Tachyarrhythmia is the medical term used when your heart rate gets too fast. Tachycardia is diagnosed when your heart rate, or pulse, exceeds 100 beats per minute on a regular basis. You can also develop fibrillation, which means your heart is beating faster than 350 beats per minute. In some cases, such as when you are working out, recovering from an illness or responding to an emergency, your heart rate may temporarily get high, but then it returns to normal when the activity or situation stops. This is a normal reaction. However, heart disease and other conditions can lead to chronic tachyarrhythmia, which in severe cases can be fatal.
A rapid heart rate may occur occasionally, such as when you are stressed or when you ingest caffeine. St. Jude Medical Center states that not all cases of tachyarrhythmia cause harmful effects or require treatment. However, a fast heart rate may lead to palpitations, in which you can feel your heart pounding or beating quickly in your chest or throat. If you notice that your heart is beating faster than it should with no known cause, you need to see your doctor for tests to rule out a serious condition.
According to Medtronic, if your heart starts beating too fast it can strain your system, because your heart can not effectively deliver the blood and oxygen your body needs. This can lead to feeling tired, dizzy, lightheaded and suffering from fainting spells. This condition can occur in any one of the heart's four chambers. No matter what part of your heart muscle is affected, your symptoms will be the same. However, if this condition originates in the upper chambers of the heart (atrium), you are less likely to have severe symptoms.
The Heart Rhythm Society states that irregular heart rates that originate in the lower two chambers of the heart (ventricles), are usually the most dangerous. If you have heart disease or are at a high risk for it, talk to your doctor if you experience chest pain or pressure, extreme fatigue or weakness, vision changes or trouble breathing. If these symptoms occur alone or along with a rapid pulse, they can be a warning sign of a life-threatening event.