LAUSR

In patients with non-ischemic cardiomyopathy (NICM), non-inducibility after catheter ablation has been associated with lower VT recurrence rates. We hypothesized that induced VT pleomorphism (PL-VT) may be indicative for a complex VT substrate that might be associated with poor ablation outcome independently of non-inducibility at the end of the procedure. Consecutive patients with left-dominant NICM undergoing VT ablation (2008–2018) were included. All patients underwent genetic screening. PL-VT was defined as occurrence of ≥1 morphologically distinct QRS lasting for ≥6 consecutive beats during the same induced VT episode. Complete acute success was defined as non-inducibility of any VT at the end of procedure. Eighty-five patients (56±15 yrs, LVEF 38±12%), inducible for 365 VTs (median 3/patient, IQR 1–6) were included. PL-VT was observed in 29 patients (34%). Patients with PL-VT had more often anteroseptal substrates, a higher number of induced VTs, and larger endocardial bipolar (<1.5 mV) and unipolar low voltage (<8.01 mV) areas. Pathogenic genetic mutations were more frequently recognized in patients with PL-VT than in those without (59 vs. 34%, P=0.03), but there was no significant correlation in each representative mutation (Lamin A/C, Phospholamban, or Titin). Complete acute success was achieved in 34 patients (40%) and comparable between patients with PL-VT and those without (41 vs. 39%, P=0.85). After a median of 24 months, 53 patients (62%) had VT recurrence and 23 (27%) died. In multivariate Cox regression analysis, PL-VT and inducibility of any VT were significantly associated with VT recurrence (HR 4.07, CI 1.82–8.92; P=0.001, HR 2.22, CI 1.10–4.78; P=0.026, respectively) independent of NYHA, LVEF, electrical storm, genetic mutations, low voltage area, substrate location, and number of induced VTs. Of importance, the co-existence of PL-VT and persistent VT inducibility identified those at highest risk for VT recurrence after 2-years. (PL-VT (−)/complete success, 27%, PL-VT (−)/non-complete success, 50%, PL-VT (+)/complete success, 58%, PL-VT (+)/non-complete success 94%, Log-rank P<0.001, see figure). Figure 1 Induced PL-VT was not associated with acute outcome but higher VT recurrence rate after catheter ablation in patients with NICM. Moreover, co-existence of PL-VT and persistent VT inducibility identifies patients at highest risk for VT recurrence whereas non-inducible patients without PL-VT have a favorable prognosis.