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In medicine, keeping the heart beating is a top priority.
But that’s not a simple task, because so many things can go wrong. Diseases such as viruses can invade and destroy heart tissue. Globs of fat can block vessels. Mechanical parts can wear out, the muscle itself can weaken with age, and its built-in timer can misfire. What can modern medicine do to fix a broken heart? Mend it—sometimes.
▲ Heart attacks happen when a piece of heart muscle dies from a clog in an artery supplying blood to the muscle. This destruction takes time. There are often warnings: a chest pain that shoots down the left arm, nausea, shortness of breath, dizziness, and sweating. Heart-attack victims may walk around for days with these symptoms.
◀ Many humans have survived without a heart. Instead of a pulsing mass of tissue, they have a mechanical pump. In 1982, Barney Clark became the first person to depend on one for his life. He survived 112 days. Mechanical pumps are used to pump blood throughout the bodies of people who have severe heart disease. Artificial hearts still can’t replace real human hearts. But they can keep someone alive until a human donor heart becomes available.
If you sprinted everywhere instead of walking, how would you feel? Hypertension is like a heart sprinting all the time. At each beat, blood presses hard against the vessel walls—a condition called high blood pressure. The heart wears down with time. In general, children don’t have high blood pressure. People who have high blood pressure should take the prescribed medication, avoid salty foods, exercise, and have their blood pressure checked regularly. ▶
▲ In 1984, a newborn known as “Baby Fae” made history. She had a fatal heart condition, so doctors gave her a baboon’s heart. Baby Fae died in a few days. Since then, animal-human heart transplants have been extremely rare, because infections can be passed from the animal to the human.
▲ Fatty lumps called plaque may be building up in your arteries right now. As you get older, more plaque will accumulate. Your artery walls will get harder. If too much plaque builds up, blood won’t be able to get through. Heart disease is the number one killer in the United States.
▲ How do you unclog an artery? A procedure called angioplasty involves a thin tube with a deflated balloon on the end. The doctor slides the tube into a blood vessel and threads it through to the blockage. The balloon inflates, pressing the blockage against the wall, so the opening inside the artery is larger. This gives the blood a larger opening to flow through. In bypass surgery, the doctor takes arteries or veins from elsewhere in the patient’s body and attaches one end to the aorta and the other end to the affected artery beyond the blockage. Blood then skips the blocked part of the artery altogether.
◀ A stent is a small expandable tube. It is used to treat narrowed or weakened arteries. In patients with heart disease, stents can open narrowed arteries and help reduce symptoms such as chest pain. They stay in the artery and press against its walls. That lets blood flow more easily.
The heart can beat even after the brain is dead—a condition called “brain death.” What if the heart stops and the brain lives? Within a minute, the patient passes out. Blood isn’t supplying oxygen to the brain. Within about 15 minutes, the patient is dead. Before then, doctors work hard to revive the heart. Electric shocks reset the heart timer to work properly. Nitroglycerine (a chemical used in explosives) makes the work of the heart easier, and it may increase blood flow to the affected area by improving flow through tributaries, called collaterals. ▶
◀ In 1967, Dr. Christiaan Barnard removed the heart from a patient. Then he sewed in a new one, completing the first-ever heart transplant. Such operations are common today, but it’s still hard to find donated hearts. It’s also hard to decide who should get the hearts when they become available: The sickest, the most likely to survive the operation, the youngest, the most famous, the first to sign up, or...? What do you think?
This foxglove flower is full of a poison that can kill humans. Yet a chemical in the leaves saves human lives. Digitalis keeps a weak heart beating in rhythm. If the heart’s timer gives out, doctors insert a mechanical timer, or pacemaker. ▶
▲ An electrocardiogram (EKG) writes each lub-dub or swoosh of a heart onto a chart. It works by detecting the electrical currents that make the heart tick. This diagram is an example of a healthy EKG.
Normal Heart
Enlarged Heart
▲ Sometimes sick hearts grow too big. If a sick heart is too big, it can’t pump blood as hard. Dr. Randas Viela Batista performed the first surgical ventricular reconstruction (SVR) in Brazil in the early 1980s. He cut a chunk out of a ventricle. Then he sewed up the heart. Now, the smaller heart could pump blood and oxygen more efficiently.
