Tachycardia is a condition where the heart beats abnormally fast, exceeding 100 beats per minute, with the most prominent symptom being an increased heart rate. This condition is often accompanied by a fluttering or pounding sensation in the chest (palpitations). Other common symptoms of tachycardia include chest pain, dizziness, shortness of breath, nausea, sudden weakness, a sensation of fainting, and low blood pressure. Emergency medical attention is particularly necessary in cases of fainting or the sensation of fainting.