Introduction

Heart attack is caused by complete blockage of a coronary artery. Interrupted blood flow to your heart can damage or destroy a part of the heart muscle. Heart attack was often fatal, however thanks to better awareness of signs and symptoms and improved treatments, the majority of people who have a heart attack survive. Still heart disease is a leading cause of death worldwide. Lifestyle modification can help you prevent a first or subsequent heart attack by controlling risk factors that contribute to the narrowing of the coronary arteries that supply blood to your heart.

Signs and Symptoms

Signs and symptoms of heart attack may be variable. Not all people who have heart attacks experience the same ones or experience them to the same degree. For example, heart attack symptoms in women, in older adults and in people with diabetes tend to be less pronounced. Some people have no symptoms at all. The more signs and symptoms you have, the greater the likelihood that you may be having a heart attack.

Signs and symptoms of a heart attack may include:

• Severe left or central chest pain, sharp, pressing or squeezing in nature that lasts for more than a few minutes
  
  
• Pain radiating to your shoulder, left arm, back or to the lower jaw
  
  
• Shortness of breath
  
  
• Sweating
  
  
• Nausea and vomiting
  
  
• Increasing episodes of chest pain
  
  
• Pain in the upper abdomen like indigestion
  
  
• Light-headedness
  
  
• Impending sense of doom
  
  
• Fainting

A heart attack can occur anytime and some heart attacks strike suddenly, but many people who experience a heart attack have warning signs and symptoms in advance. Seek medical advice immediately.

Causes

Heart attack is called myocardial infarction. There is complete obstruction to blood flow and the heart muscle dies due to lack of oxygen. The heart needs a steady supply of blood and without blood, heart cells are injured, causing pain and permanent damage. The lack of blood flow to the heart also may trigger irregular heart rhythms that can be fatal. The arteries supplying your heart encircle the heart like a crown. Blockages are usually due to a blood clot that forms suddenly where a coronary artery has narrowed over the years from a build-up of cholesterol and other substances called atherosclerosis.

A heart attack is a dynamic process that typically evolves over several hours. With each passing minute, more heart tissue is deprived of blood and dies. However, if blood flow can be restored in time, damage to the heart can be limited or completely prevented.

Risk Factors

Coronary risk factors increase your risk of a heart attack. These factors contribute to buildup of deposits (atherosclerosis) that narrows arteries throughout your body. Coronary risk factors include:

• Smoking
  Smoking damages the interior walls of arteries — including coronary arteries to your heart — allowing deposits of cholesterol to collect and restrict blood flow.
  
  
• High blood pressure
  High blood pressure can damage the interior of the coronary arteries accelerating atherosclerosis. High blood pressure can be inherited and it usually increases as you age. Eating a diet too high in salt and being overweight also contributes to high blood pressure.
  
  
• High cholesterol
  High cholesterol levels over a period accelerate atherosclerosis and narrows the arteries throughout your body, including those that supply your heart. Low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol) is most likely to narrow arteries. A high LDL level is undesirable and is often a by-product of a diet high in saturated fats and cholesterol. However, a high level of high-density lipoprotein (HDL) cholesterol (the "good" cholesterol), which helps the body clean up excess cholesterol is desirable.
  
  
• Diabetes
  Diabetes mellitus greatly increases the risk of a heart attack by speeding up atherosclerosis and negatively affecting blood cholesterol levels. Diabetes is the inability of your body to produce or respond to insulin properly. Diabetes can occur in childhood, but usually it appears more often in middle age and among obese people.
  
  
• Physical inactivity
  An inactive lifestyle contributes to high blood cholesterol levels and obesity. However, people who do regular exercise have better cardiovascular fitness, which decreases their overall risk of heart attack. Exercise helps lower high blood pressure and aids in better blood sugar control.
  
  
• Obesity
  Obesity raises the risk of heart disease because it's associated with high blood cholesterol levels, high blood pressure and diabetes.
  
  
• Stress
  Stress is a risk factor for coronary artery disease. You may respond to stress in ways that can increase your risk of a heart attack. Indulge in activities that may reduce your stress levels like listening to music or sports.
  
  
• Alcohol
  Excessive drinking can raise your blood pressure and triglyceride levels, increasing your risk of heart attack. Consumed in moderation, alcohol helps raise HDL levels — the "good" cholesterol.
  
