Causes The causes of congestive heart failure can vary greatly. All forms of heart disease can lead to heart failure
Primary Disorders Cardiomyopathy Heart muscle disorders cause the heart to lose its contracting ability. Common conditions include coronary atherosclerosis, arterial hypertension, and inflammatory or degenerative muscle disease.
Dysrythmias The heart cannot properly contract. Some of these conditions include tachycardia, atrial dysrythmias, and asynchronous contractions.
Systolic and Diastolic Heart Failure In diastolic dysfunctions of CHF the heart is unable to relax and there is abnormal filling of the ventricles. Systolic dysfunctions are due to the heart being unable to create a force great enough to eject blood normally. The left ventricle systolic dysfunction is the most common cause of CHF, occurring in 60% of patients
Secondary Disorder CHF can also be caused by other systemic alterations such as an increase in metabolic rate, hypoxia, hypoxemia, and anemia. These problems require the heart to increase the cardiac output to meet the need for more oxygen. This causes the heart to lose some of its oxygen supply increasing the risk of CHF.
Pathogenesis The first problem that occurs in the heart is a lesion to the heart muscle itself. This results in the heart being unable to cause the correct amount of velocity for the load placed on the heart. Once this occurs and cardiac output is decreased the compensatory mechanisms kick in. These mechanisms include the sympathetic mechanism, renin-angiotensin system, and ventricular hypertrophy.
Sustains cardiac function for a while. Lead to a feed-back loop causing more cardiac failure.
Symptoms A patient with CHF will notice several different changes in their bodies. One of the most common signs of CHF is swollen legs or ankles and difficult breathing.
Signs The physician will listen to the heart for distinct sounds that can indicate CHF. The patient might be tachycardic, pale in color, have inspiratory rales, or heart murmurs. If the physician hears murmurs, it can indicate that there is mitral or tricuspid regurgitation.
Diagnostic Tests Echocardiography: Most useful test for diagnosis. Uses sound waves to see a moving picture of the heart. Able to distinguish between systolic and diastolic dysfunction.
Cardiac Catheterization checks the coronary arteries for atherosclerosis to see if it is the cause of CHF. Exercise Stress Test gives an overall view of how well your heart is performing under stress.
Treatments for CHF Beta-blockers stop the sympathetic nervous system from activating. This will prevent the release of catecholamines, which in turn will reduce heart rate, blood pressure, and contractility.
Calcium channel blockers: Help to control the myocardial cells involved in pacing the heart. The result of this agent is a decreased heart rate, contractility, and causes vasodilatation.
Nitrates: Dilate the arteries and the veins in the heart reducing the filling time for the ventricles as well as increase cardiac output. Ace Inhibitors: Blocks the renin-angiotensin mechanism. Improve mortality, heart failure symptoms, left ventricle ejection fraction, as well as exercise tolerance.
Heart Rate Recovery (HRR) Experimental program which tries to improve the heart rate in patients with CHF. Short term aerobic exercise showed an increase in the HRR in some patients that were unable to exercise very well.
Outcome Patients who have heart failure will have a low chance of survival. 50% of patients with severe heart failure will die within 12 months and those with moderate CHF will die within 3-4 years. About 30-40% of patients will die suddenly with CHF and those with left ventricle dysfunction have a mortality rate of 10% per year.