Testing radiofrequency energy delivery and catheter entrapment in three left ventricular assist device models in mock circulation

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background The use of Left Ventricular Assist Devices (LVAD) as a bridge to heart transplantation (HTx) or as a destination therapy is increasing. Near half of the patients had ventricular arrhythmias (VA) in the first year of LVAD support. Ablation is common method for recurrent ventricular tachycardias in LVAD patients. Even there are many case reports about successful VT ablations in LVAD patients there is no report about consequences of RF energy delivery inside LVAD or ablation catheter contact – entrapment to the rotor of the LVAD. Method Mock circulation models were created for three mostly used LVAD models ( Figure 1) (HeartMate3, HeartMate2, HVAD) Sheep heart was located inside the mock circulation model and 4mm non-irrigated RF ablation catheter and RF generator used for RF energy delivery tissue ( sheep heart) , ostium, mid and rotor of the LVAD)(Figure 1). During RF delivery flow parameters of the LVAD systems were noted also external noncontact flow monitor located out flow canula of the LVAD. All LVADs out flows were tested for 24 hours after RF energy delivery for long term malfunction. Also RF ablation catheters were tested for mechanical and functional disfunctions after contact of the LVAD rotors. Results No malfunctions were observed during and after RF energy delivery inside the LVADs. Only LVAD flow parameters temporary decreased in HeartMate 3 when the catheters had a contact to the rotor of the LVAD. This phenomenon occurred irrespective of RF energy delivery status. There were no changes in HVAD and Heartmate 2. After 24 hours continuous testing of the flow of the LVADs any changes were not observed . Impedance changes were noticed during RF energy delivery. Impedance values were dropped when RF catheter moved from tissue to the ostium of the LVAD in all models. Small increases observed during contact to the rotor of the LVAD in HeartMate 3 ( Figure 2). No mechanical damage were observed on the tip of the catheters after contact to the rotors also RF lesion dimensions were compared before and after the contact and there were no differences. Conclusion RF energy delivery and catheter entrapment of the RF catheters to the rotors of the LVADs caused no changes in LVAD functioning in ex-vivo conditions in a mock circulation.