56 year old man with a 10 year history of coronary artery disease. During the past year, frequent episodes of palpitation lasting from minutes to several hours. This ECG  was recorded in the emergency department during one of these episodes:

• Ventricular tachycardia with capture and fusion complexes
• Ventricular rate 136/min

Five QRS complexes are narrow and represent AV capture (C). The second QRS complex in the lead II strip is wide, taller than the other broad complexes and has a late peak. It is probably a fusion complex.

The presence of capture and fusion complexes indicates AV dissociation and strongly supports the diagnosis of ventricular tachycardia.

This ECG was recorded after the return of sinus rhythm (15 minutes after the first ECG. Notice that the QRS pattern is identical to that of the capture complexes in the first ECG: