Most people think of a heart attack as something that happens quickly and causes someone to grab his or her chest and fall to the ground. That’s actually a picture of cardiac arrest. A heart attack, as
the term is commonly used today, generally means the blockage of an artery in the heart that kills some heart muscle. (Medically speaking, this is a myocardial infarction.) A heart attack usually gives some warning. Chest pain or other symptoms can prompt someone to get help before the blockage totally disrupts the heart’s rhythm.
Cardiac arrest, though, strikes suddenly and out of the blue. Most cardiac arrests occur when the heart’s powerful lower chambers, the ventricles, start beating very fast (ventricular tachycardia [ta-kih-CAR-dee-uh]) or fast and chaotically (ventricular fibrillation). Either one of these makes it impossible for the heart to pump blood to the body.
After just five seconds without blood circulation, a person passes out. In another few seconds, the lack of oxygen in the brain causes nerves to start firing, making the muscles twitch and the eyes roll back. Even that activity stops in less than a minute. The chances of surviving a cardiac arrest fall about 10 percent for each minute the heart stays in ventricular fibrillation. Shock the heart back into a normal rhythm within two minutes, and the victim has an 80 percent chance of surviving. Deliver that shock after seven minutes—the average time it takes an emergency medical team to arrive in many cities—and the odds are less than 30 percent.
If someone near you goes into cardiac arrest, calling 911 is a must. CPR is also important because it keeps blood flowing to the brain and other vital organs. If there’s an automated external defibrillator nearby, use it following the instructions on the device.
the term is commonly used today, generally means the blockage of an artery in the heart that kills some heart muscle. (Medically speaking, this is a myocardial infarction.) A heart attack usually gives some warning. Chest pain or other symptoms can prompt someone to get help before the blockage totally disrupts the heart’s rhythm.
Cardiac arrest, though, strikes suddenly and out of the blue. Most cardiac arrests occur when the heart’s powerful lower chambers, the ventricles, start beating very fast (ventricular tachycardia [ta-kih-CAR-dee-uh]) or fast and chaotically (ventricular fibrillation). Either one of these makes it impossible for the heart to pump blood to the body.
After just five seconds without blood circulation, a person passes out. In another few seconds, the lack of oxygen in the brain causes nerves to start firing, making the muscles twitch and the eyes roll back. Even that activity stops in less than a minute. The chances of surviving a cardiac arrest fall about 10 percent for each minute the heart stays in ventricular fibrillation. Shock the heart back into a normal rhythm within two minutes, and the victim has an 80 percent chance of surviving. Deliver that shock after seven minutes—the average time it takes an emergency medical team to arrive in many cities—and the odds are less than 30 percent.
If someone near you goes into cardiac arrest, calling 911 is a must. CPR is also important because it keeps blood flowing to the brain and other vital organs. If there’s an automated external defibrillator nearby, use it following the instructions on the device.
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