does valacyclovir cause tachycardia
1 Ventricular tachycardia. 2  Ventricular tachycardia is a rapid heart rate that originates with abnormal electrical signals in the ventricles. 3  The rapid heart rate doesn't allow the ventricles to fill and contract efficiently to pump enough blood to the body.achycardia is caused by something that disrupts the normal electrical impulses that control the rate of your heart's pumping action. Many things can cause or contribute to problems with the heart's electrical system. These factors include: