Heart attack is defined as death of a portion of the heart muscle because of the development of sudden obstruction to the flow of blood in the artery that supplies oxygen and nutrients to that portion.
The heart consists of a mass of muscle that contracts and relaxes periodically to supply blood to various parts of the body. Being a muscle it requires nutrients and oxygen for its function, which is supplied by three coronary arteries.
Deposits of cholesterol and calcium occur in the linings of these blood vessels as age advances and in some build up gradually resulting in obstruction to the blood flow. This leads to the symptoms of exertion related chest pain or angina as it is medically known, when the obstruction becomes severe enough to impede the required increments in blood flow according to the needs of the heart.
However due to several reasons sudden complete obstruction can occur resulting in the catastrophic consequences of a heart attack and it often results from rupture of a cholesterol rich plaque on the arterial wall with resultant clot formation that blocks the artery completely. This causes sudden onset of central chest pain often associated with sweating,fatigue,vomiting,urge to pass motion and radiation of the pain to arms, neck or back. Often the pain starts with a small intensity and gradually builds up in severity over several minutes. Each minute after the onset of the pain is important as it can result in permanent irrecoverable damage to the heart muscle cells the longer the obstruction lasts. The vast majority of the patients can be saved if they reach the hospital within the golden hour, which is the first hour after onset of pain, with minimal damage to the heart.
Causes and Prevention
Coronary artery disease and its most lethal counterpart heart attack or myocardial infarction in medical jargon, is a life style disease.A heart healthy diet consisting of plenty of fruits and vegetables, less of saturated and trans fats, whole grain cereals and nuts along with good physical exercise like brisk walking, jogging, cycling or swimming for 30 minutes daily at least for 5 days a week should do a lot to prevent this disease. Add to that, avoidance of tobacco, moderation of alcohol and maintenance of ideal body weight, one can conquer this deadly disease to a large extent.
High fat diet, obesity, tobacco and a fast stressful lifestyle on the contrary lead to injury of the lining of the coronary arteries that supply blood to the heart resulting in increased clotting tendency of the blood as well as rupture of a fat rich plaque which in turn leads to the heart attack. Coexisting diseases such as diabetes, hypertension and high cholesterol levels contribute to this.
Extreme levels of stress by itself can sometimes lead to a heart attack, what is known as “broken heart syndrome” or stress cardiomyopathy. In these cases, the coronary arteries have no obstructions but excess production of certain chemicals in the body in response to stress exert their toxic effects on the heart. Unaccustomed physical exercise can at times lead to a heart attack which is due to sudden injury to the lining of the artery called coronary dissection.
Spontaneous coronary dissections are also known to occur especially in young women of child bearing age leading to heart attacks. Certain viral infections are also known to produce heart attacks secondary to their effects on coronary arteries and heart muscle.
The immediate treatment for heart attack is restoration of the blood flow to the affected area and the most effective method accepted world over as of now is emergency coronary angioplasty which involves directly visualising the blocked artery with the help of x-ray and opening the block with a balloon followed by stenting.
This procedure has successfully brought down the death rate and the rate of heart failure which are consequences of a heart attack. Hence the responsibility on the part of the patient is to recognise the pain at the earliest and try to reach a hospital preferably with cathlab facility so that emergency angioplasty can be carried out.
The other effective method of reperfusing the artery is called thrombolysis which involves administration of a drug in to the veins so that it can go to the affected artery and dissolve the obstructing clot thereby re-establishing the blood flow. Once the patient stabilises he can be referred for angiography and angioplasty if needed preferably within 24 hours.
Of course, there are various adjunctive drugs to be given along with the above said procedures to maintain the stability of the heart and routinely the patient is kept under observation in the intensive care unit for 24-48 hours.