BIntroduction
A heart attack is an injury to the heart muscle caused by a loss of blood supply. It usually occurs when a blood clot blocks the flow of blood through a coronary artery – a blood vessel that feeds blood to a part of the heart muscle. Interrupted blood flow to your heart can damage or destroy a part of the heart muscle.
Signs and symptoms
Heart attacks have many variable signs and symptoms. Not all people who have heart attacks experience the same ones or experience them to the same degree.
Warning signs and symptoms of a heart attack include:
Pressure, fullness or a squeezing pain in the centre of your chest that lasts for more than a few minutes
Pain extending beyond your chest to your shoulder, arm, back, or even to your teeth and jaw
Increasing episodes of chest pain
Prolonged pain in the upper abdomen
Shortness of breath
Sweating
Impending sense of doom
Lightheadedness
Fainting
Nausea and vomiting
Causes
The factors that increase the risk of a heart attack include:
Men over 45 and women over 55
Smoking
Being overweight or obese
High blood pressure
A high blood cholesterol level
A diet high in saturated fats (animal fats)
Diabetes
A family history of heart disease
Lack of regular exercise
When to seek medical advice
During a heart attack, some people waste precious minutes because they don’t recognize the important signs and symptoms – or they deny them. Some people also delay calling for help because they’re afraid to risk the embarrassment of a false alarm. Of the people who die of heart attacks, about half die within the first hour after the onset of signs and symptoms.
Don’t ‘tough out’ the symptoms of a heart attack for more than five minutes. Call emergency medical services for help. If you don’t have access to emergency medical services, have someone such as a neighbour or friend drive you to the nearest hospital.
If it turns out you weren’t having a heart attack, doctors may be able to pinpoint the cause of your signs and symptoms and treat them.
Screening and diagnosis
Ideally, your doctor should screen you during regular physical exams for risk factors that can lead to a heart attack.
Electrocardiogram (ECG)
This is often the first test done to diagnose a heart attack. This test records the electrical activity of your heart via electrodes attached to your skin.
Blood tests
Certain heart enzymes slowly leak out into your blood if your heart has been damaged by a heart attack. Emergency room doctors may take samples of your blood to test for the presence of these enzymes.
Additional tests
If you’ve had a heart attack or one is occurring, doctors will take immediate steps to treat your condition. You may also undergo these additional tests:
Chest X-ray: An X-ray image of your chest allows your doctor to check the size and shape of your heart and its blood vessels.
Nuclear scan: This test helps identify blood flow problems to your heart. Trace amounts of radioactive material, such as thallium, are injected into your bloodstream. Areas of reduced blood flow to the heart muscle – through which less of the radioactive material flows – appear as dark spots on the scan.
Echocardiogram: This test uses sound waves to produce an image of your heart. An echocardiogram can help identify whether an area of your heart has been damaged by a heart attack and isn’t pumping normally or at peak capacity.
Coronary catheterization (angiogram): This test can show if your coronary arteries are narrowed or blocked. A liquid 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. As the dye fills your arteries, the arteries become visible on X-ray and videotape, revealing areas of blockage.
In the days or weeks following your heart attack, you may also undergo a stress test. Stress tests measure how your heart and blood vessels respond to exertion. You may walk on a treadmill or pedal a stationary bike while attached to an ECG machine. Or you may receive a drug intravenously that stimulates your heart similar to exercise. Stress tests help doctors diagnose coronary artery disease, which can cause chest pain and may underlie a recent or future heart attack.
Treatment
During a heart attack, act immediately.
Call for emergency medical help. If you even suspect you’re having a heart attack, don’t hesitate. Immediately call your local emergency number.
A heart attack is a medical emergency which demands both immediate attention and activation of the emergency medical services. The ultimate goal of the management in the acute phase of the disease is to salvage as much heart muscle as possible and prevent further complications.
First line
Oxygen, aspirin, glyceryl trinitate (nitroglycerin) and analgesia (usually morphine, are administered as soon as possible. In many areas, first responders can be trained to administer these prior to arrival at the hospital.
Once the diagnosis of myocardial infarction is confirmed, other pharmacologic agents are often given. These include beta blockers, anticoagulation (typically with heparin, and possibly additional antiplatelet agents such as clopidogrel. These agents are typically not started until the patient is evaluated by an emergency room physician or under the direction of a cardiologist.
Surgical and other procedures
In addition to medications, you may undergo one of the following procedures to treat your heart attack:
Coronary angioplasty: Emergency angioplasty opens blocked coronary arteries, letting blood flow more freely to your heart. Doctors insert a long, thin tube (catheter) that’s passed through an artery, usually in your leg, to a blocked artery in your heart. At the same time, a metal mesh stent may be inserted into the artery to keep it open long term, restoring blood flow to the heart. When getting an angioplasty for heart attack treatment, studies have shown the sooner the better.
Coronary artery bypass surgery: In rare cases, doctors may perform emergency bypass surgery at the time of a heart attack. Bypass surgery involves sewing veins or arteries in place at a site beyond a blocked or narrowed coronary artery (bypassing the narrowed section), restoring blood flow to the heart.
Next week, we will discuss lifestyle modifications that should be followed to reduce the incidence of heart attacks.
