Congestive Heart Failure

Congestive Heart Failure



Definition of Congestive Heart Failure

 

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 maintain 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 by patient physical examination and confirmed with echocardiography. Blood tests help to determine the cause. Treatment depends on severity and cause of heart failure. In a chronic patient already in a stable situation, treatment commonly consists of lifestyle measures such as smoking cessation, light exercise, dietary changes, and medications. Sometimes, depending on etiology, it is treated with implanted devices (pacemakers or ventricular assist devices) and occasionally a heart transplant is required.

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 as myocardial 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%.

 

Causes of Congestive Heart Failure

 

The predominance of causes of heart failure are difficult to analyze due to challenges in diagnosis, differences in populations, and changing prevalence of causes with age.

A study of healthy adults in the United States found the following causes risks:

  • Ischaemic heart disease 62%
  • Cigarette smoking 16%
  • Hypertension (high blood pressure) 10%
  • Obesity 8%
  • Diabetes 3%
  • Valvular heart disease 2% (much higher in older populations)

Italians had the following underlying causes:

  • Ischaemic heart disease 40%
  • Dilated cardiomyopathy 32%
  • Valvular heart disease 12%
  • Hypertension 11%
  • Other 5%

Rarer causes of heart failure include:

  • Viral myocarditis (an infection of the heart muscle)
  • Infiltrations of the muscle such as amyloidosis
  • HIV cardiomyopathy (caused by human immunodeficiency virus)
  • Connective tissue diseases such as systemic lupus erythematosus
  • Abuse of drugs such as alcohol and cocaine
  • Pharmaceutical drugs such as chemotherapeutic agents
  • Arrhythmias.

Obstructive sleep apnea (a condition of sleep wherein disordered breathing overlaps with obesity, hypertension, and/or diabetes) is regarded as an independent cause of heart failure.

Acute decompensation

Chronic stable heart failure may easily decompensate. This most commonly results from an intercurrent illness (such as pneumonia), myocardial infarction (a heart attack), arrhythmias, uncontrolled hypertension, or a patient’s failure to maintain a fluid restriction, diet, or medication. Other well recognized factors that may worsen CHF include: anemia and hyperthyroidism which place additional strain on the heart muscle, excessive fluid or salt intake, and medication that causes fluid retention such as NSAIDs and thiazolidinediones. NSAIDs in general increase the risk two fold.

FAILURE F – Forgot medication A – Arrhythmia/Anaemia I – Infarction/Infection/Ischaemia L – Lifestyle (Too much Salt) U – Upregulation of cardiac output (e.g. pregnancy/thyrotoxicosis) R – Renal Failure E – Embolism (pulmonary)

 

Signs and Symptoms of Congestive Heart Failure

 

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

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 of pulmonary 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 murmurs may 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.

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 orthopnea, 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

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, a parasternal heave may be present, signifying the compensatory increase in contraction strength.

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 (termed peripheral 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.

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 a pleural 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.

 

Risk Factors for Congestive Heart Failure

 

  • Ischaemic heart disease
  • Cigarette smoking
  • Hypertension (high blood pressure)
  • Obesity
  • Diabetes
  • Valvular heart disease (much higher in older populations)
  • Viral myocarditis (an infection of the heart muscle)
  • Infiltrations of the muscle such as amyloidosis
  • HIV cardiomyopathy (caused by human immunodeficiency virus)
  • Connective tissue diseases such as systemic lupus erythematosus
  • Abuse of drugs such as alcohol and cocaine
  • Pharmaceutical drugs such as chemotherapeutic agents
  • Arrhythmias

 

 

Diagnosis of Congestive Heart Failure

No system of diagnostic criteria has been agreed as the gold standard for heart failure. Commonly used systems are the “Framingham criteria” (derived from the Framingham Heart Study), the “Boston criteria”, the “Duke criteria”, and (in the setting of acute myocardial infarction) the “Killip class”.

Imaging

Echocardiography is commonly used to support a clinical diagnosis of heart failure. This modality uses ultrasound to determine the stroke 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).

Classification

There are many different ways to categorize heart failure, including:

  • the side of the heart involved (left heart failure versus right heart failure). Right heart failure compromises pulmonary flow to the lungs. Left heart failure compromises aortic flow to the body and brain. Mixed presentations are common; left heart failure often leads to right heart failure in the longer term.
  • whether the abnormality is due to insufficient contraction (systolic dysfunction), or due to insufficient relaxation of the heart (diastolic dysfunction), or to both.
  • whether the problem is primarily increased venous back pressure (preload), or failure to supply adequate arterial perfusion (afterload).
  • whether the abnormality is due to low cardiac output with high systemic vascular resistance or high cardiac output with low vascular resistance (low-output heart failure vs. high-output heart failure).
  • the degree of functional impairment conferred by the abnormality
  • the degree of coexisting illness: i.e. heart failure/systemic hypertension, heart failure/pulmonary hypertension, heart failure/diabetes, heart failure/renal failure, etc.

