Supraventricular tachycardia (SVT) causes an abnormal heart rhythm. During an episode of supraventricular tachycardia (SVT), the heartbeat is not controlled by the sinoatrial (SA) node (the normal timer of the heart). Another part of the heart overrides this timer with faster impulses. The source or trigger of the impulse in an SVT is somewhere …
https://patient.info/heart-health/palpitations-leaflet/supraventricular-tachycardia

