P593Hypereosinophilic carditis (HEC): a cmr-based case series from a quaternary cardiology centre

Abstract

Background: Hypereosinophilic syndrome is a rare group of disorders where eosinophil overproduction results in end organ damage. Heart involvement is common and is known as hypereosinophilic carditis (HEC). Stages include: (1) Acute phase - eosinophilic myocarditis; (2) Subacute phase - Loefflers endocarditis with mural endocardial thrombi (figure 1); (3) fibrotic phase - endomyocardial fibrosis, leading to restrictive cardiomyopathy. Objective: Data on HEC are limited and the role of CMR in diagnosis and management is unclear. We describe our single centre experience of diagnosis, management and follow-up of these patients. Methods: Searches of histopathology and CMR databases from 2012 to 2017 identified 18 patients with HEC. Each case was manually abstracted using a pre-defined case note abstraction form. Results: 9 (50%) were female and mean age at presentation was 53 (±4.6 years). Ethnicity included 10 White British, 1 Greek, 1 Pakistani, 1 Chinese and 5 Black British. The most frequent presenting symptom was shortness of breath (70.5%), followed by presyncope (22%) and syncope (11%). 3 (16.7%) cases had eosinophilic granulomatosis with polyangiitis and 1 (5.5%) had multiple myeloma. In the 10 patients where family history was documented, 0 reported a family history of cardiomyopathy or sudden death. Only 3 (16.7%) patients had an eosinophil count >1.5 of the upper limit of normal. ECG abnormalities included LBBB in 7 (28.9%). 2 (11%) had an out of hospital VT/VF arrest as the sentinel event. In-patient telemetry revealed sustained VT in 1 (5.5%). Holter monitoring was performed in 7 and 5 (71.4%) demonstrated episodes of non-sustained monomorphic VT. TTE revealed 6 (33.3%) with normal left ventricular ejection fraction (LVEF), 10 (55.5%) with moderately reduced LVEF and 4 (22.2%) with severely reduced LVEF. In all cases, HEC was diagnosed using CMR. 3 also had endomyocardial biopsy (EMB) - 2 confirmed HEC; the 3rd was non-diagnostic. CMR revealed late gadolinium enhancement (LGE) in a global and non-coronary distribution in 40% of all cases. The remaining cases had LGE predominanlty in the left ventricular apical, basal and inferolateral segments. 14 had ventricular thrombus (78%): 4 (28.5%) in the left ventricle, 2 (11.1%) in the right ventricle and 8 (44.4%) with biventricular involvement, not seen on TTE. Mortality at 1-year was 16.6% and at 3-years post-diagnosis was 38.8%. Patients who survived beyond 3-years from the initial evaluation were clinically stable with NYHA I-II symptoms. Only 2 (11.1%) required long-term immunosuppression with prednisolone. Conclusions: HEC is an often a fatal disease that requires prompt diagnosis and treatment, even in the absence of hypereosinophilia. EMB can be difficult to perform with high false negative rates and TTE is often non-diagnostic. CMR is a viable, non-invasive, alternative to EMB in the diagnosis of HEC and to monitor disease progression and treatment response.