Heart Failure and Cardiac Output Quiz
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Questions and Answers

What primarily influences cardiac output?

  • The stroke volume only
  • The venous return of blood from the body (correct)
  • The heart rate only
  • The total blood volume in the body

    • If the stroke volume is 70 ml and the heart rate is 70 beats per minute, what is the cardiac output?

  • 3500 ml per minute
  • 1400 ml per minute
  • 4900 ml per minute (correct)
  • 490 ml per minute

    • What is the approximate normal range for ejection fraction?

  • 70-80%
  • 40-50%
  • 30-40%
  • 50-70% (correct)

    • What indicates a person may be in systolic heart failure?

    <p>An ejection fraction of 40% or less</p> Signup and view all the answers

    What characterizes diastolic heart failure?

    <p>The heart pumps blood but does not fill enough</p> Signup and view all the answers

    If a total volume of the left ventricle is 69 ml with a stroke volume of 44 ml, what is the ejection fraction?

    <p>64%</p> Signup and view all the answers

    What term describes the volume of blood in the ventricle before contraction?

    <p>Preload</p> Signup and view all the answers

    What happens if the preload is reduced?

    <p>The heart cannot pump effectively, leading to diastolic heart failure.</p> Signup and view all the answers

    What is the primary use of diuretics in patients with heart failure?

    <p>To relieve pulmonary congestion and peripheral edema</p> Signup and view all the answers

    Which drug class is indicated for patients with chronic heart failure to prevent the damaging effects of norepinephrine on cardiac muscle?

    <p>Beta Blockers</p> Signup and view all the answers

    What effect does hydralazine primarily have on the cardiovascular system?

    <p>Reduces systemic arteriolar resistance</p> Signup and view all the answers

    Which of the following is a common side effect of vasodilators?

    <p>Hypotension</p> Signup and view all the answers

    What is the preferred class of diuretics for patients with significant fluid retention in heart failure?

    <p>Loop diuretics</p> Signup and view all the answers

    How are beta blockers typically administered to patients with chronic heart failure?

    <p>Gradually titrated from low doses</p> Signup and view all the answers

    Which of the following diuretics also functions as an aldosterone antagonist?

    <p>Spironolactone</p> Signup and view all the answers

    Which of the following statements about digoxin in heart failure patients is accurate?

    <p>It enhances cardiac contractility.</p> Signup and view all the answers

    What is a common consequence of cardiac remodeling in heart failure?

    <p>Hypertrophy of cardiomyocytes</p> Signup and view all the answers

    Which of the following is a symptom of decompensated heart failure?

    <p>Fatigue</p> Signup and view all the answers

    How does heart failure initially affect cardiac output?

    <p>It initially increases then later decreases</p> Signup and view all the answers

    What is one of the therapeutic goals in treating heart failure?

    <p>Alleviate symptoms</p> Signup and view all the answers

    What effect do vasodilators have in heart failure treatment?

    <p>Decrease extracellular fluid volume</p> Signup and view all the answers

    Which pharmacological class is used to improve cardiac contractility in heart failure?

    <p>Inotropics</p> Signup and view all the answers

    What is the effect of increased sympathetic discharge during heart failure?

    <p>Increased afterload</p> Signup and view all the answers

    Which of the following medications should generally be avoided in heart failure?

    <p>Nondihydropyridine calcium channel blockers</p> Signup and view all the answers

    What role do cardiac glycosides play in heart failure treatment?

    <p>They increase cytoplasmic calcium concentration</p> Signup and view all the answers

    Which statement correctly describes compensatory responses during heart failure?

    <p>They initially improve cardiac output.</p> Signup and view all the answers

    What is the primary action of Digoxin on cardiac muscle function?

    <p>Enhances cardiac muscle contractility</p> Signup and view all the answers

    How does Digoxin affect the Na+/K+-ATPase enzyme?

    <p>It inhibits the enzyme, increasing intracellular Na+</p> Signup and view all the answers

    What effect does hypokalemia have on Digoxin's activity?

    <p>Enhances Digoxin's activity</p> Signup and view all the answers

    Which mechanism explains increased contractility when Digoxin is administered?

    <p>Inhibition of Na+/Ca2+ exchanger activity</p> Signup and view all the answers

    What impact does Digoxin have on heart rate?

    <p>It decreases heart rate by enhancing vagal tone</p> Signup and view all the answers

    What is a significant risk associated with the use of Digoxin?

    <p>Risk of arrhythmias due to altered resting membrane potential</p> Signup and view all the answers

    What is a therapeutic effect of low doses of Digoxin in heart failure (HF) patients?

    <p>Improved survival rates</p> Signup and view all the answers

    Which of the following effects of Digoxin is beneficial for treating atrial fibrillation?

    <p>Decreases conduction velocity through the AV node</p> Signup and view all the answers

    Which condition would NOT typically indicate the use of Digoxin?

