What is a Heart Attack?
A heart attack or myocardial infarction is a life-threatening emergency requiring immediate medical care. It happens when the blood flow to a section of the heart suddenly stops and the muscle cells do not receive enough oxygen. Usually, a heart attack is caused by a blockage of one or more coronary arteries. Without a blood supply, the heart cannot work properly and cardiac function is reduced or even fails completely, and in the latter case, death may occur suddenly. If only a small section of the heart's muscle is affected, the heart may be injured but still able to function at a reduced capacity. The longer the heart's blood circulation is disturbed, however, the higher the risk that muscle cells will die and be replaced by scar tissue. The scar tissue is not able to perform the tasks of the muscle and the heart will never regain its original power and capacity. Sometimes, scar tissue may cause irregular heartbeats because it cannot conduct the electrical impulses that control the heart's activity. If the heart is severely damaged, even minor stresses may overstrain its capacity, causing a potentially fatal heart attack. It is therefore crucial to find and treat the blockage of the blood flow as quickly as possible.
One of the main causes of heart attack is coronary artery disease, which is characterised by a narrowing of the coronary arteries. Generally, coronary artery disease results from arteriosclerosis – the thickening and hardening of the walls of the arteries. The heart muscle’s blood circulation can also be disturbed by other blood vessel diseases, scar tissue, heart failure or heart rhythm disorders.
People at a high risk of myocardial infarction are those with a genetic predisposition, men over 45 and women over 55 years old, and patients who have already had bypass surgery. These risk factors cannot be influenced. The following risk factors cannot be influenced, but can be reduced or mitigated with appropriate treatment of lifestyle changes:
- Hypertension (high blood pressure)
- High blood fats, especially "bad" cholesterol (LDL)
- Being overweight or obese
- Lack of exercise
Usually, a heart attack occurs suddenly and without any warning. The symptoms of a heart attack may vary from person to person. Women and men often experience very different symptoms. In about one-third of heart attacks, patients are not aware they have had a heart attack because it barely causes symptoms. This “silent” myocardial infarction often occurs in people with diabetes1. In many cases, it is detected randomly during an electrocardiogram examination.
Most heart attacks in men cause severe and long-lasting chest pain predominantly located right below the breastbone. The pain usually lasts much longer than the pain caused by angina pectoris (pain or discomfort due to coronary artery disease). The chest pain may spread to the arms, shoulders, jaw or upper abdomen. The patient may break out in a cold sweat and experience shortness of breath, nausea and fainting.
Women may have the above mentioned symptoms, but more commonly experience pain in the upper abdomen combined with nausea and vomiting.
Since all heart attacks can be life threatening or cause complications, always call emergency services if you have the slightest suspicion that you or someone near you is having a heart attack.
The most important examination for quickly diagnosing a heart attack is the electrocardiogram. If the electrocardiogram findings confirm a heart attack, the heart’s electrical activity will be observed during emergency treatment in order to detect any heart rhythm disorders early.
As a second step, the medical team has to find out where the affected section of the heart is and which coronary artery is blocked. To do this, they will perform echocardiography – an examination of the heart with ultrasound waves. Coronary arteries are usually examined via a catheter in a hospital’s catheterization laboratory. The medical team may also run blood tests, which indicate if a heart attack has occurred and how severe it was. Examinations like computed tomography or magnetic resonance imaging may provide additional information.