Definition of Congestive Heart Failure / Cardiac failure
Heart failure is a pathophysiological state in which the heart is not able to pump adequate amounts of blood to meet the demands of the body. When the heart muscles become weak, it loses the capacity to pump the blood to different parts of the body or, because of some reason or other, the blood reaching the heart becomes less in quantity. Because of these two reasons, heart failure results.
Functionally, heart failure can be divided into right or left heart failure, depending on the side of the chamber which fails initially.
Right-sided heart failure:- The bad blood coming from various parts of the body reaches the right side of the heart. This part pumps the blood into the lungs for purification.
When the right side of the heart-for whatever be the reason-becomes weak, it fails to pump the blood completely into the lungs. And because of back pressure, the quantity of blood in the right part of the heart increases, and the liver suffers from extra pressure. The systolic output of the right ventricle and/or the right atrium falls. Common causes include pulmonary hypertension in mitral stenosis, atrial septal defect, and cor pulmonale; pericardial diseases, pulmonary stenosis, right sided cardiomyopathy, massive pulmonary embolism and tricuspid stenosis. Right heart failure leads to rise in right atrial pressure (manifested as jugular venous pressure), and systemic venous congestion (manifested as tender hepatomegaly and dependent edema).
Left-sided heart failure :
Blood purified by receiving oxygen in the lungs reaches the left side of the heart, and from there to other parts of the body. When the left side becomes weak, it loses its capacity to pump the purified blood to other parts of the body. Then the lungs suffer from back pressure and as a result, fluid will be stored in them.
The fluid thus stored there, obstructs the receiving of oxygen or the releasing of carbon-dioxide. The patient thus becomes breathless for want of enough As a result, water and salt enter all the tissues of the body, and inflammation of the legs and expansion of the liver result. Lower abdomen loses its strength and looks distended.
It is caused by primary dysfunction of the left ventricle or left atrium. Common causes are acute myocardial infarction, chronic ischemic heart disease, systemic hypertention, aortic valvular disease, mitral incompetence, and mitral stenosis. Left sided heart failure leads to pulmonary congestion and pulmonary edema (manifested as orthopnea and paroxysmal nocturnal dyspnea). Persistent left-sided heart failure gives rise to pulmonary hypertension which results in right-sided heart failure as well.
How serious is Heart Failure?
Heart failure is a serious condition that may not be detected at its earliest stages. In its later stages it can have a major effect on quality of life and feeling of wellbeing. In advanced stages, patients may become inactive or bed ridden and unable to perform normal functions and it can be life-threatening. Heart failure is a major cause of sudden death due to production of arrhythmias. Persons with diabetes have a much greater risk of developing heart failure than those without because diabetes is associated with other heart failure risk factors such as high blood pressure, obesity and high cholesterol levels.
Symptoms of Heart Failure / Cardiac Failure
Commonest symptom is dyspnea, which is more marked in left-sided heart disease. Orthopnea, paroxysmal nocturnal dyspnea and Cheyne-Stokes respiration are seen in left-sided heart failure.Weakness, fatigue, and apathy are suggestive of low cardiac output states. Oliguria and nocturia may develop even before dependent edema manifests. Nocturia occurs in the early stages of heart failure. During daytime when the patient is ambulant cardiac function is impaired and fluid accumulates. At night, with recumbency edema fluid is reabsorbed into the circulation, cardiac function improves with rest, and the excess fluid is eliminated.
Edema is the most prominent symptom in right-sided heart failure. Initially the edema is dependent, later it becomes generalized. In the early stages the edema readily pits on pressure but in long standing cases the part becomes indurated and pigmented. Hepatic congestion manifests with upper abdominal pain and tender hepatomegaly, In longstanding congestive heart failure, weight loss and emaciation develop as a result of inadequate intake of food and wasting of tissues. This picture is termed "cardiac cachexia ". Alterations in the cytokine system, especially increase in levels of tumor necrosis factor, interferon gamma and interleukin III also playa part in the production of cardiac cachexia.
Diagnosis of Heart Failure:-
* Pulse and blood pressure: The pulse becomes rapid as a result of compensatory adrenergic activity. Pulsus altemans is suggestive of left ventricular failure. The blood pressure is not generally affected in mild and moderately severe cases. But in severe heart failure the systolic pressure may fall due to reduction in cardiac output. The diastolic pressure is maintained by increase in the peripheral resistance.
* Engorgement of the Jugular vein: This is seen characteristically in right-sided and combined heart failure. Abnormality of the hepatojugular reflux can be demonstrated even before the jugular venous pressure is elevated.
* Examination of the precordium: In the majority of cases the heart is dilated, though in many cases (e.g., mitral stenosis, acute myocardial infarction, myocarditis, and constrictive pericarditis) it may not be so. Evidence of the underlying heart disease may be found. In left ventricular failure a protodiastolic gallop (S3) may be heard over the apex beat, and it is better heard during expiration. In right ventricular failure S3 gallop is heard over the lower left sternal border and it is better heard during inspiration. Rise in pulmonary arterial pressure gives rise to accentuation of the pulmonary second sound. Dilatation of the ventricle gives rise to valvular incompetence. Functional pansystolic murmurs arising from the mitral or tricuspid valves may be audible, which disappear when the heart size returns to normal.
* Abdomen: The liver is enlarged, soft and tender and this may be evident even before overt edema manifests. Hepatic enlargement persists for varying periods after edema clears up with treatment, but with intensive therapy it recedes completely. Mild jaundice and impairment of hepatic function may occur. In longstanding right-sided heart failure with cardiac cirrhosis, the liver is firm and nontender. It does not recede with treatment at this stage. Mild to moderate splenomegaly occurs in some cases initially due to passive venous congestion, later the organ may become fibrotic. Significant splenomegaly should suggest the possibility of infective endocarditis. Ascites may develop as a result of passive venous congestion. Prominent ascites occurs in organic tricuspid valve disease, constrictive pericarditis, and right. ventricular endomyocardial fibrosis.
* Lungs: Pulmonary abnormalities are more pronounced in left-sided heart failure. These are the presence of rales over the infrascapular regions, bronchospasm, unior bilateral hydrothorax, frequent respiratory infections (pneumonia, bronchopneumonia or bronchitis) and pulmonary infarcts.
* Urine: The volume is small and urine is concentrated. Proteinuria may occur as a result of renal congestion even in the absence of renal disease.
* Blood: The erythrocyte sedimentation rate is generally lowered.
* Radiology:- Left-sided heart failure gives rise to abnormalities in the chest radiograph. These include dilatation of the upper lobe veins, dilatation of the main pulmonary artery and its branches, interstitial edema and pleural effusion. Acute pulmonary edema gives a characteristic butterfly-shaped opacity extending on both sides.
The electrocardiogram may reveal the underlying cardiac abnormality. Though ECG is not directly diagnostic of cardiac failure, which is predominantly a mechanical event, many findings such as ischemia, ventricular hypertrophy, conduction defects and arrhythmias give indirect clues to the underlying structural and electrical abnormalities.
The systolic and diastolic dysfunction can be well brought out by echocardiography. In addition to anatomical abnormalities, complications secondary to cardiac failure such as intracardiac thrombi can be identified.
2007-03-05 09:32:32
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answer #5
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answered by Dr.Qutub 7
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