Case Presentation
A 55-year-old male patient with a DDD-pacemaker for complete AV-block
after septal ablation for hypertrophic obstructive cardiomyopathy
presented with symptomatic non-sustained ventricular tachycardia (VT) at
a rate of 166 bpm. The patient carried a right-sided transvenous
DDD-pacemaker (right atrial lead: Intermedics 432-04; right ventricular
lead: Intermedics 430-10). He was completely pacemaker dependent without
ventricular escape rhythms. Due to multiple non-sustained VT an upgrade
to a dual-chamber ICD was indicated. We decided to perform a left-sided
de-novo DDD-ICD implantation and to deactivate the right-sided atrial
and ventricular lead which were 21 years old.
An integrated bipolar ICD lead (Boston Scientific 0181) was placed in
the right ventricular apex via the left axillary vein paying attention
to maintain an adequate distance to the old ventricular lead. A new
atrial lead (Boston Scientific 7741) was inserted into the right atrial
appendage. The atrial and the ventricular defibrillator lead were
connected to the new DF1-generator (Boston Scientific D143 Inogen).
Shortly after explantation of the old pacemaker generator, complete
heart block occurred. The old pacemaker battery was quickly reconnected
to reestablish pacing and to assess the situation. What is the mechanism
of ventricular pacing inhibition, and what is the best solution? [Fig.
1, Fig. 2]