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CONGESTIVE HEART FAILURE AND PUBLIC HEALTH
Marwan Nasif, MD, Alaa Alahmad, MD
Outline of Chapter
1. Definition
2. Epidemiology
3. Risk Factors
4. Types and causes
5. Common symptoms and signs
6. Diagnosis
7. Classes and stages of heart failure
8. Treatment
9. Lifestyle modification
10. Heart failure in minorities
11. Cardiac rehabilitation programs
12. Public policy
13. Beneficial websites
14. References
1- Definition
Heart failure (HF) is a chronic disease characterized by the inability of the heart
to pump an adequate amount of blood to achieve the demand of the different
organ systems and/or doing so at increased filling pressures. It is a serious
condition representing the end-stage of a myriad of other cardiac diseases
without a curative treatment. Once diagnosed, medication is required for the rest
of the patient’s life to improve their life quality and survival [1].
2- Epidemiology
The treatment and prevention of HF has become a burgeoning public health
problem reaching epidemic levels especially for the elderly population. There are
more than 20 million people affected worldwide and has a prevalence of 2% in
developed countries [2]. According to the American Heart Association, 5.3 million
Americans have congestive heart failure (CHF), 660,000 new cases are
diagnosed yearly, with an incidence approaching 10 per 1000 population among
persons older than 65 years of age. The estimated yearly mortality related to
heart failure is around 287 thousand people. Heart failure prevalence follows an
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exponential pattern, which rises with age and affects 6-10% of people over age
65 [1,3,4]. It seems that the success in treating other heart conditions like
myocardial infarction, valvular heart disease, and arrhythmias has increased the
prevalence of heart failure now that patients survive longer. Congestive heart
failure is the leading cause of admissions to hospitals among the elderly
according to the National Hospital Discharges in the United States. The
expected cost of the disease in the United States for 2009 is $34.8 billion, with
hospital admissions being a significant portion of the total costs [3]. According to
The Census Bureau and the Centers for Disease Control and Prevention, African
Americans (AAs) between the age of 45 and 65 have a 70% higher rate of HF,
with mortality rates of 2.5 times more than the Caucasian population. The
current estimated number of AAs with heart failure is about 700,000 with an
expected increase to 900,000 in 2010. The Hispanic/Latino population has a
higher incidence of heart failure than the white non-Hispanic population;
however, more population-based studies are needed to accurately estimate the
prevalence of HF in the Hispanic population [5]. The Hispanic population tends
to have HF at younger ages, die earlier, and have higher admission rates than
the Caucasian population [6]. The crest of the problem is still to come over the
next decades when the number of senior citizens above age 65 will double to a
projection of 70 million. Despite many recent advances in medication, the rate of
people with chronic congestive heart failure is rising. Another problem is the
increased concerns regarding the prevalence of asymptomatic heart failure yet to
be diagnosed which might be as prevalent as symptomatic heart failure [7,8].
3- Risk Factors
The risk factors that contribute to the development of heart failure are similar to
risks of coronary artery disease, stroke, and peripheral artery disease. In fact,
coronary artery disease and previous history of myocardial infarction (heart
attack) is one of the major risk factors in developing HF. Based on the data from
the Framingham study, which commenced in the United States back in 1949,
hypertension (high blood pressure) is the most important risk factor accounting
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for approximately 39% of cases in men and 59% in women. Previous history of
heart attack was the second most common risk accounting for 34% in men and
13% in women [9]. Cigarette smoking, elevated cholesterol, obesity, and diabetes
are the major preventable risk factors for both congestive heart failure and
coronary artery disease. Other less common diseases and risk factors are
valvular heart disease, cardiomyopathy (the diseases of the heart muscle),
alcohol abuse, or infections.
4- Types and Causes
Several classification categories have been developed to classify heart failure.
These include, acute vs. chronic, left vs. right sided, high output vs. low output,
and systolic vs. diastolic heart failure. This chapter will focus more on the latter
classification which is the most commonly used because of its implication in the
treatment and long term outcome of heart failure patients.
