Learn About Your Heart...
Made Simple

By Nicolas Shammas, MD

A new, comprehensive sourcebook for
heart and vascular disease patients

Cardiovascular Health Topics

Statistics about Heart and Blood Vessel Diseases in the United States
Structure and Function of the Heart and Blood Vessels
Diseases of the Blood Vessels of the Heart
Surgical Therapies for the Cardiovascular Patient
Peripheral Vascular Disease
Diseases of the Blood Vessels of the Head and Neck
Strokes: How to Survive Them and How to Prevent Them
Valvular Heart Disease
Heart Rhythms: How to Recognize Them and Treat Them
Congestive Heart Failure
11. Understanding Cardiomyopathy, or Weak Heart Muscle
12. Children and Heart Disease
13. Diseases of the Pericardium
14. Systemic Illnesses, Infections and Drugs that Affect the Heart
15. Erectile Dysfunction: a Vascular Disease
16. Cardiovascular Disease Prevention
17. Heart Healthy Nutritional Tips
18. Cardiac Rehabilitation
19. Medications for Cardiovascular Disorders
20. Heart Tests You Need to Know
21. Learn What to Do in a Medical Emergency
22. How to Choose Your Doctor and Hospital
23. Medical Research and How You Can Get Involved
24. Taking the Next Step — A Few Community Resources to Help You Live More Healthfully
25. How Much Did You Learn from This Book: Take a Simple Test

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Figure 1.

Figure 2.


Nicolas W. Shammas, MS, MD, FACC, FACP

How does the heart receive its blood supply? The heart is a pump that continuously beats at 60 to 100 beats per minute during the life of a person. This pump requires oxygen and nutrients to achieve its tasks. These are delivered to the heart via blood vessels called the coronary arteries (see Figure 1). There are 3 or 4 major coronary arteries that deliver blood to the heart.These supply the top (left anterior descending artery), the side (left circumflex artery), and the bottom (right coronary artery) of the heart. Any interruption of blood supply to any of those coronary arteries can lead to heart damage to a correspondent part of the heart muscle.

How do the coronary arteries fill with plaque and become obstructed?

The coronary arteries are covered on the inside by a lining called the endothelium, a single layer of cells that covers every single blood vessel in our body. It has been estimated that if thislining of all the blood vessels from a single individual is spread on a flat surface, it could cover 2 tennis courts in size. This single layer of cells, however, separates the blood vessels from health and disease.

Any damage to the endothelium can lead to its invasion by blood elements called monocytes. These monocytes penetrate under the lining of those blood vessels and absorb fat from the bloodstream. They become enlarged in size and are called foam cells. These foam cells promote a complex reaction under the endothelium, which subsequently causes inflammation and attracts various other cells to the plaque area. The plaque expands and starts to impinge on the opening of the blood vessels that supply the heart (see Figure 2).

It is well known that the process of plaque formation starts very early in childhood. Autopsies on young soldiers who died in wars have shown that the blood vessels of their bodies already show the buildup of fat under the endothelium. Over two-thirds of people over the age of 40 show the buildup of plaque in the blood vessels that supply their heart, as seen by ultrasound scanning of those blood vessels.

What is angina?

Angina is a symptom of chest pain—also described as chest pressure, a heavy feeling in the chest, or a squeezing sensation in the chest—that is caused by a lack of blood supply to a part of the heart muscle. Angina is described as either stable or unstable.

A narrowing in 1 of the blood vessels of the heart by plaque buildup causes stable angina. Stable angina occurs when a person is active and doing physical exertion. It typically resolves within 2 to 3 minutes of resting. This type of angina does not occur at rest. As a person becomes active and exerts himself or herself, the heart has to pump faster and stronger. With the increase in the heart rate, there is a need to increase the blood supply to the heart to continue to match its demands. If plaque buildup is severe enough to narrow the coronary arteries, the blood supply to the heart cannot increase at the rate needed by the heart. A mismatch of demand and blood supply occurs. This generates discomfort in the heart—angina. Once the patient rests and the demands of the heart for blood supply returns to normal, the pain resolves.

In contrast to stable angina, a rupture of the plaque inside the blood vessels causes unstable angina. This leads to a subsequent accumulation of a clot at the area of the plaque rupture, which abruptly interrupts the blood supply to the heart. Angina then occurs with very minimal activity or at rest. This type of angina requires immediate medical attention.

How does the patient perceive angina?

Angina is perceived as chest pressure, tightness, a squeeze, or heaviness in the chest. This could radiate to the arm and the jaw, the shoulders, the back, or the abdomen. The pain can be associated with an increase in shortness of breath, a feeling of nausea,and occasional vomiting. Also,patients break out in a sweat, which is called diaphoresis. Lightheadedness and anxiety accompany these symptoms. Patients might describe 1 or more of these symptoms, without any chest discomfort on many occasions. Women and people with diabetes tend to present with atypical symptoms without chest pain.

What should you do if you experience chest pain or other symptoms of angina?

If you experience chest pain or any of the previously described symptoms, it is important that you not attempt to self-diagnose. In this situation, it is very important to seek immediate medical attention. If the pain occurs at rest, this is essentially an emergency and driving to the hospital or having someone drive you can be very dangerous. The best way to deal with your rest angina is to call 9-1-1 and allow paramedics to transport you to the hospital. The first hour of the onset of chest discomfort is the most dangerous. Electrical disturbances in the heart can occur, and the heart could cease pumping blood to the brain and the vital organs of the body. This can be corrected easily if you are being transported to the hospital with trained professionals. However, sudden cardiac death can occur if you are still at home or you are in a regular car on your way to the hospital. A sudden change in symptoms—such as the occurrence of nausea or vomiting, sudden worsening of breathing, or the occurrence of chest pain—warrants immediate hospital evaluation.

