Before explaining what happens during a heart attack, we will discuss about heart attack and its causes and risk factors. This article explains,
1. What is a Heart Attack
2. What Causes a Heart Attack
– Causes
– Risk Factors
3. What Happens During a Heart Attack
What is a Heart Attack
The heart is the organ which pumps oxygenated blood around our body. It also has an extraordinary oxygen-rich blood supply in its own muscles which maintain an efficient pumping mechanism, necessary to provide the required degree of perfusion to vital organs in the body.
This blood supply can get cut off due to several reasons, by which the coronary blood vessels supplying the heart get obstructed or narrowed. The cardiac cells which get poorly perfused as a result will die due to lack of adequate oxygen supply. This is what is known as a heart attack where the heart stops pumping for a temporary period of time until an adequate blood supply is restored.
What Causes a Heart Attack
According to the American Heart Association, Ischemic heart Disease which is caused by narrowed blood vessel is a main cause for heart attacks.
Atherosclerosis is the commonest cause for the obstruction of these coronary blood vessels. This takes place due to the development of plaques made up of cholesterol, fatty substances, calcium, fibrin and several other cellular metabolites inside the lumen of vessels. Coronary artery Spasms are another pathophysiological mechanism by which coronary arteries get narrowed and hardened, resulting in a poorly oxygenated blood supply to cardiac muscles.
Other risk factors for the development of a heart attack include,
- Age: men over 45 years and women over 55 years are at a higher risk.
- Tobacco smoking and Alcohol
- Obesity
- High cholesterol levels
- Uncontrolled Diabetes mellitus
- Stress
- Illegal drug abuse: Amphetamines, Cocaine
- History of Autoimmune conditions: SLE, Rheumatoid Arthritis
Some scientists also suggest that a heart attack is not merely an outcome of an obstruction of blood supply to the heart, but an imbalance between sympathetic and parasympathetic section of the central nervous system, including brain and spinal cord. According to them, chronic stress accounts for the major pathophysiology behind it which triggers a long term releasing of Adrenaline hormone due to the stimulation of sympathetic nervous system which overrules the compensatory mechanisms of the parasympathetic section. This will eventually harm myocardial cells and result in their death which causes a heart attack.
What Happens During a Heart Attack
Long-term development of plaques, which are due to various risk factors described above, can gradually obstruct the coronary arteries resulting in a shortage of perfusion to the cardiac muscles. However, other remaining arteries could compensate this imbalance up to a certain extent as long as there is a sufficient remnant of the unaffected arterial system.
Moreover, the plaque which has a solid, fibrous capsule covering it can rupture due to sudden triggering factors like stress, exposing the fatty substances resulting in an acute rush of platelets to the site. This can further enhance the blockage by the fibrin clot.
When this scenario takes place, your heart will run out of oxygen-rich blood, which acts as a signal to the brain, resulting in several symptoms like sweating, increase heart rate, flushing, etc. You will also start feeling weak and dizzy, depending on the degree of severity. Dying myocardial cells will trigger a chest pain which may radiate to shoulders, arms, jaw, neck and even to the abdominal area. Survivors from heart attacks describe this pain as a squeezing pain which may last from minutes to hours.
If proper treatment is not given as early as possible, myocardial cells will die beyond repair and result in a weak heart. If the level of injury exceeds the level of tolerance, the heart will stop beating completely leading to a stoppage of blood supply to the brain which will result in its death within 3-5 minutes.
However, even if the proper and timely treatment is provided, already damaged tissues cannot be repaired. So you will never have the completely functioning heart as before, which will need several lifestyle modifications and post-heart attack rehabilitation procedures, where you will be taught how to lead a healthy life, by helping your heart to function in its best possible efficiency.
Image Courtesy:
“Heart attack diagram” (Public Domain) via Commons Wikimedia
