Substrate Characterization and Outcomes of Ventricular Tachycardia Ablation in Amyloid Cardiomyopathy: A Multicenter Study

MRI-Extracellular Volume Fraction Versus Histological Amyloid Load in Cardiac Amyloidosis: The Importance of T2 Mapping

BACKGROUND

Magnetic resonance imaging (MRI)-derived myocardial extracellular volume fraction (ECV) is elevated in the presence of fibrosis, amyloid deposition, inflammation, and edema. In patients with cardiac amyloidosis and prolonged T2 due to concomitant inflammation or edema, MRI-ECV may not correctly reflect histological amyloid load. The authors sought to determine whether MRI-ECV can accurately reflect histological amyloid load in 2 groups of patients with wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM), with and without T2 prolongation.

METHODS

This retrospective study included consecutive patients with ATTRwt-CM who underwent endomyocardial biopsy and cardiac MRI from March 2017 to October 2021 for initial evaluation of ATTRwt-CM. We measured MRI-ECV and T2, and evaluated correlation between MRI-ECV and amyloid load from endomyocardial biopsy by means of Pearson correlation analysis.

RESULTS

Of 44 patients (mean age, 75±6 years [SD]; 40 men), 24 showed T2 prolongation (T2≥50 milliseconds). All specimens obtained by endomyocardial biopsy were suitable for analysis. The interval between endomyocardial biopsy and cardiac MRI examination was a median of 3 days (interquartile range, 2-4). In the absence of T2 prolongation due to increased water content, MRI-ECV and amyloid load showed a moderately significant correlation (Spearman ρ=0.50, P=0.03). However, in the presence of T2 prolongation, there was no significant correlation between MRI-ECV and amyloid load (Spearman ρ=-0.05, P=0.83).

CONCLUSIONS

In patients with ATTRwt-CM and prolonged T2, MRI-ECV did not accurately reflect histological amyloid load. Our findings underscore the need for a multiparametric imaging approach, combining both ECV and T2 mapping, to better characterize myocardial tissue in patients with ATTRwt-CM, and further prospective research in larger and more diverse cohorts is needed to validate our results.

Epicardial ventricular arrhythmia ablation: a clinical consensus statement of the European Heart Rhythm Association of the European Society of Cardiology and the Heart Rhythm Society, the Asian Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society, and the Canadian Heart Rhythm Society

Epicardial access during electrophysiology procedures offers valuable insights and therapeutic options for managing ventricular arrhythmias (VAs). The current clinical consensus statement on epicardial VA ablation aims to provide clinicians with a comprehensive understanding of this complex clinical scenario. It offers structured advice and a systematic approach to patient management. Specific sections are devoted to anatomical considerations, criteria for epicardial access and mapping evaluation, methods of epicardial access, management of complications, training, and institutional requirements for epicardial VA ablation. This consensus is a joint effort of collaborating cardiac electrophysiology societies, including the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society, and the Canadian Heart Rhythm Society.

Sigmoid ventricular septum treated with endocardial ablation to improve left ventricular outflow: cases report

Background

Sigmoid Ventricular Septum (SVS) is a type of hypertrophic cardiomyopathy characterized by a reduced angle between the basal interventricular septum and the ascending aorta, and SVS can lead to dynamic Left Ventricular Outflow Tract obstruction (LVOTO) during hypercontractile states. Patients experiencing LVOTO may manifest symptoms such as angina, syncope, etc. Radiofrequency ablation (RFA) has been utilized to treat patients with hypertrophic obstructive cardiomyopathy, but there is no reports on its use in treating LVOTO resulting from SVS. Our report describes two cases of SVS treated with endocardial ablation to improve LVOTO.

Case report

Case 1: A 74-year-old female patient with angina and syncope was admitted to the hospital and diagnosed with SVS by transthoracic echocardiogram. The patient exhibited LVOTO and Systolic Anterior Motion (SAM) phenomena during the administration of the dobutamine stress test. After RFA was performed, the patient's symptoms significantly improved. Additionally, septum decreased from 16 to 13 mm after ten months, and the morphological changes associated with SVS also disappeared. Case 2: A 57-year-old female was admitted to the hospital due to recurrent chest pain after physical activity for more than four years. The transthoracic echocardiogram indicated that the patient met the diagnostic criteria for SVS, and LVOTO and SAM phenomenaoccurred following dobutamine stress test. The patient had significant improvement in symptoms after undergoing RFA treatment.

Conclusions

These two cases represent the first documented instances where dynamic LVOTO caused by SVS could be effectively managed through endocardial RFA.