A disruption in the normal electrical impulses controlling the pumping action of the heart causes tachycardia, according to Mayo Clinic. Many different factors cause these disruptions and the related faster-than-normal resting heart rate of tachycardia.
Heart disease can damage the tissues of the heart and cause tachycardia, which is a condition characterized by a rested heart rate higher than the normal 60 to 100 beats per minute. Congenital defects can be present from birth that cause abnormalities in the pathways of the heart's electrical system. Congenital abnormalities and diseases can also play a role in the development of tachycardia, notes Mayo Clinic.
Certain lifestyle behaviors can contribute to tachycardia's development. Smoking cigarettes, consuming an excessive amount of alcohol, drinking beverages with a lot of caffeine and abusing illegal drugs such as cocaine can also bring on tachycardia, explains Mayo Clinic. Notably, a sudden influx of stress or being scared or frightened can cause symptoms of tachycardia.
Certain diseases can contribute to tachycardia, including hyperthyroidism and anemia, and tachycardia can be an accompanying symptom of fever in some illnesses. An imbalance in the body's electrolytes can cause tachycardia, and it is a side effect of some therapeutic medications, according to Mayo Clinic. Some instances of tachycardia are not understood in the medical community.