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CREATININE CHEMISTRY

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Thursday 21 April 2016

CONGESTIVE HEART FAILURE (CHF)-TREATMENTS

CONGESTIVE HEART FAILURE

It is a pathological condition with multiple etiologies in which the left ventricle fails to contract sufficiently to deliver the blood through the aorta to our body tissues for their metabolic needs.The inability of the left ventricle to function properly the result is collection of waste fluids into its muscles and make it more congestive.Hence the name Congestive Heart Failure
CHF is commonly occuring in elderly patients of above 40 yrs.But it may occur at any age as a result of any one of the underlying heart and vascular diseases such as Angina,MI, Hypertension and Coronary Artery Disease etc.etc.
Myocardial stress such as heavy stress on the wall of left ventricle due to the absence of the interventricular wall (septal wall) or its dysfunctioning (Congenial Heart Failure),traumas,diseases like Rheumatic fever,pulmonary embolism, infections, anemia,pregnancy,drugs,fluid overload,arrhythmias and valve defects may all become the etiological factors.
Types of HFs
1.Low output vs High out put HF
If the metabolic demands are normal but the heart cannot meet the requirements is known as Low output Heart Failure (The most common type)
In case of high metabolic demand conditions due o hypertension or anemia and if the heart is unable to meet he requirements then it is known as High output Heart Failure.
2.Left side vs. Right side Failure
The sighns and symptoms are result from blood backing up in the failing ventricle except in the HF due to increased body demand in which blood will not be much backed up but there is left ventricle failure occurs.
Initially the symptoms tends to be specific to one sided failure but later eventually both side involvement is seen.
Leftside failure can be attributed by when the blood cannot be properly pumped by the inability of the left ventricle into the aorta through the aortic valve,leads to he accumulation of blood in it.
Because of this the left ventricle cannot receive further blood flow from the left atrium through the Miral valve (the valve between the left atrium and left venricle),and inturn because of the blood accumulation in the left atrium it itself cannot accept further blood flow from the pulmonary(lungs) vein and hence the fluid portion of the blood will be pumped back to the lungs leads to Pulmonary Edema.
Right side failure can be atributed by the inability of right ventricle to pump the blood into the pulmonary artery through the pulmonic valve.The blood get accumulated inside the ventricle and is known as Right side failure.
Because of this accumulation the fluid portion of the blood backs up throughout the body (in the veins,liver,legs and bowels) leads to Systemic Edema
Treatment Options is composed of avoiding drugs which can exacerbate the cause as follows.
The followings are the substances which should not be taken in CHF:-
1.Androgens
2.Corticosteroids
3.Estrogens
4.Licorice
5.Guanethidine
6.Lithium carbonate
7.Methyldopa (a centrally acting antihypertensive drug)
8.Salicylates and other NSAIDs
Because all the above drugs causes sodium and water retensions
Second options are releiving the symptoms and improve pump functions by,
a)Reducing metabolic congestion and needs by relaxations,rest,and medications.
b)Reducing fluid intakes
c)Taking digitalis and other inotropic(improving heart contractions)
  drugs
d)Patient educations
Pathophysiology God has given to our body every aspects of self defence and self corrections to some extend inorder to minimise the inconveniences caused by the disorders.Similarly in case of CHF if we left uncare at first our body trys to care it by some compensative activities as follows:-
Sympathetic Responses by which the norepinephrine outflow will act on the heart to increase the contractility,heart rate and the bloodflow which with no otherway redisributed to ensure perfusion of the heart.
Hormonal Stimulation The redistribution of bloodflow to the heart will result in renal insult which decreases glomerular filteration rate (GFR),leads to sodium retension,water retension,activation of the renin-angiotensin-aldosteron system to add to more sodium and water retension.
Cardiac Hypertrophy, The above process of fluid retension will lead to thickening and enlargement of cardiac wall.This will make larger contractile cells and diminishing the capacity of the cavity in an attempt to precipitate expulsion of blood at lower volumes.
Frank-Sterling Mechanism is that increase fiber dilation hightens the contractile force which then increase the energy released.
as a result,1)the heart pumps all the blood it receives.2)as blood volume increases the various cardiac chambers dilate by stretch and enlarge in attempt to accommodate excess fluid.c)as these stretched muscles contract and the contractile force increase proportionally to their dilation.Then the stretched fibers snap back like a rubber band expelling the extra fluid into the arteries.
The above compensation processes may or may not result in a permenant solution as it depending upon the severity of the condition.If the condition is mild the above compensation process may be successful with the Grace of Almighty.If not the tragic events of decompensation process follows as below:-
Overtime the body gets exhausted of its all compensation mechanism and become self defeated.
As the strain continues,total peripheral resistance and afterload pressure further increase and thereby making the ventricular muscle further weaker to expell the blood.
After load is the amount of contractile force required to overcome the interventricular forces and the pressure in aorta (in case of left ventricle) to eject the blood.
Afterload is defined as the pressure in ventricular muscles during contraction.It is the interventricular systolic pressure.
Preload is the force exerted on the ventricular muscle at the end of diastole.
As the fluid volume expands proportionally  the demand also expands on the already exhausted pump,allowing increased volume remain in the ventricle.
The resulting fluid backup produces signs of CHF 
Physical Symptoms
1.Tiredness and fatigue
2.Coughing
3.Shortness of breath or difficult to breath (Due to Left Ventricle failure)
4.Swelling of abdomen and systemic edima(Due to right sided CHF)
Mostly the symptoms are very similar to that of Heart Attack
The following image will illustrate the symptoms diagrammatically
MEDICATIONS
The pharmaceutical therapeutics is based on three approaches as follows:-
1.Improving heart muscle contractions
2.Reduce preload (The filling of ventricles)
3.Reduce afterload(The resistance pressure against which the heart must pump)
The Drugs Options are as follows:-
1.Cardiac Glycosides (e.g)Digoxin(Lanoxin);Digitoxin
2.Bipyridinederivatives(e.g)Amrinone(Inocor);Milrinone(Primacore)
3.Beta-Adrenergic Agonists (e.g) Dolbutamine (e.g) and Dopamine
4.Vasodilators (e.g) Nitrates (Nitroglycerine,Isordil,Amylnitrate);Hydralazine and ACE Inhibitors (Enalapril and other ...prils)
5.Diuretics (No monotherapy,as an adjunct only)
 

 

 
   

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