Background—: Arrhythmic mitral valve prolapse (MVP) is characterized by myxomatous leaflets and left ventricular (LV) fibrosis of papillary muscles and inferobasal wall. We searched for morphofunctional abnormalities of the mitral valve that could explain a regional mechanical myocardial stretch. Methods and Results—: Thirty-six (27 female patients; median age: 44 years) arrhythmic MVP patients with LV late gadolinium enhancement on cardiac magnetic resonance and no or trivial mitral regurgitation, and 16 (6 female patients; median age: 40 years) MVP patients without LV late gadolinium enhancement were investigated by morphofunctional cardiac magnetic resonance. Mitral annulus disjunction (median: 4.8 versus 1.8 mm; P <0.001), end-systolic mitral annular diameters (median: 41.2 versus 31.5; P =0.004) and end-diastolic mitral annular diameters (median: 35.5 versus 31.5; P =0.042), prevalence of posterior systolic curling (34 [94%] versus 3 [19%]; P 1.5 (22 [61%] versus 4 [25%]; P =0.016) were higher in MVP patients with late gadolinium enhancement than in those without. A linear correlation was found between mitral annulus disjunction and curling ( R =0.85). A higher prevalence of auscultatory midsystolic click (26 [72%] versus 6 [38%]; P =0.018) was also noted. Histology of the mitral annulus showed a longer mitral annulus disjunction in 50 sudden death patients with MVP and LV fibrosis than in 20 patients without MVP (median: 3 versus 1.5 mm; P <0.001). Conclusions—: Mitral annulus disjunction is a constant feature of arrhythmic MVP with LV fibrosis. The excessive mobility of the leaflets caused by posterior systolic curling accounts for a mechanical stretch of the inferobasal wall and papillary muscles, eventually leading to myocardial hypertrophy and scarring. These mitral annulus abnormalities, together with auscultatory midsystolic click, may identify MVP patients who would need arrhythmic risk stratification.

Arrhythmogenic Cardiomyopathy (ACM) is a heredo-familial cardiac disease characterized by fibro-fatty myocardial replacement and increased risk of sudden cardiac death. The diagnosis of ACM can be challenging due to the lack of a single gold-standard test: for this reason, it is required to satisfy a combination of multiple criteria from different categories including ventricular morpho-functional abnormalities, repolarization and depolarization ECG changes, ventricular arrhythmias, tissue characterization findings and positive family history/molecular genetics. The first diagnostic criteria were published by an International Task Force (ITF) of experts in 1994 and revised in 2010 with the aim to increase sensitivity for early diagnosis. Limitations of the 2010 ITF criteria include the absence of specific criteria for left ventricle (LV) involvement and the limited role of cardiac magnetic resonance (CMR) as the use of the late gadolinium enhancement technique for tissue characterization was not considered. In 2020, new diagnostic criteria (“the Padua criteria”) were proposed. The traditional organization in six categories of major/minor criteria was maintained. The criteria for identifying the right ventricular involvement were modified and a specific set of criteria for identifying LV involvement was created. Depending on the combination of criteria for right and LV involvement, a diagnosis of classic (right dominant) ACM, biventricular ACM or left-dominant ACM is then made. The article reviews the rationale of the Padua criteria, summarizes the main modifications compared to the previous 2010 ITF criteria and provides three examples of the application of the Padua criteria in clinical practice.

Mitral valve prolapse (MVP) may be associated with ventricular arrhythmias (VA) even in the absence of significant valvular regurgitation. Curling, mitral annulus disjunction (MAD) and myocardial fibrosis (late gadolinium enhancement [LGE]) may account for arrhythmogenesis. This study investigated the determinants of VA in patients with MVP without significant regurgitation. This study included 108 patients with MVP (66 female; median age: 48 years) without valve regurgitation. All patients underwent 12-lead electrocardiography, 12-lead 24-hour electrocardiographic Holter monitoring, exercise stress test, and cardiac magnetic resonance. Patients were divided into 2 groups (arrhythmic and no-arrhythmic MVP), according to the presence of VA with a right bundle branch block pattern. The 62 patients (57%) with arrhythmic MVP showed: 1) higher MAD (median length: 6.0 vs 3.2 mm; P = 0.017); 2) higher prevalence of curling (79% vs 52%; P = 0.012); and 3) higher prevalence of left ventricular LGE (79% vs 52%; P = 0.012). Mediation analysis showed that curling had both a direct (P = 0.03) and indirect effect mediated by LGE (P = 0.04) on VA, whereas the association between MAD and VA was completely mediated by LGE. Patients with severe VA showed more pronounced morphofunctional alterations, in terms of MAD (7.0 vs 4.6 mm; P = 0.004) and presence and severity of curling (respectively, 91% vs 64%; P = 0.010; and 4 vs 3 mm; P = 0.004), compared to those without severe VA. In patients with MVP the occurrence of VA with right bundle branch block morphology is the expression of more severe morphologic, mechanical, and tissue alterations. Curling has both a direct and an indirect effect on VA.

Aims: Myocardial longitudinal strain (LS) by two-dimensional (2D) speckle-tracking echocardiography has a diagnostic and prognostic role in cardiac amyloidosis (CA). Typically, the apical segments of the left ventricle (LV) are less affected by LS abnormalities, a finding called relative apical sparing (RELAPS). Whether a variable burden of CA might explain the RELAPS remains unknown. We aimed to evaluate the extent, distribution, and deposition pattern of amyloid in autopsy hearts of CA patients and to correlate the histopathology findings with 2D echocardiography. Methods and results: This is a retrospective study of whole heart specimens of CA patients who died and underwent autopsy and 2D echocardiography. Amyloid burden quantification was assessed by histomorphometry in each segment at different LV levels. The LS analysis results were compared with the amyloid burden and the base-to-apex distribution. Histopathology investigation of 27 hearts with CA [immunoglobulin light chains (AL) 17 cases and transthyretin (ATTR) 10 cases] demonstrated an amyloid base-to-apex gradient. In 11 CA patients with 2D echocardiography, analysis of LS and histological amyloid burden allowed to identify different patterns: RELAPS (8 cases, 73%), with (2) or without (6) amyloid gradient, normal or mildly reduced LS with diffuse low amyloid (2, 18%), and severely reduced LS with diffuse high amyloid (1, 9%). Conclusion: The typical RELAPS pattern at echocardiography is not always explained by a base-to-apex gradient of amyloid burden at histopathology, suggesting that RELAPS might be an epiphenomenon of complex interactions among amyloid infiltration, myocardial structure, and adaptation.

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.