Prevalence of 18F-fluorodeoxyglucose positron emission tomography abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy

Abstract

Background Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a heritable heart muscle disease that causes sudden cardiac death in the young. Inflammatory myocardial infiltrates have been described at autopsy and on biopsy, but there are few data on the presence of myocarditis in living patients with ARVC using non-invasive imaging techniques. FDG-PET is a validated technique for detecting myocardial inflammation in clinically suspected myocarditis. We aimed to determine the prevalence of myocardial inflammation in patients with ARVC using 18 Ffluorodeoxyglucose positron emission tomography (FDG-PET). Methods and Results We performed a retrospective analysis of a single centre cohort of patients with ARVC referred for FDG-PET scans between 2012 and 2017 for investigation of symptoms or suspected device infection. Sixteen patients (12 male; age 42±13 years) with a definite diagnosis of ARVC were identified. Seven had positive FDG-PET scans, two of whom had cardiac sarcoidosis on endomyocardial biopsy. Of the remaining five, two carried pathogenic desmoplakin mutations. FDG uptake was found in the left ventricular myocardium in all cases. One patient also had right ventricular uptake. Conclusion In this exploratory study, we show that some patients with ARVC have evidence for myocardial inflammation on FDG-PET, suggesting that myocarditis plays a role in disease pathogenesis.

Arrhythmogenic Cardiomyopathy: A Disease or Merely a Phenotype?

“…34-37 18 F-fluorodeoxyglucose PET can be positive in a subset of symptomatic AC patients, particularly in cases with left-dominant AC. 32 Cardiac MRI in AC often demonstrates patterns of subepicardial scarring with a predilection for the inferior and lateral walls of the LV, similar to that seen following myocarditis. [36][37][38] There are two studies showing raised cytokine levels in the blood of patients compared to controls.…”

“…30,31 The subepicardial distribution of the typical AC lesions is very similar to that reported in myocarditis, and on occasion, patients with AC seek medical attention with symptoms of chest pain and palpitations accompanied by electrocardiographic changes and cardiac biomarkers consistent with myocarditis. 32,33 These 'hot phases' can be the initial presentation of AC, sometimes preceding the development of classical ECG, imaging and histological features. 34-37 18 F-fluorodeoxyglucose PET can be positive in a subset of symptomatic AC patients, particularly in cases with left-dominant AC.…”

“…38,39 Cardiac sarcoidosis can show marked resemblance to genetic forms of AC, and the differential diagnosis is sometimes only made at a histological level. 32 Furthermore, a link at the molecular level is also present, as both giant cell myocarditis and sarcoidosis exhibit a similar pattern of reduced plakoglobin staining in the absence of any mutations in the desmosomal genes. 38 Finally, there is recent evidence of cardiac autoimmunity in a study of AC reporting anti-desmoglein antibodies associated with the extent of the disease.…”

“…As mentioned previously, myocardial inflammation is an important component of the AC spectrum. 32,46 Identification of specific forms of inflammation, such as sarcoidosis, can be challenging, as a definite diagnosis can be reached only by endomyocardial biopsy, but is critical as it can dictate further management with corticosteroid therapy and long-term immunosuppression. [47][48][49] The effects of anti-inflammatory therapy in gene-positive individuals presenting with a 'hot phase'…”

Cardiac sarcoidosis: diagnosis and management

“…Left ventricle scar on CMR points to ICS, while solely RV fibrosis points to ARVC, although both of these clues are not pathognomonic (Macias et al, 2014). The FDG-PET CT scan may test positive in ARVC as well as in ICS, as shown by Protonotarios et al (Protonotarios et al, 2019). Hoogendoorn et al applied electroanatomical voltage mapping in order to characterize RV scar characteristics and distribution in ICS and ARVC.…”