Pacing spikes following QRS complexes: What is the mechanism?

: The electrocardiogram (ECG) interpretation in patients with implantable cardioverter defibrillator (ICD) is often a puzzling problem. The difficulty of the device function evaluation further increases in the presence of unfamiliar timing cycles and additional functions. Authors present a special function of a Biotronik ICD devices called the thoracic impedance monitoring, and demonstrate its behavior in a patient with sinus rhythm, ventricular ectopic beats, and ventricular tachycardia episode. This report shows unexceptional occurrence of tricky ECG finding in patient with Biotronik ICD.