Heart failure is an increasingly common disease because of the improved survival rates of patients after coronary heart disease events. About 4.6 million persons are being treated for heart failure in the United States, and 550,000 new cases are diagnosed each year. The prevalence of heart failure increases with age; approximately 80% of all heart failure admissions occur in persons older than 65 years of age. Heart failure has a tremendous impact on U.S. health care costs, disability, and loss of employment.
Heart failure is a disease state in which the heart is unable to pump blood at a rate required by the body’s metabolism. This can result either from a diseased heart (myocardial failure), or because of excess load placed on the normal heart due to various other disease states. Heart failure is usually the end point for all forms of heart disease.
Heart failure can result from two causes:
- Inability to pump blood due to defective heart contractility and/or filling and emptying. The type of heart disease in which the predominant problem is a defect in contractility is called “systolic” heart failure. In contrast, a defective or impaired filling/emptying state resulting in heart failure is called “diastolic” heart failure.
- Heart failure due to other disease states like systemic infections, severe anemia, thyroid disease, and the like. In these conditions, the heart may be structurally normal, but due to increased load, the heart fails to keep up with the demand.
Forms of heart failure
- Heart failure can be right heart failure, left heart failure, or a combination of both. Right heart failure occurs in people with lung diseases like emphysema, in which increased blood pressure in lung arteries (pulmonary vessels) results in right ventricular failure. Left heart failure is the failure of left ventricle, which is responsible for pumping blood throughout the body, and eventually leads to right ventricular failure also.
- Acute or chronic heart failure: As described above, related to the time of onset of symptoms.
- Low-output heart failure is due to weak and defective heart as mentioned above, whereas high-output heart failure is due to other diseases where the demand on the heart is very high (Table 1).
- Systolic and diastolic heart failure: Problems with contractility or forward pumping function of the heart, or impaired filling (e.g., due to a thickened ventricular wall due secondary to hypertension) of the heart.
|Table 1. Causes of heart failure|
|Low-output heart failure (systolic or diastolic heart failure)||High-output heart failure (other disease states)|
|• Congenital heart disease||• Severe chronic anemia|
|• Valve diseases (most commonly aortic or mitral valve disease)||• Thyrotoxicosis (severe hyperthyroidism)|
|• Rheumatic heart disease||• Beriberi disease (vitamin B1 deficiency—rare)|
|• Hypertension (high blood pressure)|
|• Diabetes||• Bone diseases like Paget’s and multiple myeloma|
|• Coronary heart disease|
|• Viral cardiomyopathya||• Blood disorders like polycythemia vera|
|• Drug-induced cardiomyopathy (such as adriamycin)a||• Pregnancy|
|• Tumor-like carcinoid syndrome|
|• Peripartum cardiomyopathy a||• Arteriovenous fistulas (as in hemodialysis patients)|
|• Alcoholic cardiomyopathy a||• Congenital arteriovenous fistulas|
|• HIV cardiomyopathy a|
|• Other infiltrative and metabolic diseases (rare)|
|• Familial (rare)|
|• Idiopathic (unclear etiology)|
|a Cardiomyopathy: weak heart muscle.|
Symptoms of heart failure
Patients with heart failure can develop these symptoms either suddenly over hours (acute heart failure or flash pulmonary edema) or over days and months (chronic heart failure) by progressively becoming short of breath and manifesting slow weight gain.
- Shortness of breath or dyspnea on exertion.
- Orthopnea: Dyspnea that develops in the recumbent position and is relieved by elevation of the head with pillows.
- Cough: Usually with clear sputum or nonproductive. However, pink frothy sputum is characteristic of pulmonary edema (lungs filled with fluid).
- Paroxysmal nocturnal dyspnea: Attacks of dyspnea occurring at night that awake the patient from sleep suddenly. Associated with anxiety and suffocation due to bronchospasm and lung congestion.
- Edema: Usually dependent in lower extremities, ankles, and sacrum if the patient is recumbent most of the time.
- Weight gain: Patients gain weight progressively or suddenly due to fluid buildup and edema.
- Right upper abdominal pain: Due to congestion of the liver because of fluid backup and edema.
- Ascites (abdominal distention due to fluid accumulation) or pleural effusion (fluid accumulation around the lungs).
Clinical and laboratory findings
- On physical examination, patients with heart failure can have tachycardia (fast heart rate), low or high blood pressure, increased respiratory rate due to shortness of breath, low blood oxygen levels, increased neck vein distention (increased jugular venous distention due to increased right atrial pressure), cardiomegaly (large heart), murmurs or gallops (extra heart sounds), edema, hepatomegaly (distended liver).
- Laboratory data: Elevated kidney function tests (serum creatinine, blood urea nitrogen), liver enzymes (due to congestion of the liver), and abnormal electrolytes (serum sodium, potassium, and chloride). Electrocardiogram, echocardiogram, and heart catheterization may be performed depending on the patient’s clinical status.
