Heart failure (HF), often called congestive heart failure (CHF) or
congestive cardiac failure (CCF), occurs when the heart is unable to
provide sufficient pump action to distribute blood flow to meet the
needs of the body. Heart failure can cause a number of symptoms
including shortness of breath, leg swelling, and exercise intolerance.
The condition is diagnosed with echocardiography and blood tests.
Treatment commonly consists of lifestyle measures such as smoking
cessation, light exercise including breathing protocols, decreased salt
intake and other dietary changes, and medications. Sometimes it is
treated with implanted devices (pacemakers or ventricular assist
devices) and occasionally a heart transplant.
Common causes of heart failure include myocardial infarction and other
forms of ischemic heart disease, hypertension, valvular heart disease,
and cardiomyopathy. The term heart failure is sometimes incorrectly used
for other cardiac-related illnesses, such asmyocardial infarction
(heart attack) or cardiac arrest, which can cause heart failure but are
not equivalent to heart failure.
Heart failure is a common, costly, disabling, and potentially deadly
condition. In developed countries, around 2% of adults suffer from heart
failure, but in those over the age of 65, this increases to 6–10%.
Signs and symptoms
Signs
Left-sided failure
Common respiratory signs are tachypnea (increased rate of breathing) and
increased work of breathing (non-specific signs of respiratory
distress). Rales or crackles, heard initially in the lung bases, and
when severe, throughout the lung fields suggest the development
ofpulmonary edema (fluid in the alveoli). Cyanosis which suggests severe
hypoxemia, is a late sign of extremely severe pulmonary edema.
Additional signs indicating left ventricular failure include a laterally
displaced apex beat (which occurs if the heart is enlarged) and a
gallop rhythm (additional heart sounds) may be heard as a marker of
increased blood flow, or increased intra-cardiac pressure. Heart
murmursmay indicate the presence of valvular heart disease, either as a
cause (e.g. aortic stenosis) or as a result (e.g. mitral regurgitation)
of the heart failure.
Right-sided failure
Physical examination may reveal pitting peripheral edema, ascites, and
hepatomegaly. Jugular venous pressure is frequently assessed as a marker
of fluid status, which can be accentuated by eliciting hepatojugular
reflux. If the right ventricular pressure is increased, aparasternal
heave may be present, signifying the compensatory increase in
contraction strength.
Biventricular failure
Dullness of the lung fields to finger percussion and reduced breath
sounds at the bases of the lung may suggest the development of apleural
effusion (fluid collection in between the lung and the chest wall).
Though it can occur in isolated left- or right-sided heart failure, it
is more common in biventricular failure because pleural veins drain both
into the systemic and pulmonary venous system. When unilateral,
effusions are often right sided.
Symptoms
Heart failure symptoms are traditionally and somewhat arbitrarily
divided into “left” and “right” sided, recognizing that the left and
right ventricles of the heart supply different portions of the
circulation. However, heart failure is not exclusively backward failure
(in the part of the circulation which drains to the ventricle).
There are several other exceptions to a simple left-right division of
heart failure symptoms. Left sided forward failure overlaps with right
sided backward failure. Additionally, the most common cause of
right-sided heart failure is left-sided heart failure. The result is
that patients commonly present with both sets of signs and symptoms.
Left-sided failure
Backward failure of the left ventricle causes congestion of the
pulmonary vasculature, and so the symptoms are predominantly respiratory
in nature. Backward failure can be subdivided into failure of the left
atrium, the left ventricle or both within the left circuit. The patient
will have dyspnea (shortness of breath) on exertion (dyspnée d’effort)
and in severe cases, dyspnea at rest. Increasing breathlessness on lying
flat, called orthopnea, occurs. It is often measured in the number of
pillows required to lie comfortably, and in severe cases, the patient
may resort to sleeping while sitting up. Another symptom of heart
failure is paroxysmal nocturnal dyspnea a sudden nighttime attack of
severe breathlessness, usually several hours after going to sleep. Easy
fatigueability and exercise intolerance are also common complaints
related to respiratory compromise. “Cardiac asthma” or wheezing may
occur.
Compromise of left ventricular forward function may result in symptoms
of poor systemic circulation such as dizziness, confusion and cool
extremities at rest.
Right-sided failure
Backward failure of the right ventricle leads to congestion of systemic
capillaries. This generates excess fluid accumulation in the body. This
causes swelling under the skin (termedperipheral edema or anasarca) and
usually affects the dependent parts of the body first (causing foot and
ankle swelling in people who are standing up, and sacral edema in people
who are predominantly lying down). Nocturia (frequent nighttime
urination) may occur when fluid from the legs is returned to the
bloodstream while lying down at night. In progressively severe cases,
ascites (fluid accumulation in the abdominal cavity causing swelling)
and hepatomegaly (enlargement of the liver) may develop. Significant
liver congestion may result in impaired liver function, and jaundice and
even coagulopathy (problems of decreased blood clotting) may occur.
Diagnosis
No system of diagnostic criteria has been agreed as the gold standard for heart failure.
Imaging
Echocardiography is commonly used to support a clinical diagnosis of
heart failure. This modality uses ultrasound to determine thestroke
volume (SV, the amount of blood in the heart that exits the ventricles
with each beat), the end-diastolic volume (EDV, the total amount of
blood at the end of diastole), and the SV in proportion to the EDV, a
value known as the ejection fraction (EF). In pediatrics, the shortening
fraction is the preferred measure of systolic function.
