Systemic sclerosis (SSc) myocarditis was found to occur more frequently in individuals with heart failure and a higher dyspnea class; SSc-myocarditis was also found to be associated with higher degrees of myocardial fibrosis, according to study results published in Rheumatology.

According to the researchers, a comprehensive description and distinctive representation of SSc myocarditis is currently lacking, but it is needed to accurately identify the disease in its early stages to initiate therapy. The objective of this study was to characterize specific features of SSc myocarditis and to evaluate the clinical, histologic, and prognostic features of SSc-myocarditis diagnosed with endomyocardial biopsy (EMB), as well as to compare these features with those of other EMB-proven virus-negative myocarditis (VNM).

In this retrospective analysis, the data of 3 cohorts of patients with EMB-proven myocarditis (n=12 with SSc-related VNM [SSc-VNM]; n=12 with isolated VMN [i-VNM]; n=10 with EMB-proven VNM associated with other systemic autoimmune diseases [a-VNM]) were examined. The 22 patients with i-VNM and a-VNM groups were considered controls.

The degree of myocardial fibrosis was assessed as a relative percentage and with a 0 to 3 fibrotic score (0: minimal [0%-10%]; 1: mild [10%-30%]; 2: moderate [30%-50%]; and 3: severe [≥50%]). Clinical data, clinical enzymes, echocardiogram, 24-hour echocardiogram Holter, and cardiac magnetic resonance were collected at baseline and follow-up. The majority of patients with SSc were women (91.7%). Dyspnea class was higher at presentation in patients with vs without SSc-VNM (P =.041), and heart failure was found only in patients with SSc (25%; P =.05). Patients with SSc-VNM had a higher percentage of myocardial fibrosis (44.8% [18.8%]) compared with patients with i-VNM and a-VNM (24.9 [10.3]% and 28.6 [16.5]%, respectively; compared with the other 2 groups, P =.019), and a higher fibrotic score (2.3; 1.2; and 1.4, respectively; P = .002).

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In patients with SSc, myocardial fibrosis was found to directly correlate with skin score (r=0.625; P =.03) and with the number of ventricular ectopic beats during a 24-hour period (measured using an electrocardiogram Holter; r=0.756; P =.01). All participants were treated with immunosuppressive agents after a myocarditis diagnosis. Patients who died vs survived during follow-up had higher degrees of myocardial fibrosis on EMB (52.2 [11.6]% vs 27.5 [12.9]%, respectively; P =.024), and higher fibrotic scores (2.83 [0.41] vs 1.4 [0.9], respectively; P <.001).

Limitations included the study’s retrospective nature, a small cohort, and clinical heterogeneity in patient selection. 

“[Systemic sclerosis]-myocarditis has unique clinical and histological features: it tends to present more frequently with [heart failure] and a higher [dyspnea] class and to show higher degrees of myocardial fibrosis on EMB compared with different EMB-proven myocarditis. These specific and distinctive features are paralleled by a worse cardiac prognosis,” the investigators concluded.

Reference

De Luca G, Campochiaro C, De Santis M, et al. Systemic sclerosis myocarditis has unique clinical, histological and prognostic features: a comparative histological analysis [published online January 28, 2020]. Rheumatology. doi:10.1093/rheumatology/kez658