The rhythm is either sinus rhythm or not sinus rhythm. Sinus rhythm refers to the origination of the electrical activity coming from the sinus node — also known as the sinoatrial node, or SA node.

Ventricular tachycardia refers to a wide QRS complex heart rhythm — that is, a QRS duration beyond 120 milliseconds — originating in the ventricles at a rate of greater than 100 beats per minute.