Tachycardia is a faster than normal heart rate. It occurs when an abnormality in the heart produces rapid electrical signals. In some cases, tachycardia can seriously disrupt normal heart function, increase the risk of stroke, or cause sudden cardiac arrest or death. When your heart’s rate is too rapid, it may not effectively pump blood to the rest of your body, depriving your organs and tissues of oxygen.
Symptoms of tachycardia include: dizziness, shortness of breath, lightheadedness, rapid pulse rate, heart palpitations, chest pain, and fainting. Causes of tachycardia include damage to heart tissues, abnormal electrical pathways in the heart present at birth, disease, high blood pressure, smoking, fever, too much alcohol, too much caffeine, side effects of medications, or overactive thyroid.
Tachycardia, Mayo Clinic (Mar. 8, 2018), https://www.mayoclinic.org/diseases-conditions/tachycardia/symptoms-causes/syc-20355127