Complications of coronary artery disease

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Coronary artery disease (CAD, also called coronary heart disease, or CHD) develops if the large blood vessels that supply the heart with oxygen become too narrow. That can cause symptoms such as shortness of breath and a tight feeling in the chest. It can also lead to a . The blood vessels that supply the heart with oxygen are called coronary arteries. CAD is caused by deposits building up in these arteries (arteriosclerosis). This can also lead to other types of heart disease.

The heart may get weaker, or your heartbeat may become irregular. Heart attacks are also more likely.

Heart failure

Over time, CAD can cause part of the heart to lose strength (heart failure, also known as cardiac insufficiency). Depending on which part of the heart is affected, heart failure can cause different problems: If the right side of the heart is weak, blood builds up in the veins that carry blood from the tissue and organs to the heart. This can cause edema (swelling) in the legs and, if the heart failure is advanced, in the abdomen (belly) or liver too.

If the left side of the heart is weak, blood builds up in the vessels that carry blood away from the lungs. This may cause shortness of breath, especially during more strenuous activities. Sometimes, heart failure affects both the left and right sides of the heart.

The severity of heart failure can vary quite a lot. There may be no symptoms or only mild symptoms, or it could greatly reduce your physical fitness. The possible symptoms include exhaustion, shortness of breath, chest pain and heart palpitations. In severe heart failure, it is even difficult to do normal everyday activities like walking longer distances or climbing a short flight of stairs.

Irregular heartbeat (arrhythmia)

Our heartbeat is regulated by special muscle cells in certain areas of the heart. These cells send electrical signals that make the heart beat.

If the heart no longer gets enough oxygen because of CAD, the special muscle cells may become damaged. As a result, the heart rate may be irregular, or the heart may beat faster or slower. This can lead to a pounding or racing heart, tiredness or dizziness. An irregular heartbeat can be diagnosed with the help of an electrocardiogram (ECG). The most common type of irregular heartbeat is known as atrial fibrillation.

Heart rhythm problems can reduce the heart's pumping strength, which can cause heart failure or make existing heart failure worse. Some types of irregular heartbeat, like , can cause blood clots to form in the heart. If blood clots are carried around the body in the bloodstream, they can cause problems if they block a blood vessel somewhere (for instance, a stroke in the brain).

Heart attack

Narrow coronary arteries increase the risk of a . CAD can also cause a without having caused any other symptoms before. People who have already had a are more likely to have (further) heart attacks.

Heart attacks happen if a coronary artery becomes completely blocked or almost completely blocked. The blockage stops part of the heart muscle from getting enough oxygen. If this goes on for too long, that part of the heart muscle dies and the situation becomes life-threatening. It is then important to get medical help immediately.

But the odds of surviving a are good: Most people in Germany and many other countries survive heart attacks nowadays.

There are two main types of . Doctors call them

  • ST segment elevation myocardial infarctions (STEMI) and
  • non-ST segment elevation myocardial infarctions (NSTEMI).

A heartbeat is seen as a wave-like form on an electrocardiogram (ECG). In STEMI, a certain part of the wave is abnormal. In NSTEMI, this part of the wave is normal.

Most heart attacks are treated using a thin flexible tube called a cardiac (heart) . This procedure is known as angioplasty. The blood clot that blocked the coronary artery can sometimes be broken up and removed by fast-acting medication given through a drip (thrombolysis).

Anderson JL, Morrow DA. Acute Myocardial Infarction. N Engl J Med 2017; 376(21): 2053-2064.

Bundesärztekammer (BÄK), Kassenärztliche Bundesvereinigung (KBV), Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF). Nationale Versorgungsleitlinie Chronische KHK. Langfassung. AWMF-Registernr.: nvl-004. 2019.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on February 18, 2022
Next planned update: 2025


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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