Feasibility and utility of intraoperative epicardial scar characterization during left ventricular assist device implantation

Abstract

Introduction: Ventricular arrhythmias (VA) after left ventricular assist device (LVAD) placement are associated with increased morbidity and mortality.We sought to assess epicardial voltage characteristics at the time of LVAD implantation and investigate relationships between scar burden and postimplant VA. Methods and Results: Consecutive patients underwent open chest epicardial electroanatomic mapping immediately before LVAD implantation. Areas of low voltage and sites with local abnormal potentials were identified. Patients were followed prospectively for postimplant VA and clinical outcomes. Between 2015 and 2017, 36 patients underwent high-density intraoperative epicardial voltage mapping; 15 had complete maps suitable for analysis. Mapping required a median of 11.8 (interquartile range [IQR], 8.5-12.7) minutes, with a median of 2650 (IQR, 2139-3191) points sampled per patient. Over a median follow-up of 311 (IQR, 168-469) postoperative days, four patients (27%) experienced sustained VA. Patients with postimplant VA were more likely to have had preimplant implantable cardioverter defibrillator shocks (100% vs 27%; P = 0.03), ventriculartachycardia storm (75% vs 9%; P = 0.03), and lower ejection fraction (13.5 vs 19.0%, P = 0.05). Patients with postimplant VA also had a significantly higher burden of epicardial low bipolar voltage points: 55.4% vs 24.9% of points were less than 0.5 mV (P = 0.01), and 88.9% vs 63.7% of points less than 1.5 mV (P = 0.004).Conclusions: Intraoperative high-density epicardial mapping during LVAD implantation is safe and efficient, facilitating characterization of a potentially arrhythmogenic substrate. An increased burden of the epicardial scar may be associated with a higher incidence of postimplant VA. The role of empiric

Open surgical ablation of ventricular tachycardia: Utility and feasibility of contemporary mapping and ablation tools

“…After epicardial access was achieved surgically, the opened chest cavity was filled with sterile lactated ringer's solution in order to minimize distortion within the impedance-based EAM while mapping, 12 and EAM was performed by the cardiac electrophysiologist by manually sweeping a multipolar mapping catheter (Livewire Steerable Duo-Deca or Advisor HD Grid, Abbott, or DecaNav, Biosense Webster) along the epicardial surface. Epicardial voltage maps were created in sinus rhythm, identifying low-amplitude electrograms using bipolar amplitude cut-offs of ,0.5 mV for dense scar and 0.5-1.0 mV as border zone tissue; 15 activation maps for late potential timing, as previously defined, 17 were also performed in sinus rhythm.…”

“…For these cases, surgical ablation (SurgAbl) has been performed as a bailout strategy, often in the context of previously attempted endocardial catheter ablation, or in conjunction with another planned cardiac surgery, such as left ventricular assist device (LVAD) implantation, following which subsequent epicardial access for ablation would be far more challenging. [10][11][12][13][14] However, in the absence of real-time electroanatomic mapping (EAM), guidance about location and extent of ablation is limited to visual identification of scarred regions by the surgeon or by preoperative data acquired in the electrophysiology (EP) laboratory or with cardiac imaging. The feasibility of performing surgical cryoablation guided by use of contemporary EAM has been demonstrated 12 ; however, cases reported to date have been limited in number and have not incorporated a technique with which to visualize cryoprobes, which are commonly used in open SurgAbl of arrhythmias, within the EAM, at the time of ablation.…”

Massive myocardial edema and inflow cannula obstruction due to epicardial surgical ventricular tachycardia cryoablation at time of left ventricular assist device implantation

“…Although there are a number of anecdotal reports of this approach, there are small case series that have been published. 4 , 5 , 6 , 7 …”

“…The final study 7 surgically examined epicardial mapping and ablation at the time of VAD implantation. This multicenter prospective cohort study involved 36 patients, of which 15 were included in the final analysis (11 were excluded as part of an early-phase/learning cohort, and a further 11 did not have analyzable maps).…”

Intraoperative ventricular tachycardia substrate mapping: What is old is new again

“…In the current edition of the Journal of Cardiac Electrophysiology , Moss et al present their experience with epicardial mapping during VAD implantation. In this retrospective study, the authors demonstrate that comprehensive epicardial mapping is feasible and rapid, though occasionally limited due to pericardial adhesions and the constraints of impedance‐based mapping in an open chest that can affect the 3‐D reconstruction of the electroanatomic map.…”