Systolic heart failure (depressed ejection fraction)
This category describes the decrease in the heart muscle’s ability to
contract and pump blood against the systemic vascular resistance,
which usually is increased. Coronary artery disease (CAD) is the
predominant cause of heart failure in general and systolic dysfunction,
in particular, accounting for 60 to 75% of all cases in industrialized
countries. Both hypertension (high blood pressure) and diabetes
interact with a genetic predisposition augmenting the development of
CAD, as does dyslipidemia. Other etiologies include nonischemic
idiopathic cardiomyopathy, valvular heart disease, myocarditis, alcohol,
and drugs. Rheumatic fever remains a leading cause of heart failure in
Africa and Asia, particularly in the young population.
Diastolic heart failure (preserved ejection fraction)
In this category, the contractility of the cardiac muscle is intact or
increased, however, the relaxing phase of the cardiac cycle is impaired.
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The heart chambers are thickened and rigid. The vascular resistance is
increased to increase the filling volume of the heart. The most common
cause of diastolic heart failure is hypertension, which contributes also to
the development of coronary artery disease and systolic dysfunction.
Other less common causes include primary hypertrophic
cardiomyopathies, valvular heart disease, restrictive cardiomyopathy,
amyloidosis, and constrictive pericarditis.
5- Common symptoms and signs
Some studies suggest that asymptomatic heart failure is as prevalent as heart
failure with clinical manifestations. The cardinal symptom associated with HF is
shortness of breath, which in the early stages is associated with exertion. As the
disease progresses, the dyspnea occurs at rest. At times, the difficulty in
breathing is associated with the recumbent position due to the increase in
venous return to the heart. This phenomenon is called orthopnea. Patients may
also have paroxysmal nocturnal dyspnea (PND), which refers to the sudden
development of severe shortness of breath at night that awakens the patient from
sleep. All of the pervious symptoms are related to pulmonary congestion with
accumulation of fluid in the interstitial and alveolar spaces that occasionally might
lead to the development of acute pulmonary edema. Other symptoms common
in patients with CHF are peripheral edema, fatigue, anorexia, early satiety, liver
congestion, confusion, sleeping disorders, and nocturia, frequent awakenings
throughout the night in order to urinate.
6- Diagnosis
A careful physical examination is essential for the initial assessment of patients
with symptoms that suggest CHF. The diagnosis becomes straightforward when
it is associated with cardinal symptoms like exertional dyspnea and peripheral
edema. Initial routine laboratory testing with complete blood count, electrolyte
panel, blood urea nitrogen, serum creatinine, and hepatic panel would be helpful
to assess other causes that might contribute to fluid retention or precipitate heart
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failure like severe anemia or kidney failure. A routine 12 lead ECG is of great
importance to determine the presence of arrhythmias, left ventricular
hypertrophy, or prior myocardial infarction. All patients with heart failure should
be screened for dyslipidemia, diabetes mellitus, and thyroid dysfunction. A
chest X-ray is not a very sensitive test to confirm or refute congestive heart
failure; nonetheless, it might provide useful information about cardiac size,
pulmonary vasculature, and interstitial edema. Also, it is useful in evaluating
other causes of pulmonary disease that could simulate the presentation of HF.
2-D echocardiography with Doppler has become the gold standard noninvasive
test to evaluate ventricular and valvular functions. It provides semiquantitative
assessment of ventricular size, thickness, and contractility. The pulsed Doppler is
also an invaluable technique to study the valvular apparatus functions and blood
flow across the valves. A relatively new biomarker called brain natriuretic peptide
(BNP) has a relative sensitivity for the presence of HF with depressed left
ventricular function. BNP also has prognostic value, as it has been shown in
several studies that elevated levels of BNP were associated with increased
mortality and hospitalization. The use of invasive studies like right and left heart
catheterization currently are reserved to assess the presence of coronary artery
disease or primary pulmonary hypertension, which may require specific
treatment.
7- Classes and stages of heart failure
Until November 8, 2001, New York Heart Association (NYHA) classification was
the only system used to assess stages of congestive heart failure. This
classification concentrated more on functional capacity, ranging from
asymptomatic patients to patients with severely limited activity secondary to
dyspnea at rest. The American College of Cardiology/American Heart
Association (ACC/AHA) stages focus more on the continuum and progressive
nature of this condition adding a new stage that includes patient at high risk for
the development of heart failure. The outlines of the two classifications are
described below.
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