Congestive Heart Failure 5
How is CHF Treated?
The treatment of CHF is divided into the following four parts:
- Prevention of Initial Cardiac Injury: Coronary artery disease and hypertension are the two most common causes of CHF. Dietary restrictions, exercise, weight reduction in obese individuals, cessation of smoking, and treatment of risk factors like high cholesterol levels and diabetes are important in the prevention of CAD. Medications to control blood pressure also go a long way in preventing CHF. Since heavy alcohol use can contribute to the development of CHF, such tendencies need to be discouraged.
- Prevention of further injury: Aggressive early treatment of a heart attack reduces the amount of damaged muscle and decreases the likelihood and severity of CHF.
- Prevention of post-injury deterioration: Studies have shown that patients who have suffered considerable muscle damage after a heart attack tend to do better if they are maintained on a class of drugs known as ACE inhibitors. It is believed that these medications prevent further deterioration.
- General treatment.
Medications Commonly Used to Treat CHF
Diuretics (Plus Reduction of Salt and Fluid Intake)
All patients with CHF benefit from moderate salt restriction with daily weight measurement. This permits the use of lower and safer doses of diuretics or "water pills", which include furosamide (Lasix®), torsemide (Demadex®), bumetanide (Bumex®), HCTZ (hydrochlorothiazide), etc.
CHF results in retention of salt and water. This causes an increase in body weight, swelling, and shortness of breath. Diuretics or "water pills" are effective because they increase the excretion of urine and sodium (salt). There are several different types of diuretics available. Their selection is based upon the patient's kidney function and severity of heart failure. At times, a combination of two diuretics may be used. The goal of this form of treatment is to eliminate symptoms and the physical signs of fluid retention. Daily weight measurement is important in monitoring diuretic treatment. A steady weight gain could indicate inadequate effects.
Patients need to remember that diuretics have a tendency to increase thirst. The purpose of taking a diuretic is defeated if one succumbs to thirst and drinks an extra 1500cc of fluids after taking a diuretic and having the same amount of urine. Check with your physician regarding the amount of fluids that you are allowed per day, then stick to that restriction. Use a measuring cup to help determine your fluid intake, or at least know the size of your drinking glass (i.e., 6 ounces, etc.). Remember that fluids include water, juice, coffee, tea, soda, milk, soups, and any fluid that is liquid at room temperature (popsicles, ice and gelatin). Also, note that watermelon, when eaten in large amounts, can result in the intake of a lot of fluid.
Taking a diuretic can result in the depletion of important electrolytes or minerals such as potassium. For this reason, the use of a diuretic is frequently accompanied by the addition of a medication that contains potassium. Alternatively, your physician may combine a different type of diuretic ("potassium sparing" which will help reduce the wasting of potassium. Potassium sparing diuretics include Maxzide®, Dyazide®, Triamterene-HCTZ, spironololactone (Aldactone® and Aldactazide®), etc. Excessive use of diuretics can decrease the volume of circulating blood. This in turn can result in decreased blood pressure, weakness and worsening kidney function. It is more likely to occur if one has a reduced intake of fluids (loss of appetite, nausea, etc.), or loses fluids due to diarrhea and vomiting. Monitoring of your weight and periodic check of your potassium level and kidney function helps to avoid this problem.
While taking a diuretic, your physician may advise you to eat foods that are rich in potassium.
Very good sources of potassium include bananas, cantaloupes, honey dew melons, prunes, grapefruits and oranges.
Good sources of potassium are cooked dried beans, cooked greens, sweet potatoes, green lima beans, white potatoes, winter squash, fruit cocktail, raisins, apple juice and peaches.
Patients with CHF also need to limit the intake of salt. Most of the sodium (component of salt) comes from salt shakers and processed foods, including canned food, boxed mixes, and most ready-to-eat foods in the grocery store. Sodium is also consumed in salted nuts, fast foods, salad dressing, buttermilk, soup, salt pork, bacon, cereals, vegetable juice, cheese, pickles, cured meats, peanut butter, snack foods, and sauces. A patient can significantly improve the management of CHF by paying attention to food labels.
ACE (angiotensin-converting enzyme) Inhibitors
ACE inhibitors are extremely important in the treatment of CHF. They are almost always employed, unless contraindicated or not tolerated by the patient.
ACE is released in patients with CHF and is responsible for making certain arteries constrict or "clamp down". ACE is responsible for increasing blood flow to the brain and other vital organs by constricting arteries and reducing flow to the less essential skin and muscles of the arm and legs. Unfortunately, this action increases the resistance against which the heart has to contract. This translates into extra work for a heart that is already weak and failing. Ironically, an action that was designed to help a heart with a reduced output turns out to be harmful to the failing heart. ACE inhibitor drugs blocks the ACE system and relax the walls of the artery. This lowers pressure and the resistance against which the failing heart has to pump and reduces the work that it has to perform. Multiple research studies have shown that ACE inhibitors, when used in patients with CHF, can improve symptoms, decrease the need for emergency care, reduce the dosage of diuretics, and lower the risk of death.
Examples of ACE Inhibitors include benazepril (Lotensin®), captopril (Capoten®), enalapril (Vasotec®), fosinopril (Monopril®), Lisnopril (Zestril® or Prinivil®), moxepril (Univasc®), perindopril (Aceon®), quinapril (Accupril®), ramipril (Altace®), trandolapril (Mavik®), etc. Many ACE Inhibitors are also marketed in combination with a diuretic (HCTZ).
