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Heart failure (HF) has an incidence of 1% at age 50 and roughly doubles for each decade of life thereafter. The 5-year mortality rate is 62% in men.
Pathophysiology of heart failure
HF is defined as insufficient cardiac function to supply the metabolic demands of the body. Systolic dysfunction produces ventricular dilation with poor contractile function.
Impaired ventricular filling, or diastolic dysfunction, is common, especially in elderly hypertensive patients, and may be seen in 30% of patients who have clinical evidence of HF. It is characterized by ventricular hypertrophy, with preserved cardiac contractility. Impaired diastolic filling leads to a reduction in stroke volume.
Clinical manifestations and evaluation
Symptoms of heart failure include weakness, fatigue, lethargy, light-headedness, mental confusion, and ultimately "cardiac cachexia"--generalized exhaustion with loss of muscle mass.
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New York Heart Association Criteria for Heart Failure |
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Class I Asymptomatic Class II Symptoms with moderate activity Class III Symptoms with minimal activity Class IV Symptoms at rest |
Common clinical signs of HF include peripheral edema, pulmonary rales, an S3 gallop, sinus tachycardia, increased jugular venous pressure, and abdominojugular reflux. Signs of chronic HF are often found in noncardiac disorders.
Other disorders may mimic HF include volume overload from renal disease, regurgitant valvular disease, aortic stenosis, high output failure (anemia, sepsis, hyperthyroidism), pericardial disease.
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Laboratory Workup for Suspected HF |
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Blood urea nitrogen Cardiac enzymes (CK-MB, troponin, or both) Complete blood cell count Creatinine Electrolytes Liver function tests |
Magnesium Thyroid-stimulating hormone Urinalysis Echocardiogram Electrocardiography |
Treatment of chronic heart failure
Nonpharmacologic treatments include salt restriction (a diet with 2 g sodium or less), alcohol restriction, water restriction for patients with severe renal impairment or psychogenic polydipsia, and regular aerobic exercise as tolerated.
Diuretics
Diuretics are the most rapidly effective drugs for treating the symptoms of pulmonary congestion.
ACE inhibitors and angiotensin II receptor antagonists
ACE inhibitors reduce preload, afterload, right atrial pressure, pulmonary capillary wedge pressure, arterial blood pressure.
Digoxin
Digoxin, 0.25 mg po daily, increases the force and velocity of myocardial contractions, although this positive inotropic effect is mild. Digoxin has very limited utility in the treatment of acute symptomatic HF.
Beta-blockers
Long-term use of beta-blockers in patients with end-stage HF may improve LV function and increase survival.
Carvedilol ( Coreg) is the only beta-blocker that is FDA-approved for systolic dysfunction.
Beta-blockers should be reserved for patients who do not respond to more traditional agents.
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