is a condition where the heart can't pump enough blood to meet the body's needs.
• Ejection fraction is the percentage of blood pumped out of the heart with each beat (65%).
• Hemostasis is the process that helps stop bleeding.

Types of Angina

• Chronic stable angina: Triggered by a stressor.
• Unstable angina: Pre-infarction.
• At rest angina
• Vasospastic angina: Follows a predictable pattern.

Drug Therapy for Angina

• Objective: Minimize attacks and pain duration/intensity, improve patient function with few adverse effects, prevent or delay MI.
• Drugs: Nitrates, Beta-Blockers, Calcium channel blockers.

Nitrates: Mechanism of Action

• Cause coronary vasodilation by relaxing smooth muscles.
• Dilate all blood vessels in the body.
• Forms: Sublingual, chewable tablets, oral capsules/tablets, IV solutions, transdermal patches, ointments, translingual sprays.
• Rapid-acting forms: Used to treat sudden attacks (SL tablets or spray, IV infusion).
• Long-acting forms: Used to prevent attacks.

Nitroglycerin

• IV form used for controlling blood pressure (perioperative hypertension), treating heart failure, ischemic pain, pulmonary edema, acute MI, and hypertensive emergencies.
• Adverse effects: Headaches, reflex tachycardia, postural hypotension, tolerance development, skin irritation from patches, severe hypotension.
• Other meds: Isosorbide dinitrate (ISDN), Nitrol, Imdur, Trinipatch.

Tolerance

• Occurs in patients taking nitrates continuously or with long-acting forms.
• Prevented by a regular nitrate-free period.
• Transdermal forms: Remove patch at bedtime for 8 hours, apply a new one in the morning.

Nitrates: Contraindications

• Known drug allergies
• Severe anemia
• Closed-angle glaucoma
• Hypotension
• Severe head injury
• (Interaction with Viagra®, Cialis®, Levitra®)

Beta-Blockers

• Angina (atenolol, metoprolol, propranolol, nadolol)
• Decrease heart rate for decreased myocardial oxygen demand.
• Decrease myocardial contractility for decreased energy demands.
• After MI: Block harmful catecholamine effects, improve survival.
• Most effective in treating exertional angina.
• Blunt physiologic effects of increase in heartrate and systolic BP during exercise.
• Contraindications: Systolic heart failure and respiratory issues.
• Side effects: Bronchoconstriction, increased airway resistance, decreased heart rate, cardiac output, cardiac contractility.

CCBs for Stable Angina: MOA

• Amlodipine, diltiazem, nifedipine, verapamil
• Prevent calcium from entering the excitation-contraction process.
• Cause coronary artery vasodilation.
• Cause peripheral arterial vasodilation, decreasing systemic vascular resistance (SVR)
• Reduce the workload of the heart and myocardial oxygen demand.
• Increase blood supply.
• Decrease conduction through the SA and AV nodes.

CCBs: Contraindications and AEs

• Drug allergy
• Acute myocardial infarction
• Second- or third-degree atrioventricular block (unless pacemaker present)
• Hypotension
• Hypotension, palpitations, tachycardia or bradycardia, constipation, nausea, dyspnea.

Nursing Implications

• Limit caffeine
• Record attacks, precipitating factors, and medication use.
• Monitor for adverse reactions (allergic reactions, headache, lightheadedness, hypotension, dizziness).
• Take extra care with alcohol, saunas, and hot tubs.
• Nitroglycerin: Do not chew or swallow sublingual form, keep fresh supply, rotate patch sites.
• Nitroglycerin: Take as-needed at first hint of pain. Lie down with SL nitroglycerin. If no relief in 5 minutes, call 911 and take another tablet, and a third if pain still persists.

Heart Failure: Left versus Right

• Left Sided: Pulmonary Edema, Coughing, Shortness of Breath, Dyspnea.
• Right Sided: Systemic Venous Congestion, Pedal Edema, Jugular Vein Distention, Ascites, Hepatic Congestion

Heart Failure: Causes

• Myocardial deficiency: Inadequate contractility, myocardial infarction, coronary artery disease, cardiomyopathy, valvular insufficiency, inadequate filling, atrial fibrillation, infection, tamponade, ischemia.
• Increased workload: Pressure overload, pulmonary hypertension, systemic hypertension, outflow obstruction, volume overload, hypervolemia, congenital abnormalities, anemia, thyroid disease, infection, diabetes.