Normally, the EF should be between 50% and 70%; in systolic heart
failure, it drops below 40%. Echocardiography can also identify valvular
heart disease and assess the state of the pericardium (the connective
tissue sac surrounding the heart). Echocardiography may also aid in
deciding what treatments will help the patient, such as medication,
insertion of an implantable cardioverter-defibrillator or cardiac
resynchronization therapy. Echocardiography can also help determine if
acute myocardial ischemia is the precipitating cause, and may manifest
as regional wall motion abnormalities on echo.
Chest X-rays are frequently used to aid in the diagnosis of CHF. In the
compensated patient, this may show cardiomegaly (visible enlargement of
the heart), quantified as the cardiothoracic ratio (proportion of the
heart size to the chest). In left ventricular failure, there may be
evidence of vascular redistribution (“upper lobe blood diversion” or
“cephalization”), Kerley lines, cuffing of the areas around the bronchi,
and interstitial edema.
Electrophysiology
An electrocardiogram (ECG/EKG) may be used to identify arrhythmias,
ischemic heart disease, right and left ventricular hypertrophy, and
presence of conduction delay or abnormalities (e.g. left bundle branch
block). Although these findings are not specific to the diagnosis of
heart failure a normal ECG virtually excludes left ventricular systolic
dysfunction.
Blood tests
Blood tests routinely performed include electrolytes (sodium,
potassium), measures of renal function, liver function tests, thyroid
function tests, a complete blood count, and often C-reactive protein if
infection is suspected. An elevated B-type natriuretic peptide (BNP) is a
specific test indicative of heart failure. Additionally, BNP can be
used to differentiate between causes of dyspnea due to heart failure
from other causes of dyspnea. If myocardial infarction is suspected,
various cardiac markers may be used.
According to a meta-analysis comparing BNP and N-terminal pro-BNP
(NTproBNP) in the diagnosis of heart failure, BNP is a better indicator
for heart failure and left ventricular systolic dysfunction. In groups
of symptomatic patients, a diagnostic odds ratio of 27 for BNP compares
with a sensitivity of 85% and specificity of 84% in detecting heart
failure.
Angiography
Heart failure may be the result of coronary artery disease, and its
prognosis depends in part on the ability of the coronary arteries to
supply blood to the myocardium (heart muscle). As a result, coronary
catheterization may be used to identify possibilities for
revascularisation through percutaneous coronary intervention or bypass
surgery.
Monitoring
Various measures are often used to assess the progress of patients being
treated for heart failure. These include fluid balance (calculation of
fluid intake and excretion), monitoring body weight (which in the
shorter term reflects fluid shifts).
Treatment
Treatment focuses on improving the symptoms and preventing the
progression of the disease. Reversible causes of the heart failure also
need to be addressed: (e.g. infection, alcohol ingestion, anemia,
thyrotoxicosis, arrhythmia, hypertension). Treatments include lifestyle
and pharmacological modalities.
Acute decompensation
In acute decompensated heart failure (ADHF), the immediate goal is to
re-establish adequate perfusion and oxygen delivery to end organs. This
entails ensuring that airway, breathing, and circulation are adequate.
Immediated treatments usually involve some combination of vasodilators
such as nitroglycerin, diuretics such as furosemide, and possiblynon
invasive positive pressure ventilation (NIPPV).
Chronic management
The goal is to prevent the development of acute decompensated heart
failure, to counteract the deleterious effects of cardiac remodeling,
and to minimize the symptoms that the patient suffers. First-line
therapy for all heart failure patients is angiotensin-converting enzyme
(ACE) inhibition. ACE inhibitors (i.e., enalapril, captopril,
lisinopril, ramipril) improve survival and quality of life in heart
failure patients, and have been shown to reduce mortality in patients
with left ventricular dysfunction in numerous randomized trials. In
addition to pharmacologic agents (oral loop diuretics, beta-blockers,
ACE inhibitors or angiotensin receptor blockers, vasodilators, and in
severe cardiomyopathy aldosterone receptor antagonists), behavioral
modification should be pursued, specifically with regard to dietary
guidelines regarding salt and fluid intake. Exercise should be
encouraged as tolerated, as sufficient conditioning can significantly
improve quality-of-life.
Anemia is an independent factor in mortality in people with chronic
heart failure; it may also impact on quality of life.Treatment of
anaemia improves quality of life and decreases mortality rates.
In patients with severe cardiomyopathy, implantation of an automatic
implantable cardioverter defibrillator (AICD) should be considered. A
select population will also probably benefit from ventricular
resynchronization.
In select cases, cardiac transplantation can be considered. While
this may resolve the problems associated with heart failure, the patient
generally must remain on an immunosuppressive regimen to prevent
rejection, which has its own significant downsides.
Home dobutamine and milrinone
These two medications are both inotropes with sympathomimetic effect.
Both can be used in severe heart failure, generally in patients who
require frequent exacerbations with hospitalization and/or refractory
symptoms. While both medications have proven to improve symptoms, both
also increase the risk of sudden cardiac death, and the research
suggests an increased mortality rate for patients who are started on
these medications. Extensive counseling about symptom management vs.
risk of earlier death needs to be undertaken before starting the
medication.
Palliative care
Patients with CHF often have significant symptoms, such as shortness of
breath and chest pain. Both palliative care and cardiology are trying to
get palliative care involved earlier in the course of patients with
heart failure, and some would argue any patient with NYHA class III CHF
should have a palliative care referral. Palliative care can not only
provide symptom management, but also assist with advanced care planning,
goals of care in the case of a significant decline, and making sure the
patient has a medical power of attorneyand discussed his or her wishes
with this individual.
Hospice
Without transplantation, heart failure may not be reversible and cardiac
function typically deteriorates with time. The growing number of
patients with Stage IV heart failure (intractable symptoms of fatigue,
shortness of breath or chest pain at rest despite optimal medical
therapy) should be considered for palliative care or hospice.