If chest pain or the anginal symptoms have been occurring primarily with exertion or activity but never at rest, this tends to be somewhat less of an emergency. However, evaluation should be performed relatively soon. Calling your doctor and getting evaluated relatively soon is important. The symptoms of pain with exertion are classic anginal symptoms, and they have a high chance of being related to obstructive plaque in the coronary arteries.

How does a patient die from a heart attack?

The most common cause of death from heart attack is electrical instability to the heart. Once the blood supply is interrupted, the electrical conduction inside the heart becomes disturbed.Abnormal electrical circuits are generated in the bottom chambers of the heart. These lead to quivering of the heart muscle. The heart muscle becomes inefficient in pumping blood. These arrhythmias are called ventricular tachycardia or ventricular fibrillation. The blood will be able to generate minimal to no blood supply to the vital organs of the body, including the brain. A person loses consciousness usually within 5 to 10 seconds of the occurrence of this event. Death occurs if the electrical system of the heart is not restored back to its normal condition within 5 to 6 minutes of the electrical disturbance. Rarely, heart failure resulting from the heart attack leads to death. By far, the majority of deaths are related to this electrical instability. Paramedics and hospitals are equipped with machines called defibrillators that are capable of aborting those electrical heart rhythms by delivering an electrical shock to the chest. Automatic external defibrillators are now widely placed in public places, such as airports, schools, and large business centers. Operation Heartbeat, a program of the American Heart Association, has intended to extend the use of automatic external defibrillators in public places in order to save lives of heart attack victims.

Cardiopulmonary resuscitation (CPR), which includes artificial respiration and chest compression, can sustain enough blood circulation for the first 10 minutes after the electrical instability has occurred.

However, without the more definitive therapy of defibrillation using the defibrillator, CPR alone is inadequate to restore a normal heart rhythm. In fact, survival rate after 6 minutes of the arrhythmia is slim despite CPR and without defibrillation.

What does my doctor do when I come to the emergency room with chest pain?

Your doctor will evaluate you with a full history and physical exam. Details of the chest pain, such as its onset, severity, radiation, and association with other symptoms or with activity, will all be important information to provide. A physical exam to listen to your lungs and heart will be important. Based on all the information gathered, including blood testing, your physician will attempt to determine whether your symptoms could be related to your heart or are noncardiac in origin.

If it is a possibility that these symptoms are heart-related, you will be asked to stay in the hospital. Many hospitals have a chest pain unit where you will be observed for several hours on a monitor. Serial blood testing will be obtained to rule out the possibility of heart injury. An electrocardiogram also will be obtained. Eventually, if all your tests are unremarkable, a stress test will be performed.

All these tests will help your doctor decide whether to admit you to the hospital for further testing, such as a coronary angiogram. On the other hand, if your chest pain has occurred at rest and continues to do so in the emergency room, your doctor will have to assume that this is an unstable anginal symptom. You will then be directly admitted to the hospital and placed on medical treatment. If the suspicion for cardiac-related symptoms is high, your doctor might proceed directly with an angiogram.

What is a cardiac catheterization or a coronary angiogram?

A cardiac catheterization is essentially the same as a coronary angiogram.This procedure is performed in the cardiac catheterization laboratory. During this procedure, a small plastic tube is inserted in the blood vessel in the groin, called the common femoral artery. This small plastic tube or catheter is placed under a local anesthetic.Through this catheter, plastic tubes are placed inside the blood vessels under x-ray guidance. These go to the heart, where a contrast dye is injected. The dye is injected directly in the heart's chamber as well as in the blood vessels of your heart. As the dye is being injected in those blood vessels, a camera takes multiple pictures of your heart, which will allow your physician to see your coronary arteries and determine the location of the blockages, if present.

The angiogram is considered an invasive procedure. It carries some risks with it. These risks vary depending on the condition of the patient. Patients with heart failure and reduced heart function, diabetes, or kidney problems tend to be at exceptionally high risk. Diabetes care is crucial among patients with previous history of heart attacks, strokes, and blockages in the blood vessels of the legs are also at higher risk. However, the overall risks of the procedure remain small. In a non-emergent angiogram, the risk of death should be less than 1 in 1,000, risk of strokes 1 in 500, and the risk of major bleeding from the insertion site of the catheter should be less than 1%. Obviously, these risks also vary if the angiogram is only for diagnostic purposes to identify the location of the blockage or for treatment purposes to treat the blockage.

During the treatment of blockages, large amounts of blood thinners are administered, which increases the risk of bleeding and complications. Other risks of the angiogram also include infection, damage to the nerves in the groin area, damage to the arteries of the heart themselves, as well as the aorta, the main artery that comes out of the heart and supplies blood to the rest of the body. Your doctor will weigh carefully all those risks compared to the potential benefits of the test.

Typically, an informed consent—a legal contract that authorizes the physician to proceed with the test—is obtained after you understand these risks and your questions and concerns are answered. Signing a consent form essentially acknowledges your understanding of these risks and your willingness to proceed with the test. You should treat it seriously, carefully read it, and understand it. The physician or the nurse should be available to answer any questions you might have.

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