Science Insider
WHAT IS ARRHYTHMIA? An arrhythmia occurs when there is a change in the heart's rhythm causing the heart to beat too fast, too slow, or irregularly. This keeps the heart from pumping blood properly. Normally, the heartbeat starts in the right atrium, when a special group of cells (the "pacemaker" of the heart) sends an electrical signal causing the muscles to contract. These signals travel through connecting fibers to all parts of the ventricles, and must follow an exact route in order for the heart to pump properly. There are many types of arrhythmias, identified by where they occur in the heart (in the atria or ventricles), and by what happens to the heart's rhythm when they occur. One example is atrial fibrillation, an irregular heartbeat that interferes with the heart's ability to pump blood. Abnormal electrical signals cause the atria, or upper chambers of the heart, to contract erratically. Blood then pools in the atria and forms clots. These can travel to the brain and cause a stroke. The most serious arrhythmia is ventricular fibrillation, where the lower chambers quiver and the heart can't pump any blood. Without immediate medical attention, this results in collapse and sudden death
CPR AND DEFIBRILLATION: Cardiac arrest is the sudden, abrupt loss of heart function resulting from such factors as heart disease, electrocution, drowning, choking and trauma. Cardiopulmonary resuscitation (CPR) combines rescue breathing and chest compressions to keep victims of cardiac arrest alive until medical treatment is available. During cardiac arrest, the heart stops pumping blood; proper CPR supports a small amount of blood flow to the heart and brain to buy time until the heart begins to function normally again or emergency medical help arrives. If the arrest is caused by an abnormal heart rhythm, delivering an electric shock to the heart (defibrillation) can restore the normal rhythm.
The American Physical Society, The American Association of Physicists in Medicine, the Institute of Electrical and Electronics Engineers, Inc.-USA, and the Biophysical Society contributed to the information contained in the TV portion of this report.