Heart failure causes and diagnosis

Definition

One speaks of heart failure (or heart failure in general) when the heart is no longer able to pump the necessary amount of blood through the circulation. This is mainly due to the fact that the two chambers of the heart no longer have sufficient strength to maintain stable circulation. As a result, physical resilience is reduced, fatigue and weakness attacks occur. Nowadays, heart failure is widespread and is one of the most common causes of death in industrialized countries. Depending on the stage and progress of heart failure, life expectancy ranges from a few years to decades.

Causes

Many factors are known to cause heart failure. These include various heart diseases that weaken the heart in the long term. Due to cardiac arrhythmia, the heart can no longer pump evenly and purposefully.

Either it beats too fast, too slowly or generally uncoordinated. Such a condition puts a strain on the heart, as it has to work harder to transport the same amount of blood. Other causes can be heart valve diseases such as blockages or narrowing of the heart valves.

Just as with leaking heart valves, the heart has to work much harder. Increased blood pressure in the body or pulmonary circulation also puts a strain on the heart, because it has to fight against higher pressure with every heartbeat. If the heart does not manage to pump all the blood out of the chamber, even more blood enters the chamber during the filling phase and the heart must also cope with a higher volume load.

In addition, as a consequence of so-called coronary heart disease (constrictions or blockages in the coronary arteries), the heart muscles may be undersupplied with blood and thus oxygen and other important nutrients. This damages the muscle cells and can lead to a heart attack, for example. The weakening of the heart muscles can also lead to heart failure.

Diagnosis

Several tests are required to diagnose heart failure. First of all, symptoms such as shortness of breath and reduced resilience give rise to the suspicion of heart failure. With a heart ultrasound (echocardiography) the performance of the heart in the tensing and relaxing phase can be measured, as well as the size of the different heart cavities and the thickness of the heart muscles.

All this information can provide indications of heart failure. An X-ray examination can also reveal whether the heart is enlarged. In addition, it may also be possible to determine whether the blood is backed up in the pulmonary circulation or the veins (vessels leading to the heart).

Doctors divide heart failure into so-called NYHA stages. (NYHA stands for New York Heart Association.) The classification is made into four different NYHA classes based on the clinical symptoms.

In other words, according to which stress causes which symptoms.

  • NYHA Class I is characterized by normal physical endurance. In addition, no complaints occur at rest.

    The heart is able to transport the necessary amount of blood into the circulation without any problems. However, NYHA Class I is characterized by a recognizable structural damage to the heart.

  • Patients without symptoms are also assigned to NYHA Class II at rest. However, complaints occur in cases of severe physical stress.

    At rest and under little exertion, the cardiac output (the amount of blood the body pumps into the circulation per minute) is sufficient, but this is no longer the case under heavy exertion.

  • In NYHA Class III, symptoms occur even at low levels of exercise, and the cardiac output is limited during exercise.
  • Patients in NYHA Class IV already have symptoms at rest and the heart cannot pump enough blood into the circulatory system even without physical exertion.

According to the American Heart Association (AHA), heart failure is divided into stages A to D. The disease is most advanced in stage D.

  • In stage A, no structural changes in the heart are visible yet. In addition, no symptoms of heart failure are known in the patients. However, there are various risk factors that promote the development of heart failure.
  • From stage B on, patients show recognizable structural changes in the heart, which indicate heart failure.

    Even in this stage, there are no symptoms of heart failure.

  • Stage C is characterized by current or previously known symptoms of heart failure.In addition, there is a structural heart disease.
  • In stage D, structural heart disease is already in an advanced stage. Even at rest, severe symptoms and discomfort occur, and the patients are not able to cope with stress despite drug therapy. Special medications or measures (artificial heart/heart transplantation) are required to restore health.