Heart failure and its dietary management

What is heart failure?

According to McDonagh (2011), heart failure does not mean the heart has stopped working. Rather, it means that the heart’s pumping power is less effective than normal. With heart failure, blood moves through the heart and body at a slower rate, and pressure in the heart increases. As a result, the heart cannot pump enough blood carrying oxygen and nutrients to meet the body’s needs. The chambers of the heart may respond by stretching to carry more blood to pump through the body or by becoming more stiff and thickened. This helps to keep the blood moving for a while, but in time, the heart muscle walls may weaken and are unable to pump as strongly. As a result, the kidneys respond by causing the body to retain fluid (water) and sodium (McMurray and Pfeffer, 2005). If fluid builds up in the arms, legs, ankles, feet, lungs, or other organs, the body becomes congested, and congestive heart failure is the term used to describe the condition.

Types of heart failure

Heart failure according to Eyal (2012) can be characterised into two major types which are systolic and Diastolic dysfunction

Systolic dysfunction

Heart failure caused by systolic dysfunction is more readily recognized. It can be simplistically described as failure of the pump function of the heart. It is characterized by a decreased ejection fraction (less than 45%). The strength of ventricular contraction is attenuated and inadequate for creating an adequate stroke volume, resulting in inadequate cardiac output. In general, this is caused by dysfunction or destruction of cardiac myocytes or their molecular components.

Because the ventricle is inadequately emptied, ventricular end-diastolic pressure and volumes increase. This is transmitted to the atrium. On the left side of the heart, the increased pressure is transmitted to the pulmonary vasculature, and the resultant hydrostatic pressure favours extravasation of fluid into the lung parenchyma, causing pulmonary oedema. On the right side of the heart, the increased pressure is transmitted to the systemic venous circulation and systemic capillary beds, favouring extravasation of fluid into the tissues of target organs and extremities, resulting in dependent peripheral oedema.

 Diastolic dysfunction

Heart failure caused by diastolic dysfunction is generally described as the failure of the ventricle to adequately relax and typically denotes a stiffer ventricular wall. This causes inadequate filling of the ventricle, and therefore results in an inadequate stroke volume. The failure of ventricular relaxation also results in elevated end-diastolic pressures, and the end result is identical to the case of systolic dysfunction (pulmonary oedema in left heart failure, peripheral oedema in right heart failure).

Diastolic dysfunction can be caused by processes similar to those that cause systolic dysfunction, particularly causes that affect cardiac remodeling.

Diastolic dysfunction may not manifest itself except in physiologic extremes if systolic function is preserved. The patient may be completely asymptomatic at rest. However, they are exquisitely sensitive to increases in heart rate, and sudden bouts of tachycardia (which can be caused simply by physiological responses to exertion, fever, or dehydration, or by pathological tachyarrhythmias such as atrial fibrillation with rapid ventricular response) may result in flash pulmonary oedema. Adequate rate control (usually with a pharmacological agent that slows down AV conduction such as a calcium channel blocker or a beta-blocker) is therefore key to preventing decompensation.

Causes of heart failure

Faris, Flather, Purcell, Poole-Wilson and Coats (2012) stated that heart failure is caused by many conditions that damage the heart muscle, including:

  • Coronary artery disease: Coronary artery disease (CAD), a disease of the arteries that supply blood and oxygen to the heart, causes decreased blood flow to the heart muscle. If the arteries become blocked or severely narrowed, the heart becomes starved for oxygen and nutrients.
  • Heart attack: A heart attack may occur when a coronary artery becomes suddenly blocked, stopping the flow of blood to the heart muscle and damaging it. All or part of the heart muscle becomes cut off from its supply of oxygen. A heart attack can damage the heart muscle, resulting in a scarred area that does not function properly.
  • Cardiomyopathy: Damage to the heart muscle. Causes include artery or blood flow problems, infections, and alcohol and drug abuse.
  • Conditions that overwork the heart: Conditions including high blood pressure, heart valve disease, thyroid disease, kidney disease, diabetes, or heart defects present at birth can all cause heart failure. In addition, heart failure can occur when several diseases or conditions are present at once.

