55 ARE TWO PACEMAKERS BETTER THAN ONE? SYNCOPE WITHOUT PRODROMES IN A YOUNG PM-DEPENDENT SUBJECT: A CASE STUDY


 
 
 A 33-year-old woman was admitted to the ER of our hospital because of syncope without prodromes during her routine cycling training.
 The patient's clinical history is characterized by congenital heart disease, interventional and cardiac surgical procedures in 1992-2021: percutaneous aortic valve (AoV) reconstruction for severe aortic stenosis in bicuspid AoV; conservative surgical Ao valvuloplasty and mitral valve (MV) commissuroplasty; MV substitution surgery; surgical AoV and MV replacement; surgical iatrogenic IVD closure. Atrial fibrillation became chronic and, following repeated interventions, an iatrogenic AV block developed requiring pacemaker implantation. In Dec. 2019, a submuscular PM (epicardial leads) was implanted (Medtronic Adapta DDDRR programmed in VVIRR for permanent atrial fibrillation). 2 years later, a transvenous-lead PM was implanted (Biotronik Evity 8 SR-T VVI-RR MRI conditional) without extracting the Medtronic PM (re-programmed in “back-up” VVI 30 bpm).
 
 
 
 A conservative strategy was adopted by programming the Biotronik/endocardial device in VOO-R mode stimulation only, while waiting for the total discharge of the old (Medtronic/epicardial) device. An alternative strategy could have been the removal of the epicardial PM. PM follow-up was performed via “remote” control and clinical checks in our Congenital Heart Disease Center.
 The complex clinical history and the choice of up-grading to an endocardial device without removing the epicardial device, has caused a predictable condition that was overlooked.
 The entry into operation of the ERI VOO 65 bpm mode of the epicardial device, in addition to causing a physiological increase in the pacing threshold of the epicardial catheter itself, produced the inhibition of the endocardial device whenever there was a pacing capture failure of the epicardial system. This situation set asystole off and consequent patient's loss of consciousness.
 
 
 
  
