Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inheritable heart muscle disease that predominantly affects the right ventricle (RV) and predisposes to ventricular arrhythmias and sudden cardiac death (SCD).1–17 In the last three decades, there have been a significant number of studies defining the pathogenesis, genetic aspects, and clinical manifestations of the disease (See ‘Etiology, pathogenesis, diagnosis and natural history’ in the online-only Data Supplement). In 1994 and 2010, an International Task Force (ITF) document proposed guidelines for the standardized diagnosis of ARVC/D based on electrocardiographic (ECG), arrhythmic, morphological, histopathologic, and clinico-genetic factors.18,19 The growing knowledge regarding arrhythmic outcome, risk factors, and life-saving therapeutic interventions, make it particularly timely to critically address and place into perspective the issues relevant to the clinical management of ARVC/D patients. The present ITF consensus statement is a comprehensive overview of currently used risk stratification algorithms and approaches to therapy, either pharmacological or nonpharmacological, which often poses a clinical challenge to cardiovascular specialists and other practitioners, particularly those infrequently engaged in the management of ARVC/D. This document should be regarded as a guide to clinical practice where rigorous evidence is still lacking, because of the relatively low disease prevalence and the absence of controlled studies. Recommendations are based on available data derived from nonrandomized and observational studies and consensus within the conference panellists. When development of prognostic-therapeutic algorithms was controversial, management decisions were recommended to be individualized. Recommendation and level of evidence of specific management options were classified according to predefined scales, as outlined in Tables 1 and 2 (http://www.escardio.org/guidelines-surveys/esc-guidelines/about/Pages/rules-writing.aspx). Because randomized studies are not available, most consensus recommendations on treatment of ARVC/D are based on data derived from follow-up registries and/or experts opinions (ie, level of evidence B or C). View this table: Table 1. Classes of Recommendations View this table: Table 2. Levels of Evidence All members of …

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.6% reduction of ICD placements with the same proportion of protected patients (P < 0.001). Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).

Aims Magnetic resonance imaging (MRI) is well established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. In this study, heating effects at the myocardium–pacemaker lead tip interface have been investigated in a chronic animal model during MRI at 1.5 Tesla. Methods and results Pacemaker leads with additional thermocouple wires as temperature sensors were implanted in nine animals. Temperature increases of up to 20°C were measured during MRI of the heart. Significant impedance and minor stimulation threshold changes could be seen. However, pathology and histology could not clearly demonstrate heat-induced damage. Conclusions MRI may produce considerable heating at the lead tip. Changes of pacing parameters due to MRI could be seen in chronic experiments. Potential risk of tissue damage cannot be excluded even though no reproducible alterations at the histological level could be found.

Short QT syndrome (SQTS) is a genetically determined ion-channel disorder, which may cause malignant tachyarrhythmias and sudden cardiac death. Thus far, mutations in five different genes encoding potassium and calcium channel subunits have been reported. We present, for the first time, a novel loss-of-function mutation coding for an L-type calcium channel subunit. The electrocardiogram of the affected member of a single family revealed a QT interval of 317 ms (QTc 329 ms) with tall, narrow, and symmetrical T-waves. Invasive electrophysiological testing showed short ventricular refractory periods and increased vulnerability to induce ventricular fibrillation. DNA screening of the patient identified no mutation in previously known SQTS genes; however, a new variant at a heterozygous state was identified in the CACNA2D1 gene (nucleotide c.2264G > C; amino acid p.Ser755Thr), coding for the Ca_vα₂δ-1 subunit of the L-type calcium channel. The pathogenic role of the p.Ser755Thr variant of the CACNA2D1 gene was analysed by using co-expression of the two other L-type calcium channel subunits, Ca_v1.2α1 and Ca_vβ_2b, in HEK-293 cells. Barium currents (I_Ba) were recorded in these cells under voltage-clamp conditions using the whole-cell configuration. Co-expression of the p.Ser755Thr Ca_vα₂δ-1 subunit strongly reduced the I_Ba by more than 70% when compared with the co-expression of the wild-type (WT) variant. Protein expression of the three subunits was verified by performing western blots of total lysates and cell membrane fractions of HEK-293 cells. The p.Ser755Thr variant of the Ca_vα₂δ-1 subunit was expressed at a similar level compared with the WT subunit in both fractions. Since the mutant Ca_vα₂δ-1 subunit did not modify the expression of the pore-forming subunit of the L-type calcium channel, Ca_v1.2α1, it suggests that single channel biophysical properties of the L-type channel are altered by this variant. In the present study, we report the first pathogenic mutation in the CACNA2D1 gene in humans, which causes a new variant of SQTS. It remains to be determined whether mutations in this gene lead to other manifestations of the J-wave syndrome.