Drugs Used For Congestive Cardiac Failure/Heart Failure (chf medications)

To understand how chf medications work we have to first understand the normal physiology of heart.what happens to failing heart and what are the natural ways to avoid heart failure .We will also highlight some chf medications and possible management proctocols .

Cardiac/Heart Failure :

In Congestive Cardiac/Heart failure the heart fails to supply enough blood to the tissues due to decrease in cardiac out put.cardiac output depends upon the following four factors;
1)Preload
2)After load
3)Force Of heart contractility
4)Heart rate

Preload:

It can be defined as the volume of blood which flows into the heart and causes its stretch.stretching of the heart upto a certain point increases its force of contraction,as is explained by the frank starling law.thus increase in blood flow to the heart will increase its force of contraction upto a certain limit.beyond this point further increase in blood volume will lead to failure of the heart.a common example of this type of heart failure occurs in case of valvular incompetence.

Afterload:

It is the resistance offerd by the arterial system to the left ventricular contraction.increase in the arterial resistance causes the left ventricle to contract with more force.This out put load on the left ventricle and it is hypertrophied and thus ultimately fails.A common example of this occurs in chronic hypertension.here increase in arterial resistance causes decrease in systolic blood flow to kidney and other organs of the body.Decrease in renal blood flow leads to stimulation of renin secretion that causes formation of angiotensin 2.Angiotnesin 2 causes generalised vasoconstriction and increased release of aldosterone.Aldosterone causes retention of salt and water in the body by increasing their reabsoprtion from the distal renal tubules.this results in increase in the blood volume that further increase load on the heart.ultimately heart failure occurs.

Cardiac contractility:

Weaknes of the myocardium of the right and left ventricle will lead to decrease force of their contraction.coronary artery disease may lead to chronic right or left ventricle failure.acute myocardial infarction may lead to acute right or left ventricular failure.

Heart rate :

Any factor which decrease the force of contraction of the left ventricle will lead to decrease in cardiac output.This will cause relfex sympathetic nervous system stimulation,causing increase in the heart rate.

chf medications are used to control these four factors which ultimately decrease the chances of heart failure .

SIGNS AND SYMPTOMS OF CARDIAC FAILURE:

1)Tachycardia
2)Shortness of breath
3)Decrease in exercise tolerence
4)Pulmonary oedema
5)Cardiomegaly
6)Peripheral oedema

Classification Of chf medications:

Drugs Used For Congestive Cardiac Failure or chf medications are ,

1)Drugs used to decrease preload:
A)Diuretics
B)organic nitrate
2)Drugs which decrease after load
A)Hydralazine
B)Minoxidil
3)Drugs which decrease both preload and afterload:
A)Captopril
B)Enalapril
C)Lisinopril
D)Fosinopril
E)Quinapril
4)Positive ionotropic drugs:
They can be further divided into three groups;
1)Cardiac glycosides:
A)Digoxin
B)Digitoxin
C)Ouabin
D)Lanatoside.
2)Phosphodiestrase inhibitors:
A)inamrinonone (Amrinone)
B)Milrinone
3)Sympathomimetics:
A)Dopamine
B)Dobutamine
C)Depoxamine
D)Xamoterol

How to Manage Chronic Heart Failure:

Following steps should be taken for the managment of chronic heart failure:
1)Rest-Physical activity should be avoided
2)Hypertension and other underlying conditions should be treated.
3)Reduce weight if overweighted.
4)Reduce salt in diet.
5)Mild cardiac failure can be treated with diuretics for example frusemide in order to prevent K+ Loss amiloride or another K+ Sparing diuretic can be used with frusemide or other loop diuretics.
6)If cardiac failure is not controlled with diuretics then angiotensin converting enzyme inhibitors can be used,provided there is no hyptension.if hypotension is present then organic nitrates cannbe used.
7)Digoxin or other cardiac glycoside can be used if heart failure is not adequately controlled by the above methods.

How to manage Acute Ventricular Failure:

1)Patient should be put to complete bed rest.in severe left ventricular failure,legs should be kept dependent (Hanging from the bed)to reduce venous return from the legs.
2)A loop diuretic ,such as frusemide,should be given intravenously to produce dilatationof viens and later on diuresis.40-80 mg of frusemide can be given.Morphine can also be given intravenously to produce vasodilation as well as to reduce anxiety of the patient.

Related Article: Important Information About Digoxin