SHOW 305: "Muscle-Wrap" Heart Surgery
Sixty-year-old John Robl's enlarged heart is badly damaged. If he does not get a new heart soon, he will die. Like at least half the people waiting for a donor heart, his chances of getting one in time are slim. But a bold experiment in cardiac surgery, performed here on FRONTIERS, may prolong his life. At Allegheny General Hospital in Pittsburgh, surgeons try a radical technique for salvaging a damaged heart: they wrap it in the patient's own back muscle and, using a special pacemaker, train the muscle to pump.
Activity: Test Your Heart I.Q.
Notes & Discussion
Report From the Field: Ignacio Y. Christlieb, M.D., Research Professor and Associate Director at Allegheny-Singer Research Institute
ACTIVITY: TEST YOUR HEART I.Q.
As you see on FRONTIERS, patient John Robl undergoes experimental heart surgery in an effort to prolong his life. His heart is so damaged that his only remaining option is to wait for a heart transplant -- which may never arrive in time, or risk undergoing experimental surgery. In the surgery, doctors try a radical approach to saving the heart: they wrap it in John's own back muscle and train the muscle to pump like the heart.
A. HOW MUCH DO YOU KNOW?
Find out what you know about the heart and heart disease by answering the questions below. For each question that is false, explain why.
- Heart disease is the leading cause of death and disability in the industrialized world.
- Risk factors in heart disease cannot be controlled.
- Victims of cardiac arrest usually experience signs of heart problems before they have a heart attack.
- A heart transplant is a treatment of last resort for those suffering from heart disease.
- Although cigarette smoking is known to cause lung cancer, it is not considered a major risk factor in heart disease.
- A sedentary lifestyle will cause heart disease.
- Approximately 1,500 people die from heart attacks every day in the U.S.
- Women don't have to worry about heart problems as much as men.
- The heart of a smoker must work harder than that of a non-smoker.
- Stress does not affect the physiology of the body, only the psychological well-being.
B. GIVE YOURSELF AN EDGE
Heart disease can happen to anyone, even to people who try to live the most exemplary healthy lives. A healthier lifestyle doesn't guarantee that you'll never have problems, but it does give you an edge in preventing heart disease -- and if you ever do have problems, a healthier you means an immune system that's in better shape to battle disease. A stronger immune system also responds better to treatment, should that ever become necessary. Explain how each statement below might be a potential factor in contributing to heart disease.
- I always get hassled when I have to wait in a long line or sit in traffic.
- I make sure to get at least 20 minutes of aerobic exercise three times a week.
- I do not smoke and do not plan on starting.
- Part of my diet includes several servings of fresh fruits and vegetables every day.
- Potato chips, french fries and doughnuts are my favorite snacks.
- I spend most of my time sitting at a desk or watching television.
- I work in a place where I am exposed to second-hand smoke much of the time.
- I am constantly under pressure to meet deadlines and have very little free time between school and other responsibilities and commitments.
- I have had my cholesterol and blood pressure checked.
- I have a pattern of gaining weight, taking it off, then gaining it back again.
How much Do You Know?
- F (genetic factors cannot be changed, but lifestyle choices can be)
- F (about one-fourth of all heart attacks occur suddenly, without any previous symptoms)
- F (smoking has been found to be a major risk factor in heart disease; smoking strains the heart and blood vessels, raises blood pressure, damages the lining of the arteries, promotes blood clots and is believed to constrict the arteries; because carbon monoxide reduces the amount of oxygen the blood can carry, a smoker's heart must work harder; nicotine raises the heart rate, making more oxygen necessary)
- F (it doesn't necessarily cause a heart attack but certainly contributes to a general lack of good health)
- F (heart disease is the #1 killer of both women and men)
- F (increasingly, stress is recognized as an important risk factor)
- In this activity students learn more about the heart and heart disease. They're also asked to think about some of the lifestyle choices that may be critical in preventing heart problems. (Note that Robl's lifestyle -- he was overweight and a smoker -- surely contributed to his damaged heart.) For this portion of the activity, identify the risk factors significant to developing heart disease: smoking, people who are overweight or physically inactive, people with high blood pressure or high blood cholesterol. Consult your health textbook or the American Heart Association for more information.
