Aims: Premature ventricular contractions (PVCs) in paediatric patients often present a benign course. However, a minority of patients may develop left ventricular (LV) dysfunction, and risk factors are still under debate. The aim of this systematic review and meta-analysis was to analyse the prevalence of PVC-induced cardiomyopathy (CMP) and understand the risk factors in paediatric patients with PVCs and structurally normal hearts. Methods and results: A systematic search strategy was performed to identify original reports published between 1 January 2000 and 31 August 2024. Studies including adult patients and patients with cardiomyopathies, congenital heart diseases, or channelopathies were excluded. Seventeen studies were included and comprised 1.701 patients, with a mean age of 11.4 years. The mean burden of PVCs across the included studies was 16% (12.2–19.7). Left ventricular systolic dysfunction occurred in 40 patients, and they showed older age at presentation. Premature ventricular contraction burden emerged as significant risk factor for PVC-induced CMP (mean burden among patients with and without LV dysfunction 32.5 and 15.47%, respectively). Shorter coupling intervals and longer QRS duration were predictors in a few studies. No major adverse cardiovascular events occurred. Left ventricular dysfunction recovered in all but one patient after spontaneous or pharmacologically induced PVC reduction. Class IC drugs showed greater efficacy than other drugs. Conclusion: Premature ventricular contraction–induced CMP is rare in children, and PVC burden is the key determinant of risk. The threshold burden associated with LV dysfunction is higher in paediatric patients than in adults. Most patients with PVC-induced CMP experience normalization of LV function during follow-up.

Background/Objectives: Transcatheter ablation assisted by three-dimensional (3D) electroanatomical mapping (EAM) is the elective treatment for atrioventricular nodal reentrant tachycardia (AVNRT) in children and adolescents. In this population of patients, the most frequently employed EAM strategies are the low-voltage bridge (LVB) strategy and sinus rhythm propagation mapping (SRPM). However, the exact pathophysiology and anatomy of the AVNRT reentrant circuits are still poorly understood. The aim of this study was to investigate the relationship between SRPM and LVB and to shed light on nodal physiology in children and adolescents affected by AVNRT. Methods: We retrospectively collected data on pediatric patients who underwent cryoablation for AVNRT assisted by high-density 3D EAM by using the LVB strategy; maps were reviewed by two independent electrophysiologists and the SRPM was described. SRPM was defined as typical when only one collision area was identified and atypical whenever either no or ≥ two collision areas were localized. Results: Twenty-eight consecutive patients (11.3 ± 3.3 years) were enrolled. All procedures were acutely successful. Overall, atypical SRPM was present in 10 patients (35.7%), and it did not correlate with the presence of multiple SPs or electrophysiological data. Moreover, we observed an imperfect concordance between SRPM and LVB (only in 10/18 patients). When SRPM and LVB were assessed in different locations, the LVB identified the effective cryoablation site in more cases than SRPM (4/8 vs. 1/8). Lastly, in cases of double collision, one collision area co-localized with the LVB and the effective cryoablation spot, whereas the other was located superiorly, closer to the His bundle. Conclusions: Atypical sinus rhythm propagation in the Koch’s triangle is a frequent finding in pediatric AVNRT patients. In this series, LVB showed closer concordance with the successful cryolesion site than retrospectively reconstructed SRPM.