Background and Aims: The prediction of the first major arrhythmic event (MAE) is still an unmet need in the recently defined scenario of non-dilated left ventricular cardiomyopathy (NDLVC). Methods: A cohort of 337 patients with NDLVC and no history of MAE was retrospectively identified at two large centres. Patient-tailored diagnostic workup included cardiac magnetic resonance (CMR), endomyocardial biopsy, and genetic testing. The primary endpoint was the occurrence of the first MAE, including sustained ventricular tachycardia (VT), ventricular fibrillation, or appropriate implantable cardioverter-defibrillator therapy, by 60-month follow-up. A pool of 216 NDLVC patients from 11 European centres served as a validation cohort. Results: In the study cohort (mean age 37 ± 15 years, 62% male), the mean left ventricular ejection fraction (LVEF) was 52 ± 8%, and 79% of patients had late gadolinium enhancement (LGE) at baseline CMR. By 60-month follow-up, 51 patients (15%) experienced a MAE. The primary endpoint was predicted by male sex [hazard ratio (HR) 2.4, 95% confidence interval (CI) 1.3–4.4, P = .007], baseline non-sustained VT (HR 3.1, 95% CI 1.7–5.6, P < .001), LVEF < 45% (HR 5.5, 95% CI 2.7–11.0, P < .001), septal (HR 2.0, 95% CI 1.0–4.0, P = .046) and ring-like pattern of LGE (HR 1.3, 95% CI .6–2.6, P = .54), pathogenic/likely pathogenic variants in guideline-defined high-risk genes (HR 4.6, 95% CI 2.3–9.1, P < .001), and biopsy/CMR-proven myocardial inflammation (HR 15.7, 95% CI 6.1–40.3, P < .001). The results were confirmed in the validation cohort (Uno’s C-index 0.81, 95% CI .75–.88). A novel risk score was subsequently derived. Conclusions: In NDLVC, male sex, non-sustained VT, LVEF < 45%, septal and ring-like LGE, high-risk genotypes, and myocardial inflammation predicted the first episode of MAE by 60 months.

Patients with cardiomyopathies and channelopathies are usually younger and have a predominantly arrhythmia-related prognosis; they have nearly normal life expectancy thanks to the protection against sudden cardiac death provided by the implantable cardioverter defibrillator (ICD). The subcutaneous ICD (S-ICD) is an effective alternative to the transvenous ICD and has evolved over the years. This study aimed to evaluate the rate of inappropriate shocks (IS), appropriate therapies, and device-related complications in patients with cardiomyopathies and channelopathies who underwent modern S-ICD implantation. We enrolled consecutive patients with cardiomyopathies and channelopathies who had undergone implantation of a modern S-ICD from January 2016 to December 2020 and who were followed up until December 2022. A total of 1338 S-ICD implantations were performed within the observation period. Of these patients, 628 had cardiomyopathies or channelopathies. The rate of IS at 12 months was 4.6% [95% confidence interval (CI): 2.8–6.9] in patients with cardiomyopathies and 1.1% (95% CI: 0.1–3.8) in patients with channelopathies (P = 0.032). No significant differences were noted over a median follow-up of 43 months [hazard ratio (HR): 0.76; 95% CI: 0.45–1.31; P = 0.351]. The rate of appropriate shocks at 12 months was 2.3% (95% CI: 1.1–4.1) in patients with cardiomyopathies and 2.1% (95% CI: 0.6–5.3) in patients with channelopathies (P = 1.0). The rate of device-related complications was 0.9% (95% CI: 0.3–2.3) and 3.2% (95% CI: 1.2–6.8), respectively (P = 0.074). No significant differences were noted over the entire follow-up. The need for pacing was low, occurring in 0.8% of patients. Modern S-ICDs may be a valuable alternative to transvenous ICDs in patients with cardiomyopathies and channelopathies. Our findings suggest that modern S-ICD therapy carries a low rate of IS. URL: http://clinicaltrials.gov/Identifier: NCT02275637.

