Supraventricular tachycardia is a common type of arrhythmia. The traditional definition of supraventricular tachycardia is a tachycardia that originates above the branches of the Hitchcock’s bundle. With modern advances in electrophysiology, it is recognized that the refractory pathway involves the atria, the atrioventricular junction, the Hickory bundle, and the ventricles. The current broad definition of supraventricular tachycardia encompasses all tachycardias whose origins and conduction pathways are not limited to the ventricles, including: (1) Sinus tachyarrhythmias: physiologic sinus tachycardia, inappropriate sinus tachycardia, sinus nodal reentrant tachycardia (SNRT), and postural (upright) tachycardia syndrome; (2) Atrial tachycardia (AT): intra-atrial refractory tachycardia, atrial tachycardia triggered by ectopic arrhythmia increase or trigger mechanisms; (3) atrioventricular nodal reentrant tachycardia (AVNRT): slow-fast type, slow-slow type, fast-slow type, and left-sided variant slow-fast type; (4) atrioventricular reentrant tachycardia (AVRT): cis- or retrograde type; (5) Autorhythmic junctional tachycardia and nonparoxysmal junctional tachycardia. In contrast, paroxysmal supraventricular tachycardia in a narrow sense refers specifically to atrioventricular nodal refractory tachycardia and atrioventricular refractory tachycardia. If you have supraventricular tachycardia, you should seek medical attention and follow your doctor’s instructions.