  
• Family history
  If your siblings, parents have had early heart attacks, you may be at risk, too. High blood pressure also can run in families.
  
  
• Homocysteine, C-reactive protein and fibrinogen
  People who have higher blood levels of homocysteine, C-reactive protein and fibrinogen appear to have an elevated risk of heart disease. These factors have only recently been identified as players in increasing cardiovascular disease risk. In the meantime, homocysteine levels can be reduced with folic acid supplements and a healthy diet. Fibrinogen and C-reactive protein levels may be reduced by modifying other risk factors for heart disease, such as lowering cholesterol, stop smoking and exercising.

Men are generally at greater risk than are women of heart attacks. However, the risk for women increases after menopause, usually after age 55. If your father had heart disease before 55 or your mother had heart trouble before 65, your risk of developing heart disease is greater.

When to seek medical advice

During a heart attack, some people don’t recognize the signs and symptoms and hence waste precious minutes. Some people also delay calling for help because they're afraid to risk the embarrassment of a false alarm.

The most important things you can do to increase your survival after a heart attack is to recognize the signs and symptoms and to take immediate action. Of people who die of heart attacks, about half die within the first hour after the onset of signs and symptoms. Call the emergency medical services for help immediately.

Screening and diagnosis

If you're having a heart attack or suspect you're having one, screening and diagnosis will likely happen in an emergency room. You will have a detail history is taken and a quick physical examination by the emergency doctor. Emergency room doctors may also want to conduct tests to determine whether your signs and symptoms, signal a heart attack or another condition. These tests may include:

• Electrocardiogram (ECG)
  This is often the first test done to diagnose a heart attack. This test records the electrical activity of your heart and an injured heart muscle doesn't conduct electrical impulses normally, the ECG may show that a heart attack has occurred or is in progress.
  
  
• Blood tests
  During a heart attack certain heart enzymes slowly leak out into your blood if your heart has been damaged by the heart attack. Emergency room staff may take samples of your blood to test for the presence of these enzymes.
  
  
• Chest X-ray
  An X-ray image of your chest allows your doctor to check if you are in heart failure .It also shows the size and shape of your heart and its blood vessels.
  
  
• Additional tests
  If you've had a heart attack you may also undergo these additional tests:
  
  
  • Nuclear scan
    This test helps identify blood flow to your heart. Radioactive material, such as thallium, is injected into your bloodstream and special cameras can detect the radioactive material as it flows through your heart and lungs.
    
    
  • Echocardiogram
    This test uses ultra sound waves to produce an image of your heart. An echocardiogram can help identify areas of your heart that has been damaged by a heart attack and the pumping capacity can be assessed.
    
    
  • Coronary catheterization (angiogram)
    In recent years the blocked coronary arteries are opened as an emergency procedure- Acute PCI. A dye is injected into the arteries of your heart through a long, thin tube (catheter) that's fed through an artery, usually in your leg, to arteries in your heart. This reveals areas of blockage and they are treated by performing a coronary artery balloon angioplasty and stent deployment. The whole procedure from door to balloon is usually done in 90 to 110 minutes.

Complications

Complications are often related to the damage sustained by your heart during a heart attack.

• Arrhythmias
  If your heart muscle is damaged from a heart attack, electrical "short circuits" can develop resulting in ventricular arrhythmias which can be serious, even fatal.
  
  
• Heart failure
  The amount of damaged tissue in your heart may be so extensive that the heart muscle can’t adequately pump blood out of your heart. Pump failure decreases blood flow to tissues and organs producing shortness of breath, fatigue, and swelling in your ankles and feet. Heart failure may be a temporary problem; however, it can also be a chronic condition resulting from extensive and permanent damage to your heart following your heart attack.
  
  
• Valve problems
  Heart valves may be damaged during a heart attack and develop severe, life-threatening leakage problems.
  
  
• Heart rupture
  Muscle weakened by a heart attack can rupture, leaving a hole in part of the heart. This rupture usually causes fatal bleeding.

Treatment

During a heart attack, act immediately. Take these steps:

• Call for emergency help
  If you suspect you're having a heart attack, do not hesitate to call your local emergency ambulance service. Driving yourself to the hospital is dangerous and puts you and other road users at risk. Ambulance services are equipped with proper resuscitation equipments and hence it is the safest mode of transportation.
  
