The heart can beat as many as 240 times during tachycardia. Some tachycardias, such as paroxysmal tachycardia, are harmless and transitory phenomena that last a few minutes or hours, subside spontaneously, and cause no lasting effects. Other types, such as multifocal atrial tachycardia or ventricular tachycardia, usually occur in persons with serious heart, lung, or circulatory disease and demand immediate medical attention. The more serious tachycardias may be the first step of atrial fibrillation or even a heart attack. Tachycardias can be terminated by lying down and other basic physical measures, by administering an electrical shock to the heart to restore regular heart rhythm, or by medications.
Some common drugs used to treat tachycardia are quinidine, atropine, lidocaine, or procainamide.
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