Functional classification generally relies on the New York Heart Association functional classification. The classes (I-IV) are:

  • Class I: no limitation is experienced in any activities; there are no symptoms from ordinary activities.
  • Class II: slight, mild limitation of activity; the patient is comfortable at rest or with mild exertion.
  • Class III: marked limitation of any activity; the patient is comfortable only at rest.
  • Class IV: any physical activity brings on discomfort and symptoms occur at rest.

This score documents severity of symptoms, and can be used to assess response to treatment. While its use is widespread, the NYHA score is not very reproducible and doesn’t reliably predict the walking distance or exercise tolerance on formal testing.

In its 2001 guidelines the American College of Cardiology/American Heart Association working group introduced four stages of heart failure:

  • Stage A: Patients at high risk for developing HF in the future but no functional or structural heart disorder.
  • Stage B: a structural heart disorder but no symptoms at any stage.
  • Stage C: previous or current symptoms of heart failure in the context of an underlying structural heart problem, but managed with medical treatment.
  • Stage D: advanced disease requiring hospital-based support, a heart transplant or palliative care.

The ACC staging system is useful in that Stage A encompasses “pre-heart failure” – a stage where intervention with treatment can presumably prevent progression to overt symptoms. ACC Stage A does not have a corresponding NYHA class. ACC Stage B would correspond to NYHA Class I. ACC Stage C corresponds to NYHA Class II and III, while ACC Stage D overlaps with NYHA Class IV.

Algorithms

There are various algorithms for the diagnosis of heart failure. For example, the algorithm used by the Framingham Heart Study adds together criteria mainly from physical examination. In contrast, the more extensive algorithm by the European Society of Cardiology (ESC) weights the difference between supporting and opposing parameters from the medical history, physical examination, further medical tests as well as response to therapy.

Framingham criteria

By the Framingham criteria, diagnosis of congestive heart failure (heart failure with impaired pumping capability) requires the simultaneous presence of at least 2 of the following major criteria or 1 major criterion in conjunction with 2 of the following minor criteria:

Major criteria:

  • Cardiomegaly on chest radiography
  • S3 gallop (a third heart sound)
  • Acute pulmonary edema
  • Paroxysmal nocturnal dyspnea
  • Crackles on lung auscultation
  • Central venous pressure of more than 16 cm H
  • 2O at the right atrium
  • Jugular vein distension
  • Positive abdominojugular test
  • Weight loss of more than 4.5 kg in 5 days in response to treatment (sometimes classified as a minor criterium)

Minor criteria:

  • Tachycardia of more than 120 beats per minute
  • Nocturnal cough
  • Dyspnea on ordinary exertion
  • Pleural effusion
  • Decrease in vital capacity by one third from maximum recorded
  • Hepatomegaly
  • Bilateral ankle edema

Minor criteria are acceptable only if they can not be attributed to another medical condition such as pulmonary hypertension, chronic lung disease, cirrhosis, ascites, or the nephrotic syndrome. The Framingham Heart Study criteria are 100% sensitive and 78% specific for identifying persons with definite congestive heart failure.

Prevention from Congestive Heart Failure

Lifestyle changes you can make to help prevent heart failure include:

  • Not smoking
  • Avoiding secondhand smoke too
  • Controlling certain conditions, such as high blood pressure, high cholesterol and diabetes
  • Staying physically active
  • Eating healthy foods
  • Maintaining a healthy weight
  • Reducing and managing stress
  • Limit alcohol

Treatment of Congestive Heart Failure

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 possibly non 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 fluid intake. Exercise should be encouraged as tolerated, as sufficient conditioning can significantly improve quality-of-life.

Anaemia is an independent factor in mortality in people with chronic heart failure; treatment of anaemia significantly improves patient’s quality of life, and has been shown to improve the classification of severity of heart failure. Treatment of anaemia improves quality of life and decreases mortality rates. Due to this increasing evidence, the latest European guidelines recommend screening for anaemia and treating with parenteral iron if anaemia is found.

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.

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 attorney and 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, according to American College of Cardiology/American Heart Association guidelines.