What are the symptoms of tachycardia? A racing, uncomfortable or irregular heartbeatFeeling short of breathFeeling lightheadedFaintingHaving a fast pulseChest pain In serious cases where tachycardia is left untreated, it can cause: Heart AttacksUnconsciousnessFatigue Damage to the heart muscle In rare cases, complications may include blood clots, stroke, heart failure and sudden death. Product Mentioned on…