The two wide QRS complexes (after the 1 mV marker) constitute a ventricular couplet
1 mV: Standardization marker indicates 10 mm deflection for 1 mV. 25 mm/s above that is the tracing speed.
A couple of premature beats originating from the ventricles, occurring in a sequence with no intervening normal beats is called a ventricular couplet. Couplets indicate a higher degree of irritability of the ventricles than isolated ventricular premature beats and could be the fore runner of more severe arrhythmias like ventricular tachycardia in which several premature ventricular beats occur at a fast rate. Ventricular couplets stand out on the ECG as wide QRS complexes occurring in consecutive pairs.