Questions and Answers
What is a primary mechanical effect of Digitalis on the heart?
What is the primary reason Milrinone is preferred for short-term support in advanced heart failure?
Which of the following molecules is inhibited by Digitalis, leading to its pharmacological effects?
In which case are cardiac glycosides primarily indicated for use?
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What effect does Digitalis have on the heart rate?
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What is the therapeutic loading dose of Digoxin recommended over 24 hours?
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Which of the following statements regarding the ionic effects of Digitalis is correct?
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Which of these effects is NOT associated with Digitalis use?
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What is the primary role of loop diuretics in the treatment algorithm for heart failure?
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Which of the following medications is a potassium-sparing diuretic often used in heart failure treatment?
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What effect do vasodilator drugs have in the context of heart failure?
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What is the primary goal of using positive inotropic agents in heart failure treatment?
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Which medication class is used to manage atrial flutter and may lead to atrial fibrillation if not monitored?
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In the treatment algorithm for heart failure, which combination of medications is typically prescribed for patients in Class III?
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What is the primary therapeutic use of loop diuretics in heart failure?
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Which of the following is a characteristic of potassium-sparing diuretics?
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What effect do arteriolar and venodilators have in treating congestive heart failure?
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Which class of drugs is NOT typically associated with increased myocardial contractility?
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What is an effect of using organic nitrates in patients with congestive heart failure?
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Which statement is true regarding sympathomimetic amines like Dobutamine?
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Which of the following treatments is reserved for acute heart failure management?
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What is the role of phosphodiesterase inhibitors in treating heart failure?
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Study Notes
Short Term Support in Advanced Heart Failure
- Milrinone is the preferred agent due to a lower risk of thrombocytopenia and liver toxicity.
Cardiac Glycosides (Digitalis)
- Digoxin and Digitoxin are active orally.
- Digitalis inhibits Na+/K+ ATPase, increasing intracellular Na+ and enhancing free intracellular Ca++ via Na+/Ca++ exchange.
- Facilitates Ca++ entry through voltage-gated Ca++ channels.
Pharmacological Actions
- Mechanical Effects: Increases heart contraction force, elevating cardiac output, blood flow to organs, and diminishing compensatory sympathetic and renin-angiotensin system activation.
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Electrophysiological Effects:
- Increases vagal tone.
- Decreases sympathetic activity, resulting in reduced heart rate and AV node conduction, and shortened refractory periods in atrial and ventricular tissues.
Therapeutic Uses
- Congestive Heart Failure: Used for patients in atrial fibrillation or symptomatic despite ACEI therapy. Initiate Digoxin with 0.125 – 0.25mg/day.
- Atrial Fibrillation: Blocks AV node to protect ventricles from rapid atrial rates; loading dose of 1mg over 24 hours, maintenance dose of 0.125mg daily.
- Atrial Flutter: Can convert atrial flutter to atrial fibrillation.
Beta Blockers
- Examples include Bisoprolol, Carvedilol, and Metoprolol.
- Reduce heart rate, prevent overstimulation, improve arrhythmias, and support positive energetic effects.
- Recommended in compensated congestive heart failure; contraindicated in acute decompensated heart failure due to potential worsening of hemodynamics.
Treatment Algorithm
- Class I: Lifestyle modifications are usually sufficient.
- Class II: ACEI + (HCTZ or Furosemide) + Beta Blocker.
- Class III: ACEI + Furosemide + Digoxin + Aspirin 75 + (Isosorbide Dinitrate + Hydralazine if ACEIs intolerable).
- Class IV: Similar to Class III but includes Spironolactone.
Dietary Recommendations
- Advise patients to limit sodium intake to 2-3 grams/day.
Diuretics in Heart Failure
- Thiazide Diuretics: Useful for mild heart failure.
- Loop Diuretics: Effective for moderate to severe heart failure.
- Potassium-Sparing Diuretics (Aldosterone Antagonists): Limit potassium and magnesium loss; low-dose Spironolactone can improve survival in advanced heart failure.
Vasodilator Drugs in CHF
- Arteriolar and Venodilators: ACEIs decrease afterload, enhance cardiac output, and improve renal blood flow while reducing aldosterone secretion.
- Veno-Dilators: Organic nitrates like Isosorbide Dinitrate and Nitroglycerin decrease preload, relieving edema and dyspnea.
- Arteriolar Agents: Hydralazine and Minoxidil decrease afterload and can be effective in patients intolerant to ACEIs.
Positive Inotropic Agents
- Sympathomimetic Amines: Dobutamine and Dopamine boost myocardial contractility; Dopamine also has renal vasodilator effects, aiding diuresis.
- Phosphodiesterase Inhibitors: Inamrinone and Milrinone increase cAMP and induce arterial and venous dilation; used intravenously for acute heart failure management.
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Description
This quiz covers key pharmacological interventions for advanced heart failure, focusing on the use of Milrinone and Cardiac Glycosides. Learn about the mechanisms of Digitalis and its impact on cardiac function. Test your knowledge of drug preferences and their actions in heart failure management.
