Paroxysmal supraventricular tachycardia, in a narrow sense and in a broad sense. The broad sense refers to tachycardia that occurs above the ventricles due to an etiology. In the narrow sense, there are two types of supraventricular tachycardia: atrioventricular nodal tachycardia and atrioventricular tachycardia. The clinical term “supraventricular tachycardia” generally refers to the narrow sense of supraventricular tachycardia. Atrioventricular nodal tachycardia (AVNRT) is a tachycardia that occurs when the atrioventricular node has two or more fast or slow conduction pathways that cause regression. Multiple AV node conduction pathways may be present in normal subjects, but only under special circumstances can tachycardia occur. Atrioventricular reentrant tachycardia (AVRT) is caused by the presence of a bypass between the atria and ventricles in addition to the normal AV node conduction pathway, resulting in reentry. Depending on the parasternal pathway, this type can be divided into the following types: typical preexcitation syndrome (also known as dominant preexcitation, which means that the parasternal pathway has antegrade and usually also retrograde function; this can be confirmed by a general electrocardiogram), occult preexcitation syndrome (the atrioventricular parasternal pathway has only retrograde but not antegrade function, which is difficult to confirm by a general electrocardiogram and needs to be confirmed by esophageal pacing or electrophysiological examination), and persistent junctional tachycardia (PJRT, mostly persistent episodes, tolerated by some patients, but prone to tachycardia cardiomyopathy), tachycardia involving other specific conduction fibers.