  
• GTN (nitro-glycerine)
  If you have GTN tablets take them immediately while waiting for the Para medics. This improves the blood supply to the heart.
  
  
• CPR
  If you see someone who is unconscious from a presumed heart attack, call for emergency medical help first. Begin cardiopulmonary resuscitation (CPR) if you have received training in basic CPR. If you're not trained, then skip mouth-to-mouth rescue breathing and proceed directly to chest compression. This delivers blood to vital organs, particularly the brain and heart. Do chest compressions at a rate of 100 a minute.

A heart attack can also trigger ventricular fibrillation (quivering of the heart) in the initial minutes. This produces an ineffective heartbeat, and there is no output of blood from the heart. Without immediate treatment, ventricular fibrillation leads to sudden death. The use of an automatic external defibrillator (AED) shocks the heart back into a normal rhythm and the patient will regain consciousness.

Most ambulances, police and fire rescue units carry portable defibrillators. AEDs are also increasingly available in airplanes and public places, such as schools, shopping malls, office buildings and sports venues.

Medications

Doctors may give you aspirin in the emergency room. Aspirin inhibits blood clotting, which helps maintain blood flow through a narrowed artery. Some medications are given through a vein in your arm (intravenously):

• Aspirin
  Aspirin is a blood thinner and probably this will the first drug you receive when you reach the emergency room. It inhibits blood clotting, thus helping maintain blood flow through a narrowed artery. Aspirin can significantly decrease death rates especially when you are having a heart attack. Take an aspirin yourself while waiting for help to arrive.
  
  
• Pain relief
  If your chest pain or associated pain is great, you may receive a strong pain killer, such as morphine, to alleviate your discomfort.
  
  
• Thrombolytics
  These drugs help dissolve the blood clot that's blocking blood flow to your heart. The sooner you receive a thrombolytic drug following a heart attack, the better the chance you will survive and lessen the damage to your heart muscles. This drug is also called clot-busters and is given in an infusion through a vein usually over one hour. The usage of this medication is declining because more centres around the world are doing acute angioplasty and stent deployment to the affected artery.
  
  
• Special blood thinners
  Doctors in the emergency room may give you a drug called a platelet IIb/IIIa receptor blocker, this drug, which is more potent than regular aspirin; helps prevent new clots from forming. In combination with thrombolytics and aspirin it may prevent clot formation and keep the coronary blood vessel open.
  
  
• Nitro-glycerine
  This medication may be given intravenously if the ECG shows signs of ischaemia and you experience chest pain. GTN temporarily opens arterial blood vessels, improving blood flow the coronary arteries.
  
  
• Beta blockers
  Beta blockers can limit the amount of heart muscle damage and prevent future heart attacks. It slows your heartbeat, relax your heart muscle, and decrease blood pressure making your heart as a pump to work without strain.
  
  
• Cholesterol medications
  The most commonly used drug presently is the statins. They are very effective in decreasing the LDL cholesterol and thereby inhibiting plaque formation in the blood vessels. Fibrates are mostly used to treat raised triglycerides. Other drugs sometimes used are niacin and bile acid sequestrants.

Procedures to treat heart attacks

In addition to medications, you may undergo one of the following procedures to treat your heart attack:

• Coronary angioplasty
  Coronary angioplasty is carried out as an emergency to open the blocked coronary artery, letting blood flow more freely to your heart. A long, thin tube (catheter) is passed through an artery, usually in your leg, to the blocked artery in your heart. This catheter is equipped with a special balloon and once in position, the balloon tip is briefly inflated to open up a blocked coronary artery. After dilating the artery a stent which is like a metal mesh is deployed. This acts as scaffolding and keeps the artery open long term, restoring blood flow to the heart.
  
  
• Coronary artery bypass surgery (CABG)
  In only rare cases, surgeons perform emergency bypass surgery at the time of a heart attack. This involves sewing veins or arteries to bypass the block in the coronary arteries. This procedure restores blood flow to the heart.
  
