Loop recorder may detect cardiac conduction abnormalities in systemic sclerosis patients
Use of implantable loop recorder (ILR) in systemic sclerosis (SSc) patients with no known heart disease appears to aid incidental detection of cardiac conduction abnormalities (CCA), including serious cardiac arrhythmias and related cardiovascular magnetic resonance (CMR) anomalies, according to a study presented at the European League Against Rheumatism Annual Congress (EULAR) 2016.
Researchers enrolled 20 patients with SSc who had no diabetes and/or more than one cardiovascular (CV) risk factors to test whether ILR would help determine the spectrum of CCA in this patient population. ILR data were downloaded thrice monthly or at patient’s request if indicated. One-year CMR data were evaluated against 30 healthy controls. [Ann Rheum Dis 2016;75:S267]
ILR data were obtained from 19 patients (63 percent female; 84 percent Caucasian; mean age 53 years; time from first non-Raynaud’s phenomenon symptom 9 years). Of these patients, 10 (52 percent) had ILR abnormalities, including 4 with diffuse cutaneous SSc (dcSSc), 3 with anti-centromere antibodies (ACA+ve), 3 with Scl70+ve, 6 with palpitations hx, 4 with known interstitial lung disease, and 3 with DU hx.
In a subanalysis, 8 patients had supraventricular ectopics (SVE), 2 with ventricular ectopics (VE), 4 with arrhythmias of which 1 was atrial flutter, 1 with supraventricular tachycardia (SVT), 1 with ventricular tachycardia (VT), and 1 with complete heart block (CHB).
Of those with arrhythmias, 2 had dcSSc, 1 had ACA+ve, 1 had Scl70, 3 had palpitations hx, 2 had known ILD, and 2 had DU hx. The patient with CHB had few SVE/VEs and 3 couplets on 24-hour ECG 6 weeks prior.
CMR data on 15 SSc patients showed a trend toward lower LV mass and distensibility (greater arterial stiffness) and higher extracellular volume (ECV, fibrosis marker) in patients with ILR abnormalities compared to those without (p>0.05). There was also a trend for higher ECV in patients with SVE [unadjusted mean difference [uMD], 1.1; 95 percent CI, -2.5 to 4.7 percent), VE (uMD, 0.7; -4.9 to 6.3 percent), and arrhythmias (uMD, 1.8; -3.7 to 7.3 percent). ECV was higher in SSc than in controls (MD, 4.9; 3.2 to 6.6 percent; p<0.001; with trend for lower LV mass and distensibility).
The findings highlight the utility of ILR in the diagnosis of heart rhythm abnormalities in SSc patients with no known cardiac disease. In addition, they support the need for identification of high-risk patients that would benefit from ILR and provide insights into the pathogenesis of SSc cardiomyopathy, researchers said.
SSc is an autoimmune rheumatic disease that has an adverse influence on multiple organs, including the heart. It may impair the conduction system responsible for regulating the heartbeat and stimulating the heart muscle, heart valves, and/or the external lining of the heart. SSc patients are believed to be at high risk of heart problems without clinical symptoms or signs. [World J Cardiol 2016;6:993-1005]