Heart Failure Classifications

• Class I: Angina only during strenuous or prolonged physical activity.
• Class II: Slight limitation, with angina only during vigorous physical activity.
• Class III: Symptoms with everyday living activities, i.e., moderate limitation.
• Class IV: Inability to perform any activity without angina or angina at rest, i.e., severe.

Drug Therapy for Heart Failure

• First options: ACE inhibitors, Angiotensin receptor blockers, Beta-blockers, Diuretics.
• If first options fail, then positive inotropic drugs: Phosphodiesterase inhibitors, cardiac glycosides.

ACE Inhibitors

• Prevent sodium and water resorption by inhibiting aldosterone secretion.
• Diuresis to decrease preload, left ventricular end volume, work of the heart.
• Example: Lisinopril

Angiotensin II Receptor Blockers

• Potent vasodilators; decrease systemic vascular resistance (afterload)
• Used alone or with diuretics for hypertension or heart failure.
• Example: Valsartan

Beta-Blockers

• Decrease SNS stimulation to the heart, decrease myocardial automaticity.
• Prevent catecholamine-mediated actions by reducing or blocking sympathetic nervous system stimulation to the heart and the heart's conduction system.
• Example: Metoprolol

Aldosterone Antagonists

• Useful for severe heart failure
• Action: blocks activation of the renin-angiotensi-aldosterone system, decreasing aldosterone and sodium/water retention
• Example: Spironolactone

Phosphodiesterase Inhibitors

• Work by inhibiting the enzyme phosphodiesterase
• Results in a positive inotropic response
• Increase in calcium for myocardial muscle contraction
• Inodilators (inotropics and dilators)
• Example: Milrinone (only drug in Canada) used in ICUs (cause dysrhythmias)

Cardiac Glycosides (Digoxin)

• Not first-line treatment
• Obtained from Digitalis plant (Foxglove)
• Prototype is Digoxin
• Used in heart failure and to control ventricular response to atrial fibrillation

Digoxin: MOA

• Positive inotropic effect: Increased force and velocity of myocardial contraction (without an increase in oxygen consumption)
• Negative chronotropic effect: Reduced heart rate
• Negative dromotropic effect: Decreased automaticity at sinoatrial node, decreased atrioventricular nodal conduction

Digoxin: Drug Effects

• Increased stroke volume
• Reduction in heart size during diastole
• Decrease in venous blood pressure and vein engorgement
• Increase in coronary circulation
• Decrease in exertional and paroxysmal nocturnal dyspnea, cough, and cyanosis
• Promotion of tissue perfusion and diuresis

Digoxin: Nursing Considerations

• Very narrow therapeutic window—monitor drug levels.
• Hypokalemia may precipitate toxicity.
• Before dosing, check apical pulse for one minute.
• Apical pulse <60 or >100 BPM; do not administer and notify prescribing provider.
• AEs: dysrhythmias, headaches, fatigue, malaise, confusion, convulsions, color vision changes (green, yellow, purple, halo), anorexia, nausea, vomiting, diarrhea.

Question and Answers

(These questions and answers are provided. Information is too extensive to fit into one answer block, but this demonstrates possible use of the information to build upon.)

• Question A: A patient who has had a myocardial infarction is taking a β-blocker. What is the main benefit of β‐blocker therapy for this patient?

  • Answer A: Slowing of the heart rate.

• Question B: A person who is mowing the lawn on a hot Saturday afternoon notices chest pain. What should this person's first action be?

  • Answer B: Stop mowing and sit or lie down.

• Question C: A patient with extremely high BP is in the emergency department. The health care provider will order therapy with nitroglycerin to manage the patient's blood pressure. Which form of nitroglycerin is most appropriate?

  • Answer C: Intravenous infusion.

• Question D: A patient who was walking a dog developed chest pain and sat down. The patient continues to experience chest pain when sitting down. When should the patient call 911?

  • Answer D: If one sublingual tablet does not relieve the pain after 5 minutes.

• Question E: A patient is receiving digoxin 0.25 mg/day as part of treatment for heart failure. The nurse assesses the patient before administering medication. Which assessment finding would be of most concern?

  • Answer E: Serum potassium level of 2.9 mEq/L.

This quiz covers key concepts related to angina and heart failure, including definitions, types of angina, and drug therapy options. It is designed for students studying cardiovascular health and aims to enhance understanding of heart-related conditions. Test your knowledge on symptoms, causes, and treatments related to these critical health issues.