Types of Cardiac Implants:
Coronary Stents:
A coronary stent is a small, latticed, high-grade stainless steel tube that is used to hold the coronary artery open when coronary heat disease has caused a blockage. Stents can temporarily alleviate chest pain, but do not contribute to longevity. A more permanent way to prevent heart attacks in patients at high risk is to give up smoking, exercise regularly, and take medications to control blood pressure, cholesterol and blood clotting.
Pacemakers:
Faulty electrical signaling in the heart causes arrhythmias. Pacemakers use low-energy electrical pulses to overcome this faulty electrical signaling. Pacemakers can:
– Speed up a slow heart rhythm.
– Help control an abnormal or fast heart rhythm.
– Make sure the ventricles contract normally if the atria are quivering instead of beating with a normal rhythm (a condition called atrial fibrillation).
– Coordinate electrical signaling between the upper and lower chambers of the heart.
– Coordinate electrical signaling between the ventricles. Pacemakers that do this are called cardiac resynchronization therapy (CRT) devices. CRT devices are used to treat heart failure.
– Prevent dangerous arrhythmias caused by a disorder called long QT syndrome.
Pacemakers also can monitor and record your heart’s electrical activity and heart rhythm. Newer pacemakers can monitor your blood temperature, breathing rate, and other factors. They also can adjust your heart rate to changes in your activity.
Pacemakers can be temporary or permanent. Temporary pacemakers are used to treat short-term heart problems, such as a slow heartbeat that’s caused by a heart attack, heart surgery, or an overdose of medicine.
Temporary pacemakers also are used during emergencies. They might be used until your doctor can implant a permanent pacemaker or until a temporary condition goes away. If you have a temporary pacemaker, you’ll stay in a hospital as long as the device is in place.
Implantable Cardiac Defibrillators:
A problem with any part of the heart’s electrical system can cause an arrhythmia. Most arrhythmias are harmless, but some can be serious.
ICDs use electrical pulses or shocks to treat life-threatening arrhythmias that occur in the ventricles (the heart’s lower chambers).
When ventricular arrhythmias occur, the heart can’t pump blood well. You can pass out within seconds and die within minutes if not treated.
To prevent death, the arrhythmia must be treated right away with an electric shock to the heart. This treatment is called defibrillation (de-fib-ri-LA-shun).
An ICD has wires with electrodes on the ends that connect to your heart chambers. The ICD will monitor your heart rhythm. If the device detects an irregular rhythm in your ventricles, it will use low-energy electrical pulses to restore a normal rhythm.
If the low-energy pulses don’t restore your normal heart rhythm, the ICD will switch to high-energy pulses for defibrillation. The device also will switch to high-energy pulses if your ventricles start to quiver rather than contract strongly. The high-energy pulses last only a fraction of a second, but they can be painful.
An ICD is similar to a pacemaker, but has some differences.
Pacemakers give off only low-energy electrical pulses. They’re often used to treat less dangerous heart rhythms, such as those that occur in the upper chambers of your heart. Most new ICDs can act as both pacemakers and defibrillators.
CRT (cardiac resynchronization therapy) device:
People who have heart failure may need a special device called a cardiac resynchronization therapy (CRT) device. The CRT device is able to pace both ventricles at the same time. This allows them to work together and do a better job pumping blood out of the heart. CRT devices that have a defibrillator are called CRT-D.
Heart Valves:
How the Heart Valves Work
At the start of each heartbeat, blood returning from the body and lungs fills the atria (the heart’s two upper chambers). The mitral and tricuspid valves are located at the bottom of these chambers. As the blood builds up in the atria, these valves open to allow blood to flow into the ventricles (the heart’s two lower chambers).
After a brief delay, as the ventricles begin to contract, the mitral and tricuspid valves shut tightly. This prevents blood from flowing back into the atria.
As the ventricles contract, they pump blood through the pulmonary and aortic valves. The pulmonary valve opens to allow blood to flow from the right ventricle into the pulmonary artery. This artery carries blood to the lungs to get oxygen.
At the same time, the aortic valve opens to allow blood to flow from the left ventricle into the aorta. The aorta carries oxygen-rich blood to the body. As the ventricles relax, the pulmonary and aortic valves shut tightly. This prevents blood from flowing back into the ventricles.
Heart Valve Problems
Heart valves can have three basic kinds of problems: regurgitation (re-GUR-jih-TA-shun), stenosis (ste-NO-sis), and atresia (a-TRE-ze-ah).
Regurgitation, or backflow, occurs if a valve doesn’t close tightly. Blood leaks back into the chambers rather than flowing forward through the heart or into an artery.
In the United States, backflow most often is due to prolapse. “Prolapse” is when the flaps of the valve flop or bulge back into an upper heart chamber during a heartbeat. Prolapse mainly affects the mitral valve.
Stenosis occurs if the flaps of a valve thicken, stiffen, or fuse together. This prevents the heart valve from fully opening. As a result, not enough blood flows through the valve. Some valves can have both stenosis and backflow problems.
Atresia occurs if a heart valve lacks an opening for blood to pass through.
Some people are born with heart valve disease, while others acquire it later in life. Heart valve disease that develops before birth is called congenital (kon-JEN-ih-tal) heart valve disease. Congenital heart valve disease can occur alone or with other congenital heart defects.
Congenital heart valve disease often involves pulmonary or aortic valves that don’t form properly. These valves may not have enough tissue flaps, they may be the wrong size or shape, or they may lack an opening through which blood can flow properly.
Acquired heart valve disease usually involves aortic or mitral valves. Although the valves are normal at first, problems develop over time.
Both congenital and acquired heart valve disease can cause stenosis or backflow.
There are three main types of artificial heart valve implants: the mechanical,the biological, and the tissue engineered valves.
Content: http://www.nhlbi.nih.gov/health/