The following factors are additionally noted with ACE inhibitors
- Side-effects may occur early, but do not necessarily prevent long-term use if the dosage of this drug and other medications are adjusted.
- Significant improvement in symptoms may be delayed for several months, so it is important to continue treatment.
- ACE inhibitors reduce disease progression, even when patients do not note a significant improvement in symptoms.
Risks of treatment with ACE inhibitors include decreased blood pressure, dizziness, worsening kidney function, potassium retention, cough (in 5-15% of cases), and an allergic reaction known as angioedema (in less than 1% of cases) that can result in swelling of the face and tongue with associated difficulty in breathing.
Angiotensin-2 Receptor blockers or AR
This class of drugs, as a group, is relatively new, compared to ACE inhibitors. They are used in the treatment of CHF, particularly when ACE inhibitors are not tolerated by the patient because of side-effects. Studies have demonstrated a beneficial effect of ARBs in CHF, similar to that seen with ACE inhibitors. Although differing in chemical structure and point of action, angiotensin-2 inhibitors dilate or open-up the arteries. This reduces the workload of the failing heart, improves symptoms, and decreases the risk of death. An advantage of this class of drugs it that it is far less likely to produce cough and angioedema. Available examples of ARBs include losartan (Cozaar®), valsartan (Diovan®), irbesartan (Avapro®), candesartan (Atacand®), telmisartan (Micardis®), eprosartan (Teventen®), olmesartan (Benicar®), etc. Like ACE inhibitors, several ARBs are also marketed in combination with a diuretic (HCTZ).
Carvedilol or Coreg®
When the output volume of the heart drops in patients with CHF, the body is stressed and releases catecholamines. They are also called adrenergic agents because they are released by the adrenal gland (which sits on top of the kidneys). Adrenaline is such an adrenergic substance. It increases the heart rate and stimulates weak heart muscle to contract more forcefully. This is known as a beta adrenergic effect and increases the work that the heart has to perform. The sick heart gets tired and even more sick as it works harder.
The adrenergic substances also cause the arterial walls to constrict or tighten. This is known as "alpha adrenergic effect" and helps raise blood pressure when a weak heart cannot do so by itself. However, as in the case of ACE activity, this increases the resistance against which the weak heart has to pump, putting an additional load on the struggling heart.
Carvedilol is a fairly new class of drugs that is being used in the treatment of CHF. The drug blocks both the alpha and beta-blocking effects of the adrenergic substances produced by the body. The heart rate is slowed, the weak heart muscle is protected from the "whipping" or stimulating effects (thus reducing the chance of further deterioration) and the arteries are dilated so as to make it easier for the heart to empty. All these actions, like those of ACE inhibitors are CHF-friendly. Carvedilol, like ACE inhibitors have been shown to improve symptoms, decrease the need for hospitalization and improve survival in patients with CHF.
Carvedilol and other agents in its class are always considered in the treatment of CHF unless they are contraindicated or not tolerated. They are generally avoided in patients with asthma, extremely slow heart rates and very low blood pressure.
Beta blockers
A beta blocker blocks the beta adrenergic effects of adrenaline and thus prevents the sick heart from being forced to work harder. This "conservation effort" has a protective effect. Unlike carvedilol, beta blockers do not block the alpha receptor and are thus usually considered to be less effective in the treatment of CHF. However, like carvedilol and ACE inhibitors, beta blockers are generally expected to improve symptoms, decrease the need for hospitalization and improve survival in patients with CHF.
Beta blockers are usually selected because they are frequently less expensive than carvedilol. Also, certain beta blockers like metoprolol (Toprol XL® and Lopressor®) and bisoprolol (Zebeta®) are better tolerated than carvedilol in certain patients with lung disease. Similarly, beta blockers like pindolol (Visken®) and acebutolol (Sectral®) may be used in patients who tend to have a slower heart beat.
Hydralazine
Hydralazine is a drug that dilates arteries and thus reduces the work that the weak heart muscle performs in pumping blood through them. However, this drug is not shown to be generally beneficial as ACE inhibitors in prolonging the life of all patients with CHF. However, Bidil®, a combination of hydralazine and isosorbide (a long acting form of nitroglycerin), has been shown to benefit African-American patients with CHF.
Digitalis or Digoxin
Digoxin is recommended in the treatment of CHF that is caused by a weakened heart muscle. It is used in conjunction with other agents such as diuretics, ACE inhibitors and adrenergic blockers like carvedilol. Although it stimulates the weak heart muscle to contract a little more vigorously, it is felt that the long term beneficial effects of the drug may be related to the indirect inhibition of adrenergic substance release.
Digitalis is also useful in treating certain types of rapid heart beat (atrial fibrillation and atrial flutter) that may accompany CHF.
Other Drugs and Devices
Other drugs and devices that may be used in the treatment of CHF include spironolactone (Aldactone®, which has been shown to preserve potassium and reduce the deterioration of CHF), warfarin or Coumadin® or blood thinners (that reduce the risk of blood clots), antiarrhythmic agents (to treat dangerous irregular heart beats), blood pressure medications (when ACE inhibitors are unable to control the high blood pressure, or is contraindicated). More recently, specialized Bi-V or bi-ventricular pacemakers may be recommended in select patients with CHF and a left bundle branch block. Also, an ICD (implantable cardioverter-defibrilator) or a Bi-V ICD may be considered in patients with CHF due to coronary artery disease and prior heart attacks.
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