What is the clinical evidence from this study?

Study design: Other. Population: Scar-related ventricular tachycardia (n=41). Intervention: Parallel mapping algorithm (simultaneous multi-wavefront activation mapping). Primary outcome: Feasibility (proportion of patients in whom full protocol-compliant parallel mapping could be performed).

May 6, 2026Journal of Interventional Cardiac Electrophysiology0 citationsOpen Access

PARALLEL-VT: A pilot study of simultaneous multi-wavefront left ventricular mapping for identification of critical ablation sites

JSJakub SroubekCleveland Clinic MBMandeep BhargavaElectrophysiology KHKoji HiguchiCleveland Clinic

Key Result

Parallel multi-wavefront mapping for scar-related ventricular tachycardia ablation was feasible in 46.3% of patients, with protocol deviations primarily driven by incessant VT.

Structured PICO

Is parallel substrate mapping using multiple activation wavefronts feasible and safe for identifying ablation targets in adults with scar-related VT?

Population

41 adults undergoing scar-related ventricular tachycardia (VT) ablation. Per-protocol group (n=19): mean age 66 ± 10 years, 94.7% male, 94.7% ischemic heart disease.

Intervention

Endocardial and/or epicardial substrate parallel mapping using 2 distinct activation wavefronts (e.g., right ventricular and left ventricular pacing, 8 beats each) to identify slow-conducting regions for radiofrequency ablation.

Outcome

Feasibility, safety, and utility of the parallel mapping algorithmsafety

Parallel substrate mapping using multiple activation wavefronts is a feasible and safe novel algorithm for identifying ablation targets in patients with scar-related VT.

Limitations

Single-arm pilot study design without a control group
Under-representation of patients with non-ischemic cardiomyopathy
Small sample size of only 19 per-protocol treated patients
Heterogeneity of pacing protocols and myocardial substrates
Subjective adjudication of clinical relevance of induced VTs by operators
Arbitrary use of mechanical hemodynamic support based on operator perception

Abstract

BACKGROUND: Functional substrate mapping can identify ventricular tachycardia (VT) ablation targets. Multi-wavefront functional mapping can be laborious. In this study, we explored the feasibility, safety and utility of the new "parallel mapping" algorithm designed to streamline multi-wavefront activation mapping for VT. METHODS: This is a single center, prospective pilot study of adults undergoing scar-related VT ablation. Patients underwent endocardial and/or epicardial substrate parallel mapping using 2 distinct activation wavefronts (e.g. right ventricular RV and left ventricular LV pacing, 8 beats each). Slow-conducting regions were targeted for radiofrequency ablation. Short- and long-term outcomes were analyzed. RESULTS: Of the 41 ablation subjects, 19 (46.3%) underwent per-protocol parallel mapping. Protocol deviations mostly stemmed from incessant VT necessitating early ablation (n = 9, 40.9%). Most per-protocol treated subjects were male (n = 18, 94.7%) with a mean age of 66 ± 10 years and had a higher prevalence of ischemic heart disease compared to protocol deviations (94.7% vs. 54.6%, respectively, p = 0.005). Primary wavefront mapping was done during RV apical pacing. Secondary wavefront mapping chiefly relied on LV pacing (52.6%). The median procedure duration was 252 min (IQR 190-289). Adverse events occurred in 4 patients (21.1%; at most 1 event directly related to study protocol). In the first year of follow-up, seven (36.8%) individuals received appropriate ICD shocks and three (15.8%) patients died. In exploratory analyses, parallel mapping data appeared most informative in subjects with lateral wall scar. CONCLUSION: Parallel substrate mapping using multiple activation wavefronts is a novel, feasible and safe algorithm designed to identify ablation targets in patients with scar-related VT.

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