what are svt's of the heart
Atrial or Supraventricular Tachycardia (SVT) Atrial or Supraventricular tachycardia (SVT) is a fast heart rate that starts in the upper chambers of the heart. Some forms are called paroxysmal atrial tachycardia (PAT) or paroxysmal supraventricular tachycardia (PSVT). How it happens.