Relationship Between Ventricular Arrhythmias, Conduction Disorders, and Myocardial Fibrosis in Patients With Systemic Sclerosis.

BACKGROUND

Delayed-enhancement magnetic resonance imaging (DE-MRI) is a noninvasive diagnostic tool able to identify myocardial fibrosis. In patients with scleroderma, its relationship with arrhythmias and conduction disorders has not been fully explored.

OBJECTIVES

The aim of this study was to evaluate the possible correlations between ventricular arrhythmias, conduction disorders, and myocardial fibrosis in patients with systemic sclerosis.

METHODS

Thirty-six patients with diffuse or limited cutaneous scleroderma underwent 12-lead electrocardiogram (ECG), 24-hour Holter ECG monitoring, transthoracic echocardiography, and cardiac DE-MRI, with gadolinium administration in 33 patients.

RESULTS

High-quality DE-MRI scans were obtained in 30 patients. Myocardial fibrosis was detected in 25 patients (83.3%). Eighteen patients (60%) had ventricular arrhythmias or conduction disorders. There was no significant difference in ventricular arrhythmia burden (the total number of premature ventricular contractions [PVCs]/24 hours) (48 ± 304 vs. 69 ± 236, P = 0.97), ventricular arrhythmia severity (couplets, triplets, runs) on Holter ECG, or in the presence of conduction disorders (36% vs. 40%, P = 0.86) between patients with and without myocardial fibrosis. In univariate analysis, diffuse fibrosis was weakly associated with the number of PVCs/24 hours (R = 0.157, P = 0.03). A number of at least 597 PVCs/24 hours had a sensitivity of 60% and a specificity of 92% in predicting the presence of diffuse fibrosis on DE-MRI (area under the curve = 0.640).

CONCLUSIONS

Delayed-enhancement magnetic resonance imaging can identify myocardial fibrosis in a high percentage of scleroderma patients. Its presence does not seem to influence the ventricular arrhythmia burden and severity or the presence of conduction disorders, with the exception of diffuse myocardial fibrosis, which modestly influences the total number of PVCs/24 hours.