Part II: Explanation of death of unknown cause

Sudden death is often the result of a heart attack, also medically known as a myocardial infarction. Technically, a heart attack is not the cause of death, but the injury or illness that caused the attack.

The heart, like other organs in the body, needs oxygenated blood to perform its function, most of which comes from blood vessels, especially the coronary arteries. Diseases of these arteries are a common cause of heart attacks, and these diseases are collectively known as coronary artery disease (CAD).

Conditions that impede or impede the passage of blood through these arteries can cause a heart attack. The most common arteriosclerosis of these conditions is the narrowing of the lumen of these blood vessels due to the accumulation of “fat” or fatty streak. Not all heart attacks are fatal, but some large heart attacks can be fatal, and if death results from a heart attack, evidence of such an illness or injury is Found by postmortem examination.

Postmortem examination
Diagnosis of a heart attack may be easy if postmortem examinations clearly show obstruction, but it is difficult, especially if there is no evidence of vascular obstruction.
A proper diagnosis may require a thorough, careful examination of the heart after death, including a microscopic examination of the heart tissue (histology).

Areas of the myocardium that may have been damaged as a result of the obstruction are seen during histological examination, which is very important in diagnosing a heart attack.
However, the latest developments in the diagnosis of postmortem heart attacks are non-invasive in that the heart may not be dissected from the body, but special imaging techniques are used to show the areas that blood vessels may have. May be used blocked. In some situations, these diagnostics alone may prove inadequate or inadequate to explain the clinical suspicion of a heart attack.

Clinical diagnosis
Not all heart attacks are immediate death. Some patients die hours or days after the onset of a heart attack. These patients have medical evidence of a heart attack, including signs of illness and the results of investigations conducted. Some studies monitor the electrical activity of the heart and the elevated levels of chemicals known as biomarkers produced by damaged heart muscle.

However, there are other causes of heart damage besides a heart attack, and care must be taken when interpreting such results. This is why the history of the disease is important. Not all patients with heart disease die from myocardial infarction.

Acute obstruction
The most frequent cause of acute occlusion of the arteries of the heart has been found to be a thrombotic mass, including a thrombus, which is found in about 50-70% of sudden coronary artery deaths. Acute obstruction causes abnormal electrical activity in the heart and can be fatal. In such cases, obvious damage to the tissues of the heart may be difficult to see.

As a general rule, postmortem examinations should carefully examine the main coronary arteries and their branches to determine the cause of the obstruction, as well as to see if the blood vessels have narrowed.
These blood vessels need to be sampled and examined under a microscope. This is considered important when the lumen of the blood vessel narrows to less than 75% of the expected diameter.

Cramps
The blood vessels of the heart can undergo severe contractions as a result of spasms, which can cause obstruction of the coronary arteries. If no other explanation is provided for the infarction, the presence of an area of ​​dead myocardium can indicate arterial spasm. Spasms are known to occur in occluded arteries.
Cardiac vascular spasms are also caused by drugs such as cocaine and amphetamines, as well as physical and mental stress. As a result, they can cause a heart attack.

Other triggers
A heart attack can be caused by other diseases of small blood vessels, especially if the heart is ill. High blood pressure, alcohol, and lung disease can all affect the heart, and a sick heart has a higher risk of heart attack than a normal heart. Surprisingly, even surgical procedures to correct the occluded blood vessels in the heart can cause a heart attack.

Evidence of heart attack
Irreversible damage to the heart muscle always occurs during a heart attack. This is evidence that must be presented when a person is said to have died of a heart attack.The area of ​​injury indicates which blood vessel in the heart was responsible for the attack