Questions and Answers
What mechanism primarily contributes to increased pressure in pulmonary circulation due to left ventricular (LV) failure?
Which of the following plays a significant role in the mechanism of diastolic dysfunction?
What is a significant side effect associated with spironolactone?
What adverse effect can result from using digoxin with loop or thiazide diuretics?
Signup and view all the answers
Which statement best describes the mechanism of action of sacubitril/valsartan?
Signup and view all the answers
What is the primary therapeutic effect of dobutamine in heart failure management?
Signup and view all the answers
Which drug class helps to alleviate circulatory congestion and decreases venous pressure?
Signup and view all the answers
Which feature is characteristic of digoxin regarding its pharmacokinetics?
Signup and view all the answers
Which type of drug is primarily indicated for treating severe digoxin toxicity?
Signup and view all the answers
What is the main therapeutic purpose of angiotensin inhibitors in heart failure treatment?
Signup and view all the answers
What is the primary cause of heart failure in most cases?
Signup and view all the answers
Which process is least likely to be involved in cardiac remodeling during heart failure?
Signup and view all the answers
What is a significant consequence of heart failure that affects mortality rates?
Signup and view all the answers
Which neuroendocrine response is incorrectly paired with its role in heart failure?
Signup and view all the answers
Which of the following is considered a less common cause of heart failure?
Signup and view all the answers
What is the significance of measuring ventricular end-diastolic pressure in heart failure?
Signup and view all the answers
How does excessive stretching of muscle fibers contribute to heart failure?
Signup and view all the answers
What is the five-year mortality rate for patients diagnosed with heart failure?
Signup and view all the answers
Which of the following is NOT a characteristic of heart failure?
Signup and view all the answers
Which pathophysiological feature is a result of cardiac remodeling during heart failure?
Signup and view all the answers
Study Notes
Overview of Heart Failure
- Heart failure (HF) affects nearly 5 million individuals in the U.S., leading to over 40,000 deaths yearly.
- Contributes to 220,000 additional deaths annually, with an overall mortality rate 8 times higher in HF patients.
- The 5-year mortality rate for HF patients approaches 50%.
Pathophysiology
- HF is often the final stage of various cardiovascular disorders affecting the ventricles' ability to fill or eject blood.
- Ischemic heart disease is the most common cause of HF, followed by hypertension, valvular disorders, viral and congenital cardiomyopathy, arrhythmias, and constrictive pericarditis.
- Rare causes include severe anemia, thiamine deficiency, and certain anti-neoplastic drugs like doxorubicin.
Remodeling in Heart Failure
- Cardiac dilation, ventricular wall thinning, interstitial fibrosis, and wall stiffness are crucial remodeling features.
- Neuroendocrine activation in response to myocardial ischemia and muscle fiber stretching incites remodeling processes.
- Key factors involved include the renin-angiotensin-aldosterone axis, sympathetic nervous system, inflammatory cytokines, and mediators like endothelin.
- Leads to myocyte hypertrophy, apoptosis, collagen production, and fibrosis.
Hallmark Features
- Heart failure results in decreased stroke volume (SV) and cardiac output (CO).
- Ventricular end-diastolic pressure (preload) is critical in determining CO.
Systolic vs. Diastolic Dysfunction
- Systolic dysfunction arises from reduced cardiac contractility, commonly due to dilated or ischemic myocardium.
- Diastolic dysfunction is linked to lower compliance and increased stiffness, often from left ventricular hypertrophy (LVH) or fibrosis.
Left Ventricular Failure
- Impaired left ventricular function leads to increased pulmonary circulation pressure, causing fluid accumulation in lung interstitium, resulting in pulmonary edema.
- Reduced gas exchange leads to hypoxemia, dyspnea, orthopnea, and paroxysmal nocturnal dyspnea (PND).
Right Ventricular Failure
- Right ventricle failure results in peripheral vein congestion, causing pedal or sacral edema.
- Jugular venous distension may be present.
Drug Classes Used in Heart Failure
- Positive inotropic drugs enhance contractility, while vasodilators decrease afterload, improving CO.
- Diuretics help reduce circulatory congestion by mobilizing edematous fluid and decreasing plasma volume.
- Angiotensin inhibitors positively impact cardiac remodeling and survival rates.
Positive Inotropic Drugs
- Digoxin: A digitalis glycoside with a long half-life of 36 hours, primarily excreted through the kidneys, and has a narrow therapeutic index.
- Dobutamine: A beta-adrenoceptor agonist enhancing cardiac contractility with minimal tachycardia; decreases vascular resistance.
- Milrinone: A phosphodiesterase inhibitor that increases calcium levels in cardiac myocytes.
Digoxin Effects and Interactions
- Positive inotropic effect increases SV and CO; negative chronotropic and dromotropic effects lower heart rate and AV node conduction.
- Interactions include reduced absorption by antacids and cholestyramine, and increased serum digoxin levels when combined with diltiazem or quinidine.
Treatment for Digoxin Toxicity
- Severe toxicity is treated with digoxin immune fab (digibind), derived from sheep immunized with digoxin.
Additional Treatment Options
- Neprilysin inhibitors increase bradykinin and natriuretic peptides beneficially, but must be combined with RAAS inhibitors.
- Sacubitril/valsartan, a combined neprilysin inhibitor and ARB, reduces CV deaths and hospitalizations by 20% compared to enalapril.
- Hydralazine and nitrates lower preload and afterload, enhancing CO.
- Aldosterone antagonists like spironolactone and eplerenone help with sodium excretion and have varying endocrine side effects.
Diuretics in Heart Failure Management
- Loop diuretics (e.g., furosemide) effectively reduce plasma volume but carry risks of dehydration and electrolyte imbalances.
- Thiazide diuretics can be used when less diuresis is needed and can complement loop diuretics.
Standard Therapy Protocol
- Typical heart failure management involves diuretics, angiotensin inhibitors (potentially with sacubitril), and beta-blockers.
- Addition of aldosterone antagonists and, when warranted, digoxin or hydralazine/nitrate, might be beneficial.
- Some patients may require anticoagulants or antiplatelet therapies based on their conditions.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz provides an overview of heart failure, its prevalence in the US, and its impact on mortality rates. Additionally, it covers the pathophysiological aspects of heart failure as a consequence of various cardiovascular disorders. Test your knowledge on this critical health issue.
