CONGESTIVE HEART FAILURE
W. G. Franklin, M.D.
THE PROBLEM :
Congestive Heart Failure (CHF) most commonly entails weakness of the heart muscle, usually the left ventricle, with subsequent back up of fluid in the lungs causing shortness of breath. Frequently, fluid may back up throughout the body with swelling or edema of the legs.
CHF may result from a heart attack, arteriosclerotic coronary artery obstructions, years of high blood pressure, leaky (regurgitant) or obstructed (stenotic) heart valves, alcohol, drugs, chemotherapy, infections, thyroid abnormalities, or delivering a baby .
"Right sided" heart failure may develop when the right pumping chamber (right ventricle) weakens as a result of lung disease, blood clots (pulmonary emboli), or congenital heart defects.
CHF may also occur when the heart muscle contracts strongly (during systole) but fails to relax properly (during diastole) and thus does not fill up with sufficient blood to result in a good output. This inefficiency of the pumping chamber is called "diastolic dysfunction" or a "stiff left ventricle." It may help to think of the comparison of filling up a cellophane bag with air versus blowing air into a hot water bottle.
FLUID BALANCE :
CHF may be thought of as an imbalance of fluid or as a mishandling of fluid by the heart and kidneys.
Gravity is a very important factor. Excess fluid will shift to whatever part of the body is lowest. It is not uncommon to have a dry mouth and swollen ankles at the same time.
Excess fluid is often eliminated at night when the legs are level with the kidneys for hours at a time. Getting up at night to eliminate urine (nocturia) may occur one to six times depending on the amount of excess fluid in the body.
Symptoms of shortness of breath and hospitalizations occur more toward the end of the day after fluid accumulates.
Diuretic medication (fluid pills) are usually necessary, beneficial, and well-tolerated.
The most common diuretic prescribed for moderate or severe CHF is LASIX (means "lasts 6 hours"), generically termed furosemide. This should be prescribed at a time when fluid is in excess (afternoon). It may often be unhelpful if taken in the morning when fluid is at its lowest level of the day.
Lasix may be taken from 1-4 PM and is usually finished having an effect by 7-10 PM.
There will be a greater diuretic effect and elimination of fluid if one is able to lie down or sit down with the legs elevated (so that they tilt toward the abdomen or kidneys) for one hour after taking the Lasix. You may want to allow 30 minutes for absorption from the stomach before lying down.
Fluid limitation is important if you have CHF. If you eliminate 8 oz of urine but drink 16 oz, the net effect is an increase of body fluid. When excess fluid is evident (edema, shortness of breath), total fluids should be limited to 6 glasses, 6 oz each, per day. This includes beverages, soup, yogurt, melon, fruit, etc. If no excess fluid is apparent, then more fluid may be permitted, especially if excess sweating, fever, vomiting, diarrhea, etc., occur.
Improved sleeping may result if fluid intake is curtailed after 8 PM and the legs are tilted up for 2 hours before retiring. Having to prop one's head up to breathe better (called orthopnea) and waking up to urinate (nocturia) may be clues to the presence of extra fluid (if prostate enlargement is not present).
Weighing oneself on the same scale each morning before breakfast is a good habit. Any gain of 2 lb in one day or 3 lb over a previously established "dry weight" may be a sign of worsening CHF.
Lasix may be necessary twice a day (10 AM and 4 PM) in some people if CHF is severe.
OTHER FACTORS :
Avoidance of salt is very important. The less salt consumed, the less fluid is retained, and the less medication is needed. For mild or moderate CHF, sodium intake should be limited to less than 4 grams per day and for severe CHF less than 2 grams.
Elimination of excess body fat results in less total blood volume, lower blood pressure, and less work for the heart.
Continue activity: even walking daily up and down a hall for 15 minutes without stopping, is beneficial.
Alcohol is deposited as fat in all tissues of the body, including the heart muscle, and can be demonstrated to reduce the pumping power of the ventricles. Alcohol intake should be limited with mild CHF and avoided with moderate or severe CHF.
Caffeine raises the blood pressure and increases the heart rate, thus causing more work for the pumping chamber (LV). It also promotes premature beats and other abnormal rhythms.
Atrial fibrillation is an irregular rhythm with quivering of the receiving chambers and irregular contractions of the pumping chamber. The output of the heart may decrease 24-40% when this rhythm is present. Enlargement of the receiving chambers is a key factor and may itself result from a leaky valve (mitral regurgitation in particular).
MEDICATIONS (not all inclusive)
DIURETICS (remove excess fluid via kidneys)
MILD:
1. hydrochlorothiazide (HCTZ): potassium depleting, calcium sparing
2. triamterene: potassium sparing
3. MAXZIDE: combination of 1 and 2
STRONGER:
1. LASIX (furosemide) potassium depleting
2. BUMEX (bumetanide) potassium depleting
3. ZAROXOLYN (metolazone) potassium depleting
DIGITALIS
digoxin (Lanoxin) improves pumping power (contractility) of the left ventricle by 5%. It also regulates the heart rhythm and reduces the rate of atrial fibrillation. May cause loss of appetite or abnormal rhythm (with silent buildup) especially when the kidneys are weak or failing.
- VASODILATORS: Lower the blood pressure and the amount of work required of the pumping chamber (LV); also called afterload reducers.
ACE inhibitors (potassium sparing)
- In addition to vasodilator properties, they also act on the heart muscle to "relax" it. May cause dry cough, swelling of tongue.