Signs and symptoms of heart failure

Jessup, Abraham, and Casey (2009) opined that If you have heart failure, you may not have any symptoms, or the symptoms may range from mild to severe. Symptoms can be constant or can come and go. Heart failure symptoms are related to the changes that occur to your heart and body, and the severity depends on how weak your heart is. The symptoms can include:

  • Congested lungs: A weak heart causes fluid to back up in the lungs. This can cause shortness of breath with exercise or difficulty breathing at rest or when lying flat in bed. Lung congestion can also cause a dry, hacking cough or wheezing.
  • Fluid and water retention: A weak heart pumps less blood to your kidneys and causes fluid and water retention, resulting in swollen ankles, legs, and abdomen (called oedema) and weight gain. This can also cause an increased need to urinate during the night as your body attempts to get rid of this excess fluid. Bloating in your stomach may cause a loss of appetite or nausea.
  • Dizziness, fatigue, and weakness: Less blood to your major organs and muscles makes you feel tired and weak. Less blood to the brain can cause dizziness or confusion.
  • Rapid or irregular heartbeats: The heart beats faster to pump enough blood to the body. This can cause a fast or irregular heartbeat.

Heart failure diagnosis

He, Ogden, Bazzano and Vupputuri (2001) stated that the following are the various methods in the diagnosis of heart failure:

  • Blood tests: Blood tests are used to evaluate kidney and thyroid function and to check cholesterol levels and the presence of anaemia. Anaemia is a blood disorder that occurs when there is not enough haemoglobin (the substance in red blood cells that enables the blood to transport oxygen through the body) in a person’s blood.
  • B-type natriuretic peptide (BNP) blood test: BNP is a substance secreted from the heart in response to changes in pressure that occur when heart failure develops and worsens. The level of BNP in the blood increases when heart failure symptoms worsen, and decreases when the heart failure condition is stable. The BNP level in a person with heart failure — even someone whose condition is stable — may be higher than in a person with normal heart function.
  • Chest X-ray: Chest X-ray shows the size of your heart and whether there is fluid build-up around the heart and lungs.
  • Echocardiogram: This test (often called an “echo”) shows a graphic outline of the heart’s movement. During an echo, a wand is placed on the surface of your chest. This wand sends ultrasound waves that provide pictures of the heart’s valves and chambers so the pumping action of the heart can be studied. Echo is often combined with Doppler ultrasound and colour Doppler to evaluate blood flow across the heart’s valves.
  • Ejection fraction (EF): A normal EF is generally between 55% and 75%, which means that over half of the blood volume is pumped out of the heart with each beat. Heart failure may occur as the result of a low EF (called systolic heart failure), or from another cause, such as a valve disorder or from diastolic dysfunction.  People with diastolic dysfunction can have a normal EF.
  • Electrocardiogram (EKG or ECG): ECG records the electrical impulses traveling through the heart. During the test, small, flat, sticky patches called electrodes are placed on your chest. The electrodes are attached to an electrocardiograph monitor (ECG) that charts your heart’s electrical activity on graph paper. Your doctor will also be interested in determining your ejection fraction, or EF.  This is a measurement of how much blood is pumped out of the heart with each heartbeat.
  • Stress test: The patient’s heart is “stressed” by walking on a treadmill or by medications that increase the pumping of the heart. It helps determine if someone may have clogged heart arteries.
  • Cardiac catheterization: This is an invasive test which measures whether you have clogged heart arteries (coronary artery disease).
  • CT coronary angiogram: This is a noninvasive test which uses X-ray and intravenous contrast dye to determine whether you have coronary artery disease.
  • Cardiac MRI: This less commonly used test helps your doctor understand whether you have abnormalities of the heart muscle itself or of the tissues surrounding the heart (pericardium).

Heart failure treatment

There are multiple options for treating heart failure. Regular medications and lifestyle changes coupled with careful monitoring make up the first line of treatment. As the condition progresses, centres specializing in the treatment of heart failure can offer more advanced treatment options, such as surgery (Nieminen, Böhm, and Cowie, 2005).

Drugs used to treat heart failure

Taking your heart failure medications as prescribed is one of the most important things you can do to manage your condition. The more you know about your medications and how they work, the easier it will be for you to stay on track.