NOTES & DISCUSSION
- In the experimental surgery performed on FRONTIERS, back (skeletal) muscle is used to repair cardiac muscle. Besides these two groups, what other major muscle group is found in the body? (smooth) What are the major similarities and differences among the three types? What functions does each perform? (For more information and a related activity, see the teacher's guide for "Muscular Dystrophy" from FRONTIERS Show 201.)
- Refer to a detailed anatomy book and locate the latissimus dorsi, the back muscle used to wrap around the heart. What is its function? (located on each side of the midback, it draws the arms backward and downward and rotates the front of the arm toward the body) How might this surgery impede the patients' mobility? Have students listen for Dr. Christlieb's comment in the show about activities the patient will not be able to perform. (rowing, swimming the backstroke, climbing a rope ladder)
- The key to this experimental muscle-wrap surgery is the pacemaker used to retrain the back muscle to function like cardiac muscle. The pacemaker sends electrical signals to the back muscle that cause it to contract at the same time as the heart, or about once every other heartbeat. Unlike the pacemakers usually used in cardiac patients, the pacemaker developed for this surgery can be programmed. (Note: this surgery does not cure a sick heart, but acts as a boost. If the heart is too damaged, the surgery won't work.)
- Patient John Robl could put himself on a waiting list for a heart transplant, but according to some statistics, one out of two people die before a donor heart becomes available. Robl opts for the experimental surgery.
- Remind students that high blood pressure (hypertension) is a contributing factor in heart attacks, strokes, hardening of the arteries and kidney failure. Over a normal person's lifetime, a heart pumps enough blood to fill 13 supertankers, each with a capacity of 1,000,000 barrels. And that's just when the heart is resting.
- If you have access to a sphygmomanometer (the device that measures blood pressure), it might be interesting for students to find out what their own pressure is, under varying circumstances (early in the morning, after exercise, before an exam or competitive event). Perhaps you can consult your school nurse as a resource.
REPORT FROM THE FIELD: IGNACIO Y. CHRISTLIEB, M.D., RESEARCH PROFESSOR & ASSOCIATE DIRECTOR AT ALLEGHENY-SINGER RESEARCH INSTITUTE
The muscle-wrap heart surgery seen on FRONTIERS is still in a highly experimental stage. John Robl is only the 29th patient at Allegheny Hospital to receive the operation.
The actual procedure may be new, but as Dr. Christlieb points out, "You could realistically say that some 60 years of research have gone into making this operation possible. In 1933, a French surgeon published the first successful experimental use of free muscle grafts to repair missing areas of the heart wall. Stimulated muscle was first wrapped around the heart 25 years later.
"Although the key to the success of this procedure is part the stimulator," Christlieb continues, "the most important breakthrough was establishing a proper training program for the selected muscle to withstand exercise without fatigue." Researchers focused on the elimination of the fatigue factor in the early 1980s, and in 1985, Alain Carpentier in Paris and George J. Magovern in Pittsburgh, performed the first two successful operations. Both patients are alive and well today.
What is special about the pacemaker used in the muscle-wrap surgery? Christlieb comments, "We prefer the term 'stimulator.' The difference is that cardiac pacemakers stimulate the heart, so cardiac activity depends on their proper functioning. This device, called a cardiomyostimulator, stimulates only the muscle flap. If the stimulator fails or stops working, the heart would keep on functioning, even if the muscle flap does not contract for a period of time.
What happens to the patient's heart? "Eventually the heart and the muscle become a new functional unit and become interdependent. We could say that in this 'engine,' the muscle is the motor part and the heart acts as a pump to provide the necessary fuel for a continued, adequate function."
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