How to Induce Pacemaker-Mediated Tachycardia?

Pacemakers are devices that are used worldwide for bradyarrhythmias. They are robust devices that function properly from implantation to depletion of battery. Rarely malfunctions appear, one of them being pacemaker-mediated tachycardia in patients implanted with double-chamber devices when retrograde ventriculoatrial conduction is present. Retrograde ventriculoatrial conduction can be present in up to 50–70% of normal patients. In patients with a normal heart, usually it does not manifest clinically. Even in the case of an advanced AV block, retrograde VA conduction can still be present. Patients implanted with a cardiac device like pacemakers or defibrillators can exhibit ventriculoatrial conduction: 14% of patients with complete AV block and up to 80% of patients with sinus node disease. In patients with double-chamber pacemakers or double-chamber defibrillators, using an atrial sensing mode can serve as a second AV pathway and support reentry: antegrade pathway through the pacemaker and retrograde pathway through the AV node.