SAT0200 Abnormal Cardiac SPECT/CT in Newly Diagnosed, Untreated Patients with Idiopathic Inflammatory Myopathies

Abstract

Background Knowledge of cardiac involvement in idiopathic inflammatory myopathies (IIM) is limited and a matter of debate with reported frequencies between 6% and 75%. Although clinically overt disease is rare, cardiac events are the major cause of death in IIM. No studies of the heart by SPECT/CT in newly diagnosed, untreated adults with IIM have been performed. Objectives To examine cardiac involvement in newly diagnosed, untreated patients with IIM by cardiac SPECT/CT imaging compared to a gender- and age- matched control group. Methods In a cross-sectional, single-centre study of 14 untreated patients newly diagnosed with IIM (polymyositis 7, dermatomyositis 4, cancer-associated myositis 2, immune-mediated necrotizing myopathy 1) and of 14 gender- and age- matched healthy controls. 99mtechnetium pyrophosphate (99mTc-PYP) SPECT/CT imaging was performed and cardiac 99mTc-PYP uptake was correlated to blood 99mTc-PYP uptake and weight-adjusted. Cardiac 99mTc-PYP uptake was reported in kBq/ml with the following ranges; low uptake (< 0 kBq/ml); normal uptake (0-12 kBq/ml); or high uptake (≥ 12 kBq/ml). Furthermore, disease activity was measured by Health Assessment Questionnaire (HAQ, range 0-3), myositis intention-to-treat activity index (MITAX, range 0-1), manual muscle test of 8 muscle groups (MMT8, range 0-80), serum levels of creatinine kinase (CK), C-reactive protein (CRP) and cardiac troponin I (TnI), a highly specific marker of myocardial injury. Also presence of circulating antinuclear antibodies (ANA) and myositis specific autoantibodies (MSA) was determined. Results The mean age of the patients was 59.5 years and 57% were women. Mean duration of disease symptoms was 2 years (range 0.1-10.1). At disease onset 14% had mild, 43% had moderate and 43% patients had severe or extremely severe myositis. At study entry mean HAQ was 1.2 (range 0.25 – 3), mean MITAX was 0.42 (range 0.17 -0.72), and mean MMT8 was 69 (range 52 – 80). Increased CRP levels was found in 6 (43%) patients and 12 (86%) had elevated levels of CK. ANA was found in 6 patients and 5 patients had one or more MSA. TnI was insignificantly increased in IIM compared to healthy controls (P < 0.05). Abnormal cardiac 99mTc-PYP uptake was observed in 7 (50%) patients and no controls (P = 0.002). Conclusions Heart involvement, as detected by the presence of abnormal cardiac 99mTc-PYP uptake on SPECT/CT imaging, is more prevalent in untreated IIM patients than in age- and gender- matched healthy controls. These findings support the notion that heart involvement in IIM patients is common and that a comprehensive heart evaluation in IIM patients at disease onset is warranted. Disclosure of Interest None Declared

Myositis-specific autoantibodies and QTc changes by ECG in idiopathic inflammatory myopathies

“…QTc duration reflects the ventricular repolarization period and a prolonged QTc indicates a slowed ventricular repolarization, which is linked to increased risk of ventricular arrhythmias and sudden death (9)(10)(11). We have shown longer mean QTc intervals and more frequently left ventricular diastolic dysfunction in a cohort of patients with PM/DM compared to healthy controls (HCs) (3). Presence of myositis-specific autoantibodies (MSAs) or myositis-associated autoantibodies (MAAs) was associated with diastolic dysfunction, although no relationship between any specific autoantibody and cardiac function was found, probably due to the low number of patients with each autoantibody.…”

“…The most common subgroups are polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), antisynthetase syndrome (ASS), and immune mediated necrotizing myopathy (IMNM) (2). IIM is characterized by multisystem involvement which is associated with a poor outcome (1,3). Heart involvement is a significant cause of death in patients with PM or DM, already in the first year after diagnosis of IIM, yet, cardiac symptoms are often subclinical and may be overlooked (3,4).…”

“…IIM is characterized by multisystem involvement which is associated with a poor outcome (1,3). Heart involvement is a significant cause of death in patients with PM or DM, already in the first year after diagnosis of IIM, yet, cardiac symptoms are often subclinical and may be overlooked (3,4).…”

Multimodality Screening For (Peri)Myocarditis In Newly Diagnosed Idiopathic Inflammatory Myopathies: A Cross-Sectional Study

“…CMR was the most useful diagnostic modality ( Fig. 2 ) [ 8 ]. Similarly, our finding that approximately a third of patients with a diagnosis of probable/definite (peri)myocarditis had abnormalities on parametric T1/T2-mapping in CMR, but not with conventional LGE on CMR, is in accordance with earlier reports [ 2, 30 ].…”

Diagnostic Approach to Cardiac Involvement in Idiopathic Inflammatory Myopathies

“…In recent years, the number of reports concerning heart involvement in IIMs have increased as more sensitive, invasive, or noninvasive techniques were used to detect this extra-skeletal muscular involvement. [3][4][5][6][7] A few observational studies based on objective evidence of diseased heart have demonstrated that the incidence for cardiac involvement approximately was 9% to 72%, and those patients with diseased heart had worse prognosis, and cardiac manifestation was a major cause of deaths. [8][9][10][11] Hence, early identification for cardiac involvement may help improve the management and clinical outcomes of these patients, but currently, the diagnostic strategy is lacking.…”