Left ventricular non-compaction (LVNC) is a rare heart muscle disease defined by the presence of prominent left ventricular trabeculation, deep intertrabecular recesses, and a thin compact layer. Several hypotheses have been proposed regarding its pathogenesis, with the most recently accepted one being that compact layer and trabeculated layers develop independently according to an “allometric growth”. The current gold-standard diagnostic criteria (in particular, the Petersen index non-compaction/compaction ratio > 2.3) reflect an excess of myocardial trabeculation, which is not a specific morpho-functional feature of LVNC cardiomyopathy but merely a “phenotypic trait”, even described in association with other myocardial disease and over-loading conditions. Accordingly, the European Society of Cardiology (ESC) guidelines have definitively abolished the term ‘LVNC cardiomyopathy’. Recently, evolving perspectives led to the restoration of LVNC cardiomyopathy by distinguishing “hypertrabeculation phenotype” and “non-compaction phenotype”. It has been proposed that the disease-specific pathophysiologic mechanism is a congenitally underdevelopment of the compact layer accounting for an impairment of the left ventricular systolic function. Future prospective research should focus on the clinical and prognostic relevance of compact layer thinning rather than excessive trabeculation, which could significantly influence the management of patients with LVNC. The review aims to update current knowledge on the pathogenesis, genetics, and diagnostic criteria of LVNC, offering modern insights for future perspectives.

Transvenous lead extraction (TLE) is potentially complicated by significant tricuspid valve regurgitation increase (TRI). However, there are limited data on the effect of the bidirectional rotational mechanical sheaths on significant TRI. The aim of the present study was to investigate the rate of significant changes in tricuspid regurgitation (TR) severity following mechanical rotational TLE and their outcomes. In 158 patients (mean age 66 ± 16.9 years) undergoing mechanical rotational TLE, acute changes in TR severity were assessed by echocardiography evaluation. A significant acute TRI was defined as an increase of at least one grade with a post-extraction severity at least moderate. A total of 290 leads were extracted (mean implant duration, 93 ± 65 months). Significant TRI was noted in 5.7% of patients, and it was linked to tricuspid valve damage, TLE infection indication, and longer lead implant duration. Univariate predictors of significant TRI included implant duration of all leads [odds ratio (OR) 1.01; 95% confidence interval (CI) 1.003–1.018; P = 0.001] and right ventricular leads (OR 1.01; 95% CI 1.004–1.017; P = 0.002). Severe increase of TR following TLE was an independent predictor of mortality [hazard ratio (HR) 5.20; 95% CI 1.44–18.73; P = 0.012 ] along with severe systolic dysfunction (HR 2.37; 95% CI 1.01–5.20; P = 0.032), and systemic infection (HR 2.28; 95% CI 1.06–4.89; P = 0.035). Significant TRI was detected in 5.7% of patients following transvenous rotational mechanical lead extraction. The duration of lead implantation emerged as the sole predictor of significant TRI. Physicians engaged in TLE should exercise greater vigilance for this potential complication.

Long-term data on the potential advantages of combining the third-generation subcutaneous implantable cardioverter defibrillator (S-ICD) with modern software upgrade including the "SMART Pass", modern programming strategies and the intermuscular (IM) two-incision implantation technique in arrhythmogenic cardiomyopathy (ACM) with different phenotypic variants are lacking. In this study we evaluated the long-term outcome of patients with ACM who underwent third-generation S-ICD (Emblem, Boston Scientific) and IM two-incision technique. The study population included 23 consecutive patients [70% male, median age 31 (24-46) years] diagnosed with ACM with different phenotypic variants who received third-generation S-ICD implantation with the IM two-incision technique. During a median follow-up of 45.5 months [16-65], 4 patients (17.4%) received a at least one inappropriate shock (IS), with median annual event rate of 4.5%. Extra-cardiac oversensing (myopotential) during effort represented the only cause of IS. No IS due to T-wave oversensing (TWOS) were recorded. Only one patient (4.3%) experienced device-related complication consisting of premature cell battery depletion requiring device replacement. No device explantation because of need for anti-tachycardia pacing or ineffective therapy occurred. There was no significant difference between patients who did and did not experienced IS with regard to baseline clinical, ECG and technical characteristics. Five patients (21.7%) received appropriate shocks on ventricular arrythmias. According to our findings, although the third-generation S-ICD implanted with the IM two-incision technique appears to be associated with a low risk of complications and IS due to cardiac oversensing, the risk of IS due to myopotential mainly during effort should be considered.