ARB's (potassium sparing)
- Action is similar to that of cousin ACE inhibitors.
- Do not usually cause dry cough or swelling of tongue.
- Generally more expensive than ACE's.
- As with ACE's, may improve kidney blood flow and function.
ALPHA BLOCKERS
- prazocin (Minipress)
- terazosin (Hytrin): often used for prostate enlargement.
HYDRALAZINE
- May also increase contractility (pumping power) of LV
BETA BLOCKERS: Counteract adrenalin, reduce the heart rate, help
restore and maintain a normal rhythm. Frequently used examples include Coreg, Normodyne (labetalol), Lopressor (metoprolol), Tenormin (atenolol). Glaucoma patients are often prescribed timolol drops which act throughout the body and reduce the heart rate and blood pressure.
NITRATES
- Sublingual (SL) nitroglycerin (NTG) may help when acutely short of breath by reducing systolic blood pressure (if not too low already). If shortness of breath or chest pressure (angina) is a result of arteriosclerotic coronary obstructions, then NTG actually improves the pumping power of the heart by delivering more blood flow to the LV.
- Nitrate pills such as isosorbide (Isordil) and Imdur and topical nitrates such as Nitrol paste and Nitro-Dur cause dilation of veins with a beneficial reduction in blood volume to the heart.
SPIRONOLACTONE (ALDACTONE): An old, extremely mild diuretic with potassium sparing properties. Recently discovered to reduce the rate of death by 25-50% in multiple studies cut short because of strikingly significant positive results. May result in 5% of men in some sensitivity and enlargement of breast tissue (gynecomastia). May actually reduce formation of scar tissue (fibrosis) in heart muscle.
CALCIUM CHANNEL BLOCKERS: Second generation calcium channel blockers such as Norvasc (amlodipine) and Plendil (felodipine) have vasodilating properties that are useful in the presence of severe systolic hypertension and also when ischemia from coronary artery disease is a factor. They may have a mild tendency toward decreasing LV pumping power and may contribute somewhat to fluid retention and edema.
ANTICOAGULANTS:
- Blood has a greater tendency to clot inside the LV pumping chamber if the amount of blood pumped out each beat (ejection fraction or EF) is less than 30-40% (normal is above 55%).
- Atrial fibrillation, an irregular rhythm, may result in clot formation in the receiving chamber.
- Anticoagulation may prevent clot formation and subsequent traveling of clot through the blood (embolization) to other parts of the body, including the brain, causing stroke.
- Anticoagulation may be started in the hospital either intravenously (IV) or by injection under the skin (subq).
- Anticoagulation on a long term basis may be achieved with pills called Coumadin (warfarin). Coumadin interacts with many medications, including aspirin, and must be monitored closely, usually with a blood test called the proTime (PT) every 4-6 weeks.
IV MEDICATIONS
- When CHF is severe, requiring an ER visit or hospitalization, often an IV medication which stimulates the heart muscle to pump more strongly is administered.
- The most common is Dopamine, which at low doses also improves kidney blood flow and function.
POTASSIUM (K+)
- A mineral that is often lost in the urine when potassium depleting diuretics, such as HCTZ and Lasix, are used.
- Replacement of K+ can be achieved with KCl pills or IV KCl.
- Low potassium can result in weakness and contribute to abnormal heart rhythms, especially if digoxin levels are high.
- High potassium can cause dangerous heart rhythms as well. Kidney weakness or failure can result in high K+. In this situation, potassium rich foods, such as bananas, orange juice, and tomatoes, etc., should be avoided.
VENTRICULAR TACHYCARDIA/VENTRICULAR FIBRILLATION
VT/VF is a potentially fatal heart rhythm that is present when CHF is severe.
Medications, such as beta blockers, amiodarone (CORDARONE) and sotalol, may be helpful.
Application of an electrical shock (cardioversion, defibrillation) may be necessary.
Maintaining normal potassium and magnesium levels is important.
A catheterization study of the electrical system (EP study) may
be necessary to determine the best choice of preventive medication or the need for an implantable defibrillator.
An implantable defibrillator is a relatively small device inserted under the skin surgically with electrical catheters attached to the heart that enable the device to detect an abnormal rhythm and deliver a small electrical shock.
Usually these devices now also have the ability to act as a pacemaker to speed up the heartbeat when it is too slow. An inefficient heart may be improved by an AV sequential pacemaker which helps to synchronize contraction of the atria with ventricular contraction.
SURGICAL PROCEDURES
With the marked improvement in effective medications now available, surgical procedures are necessary in only a small percentage of patients with CHF.
When severe mitral regurgitation (leakage) or stenosis (obstruction) is present, then valve repair or replacement may be indicated.
When severe aortic stenosis (obstruction) or regurgitation (leakage) is present, then valve replacement may be necessary.
When the EF (ejection fraction) of the LV pumping chamber is less than 25% (normal greater than 55%), then consideration may be given to either a left ventricular assist device, surgical removal of an ineffective portion of the LV muscle, or cardiac transplantation.
REFERENCES:
1. Pitt, B. et al. The Effect of Spironolactone on Morbidity and Mortality in Severe Heart Failure. NEJM 9/2/99; 341:709-716.
2. Conti, C.R. Use of Calcium Antagonists to Treat Heart Failure. Clinical Cardiology 17:101-102 (1994).
3. Brater, D.C. Diuretic therapy, NEJM 8/6/98 339:387-394.
4. Greenberg, Barry Refractory Heart Failure CVRR Feb 98: 19-29