Introduction: A 56 year-old male patient was upgraded from a dual-chamber ICD to a Sorin CRT- D device (Sorin Paradigm SonR Tri-V 8970; leads: RA: Medtronic 4076, RV: Biotronik Linox S 65, LV: Sorin Celerity 2D, LV (V+): LV: Sorin Celerity 2D) in 03/2017. The patient was symptomatic with heart failure NYHA class III, LV–EF of 25% and had a history of ischemic heart disease, prior replacement of the aortic valve and the ascending aorta and simultaneous coronary artery bypass grafting in 2008. The patient classified as CRT non-responder. Heart failure progressed severely and led to implantation of a Left Ventricular Assist Device (LVAD) (Abbot Heart Mate III) in  02/2018. Last device interrogation preoperatively was unremarkable, although displacement of one of the two LV leads has to be noted on X-ray, shown in Figure 1.

Case Report: The anti- tachycardia therapies (ATT) were deactivated prior to surgery. First device interrogation 14 days after the operation revealed normal pacing threshold but RV Sensing of 0.42-8.89 mV. Furthermore 48 ventricular fibrillation (VF) episodes were registered. Lead and LVAD position after implantation are shown in Figure 2. An example of those episodes is demonstrated in Figure 3. This EGM strip clearly demonstrates RV oversensing (RVOS) with low amplitudes not visible in the ventricular EGM tracing at short cycle length and otherwise normal RV sensing. The first sensing test is depicted in Figure 4. Sensing tests were repeated with decreasing sensitivity and detection of RVOS stopped at a sensitivity of 0.6 mV. As the patient was at bed rest at first visit, permanent parameters were altered to a RV sensitivity of 0.6 mV from the standard of 0.4 mV while ATT remained deactivated. Event episodes would still be recorded in this Sorin device, so that the patient remained under telemetry until the next device interrogation. After mobilisation no further episodes showing RVOS were recorded. Settings remained as described above and ATT were reactivated.  

Discussion: To our knowledge, this is the first reported case of RVOS in a patient with a LVAD and a Sorin CRT. Interaction in form of telemetry problems have been reported before. Despite a large cohort of patients with LVAD followed-up in our clinic, a case of RVOS without lead failure has not yet been observed. Whether this is an anatomical problem of the pump position in relation to the RV lead or there is an electromagnetic interference remains unclear. This case could be solved quite easily by slightly decreasing sensitivity. If this procedure had not been possible and the sensitivity had to be increased significantly, testing with an appropriate safety margin regarding the sensitivity would have been an option. Nevertheless, in LVAD patients the need for ICD therapy remains unclear so that permanent deactivation could have been discussed with the patient as well as a repositioning of the RV lead.

Conclusion: Device interaction with LVAD can occur and may cause serious problems e.g. inadequate therapy administrations with the need of reprogramming or even reoperation.

Figure 1: Preoperative X-ray: Tri V CRT System with one dislodged LV lead (arrow).

 


  Figure 2: Postoperative X-ray: Unchanged lead positions, now Heart Mate III in situ (arrows)

 

Figure 3 EGM strip of RVOS (arrows) : A: Atrial EGM, V: Ventricular EGM.

Figure 4 EGM strip of Sensing test with RVOS (arrows): A: Atrial EGM, V: Ventricular EGM.