DRUG TREATMENT OF CONGESTIVE HEART

FAILURE

WHAT IS CONGESTIVE HEART FAILURE (CCF)?

• Heart failure is the progressive inability of the heart to supply adequate blood flow to vital organs

• It is classically accompanied by significant fluid retention

• It is a leading cause of mortality and morbidity.

• Chronic or acute

STAGE DISABILITY

CLASS 1 MILD

No symptoms Can perform ordinary activities without any limitations

CLASS 2 MILD

Mild symptoms - occasional swelling Somewhat limited in ability to exercise or do other strenuous activities

CLASS 3

MODERATE

Noticeable limitations in ability to exercise or participate in mildly strenuous activitiesComfortable only at rest

CLASS 4 SEVERE Unable to do any physical activity without discomfort Some HF symptoms at rest

3

CCF

• CCF: pumping action of ventricles is impaired resulting in back pressure of blood, with congestion of the lungs and liver

5

COMPENSATORY MECHANISMS

• Sympathetic nervous system stimulation

• Renin-angiotensin system activation

• Myocardial hypertrophy

CAUSES OF CCF• Coronary artery disease

• Hypertension

• Valvular heart disease

• Cardiomyopathies

• Chronic alcohol use

These conditions prevent the heart from providing sufficient output

SYMPTOMS OF CCFLEFT SIDED CCF RIGHT SIDED

WeaknessFatigueDizzinessConfusionPulmonary congestionShortness of breathRenal failureDeath

Distended neck veins, increased abdominal girthHepatomegaly (liver engorgement)edemaWeight: the most reliable

MEDICATIONS

1. Fluid load, Preload, Afterload

2. Improve contractility (Positive Ionotropes)

3. Workload of the heart

4. Vasodilators

ACE inhibitors, AT-antagonists Diuretics

Digoxin , Dobutamine

“Beta Blockers”

Isosorbide dinitrate & hydralazine

1. Digoxin

• Cardiac Glycoside

• Extracted from the foxglove plant (Digitalis spp.)

• The main action of digoxin is on the heart

• Positive Ionotrope

1. DIGOXIN MOA:

• ↑ force of contraction of the heart

MOA: • binds to Na+/K+ ATPase pump and inhibits it

• Increases intracellular Na+ concentrations resulting in increased intracellular Ca2+

concentrations

• Increased intracellular calcium concentration results in increased storage in the sarcoplasmic reticulum, which increases the FOC of the heart

1. DIGOXIN MOA

1. DIGOXIN MOA:

• Digoxin also slows AV conduction allowing for improved ventricular filling in CCF. Also useful in Supraventricular tachycardia

1. DIGOXIN P/KINETICS:

• Digoxin given op or iv

• Half life=36 hrs

• Interactions with amiodarone, verapamil

• Side effects: hyperkalemia*, abdominal discomfort, nausea and vomiting

1. DIGOXIN TOXICITY:

• Toxicity can be treated with higher than normal doses of potassium

• Digoxin antibody (digibind) is used specifically to treat life-threatening digoxin overdose.

2. ACE INHIBITORS (Captopril, Enalapril, Lisinopril)

• First line therapy for CCF

MOA: • Inhibits ACE, hence inhibits the conversion of

angiotensin I to angiotensin II:

1.Reduction in arterial resistance (afterload)

2.Reduction in venous tension (preload)

3.Reduction in aldosterone secretion

4.Inhibition of cardiac and vascular remodeling

• ACE inhibitors improve mortality, morbidity, exercise tolerance

2. ACE INHIBITORS

2. ACE INHIBITORS

2. ACE INHIBTORS SIDE EFFECTS

• Dry irritating persistent cough

• Hyperkalemia

• Angioedema

• Fetal toxicity

2. ACE INHIBITORS

T½ Adverse effects

Elimination

captopril 4hrs Hypotension, cough

Renal and hepatic

enalapril 30-35hrs same Renal and hepatic

lisinopril >30hrs same renal

3. ANGIOTENSIN RECEPTOR BLOCKERS Losartan, Irbesartan, Candesartan

• MOA: block the effects of angiotensin II at the angiotensin receptor

• Competitive antagonists of Angiotensin II (AT-1)

• Similar effects to ACE inhibitors

• No inhibition of ACE or Dry cough

4. BETA BLOCKERS

• These agents have paradoxical benefit in CCF

• Their MOA in CCF is not well understood

• Acts primarily by inhibiting the sympathetic nervous system

• Start at low dose and monitor for bradycardia • Carvedilol and Metoprolol are the most

commonly used for CCF amongst beta blockers

4. BETA BLOCKERS

4. BETA BLOCKERS

Selective beta-1 antagonist

MetoprololBisprolol

Reduces death rate in CCF

Non-selectivebeta antagonist

carvedilol Reduces death rate in CCF

5. VASODILATORS (Isosorbide dinitrate and hydralazine

• Isosorbide dinitrate and hydralazine used in patients who cannot tolerate ACE inhibitors

• Reduce preload and afterload

• Amlodipine and prazosin are other vasodilators can be used in CCF

6. DIURETICS

• These are useful in reducing the symptoms of volume overload by

1.decreasing the extra cellular volume 2.decreasing the venous return

• Loop diuretics like furosemide and bumetanide are the most effective and commonly used

• Thiazides are effective in mild cases only.

6. DIURETICS ADVERSE EFFECTS

• Loop diuretics and thiazides cause hypokalemia

• Potassium sparing diuretics help in reducing the hypokalemia due to these diuretics.

6. DIURETICS ADVERSE EFFECTS

Potassium Sparing Diuretics eg. Spironolactone:

• Aldosterone inhibition minimize potassium loss, prevent sodium and water retention, endothelial dysfunction and myocardial fibrosis.

• Spironolactone can be added to loop diuretics to modestly enhance the diuresis; more importantly, improve survival.