PO85 - Scar Burden in Cardiac Sarcoidosis Presenting With Malignant Ventricular Arrhythmias
Jenna Davison (United States)1 2; Selene Rubino (United States)1 3; Emma Johns (United States)1 2; Andrew Rosenbaum (United States)4 3; Courtney Arment (United States)1 3; Konstantinos Siontis (United States)4 3;
1 - Mayo Clinic Rochester Division of Rheumatology; 2 - Mayo Clinic Rochester Department of Internal Medicine; 3 - Mayo Clinic Rochester; 4 - Mayo Clinic Rochester Division of Cardiology;
Keywords: arrhythmia; scar; PET-CT;
Select the theme: Cardiac Sarcoidosis
Type: Original Papers
Presentation: Poster Presentation

Introduction: Risk stratification for implantable cardioverter-defibrillator (ICD) placement has historically relied on left ventricular ejection fraction (LVEF), though newer guidelines incorporate myocardial scar. In cardiac sarcoidosis (CS), malignant ventricular arrhythmias may occur before structural abnormalities are evident. This study examines clinical and imaging features of patients presenting with malignant ventricular arrhythmias as the initial manifestation of CS.

Objectives: Evaluate the clinical characteristics, imaging patterns, and outcomes of patients with CS who initially present with sustained ventricular tachycardia (VT) or cardiac arrest.

Materials and Methods: Retrospective review of 1,247 patients diagnosed with CS at a single center (1999-2025) using Japanese Circulation Society or Heart Rhythm Society criteria. Ninety-one patients presented with sustained VT or cardiac arrest at diagnosis. Clinical data, imaging findings, and outcomes were analyzed. Cardiac PET-CT patterns were categorized as active inflammation, mixed inflammation, or perfusion defect consistent with scar. Statistical analyses included ANOVA, Chi-square, and Fisher’s exact tests.

Results: Mean age was 57.2 years, mean LVEF 49.0%, and most patients had NYHA class II symptoms. Common presentations included dyspnea (60.4%), palpitations (45.1%), and syncope (17.6%); 4.4% presented with sudden cardiac arrest. PET-CT showed active inflammation in 49.5%, mixed inflammation in 24.2%, and scar in 26.4%. MRI identified late gadolinium enhancement in 26.2% (n=61). LVEF was lowest in the scar group (43.1%; p=0.003), while other clinical features were similar across groups. Nearly one-third of patients required rehospitalization despite relatively preserved EF.

Conclusions: Prior studies suggested that up to 77% of patients with malignant ventricular arrhythmia had myocardial scar; the prevalence in our study was 26%. Active or mixed inflammation was associated with a significantly higher EF compared to scar-based disease. Together, these findings highlight limitations of EF- and scar-based risk stratification. Earlier identification of inflammatory disease may explain the lower observed scar burden and underscores the need for improved risk stratification strategies in cardiac sarcoidosis.

Table 1 (Descriptive Statistics) and Table 2 (Hypothesis Testing)