Common types of drugs used to treat heart failure include:

  • Angiotensin converting enzyme (ACE) inhibitors
  • Angiotensin II receptor blockers (ARBs)
  • Beta-blockers
  • Digoxin
  • Diuretics
  • Blood vessel dilators
  • Potassium or magnesium
  • Aldactone inhibitors
  • Calcium channel blockers
  • Heart pump medication

Surgical procedures to treat heart failure

Surgery is aimed at stopping further damage to the heart and improving the heart’s function. Procedures used according to (Nieminen, Böhm, and Cowie, 2005) include:

  • Bypass surgery: The most common surgery for heart failure is bypass surgery to route blood around a blocked heart artery.
  • Left ventricular assist device (LVAD): The LVAD helps your heart pump blood throughout your body. It allows you to be mobile, sometimes returning home to await a heart transplant.
  • Heart valve surgery: As heart failure progresses, the heart valves that normally help direct the flow of blood through the heart to the rest of the body may no longer completely close, allowing blood to “leak” backward. The valves can be repaired or replaced.
  • Infarct exclusion surgery (Modified Dor or Dor Procedure): When a heart attack occurs in the left ventricle (left lower pumping chamber of the heart), a scar forms. The scarred area is thin and can bulge out with each beat (an aneurysm). A heart surgeon can remove the dead area of heart tissue or the aneurysm.
  • Heart transplant: A heart transplant is considered when heart failure is so severe that it does not respond to all other therapies.

 Dietary management for heart failure

Hunter, Boon, Davidson, Colledge and Walker (2006) stated that eating a healthy diet is necessary to improve your heart failure. This often means making changes in your current eating habits. A registered dietitian can provide in-depth personalized nutrition education, tailor these general guidelines to meet your needs, and help you implement a personal action plan.

  • Control the salt in your diet: Decreasing the total amount of sodium you consume to no more than 1,500 mg (1.5 grams) per day is one of the most important ways to manage heart failure.
  • Learn to read food labels: Use the label information on food packages to help you to make the best low-sodium selections.
  • Eat a variety of foods to get all the nutrients you need.
  • Include high-fibre foods in your diet: Fibre is the indigestible part of plant food that helps move food along the digestive tract, controls blood sugar levels, and may reduce the level of cholesterol in the blood. Vegetables, beans (legumes), whole-grain foods, bran, and fresh fruit are high in fibre. The goal for everyone is to consume 25 to 35 grams of fibre per day.
  • Carefully follow your fluid management guidelines: Reduce your fluid intake if you have become more short of breath or notice swelling.
  • Maintain a healthy body weight: This includes losing weight if you are overweight. Limit your total daily calories and exercise regularly to achieve or maintain your ideal body weight.
  • Reduce alcohol consumption: Because alcohol can affect your heart rate and worsen your heart failure, your doctor may tell you to avoid or limit alcoholic beverages. Alcohol may also interact with the medications you are taking. Ask your doctor for specific guidelines regarding alcohol.

References

Eyal, H. (2012). The Cardiac Care Unit Survival Guide. Lippincott: Williams & Wilkins. p. 98.

Faris, R.F; Flather, M.; Purcell, H.; Poole-Wilson, P.A and Coats, A.J. (2012). “Diuretics for heart failure.”. The Cochrane database of systematic reviews 2: CD003838.

He, J; Ogden, L.G; Bazzano, L.A. and Vupputuri, S. (2001). “Risk factors for congestive heart failure in US men and women: NHANES I epidemiologic follow-up study”. Arch. Intern. Med. 161 (7): 996–1002.

Hunter, J.G., Boon, N.A., Davidson, S., Colledge, N.R. and Walker B (2006). Davidson’s principles & practice of medicine. Livingstone: Elsevier/Churchill

Jessup, M., Abraham, W.T. and Casey, D.E. (2009). “2009 focused update: ACCF/AHA Guidelines for the Diagnosis and Management of Heart Failure in Adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines: developed in collaboration with the International Society for Heart and Lung Transplantation”. Circulation 119 (14): 1977–2016.

McDonagh, T. A. (2011). Oxford textbook of heart failure. Oxford: Oxford University Press.

McMurray, J.J. and Pfeffer, M.A. (2005). “Heart failure”. Lancet 365 (9474): 1877–89.

Nieminen, M.S., Böhm, M. and Cowie, M.R. (2005). “Executive summary of the guidelines on the diagnosis and treatment of acute heart failure: the Task Force on Acute Heart Failure of the European Society of Cardiology”. Eur. Heart J. 26 (4): 384–416.

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