Diagnosis of a silent heart attack | Diagnosis of a heart attack

Diagnosis of a silent heart attack

As with the diagnosis of any illness, the medical history (i.e. the interview with the patient) is the first step in identifying a silent myocardial infarction. The symptoms experienced by the patient, such as dizziness, nausea, sweating and fainting, play a major role in this process. A characteristic feature of a silent heart attack is the absence of pain in the chest area.If a silent heart attack is suspected, an ECG should be written immediately afterwards.

Electrodes are attached to various points on the chest wall (sometimes also on arms and legs) so that the electrical currents in the heart can be measured. In contrast to the normal case, there are special characteristics that the ECG only shows in the case of a heart attack. Furthermore, blood tests can be consulted.

An increase in the troponin T value plays a major role in this process. In addition, there are other blood values which can also give indications of a silent heart attack. Myoglobin and CK-MB play an important role.

Myoglobin is a protein contained in muscles. During a silent myocardial infarction, heart muscle cells die. This causes the substances contained in the cells to be released into the blood. CK-MB (creatine kinase type MB) is present specifically in the heart muscle and is also released into the blood when its cells die.

Laboratory values

The determination of troponin in the blood is therefore the third pillar of myocardial infarction diagnostics. Troponin T and I are proteins of the heart muscle cells that play an important role in the contraction (contraction of the heart muscle cells) of the heart. When myocardial cells die during an infarction, they enter the bloodstream, where their concentration increases at the earliest three hours after the onset of the infarction.

The maximum concentration in the blood is reached after 20 hours and one to two weeks after the infarction, troponin levels have returned to normal. The markers are particularly useful for diagnosing patients who suffer from chest pain but do not show any ECG louse changes: If the amount of troponins in the blood is elevated above a certain level, there is a very high probability of a myocardial infarction with cell death and an intervention to reopen the vessel is indicated. If the troponin determination is negative, i.e. if the marker values are below a certain limit, a myocardial infarction can almost be excluded and the diagnosis “unstable angina pectoris” can be made.

The determination of the enzyme CK-MB (creatine kinase of the heart muscle) is also performed within the scope of myocardial infarction diagnostics. In the event of a prolonged myocardial infarction, many muscle cells perish, so that a large number of this enzyme enters the bloodstream. Together with the clinical sign of chest pain, the CK-MB concentration in the blood sample can give a clear diagnostic indication of a heart attack.

The concentration in the blood increases approximately 4-8 hours after the onset of the infarction, making the CK-MB concentration a slow marker of myocardial infarction, unlike the troponins. The CK-MB determination serves more to confirm the diagnosis than to determine it. Since the aim is to achieve a rapid diagnosis and rapid initiation of therapy in order to protect further myocardial tissue from destruction, troponins are the gold standard (currently the best and most efficient method of detecting the presence of the disease in question) in enzyme diagnostics (blood tests) in cases of suspected myocardial infarction.