    <p>Diastolic heart failure</p> Signup and view all the answers

    At low doses, what effect does Digoxin have on sympathetic activity?

    <p>Inhibits sympathetic activity with minimal impact on contractility</p> Signup and view all the answers

    When prescribing Digoxin, why might dose adjustments be necessary?

    <p>Renal dysfunction</p> Signup and view all the answers

    What are initial symptoms of Digoxin toxicity that may occur at higher plasma concentrations?

    <p>Anorexia, nausea and vomiting</p> Signup and view all the answers

    Which drug may increase Digoxin levels due to its effect on P-gp?

    <p>Clarithromycin</p> Signup and view all the answers

    What is a potential consequence of hypokalemia in a patient taking Digoxin?

    <p>Increased risk of Digoxin toxicity</p> Signup and view all the answers

    Which of the following can lead to blurred vision as an adverse effect of Digoxin?

    <p>High plasma concentration</p> Signup and view all the answers

    What should be done first in the management of Digoxin toxicity?

    <p>Discontinue Digoxin</p> Signup and view all the answers

    What is a primary characteristic of Milrinone compared to Amrinone?

    <p>Milrinone does not produce thrombocytopenia.</p> Signup and view all the answers

    Which inodilator is used for the short-term treatment of acute heart failure in a hospital setting?

    <p>Milrinone</p> Signup and view all the answers

    What effect do phosphodiesterase inhibitors have on cAMP levels?

    <p>Elevates cAMP levels.</p> Signup and view all the answers

    In the treatment of heart failure, which of the following is true for long-term use of inodilators?

    <p>Associated with high rates of mortality.</p> Signup and view all the answers

    Which parameter is assessed to evaluate left ventricular (LV) function in heart failure patients?

    <p>Ejection fraction (EF)</p> Signup and view all the answers

    Which class of drugs is primarily indicated for chronic heart failure management?

    <p>Diuretics</p> Signup and view all the answers

    What is the desired patient status before the titration of diuretics in heart failure treatment?

    <p>Euvolemic state</p> Signup and view all the answers

    What is a common method for determining volume status in heart failure patients?

    <p>Checking for signs of fluid retention</p> Signup and view all the answers

    Study Notes

    Pharmacological Management of Congestive Heart Failure

    • Congestive heart failure (CHF) is a condition where the heart struggles to pump enough blood to meet the body's needs. It can result from systolic or diastolic dysfunction. Systolic dysfunction refers to a weakened heart unable to pump blood effectively. Diastolic failure involves the inability of the ventricles to properly fill during the relaxation phase (diastole).
    • Learning outcomes for pharmacological management of heart failure include identifying major drug groups used for treatment, understanding the mechanisms of action of digitalis and its toxic effects, clinical implications of diuretics, vasodilators, ACE inhibitors and other drugs, strategies used in treatment.

    What is Heart Failure?

    • Heart failure is a condition where the heart isn't able to pump enough blood to meet the body's needs. This can be due to either the heart not pumping enough blood (systolic heart failure) or not filling up properly with blood (diastolic heart failure).
    • In both cases, fluid backs up into the lungs, causing congestion, which is why it's often called congestive heart failure.
    • Heart failure results from any structural or functional issue of the heart that impairs its ability to fill or eject blood.

    Heart Failure (HF) Factors

    • Factors contributing to heart failure include:
      • Pulmonary hypertension
      • Myocardial infarction
      • Valvular heart disease
      • Dilated cardiomyopathy
      • Chronic systemic hypertension

    Cardiac Output

    • Cardiac output (CO) is the volume of blood the heart pumps per minute. It's calculated as heart rate (HR) multiplied by stroke volume (SV).
    • Normal cardiac output is about 5 liters per minute.

    Ejection Fraction

    • Ejection fraction (EF) is the percentage of blood the heart pumps out of the left ventricle with each beat.
    • A normal ejection fraction is around 50-70%. Values below 40% often indicate heart failure.

    Definitions

    • Stroke Volume (SV): The amount of blood pumped by the heart with each contraction.
    • Cardiac Output (CO): The total volume of blood pumped out of the heart per minute (SV x heart rate).
    • Preload: The volume of blood in the left ventricle at the end of diastole, primarily determined by the venous return of blood to the heart.

    Cardiac Output Example

    • In a healthy adult, the heart might beat 70 times per minute and pump out 70 ml of blood per beat, resulting in a cardiac output of 4900 ml/min (approximately 5 liters/min).
    • The stroke volume is only a fraction of the total volume in the ventricle. The other portion stays in the ventricle until the next beat.

    Cardiac Output Example - Ejection Fraction

    • Ejection fraction can be calculated by dividing the stroke volume by the total volume in the ventricle before each beat.
    • When the ejection fraction is 40% or less, it suggests systolic heart failure.

