Monomorphic VT Non-Inducibility after Electrical Storm Ablation Reduces Mortality and Recurrences

Abstract

Background: Electrical storm (ES) is defined by clustering episodes of ventricular tachycardia (VT) and is associated with severe long-term outcomes. We sought to evaluate the prognostic impact of radiofrequency catheter ablation (RFCA) in ES as assessed by aggressive programmed ventricular stimulation (PVS). Methods: Single-center retrospective longitudinal study with 82 consecutive ES patients referred for RFCA with a median follow-up (IQR 25–75%) of 45.43 months (15–69.86). All-cause mortality and VT recurrences were assessed in relation to RFCA outcomes defined by 4-extrastimuli PVS: Class 1—no ventricular arrhythmia; Class 2—no sustained monomorphic VTs (mVT) inducible, but non-sustained mVTs, polymorphic VTs, or VF inducible; Class 3—clinical VT non-inducible, other sustained mVTs inducible; and Class 4—clinical VT inducible. Results: Class 1, Class 2, Class 3, and Class 4 were achieved in 56.1%, 13.4%, 23.2%, and 7.4% of cases, respectively. The combined outcome of Class 1 + Class 2 (no sustained monomorphic VT inducible) led to improved survival (log-rank p < 0.001) and reduced VT recurrence (log-rank p < 0.001). Residual monomorphic VT inducibility (HR 6.262 (95% CI: 2.165–18.108, p = 0.001), NYHA IV heart failure symptoms (HR 20.519 (95% CI: 1.623–259.345), p = 0.02)), and age (HR 1.009 (95% CI: 1.041–1.160), p = 0.001)) independently predicted death during follow-up. LVEF was not predictive of death (HR 1.003 (95% CI: 0.946–1.063) or recurrences (HR 0.988 (95% CI: 0.955–1.021)). Conclusions: Non-inducibility for sustained mVTs after aggressive PVS post-RFCA leads to improved survival in ES, independently of LVEF.

MSA-VT Score for Assessment of Long-Term Prognosis after Electrical Storm Ablation

“…Numerous factors have proven reliable in assessing periprocedural risk and anticipating prognosis after VT ablation (however not exclusively in ES) [ 4 , 8 , 10 , 11 , 13 , 14 , 19 , 30 , 31 ].…”

“…The MSA-VT score only partially shares prediction parameters with previously published algorithms: residually inducible SMVT after ablation (shared only with the post-ablation variant of I-VT) and NYHA III-IV at admission (shared with PAINESD and mRVA), which have been thoroughly evaluated in multiple previous papers and are known prognostic factors [ 10 , 11 , 19 , 36 ]. Notably, in our cohort, mortality was highest in patients with either residual SMVT and severe HF at admission (59.4% and 51.4% respectively) which is in line with outcomes reported in larger samples [ 10 , 11 , 36 ].…”

“…This retrospective study is based on a monocentric longitudinal analysis of baseline and post-procedural characteristics of consecutive ES patients, as described in previously published papers [ 19 , 20 ]. A minimum of three separate episodes of sustained ventricular monomorphic tachycardia (SMVT) treated by adequate ICD therapies in a 24 h interval refractory to medical antiarrhythmic (AAD) treatment and without reversible triggers [ 21 , 22 , 23 ].…”

“…If VTs were spontaneously or mechanically induced and hemodynamically tolerated, activation/entrainment was performed. After scar-dechanelling, programmed electrical stimulation (PES) was routinely performed with at least 2 drive cycle lengths (CLs) and 4 extra stimuli (ESx) (3 ESx in patients with severe HF symptoms at rest or extreme frailty) (at a minimum of 200 ms or until ventricular refractoriness) from two sites (medially and laterally to the scar) to test residual inducibility (as previously described [ 19 ]). If SMVTs (which were considered relevant if their cycle lengths (CLs) ≥ 250 ms) [ 27 ] were induced, scar reconnection was reassessed and the scar-dechannelling protocol was repeated.…”

Non-revascularized chronic total occlusions impact on substrate and post-ablation results in drug-refractory electrical storm

“…After elimination of CCEs, a programmed ventricular stimulation (PVS) was routinely performed with at least 2 drive cycle lengths (CLs) and 4 extra stimuli (ESx) [3 ESx in patients with heart failure (HF) symptoms at rest or extreme frailty] (at a minimum of 200 ms or until ventricular refractoriness was reached) from 2 sites of the BZ area (usually medially and laterally to the scar) to assess for VT inducibility [as previously described ( 14 )]. PVS could not be performed in three patients (4.68% of the entire population, all of them without NR-CTOs).…”