Surgical treatment of Heart Failure
- If a combination of the above medications (Table 2; optimal medical therapy) does not improve the individual’s condition, or if the person is admitted to the hospital because of severe heart failure and is on life support, he or she may qualify for certain devices called ventricular assist devices (VADs) that can be surgically implanted into the failing heart. These devices are temporary for the most part, but recently are being evaluated for long-term use at some centers. These devices work as an auxiliary pump; patients may be discharged home with these devices in place, or may go on to wait for heart transplantation.
- If medical therapy fails in reaching symptomatic goals and patients are good candidates for heart transplant, those less than 60 years of age and without other contraindications may qualify for cardiac transplantation. Many factors including other medical illnesses and social history (tobacco smoking, alcohol dependence, and lack of social support) can preclude listing the individual on a transplant waiting list. There is a marked shortage of donor organs, and waits can be as long as 2-5 years. After transplant, close follow-up is mandatory because of the need for immunosuppressive therapy and the constant monitoring that is entailed.
- Biventricular pacing is a new modality which has shown benefit in individuals with NYHA IV (Table 3) heart failure in whom maximal medical therapy has been instituted and symptoms continue. Both ventricles of the heart are paced in order to increase synchronized pumping of the heart muscle, and thus optimize forward blood flow and reduce congestion.
|Table 2. Treatment|
|Class||Some examples||Use||Common side effects|
||Increase urine output Reduce vascular volume and congestion||Electrolyte abnormalities (particularly serum potassium levels) Kidney problems|
||Reduce fluid return to the heartReduce blood pressure and reduce load on heart||Low bloodpressureHeadache|
||Reduce blood pressure and increase the forward blood flow||High serum potassium Kidney problems Dry cough|
||Reduce heart rate and thus reduce oxygen demand on heart||Slow heart rate Fatigue|
|Inotropes||• Digoxin||Increase contractility||Avoid electrolyte abnormalities Avoid dehydration and overdose Side effects include rhythm problems, heart block|
||Used in some patients depending on etiology||Refer to particular medication side effects in reference manual (PDR)|
|Table 3- New York Heart Association Classification (NYHA Class)|
|NYHA I||Ordinary day-to-day activity is well tolerated without any limitation due to heart failure symptoms||Patients can do outdoor work, recreational activity, and work. Only prolonged recreation and strenuous activity precipitates symptoms|
|NYHA II||Slight limitation of ordinary activity due to symptoms||Daily activity as mentioned above brings on fatigue, shortness of breath, or chest tightness|
|NYHA III||Marked limitation of daily activity. Comfortable at rest||Less than ordinary activity causes symptoms|
|NYHA IV||Inability to carry on any activity and symptomatic even at rest||Nocturnal dyspnea and dyspnea at rest. Unable to perform activities of daily living|
|Note: This classification is used to assess the severity and physical limitation related to the heart condition. This classification is used for patients with heart disease and heart failure only.|
Women and heart failure
Several studies have shown that current state-ofthe-art therapy has similar benefits for both men and women with heart failure. There is no evidence for sex-specific differential outcomes in women with heart failure when compared with men.
Pregnant women with heart failure should be closely followed by a cardiologist specializing in heart failure along with a high-risk obstetrician. Medications like beta-blockers and ACE inhibitors may be contraindicated, and extreme volume shifts occur during pregnancy, requiring adjustment of medications by experienced physicians. Similarly, beta-blockers should be used during nursing only after consulting a cardiologist and obstetrician.
Peripartum cardiomyopathy is a form of heart disease in which left ventricular systolic dysfunction results in signs and symptoms of heart failure. Symptoms usually occur during the last trimester of gestation, and the diagnosis is usually made in the early peripartum period. The incidence of this condition is estimated to be approximately 1 in 15,000 in the United States. Other causes of heart failure should be ruled out before diagnosing peripartum cardiomyopathy. The illness can occur as late as 6 months after delivery, and is more likely to occur in multiparous women, those with twin pregnancies, those with preeclampsia, and in women older than 30 years of age. The etiology for this disease is not clearly understood. A majority (50-60%) of patients recover ventricular function rapidly within 6 months of delivery. Peripartum cardiomyopathy tends to recur with subsequent pregnancies. Individuals who do not improve and recover function usually deteriorate (20-30%) and require transplantation in order to avoid death or persistent heart failure. The remaining 20-30% of women with peripartum cardiomyopathy stabilize on medical therapy.
Acute heart failure is treated with oxygen, diuretics, digitalis, and vasodilator agents. Other medications of proven benefit in heart failure patients must be used with extreme caution. Because of the increased incidence of strokes associated with this disease, patients also require anticoagulation. VADs and transplantation are other options for severe cases which are refractory to medical therapy. Early delivery of the fetus may be recommended depending on the severity of the disease. Subsequent pregnancies should be considered high risk due to the propensity for recurrence of this form of cardiomyopathy. In many, if not most cases, women are counseled to avoid further pregnancies because of the risk to themselves.