If you have tachycardia, it means you have a faster than normal heart rate. The normal rate for a healthy adult heart is between 60 and 100 beats per minute at rest. Tachycardia causes the heart rate in the upper or lower or both chambers to increase. In some cases, though, tachycardia may cause not only symptoms, but it can also increase the risk of stroke or cardiac arrest.
Human Heart
The human heart comprises four chambers: the two upper chambers, or atria, and the two lower chambers, or ventricles. The sinus node, located in the right atrium, is responsible for producing electrical impulses that stimulate your heartbeat. These impulses pass through the atria, forcing them to contract and pump blood down into the ventricles. They then pass to the atrioventricular node, which slows down the signal, allowing the ventricle to fill with blood. When the signal reaches the ventricles, it contracts them, pumping blood to the rest of the body.
Tachycardia
If your heart is beating too rapidly, it cannot pump blood around the body efficiently. Gradually your organs and tissues become oxygen deprived. This may cause rapid pulse, dizziness, lack of breath, lightheadedness, chest pain, heart palpitations and fainting. You should consult your doctor if you are experiencing symptoms of tachycardia so that you can get an evaluation and diagnosis.
Causes
Tachycardia occurs when something disrupts the normal electrical impulses that control your heart's natural pumping rhythm. Risk factors include high blood pressure, damage to heart tissue, congenital heart defects, high alcohol consumption, smoking, drug abuse, high caffeine intake, electrolyte imbalance or overactive thyroid.
Exercise
There is a form of tachycardia that has been linked to exercise, known as exercise-linked ventricular tachycardia. This causes very rapid and irregular heartbeats during exercise, which may increase the risk of heart attack or dying. However, according to a study presented at the American Heart Association's annual Scientific Sessions in Orlando in 2009, no such adverse effects were found in subjects who had no previous history of heart disease. If you have a history of heart disease, consult your doctor before starting an exercise program.
