QRS-based assessment of myocardial damage and adverse events associated with cardiac sarcoidosis

Abstract

Background: Cardiac sarcoidosis (CS) generates myocardial scar and arrhythmogenic substrate. CS diagnosis according to the Japanese Ministry of Health and Welfare guidelines relies, among others, on cardiac magnetic resonance imaging with late gadolinium enhancement (CMR-LGE). However, access to CMR-LGE is limited. The electrocardiography-based Selvester QRS score has been validated for identifying myocardial scar in ischemic/nonischemic cardiomyopathy, but its efficacy has not been tested to evaluate CS.

Objective: The purpose of this study was to examine whether the QRS score can be applied to CS.

Methods: CS-associated myocardial scar was assessed by both CMR-LGE and QRS scoring in patients with extra-CS (n = 59).

Results: Of 59 patients, 35 (59%) were diagnosed with CS according to the Japanese Ministry of Health and Welfare guidelines. QRS-estimated scar mass positively correlated with that quantified by CMR-LGE (signal intensity ≥2SD above the reference; r = 0.68; P < .001). Receiver operating characteristic curves demonstrated optimal cutoffs of 9% CMR-LGE scar and 3-point QRS score to identify patients with CS. The areas under the curves of CMR-LGE and the QRS score were not significantly different (0.83 and 0.78, respectively; P = .27); both methods demonstrated similar diagnostic performance. A QRS score of ≥3 led to a higher incidence of CS-associated adverse events (death/fatal arrhythmia/heart failure hospitalization) than did a QRS score of <3 (35 ± 21 months of follow-up; P = .01). QRS score was an independent predictor of risk in multivariate analysis (P = .03).

Conclusion: The Selvester QRS scoring estimates CS-associated myocardial damage and identifies patients with CS equally well as CMR-LGE. A higher QRS score is also associated with an increased risk of life-threatening events in CS, indicating its potential use as a risk predictor.

Keywords: Cardiac magnetic resonance imaging; Cardiac sarcoidosis; Electrocardiography; Myocardial scar; Selvester QRS score.