    Compensatory Responses During Heart Failure

    • Heart failure triggers compensatory responses. For example, the body releases renin to increase blood pressure and retain sodium and water, often leading to edema.

    Cardiac Remodeling

    • Cardiac remodeling is the structural and functional changes in the heart due to heart failure.
    • These changes include hypertrophy (enlarging) of heart muscle cells, necrosis (cell death), and fibrosis (scar tissue formation).

    Compensated vs. Decompensated HF

    • Compensated heart failure (acute): Adaptive mechanisms restore cardiac output.
    • Decompensated heart failure (acute): Failure of adaptive mechanisms leads to worsening symptoms like dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, fatigue and peripheral edema.

    Goal of Heart Failure Treatment

    • Primary goals of heart failure treatment include alleviating symptoms, slowing disease progression and improving survival.

    Therapeutic Strategies in HF

    • Treatment strategies for heart failure include fluid limitation, low sodium diets, treatment of co-morbidities, appropriate diuretic doses, and avoiding drugs that may worsen the condition (e.g., Nonsteroidal anti-inflammatory drugs (NSAIDs), certain calcium channel blockers, and some anti-arrhythmics).

    Phosphodiesterase Inhibitors

    • Amrinone and milrinone are selective phosphodiesterase III inhibitors. These medications increase intracellular cAMP, improving cardiac contractility and promoting relaxation of vascular smooth muscle.

    Other Inotropic Drugs

    • Dopamine and dobutamine are inotropic agents. Used in acute heart failure situations.

    Beta-Blockers

    • Beta-blockers are used to reduce morbidity and mortality in chronic stable heart failure. They prevent the damaging effects of norepinephrine on the heart and reduce heart rate and renin release. Examples include carvedilol, bisoprolol, and metoprolol.

    ACE Inhibitors

    • ACE inhibitors, such as captopril, enalapril, ramipril, and lisinopril, are used to reduce afterload and preload to normalize blood pressure.

    Angiotensin Receptor Blockers (ARBs)

    • Angiotensin receptor blockers (ARBs), such as losartan, candesartan, valsartan, and telmisartan, block the angiotensin II receptor. They are often used in patients who cannot tolerate ACE inhibitors.

    Aldosterone Receptor Blockers

    • Aldosterone antagonists (e.g. spironolactone and eplerenone) are used in severe heart failure to reduced fluid retention.

    Digoxin

    • Digoxin is a cardiac glycoside used in heart failure and certain arrhythmias.
    • Digoxin enhances the vagal tone, decreasing heart rate and myocardial oxygen demand.

    Pharmacodynamics of Digoxin

    • In therapeutic doses, Digoxin partially inhibits Na+/K+ ATPase which leads to increased intracellular sodium leading to increased cytoplasmic calcium levels, thus increasing the force of contraction. Its mechanism of action elevates cAMP levels in myocardial cells, leading to better contraction and relaxation.
    • Digoxin has a long half-life, accumulating in cardiac muscle. Requires dose adjustment in renal dysfunction.
    • Digoxin and other drugs that slow AV conduction should be used with caution together.

    Adverse Effects of Digoxin

    • At therapeutic doses, Digoxin is generally well-tolerated.
    • Higher doses or patient factors can lead to adverse effects such as anorexia, nausea, vomiting, blurred vision (yellowish), and various cardiac arrhythmias.

    Management of Digoxin Toxicity

    • If digoxin toxicity is suspected, administering potassium supplements or digoxin antibodies is required

    DD Interactions

    • Digoxin toxicity is worsened by hypokalemia which further increases the risk of arrhythmias. Conversely, hyperkalemia reduces its effectiveness.

    Uses of Digoxin

    • Digoxin is used to treat congestive heart failure and cardiac arrhythmias, particularly atrial fibrillation and other supraventricular arrhythmias.

    Adverse Effects of Digoxin (Cardic/Extracardiac)

    • Extra-cardiac: Nausea, vomiting, vomiting, restlessness, disorientation, visual disturbance, gynecomastia
    • Cardiac: Bradycardia, Pulsus bigemini, atrial extrasystole, atrial flutter, ventricular extrasystole, tachycardia, partial heart block, complete heart block

    Treatment of Digoxin Toxicity

    • If toxicity is suspected, stopping digoxin, checking potassium levels, and administering potassium supplements are first steps.

    Other Treatment Considerations

    • PharmacoKinetics: Understanding how the drug is absorbed, distributed, metabolized, and excreted (ADME) is crucial for proper dosing and management.
    • Patient-Specific Considerations: Factors like renal function, other medications, and overall health status strongly influence treatment decisions.

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    Related Documents

    Pharmacological Management of Congestive Heart Failure PDF

    Description

    Test your knowledge on cardiac output, heart failure, and related pharmacology. Topics include stroke volume, ejection fraction, and the effects of various medications. This quiz will help reinforce your understanding of cardiovascular physiology and treatment strategies.

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