When dystrophia meets ischaemia

$\bf Background$ This case reviews the cardiac involvement of myotonic dystrophy type 2 in terms of ventricular arrhythmias (VAs) and individual myocardial scar formation as target for catheter ablation. $\textbf {Case summary}$ A 62-year-old woman with myotonic dystrophy type 2 and a severely reduced left ventricular ejection fraction (25%) presented with recurrent episodes of VAs and consecutive implantable cardioverter-defibrillator therapies. The patient already underwent two VA ablation attempts focusing on an ischaemia-related arrhythmia substrate in the left ventricle. The patient was scheduled for repeat ablation after the progression of coronary artery disease was ruled out. Interestingly bipolar voltage as well as activation mapping revealed an arrhythmia substrate along with the basal and inferior aspects of the right ventricle (RV). Catheter ablation of this scarred area in the RV resulted in specific termination of the VAs. Due to end-stage heart failure, key heart transplant criteria were met. The patient was evaluated for heart transplantation and added to the waiting list. Hitherto, no further VAs were documented during follow-up. $\bf Discussion$ As these patients present with specific dystrophia-related arrhythmia substrates, we propose pre-procedural visualization of dystrophy-associated arrhythmia substrates using cardiac magnetic resonance imaging allowing for personalized ablation approaches in these patients

Cardiovascular magnetic resonance imaging-based right atrial strain analysis of cardiac amyloidosis

$\bf Background:$ Cardiac amyloidosis (CA) manifests in a hypertrophic phenotype with a poor prognosis, making differentiation from hypertrophic cardiomyopathy (HCM) challenging and delaying early treatment. The extent to which magnetic resonance imaging (MRI) quantifies the right atrial strain (RAS) and strain rate (RASR), providing valuable diagnostic information, is not yet clinically established. $\bf Aims:$ This study assesses diagnostic differences in the longitudinal RAS and RASR between CA and HCM patients, control subjects (CTRL) and CA subtypes in addition to the impact of atrial fibrillation (AF) on the right atrial function in CA patients. The RAS and RASR of tricuspid regurgitation (TR) patients are used to assess the potential for diagnostic overlap. $\bf Methods:$ RAS and RASR quantification was conducted via MRI feature-tracking for biopsy-confirmed CA patients with subtypes identified. Strain parameters were compared for CTRL, HCM and TR patients. Post hoc testing identified intergroup differences. $\bf Results:$ In total, 41 CA patients were compared to 47 CTRL, 20 HCM and 31 TR patients. Reservoir (R), conduit and booster RAS and RASRs allow for significant differentiation ($\it p$ 0.8). CA patients with AF, in contrast to sinus rhythm, demonstrated a significantly impaired reservoir RAS and RASR and booster RASR. The discriminative power of RAS for CA vs. TR was insufficient (R: 10.6% $\pm$ 14.3% vs. 7.0% $\pm$ 6.0%, $\it p$ = 0.069). Differentiation between 21 transthyretin and 20 light-chain amyloidosis subtypes was not achievable (R: 0.7% $\pm$ 1.0% vs. 0.7% $\pm$ 1.0%, $\it p$ = 0.827). $\bf Conclusion:$ The MRI-derived RAS and RASR are impaired in CA patients and may support noninvasive differentiation between CA, HCM and CTRL