  
• Cardiac Rehabilitation
  After a heart attack subsequent treatment is to promote healing of your heart and prevent another heart attack. Many hospitals offer cardiac rehabilitation programs that may start while you're in the hospital and may continue for weeks after you return home. Cardiac rehabilitation programs generally focus on three main areas — medications, lifestyle changes and emotional issues.

Secondary Prevention

Drug therapy has become an increasingly important part of reducing the risk of a second heart attack and helping a damaged heart function better. Lifestyle modification also plays a critical role in heart attack prevention.

Medications

Drugs that help the heart function more effectively or reduce heart attack risk may include:

• Blood-thinning medications
  Aspirin makes your blood thinner and less "sticky". Aspirin is usually recommended for life. Some people who cannot tolerate aspirin will be given either Clopidogrel (Plavix) or Ticlopidine (Ticlid). Doctors may prescribe aspirin and an anti-clotting drug such as Clopidogrel (Plavix) for people undergoing an angioplasty and stent procedure to open narrowed coronary arteries.
  
  
• Beta blockers
  Beta blockers can limit the amount of heart muscle damage and prevent future heart attacks. It slows your heartbeat, relax your heart muscle, and decrease blood pressure making your heart as a pump to work without strain.
  
  
• Angiotensin-converting enzyme (ACE) inhibitors
  These drugs help people with heart failure live longer and feel better. ACE inhibitors are a type of vasodilator, a drug that widens or dilates blood vessels to lower blood pressure, improves blood flow and decrease the workload on the heart. Your doctor may prescribe ACE inhibitors if you've had a moderate to severe heart attack.
  
  
• Cholesterol-lowering medications
  A variety of medications, including statins, niacin, fibrates and bile acid sequestrants, can help lower your levels of unwanted blood cholesterol. The majority of people who've had a heart attack take cholesterol-lowering medications — drugs that help lower the risk of a second heart attack. These medications can help prevent future heart attacks even if your cholesterol was not very high at the time of the heart attack.

Lifestyle

This is an important part of the management. Taking the following steps can help you not only prevent but also recover from a heart attack:

• Do not smoke
  The single most important thing you can do to improve your heart's health is to stop smoking. Most hospitals have treatment plans to help you kick the habit.
  
  
• Cholesterol control
  Check your blood cholesterol levels regularly, through a blood test after twelve hours fast. If "bad" cholesterol levels are undesirably high, your doctor can prescribe changes to your diet and medications to help lower the numbers to reach the specified goal.
  
  
• Regular medical checkups
  The major risk factors for heart attack — high blood cholesterol, high blood pressure and diabetes — cause no symptoms in their early stages. Your doctor can perform tests to check that you're free of these conditions. If a problem exists treating it early may prevent complications that can lead to a heart attack.
  
  
• Blood pressure control
  Blood pressure should be checked every two years. Your doctor may recommend more frequent measurement if you have high blood pressure or a history of coronary artery disease.
  
  
• Regular Exercise
  Regular exercise helps improve heart muscle function following a heart attack. It is a major component of any cardiac rehabilitation program. Exercise helps prevent a heart attack by helping you to achieve and maintain normal weight, good diabetic, cholesterol and blood pressure control.
  
  
• Manage stress
  Stress is a risk factor for coronary artery disease. You may respond to stress in ways that can increase your risk of a heart attack. Indulge in activities that may reduce your stress levels like listening to music or sports.
  
  
• Alcohol
  Excessive drinking can raise your blood pressure and triglyceride levels, increasing your risk of heart attack. Consumed in moderation, alcohol helps raise HDL levels — the "good" cholesterol. One to two drinks daily is fine for men, and women can have one alcoholic beverage a day. One drink is equivalent to 12 ounces of beer, 4 ounces of wine or 1.5 ounces of an 80-proof liquor.
  
  
• Heart attack and Sex
  Most people can safely return to sexual activity after recovering from a heart attack. Many people worry that sex after a heart attack may be dangerous. Each person has a different timeline, depending on his or her level of physical comfort, psychological readiness and previous sexual activity. Ask your doctor when it's safe to resume sexual activity. With time, you'll likely be able to resume your normal sexual patterns. The demands sexual intercourse places on your heart approximate those of taking a brisk walk, scrubbing a floor, or climbing one or two flights of stairs.

Many cardiac rehabilitation programs offer counseling services and support groups for heart attack survivors.