Predictors of pacing-induced cardiomyopathy in patients undergoing AV nodal ablation: insights from a Delphi process and retrospective cohort study

Abstract Background Pacing-induced cardiomyopathy (PICM) is a recognised complication in patients undergoing ablate and pace therapy. Identifying patients at high risk for PICM can enable tailored therapy, such as upfront CRT (biventricular pacing or CSP) or adjustments to screening strategies and thresholds for CRT upgrade. However, there is an unmet need to identify clinical variables predicting PICM in this population. Purpose This study aimed to identify predictors of PICM in patients with ablate and pace therapy, using consensus-driven data from a Delphi process and validating findings in a retrospective cohort study. Methods A three-round Delphi process with 12 EP/CIED consultants and senior fellows identified potential PICM predictors. Experts proposed variables in Round 1, rated their relevance in Round 2, and reached consensus on prioritised variables for analysis in the final round, with facilitated discussion throughout. Data were collected from consecutive patients who underwent AV nodal ablation at Liverpool Heart and Chest Hospital between January 2019 and December 2024. Eligibility included patients with non-CRT devices undergoing AV nodal ablation. PICM diagnoses were adjudicated by two independent cardiologists, with a third consulted in case of disagreement. Variables identified in the univariable analysis were tested in a multivariable model to determine independent predictors of PICM. Results The Delphi process identified 17 candidate variables, with those perceived as having the highest importance for PICM risk including pre-ablation LVEF, intrinsic QRS duration, paced QRS duration, RV lead location, and comorbidities such as mitral valve regurgitation and ischaemic heart disease. For clinical validation, data on 658 patients who underwent AV nodal ablation between January 2015 and December 2019 were collected; of these, 323 (49%) with a median age of 75 (70-81) had a non-CRT device. Among these, 29 (9%) developed PICM over a median follow-up of 192 days (63-973). In multivariable analysis, four variables retained independent prognostic value for PICM: RV lead on the free wall (OR 5.20, 95% CI: 1.45–18.65, p = .011), intrinsic QRS duration (ms, OR 0.96, 95% CI: 0.92–0.997, p = .035), paced QRS duration (OR 1.05, 95% CI: 1.03–1.08, p < .001), and change in QRS duration (OR 0.94, 95% CI: 0.92–0.97, p < .001). Conclusion This study, guided by a Delphi process, identified independent predictors of PICM with strong discriminatory power in patients undergoing ablate and pace therapy. The identified predictors - RV lead position, intrinsic and paced QRS duration, and QRS duration difference - can support clinicians in early risk stratification and guide personalised pacing strategies to reduce PICM incidence. Further validation in larger multicentre cohorts is warranted to develop a comprehensive risk score for this population.Graphical Abstract