Relationship Between Fragmented QRS And Electronic Substrate Abnormalities in Cardiac Sarcoidos Simon A. Castro, MD; Daniele Muser, MD; Erica Zado, PA; Rajeev K. Pathak, MD, PhD; Tatsuya Hayashi, MD; Fermin C. Garcia, MD; Mathew D. Hutchinson, MD; Gregory Supple, MD; David S. Frankel, MD; Michael P. Riley, MD, PhD; David Lin, MD; Robert Schaller, DO; Sanjay Dixit, MD; David J. Callans, MD; Pasquale Santangeli, MD, PhD; and Francis E. Marchlinski, MD. Electrophysiology Section, Division of Cardiology, Hospital of the University of Pennsylvania, Philadelphia, PA INTRODUCTION The presence and location of fQRS were correlated with low-voltage areas (LVA –bipolar voltage <1.5 mV and/or unipolar voltage <8.3 mV) and abnormal EGMs (late, fractionated and split potentials) at mapping according to a standard 16-segment LV model. Patients with fQRS showed a greater extent of LV involvement compared to those without fQRS (percentage of bipolar LVA 12.8±11.2% vs. 4.5±7.8%, p=0.025; percentage of unipolar LVA 34.3±18.9% vs. 18.2±11.5%, p=0.046). A significant association was found between fQRS and the presence of abnormal EGMs (number of segments with abnormal EGMs, 5.1±2.1 vs. 2.7±1.6 in patients with and without fQRS, respectively, p=0.012); (Figure 2). RESULTS Figure 3. example of a patient showing QRS fragmentation in the anterior and lateral leads and its correlation with inflammation (A), scar (B) and electroanatomical voltage abnormalities (C-F). A fragmented QRS complex (fQRS) on the electrocardiogram (ECG) is a marker of conduction delay from inhomogeneous myocardial activation due to presence of scar. We evaluated whether analysis of fQRS may be helpful to detect the presence and extent of endoardial electroanatomic voltage abnormalities in patients with cardiac sarcoidosis (CS). Fragmented QRS at pre-procedural ECG was detected in 15 (48%) patients and was more commonly observed in the inferior 12/15 (80%) followed by the anterior 7/15 (47%) and lateral 7/15 (47%) leads (Figure 1, 3). Figure 1. example of a patient showing QRS fragmentation in the inferior leads (top panel) and its correlate with scar on MRI (Bottom panel). Figure 2. Electroanatomic mapping characteristics according to presence of fQRS II III aVF METHODS Thirty-one consecutive patients with diagnosis of CS according to HRS criteria underwent high-density electroanatomic voltage mapping as part of VT ablation. Fragmented QRS on pre-procedural ECG was defined as an R’ wave, notching in the nadir of the S wave, or the presence of >1 R’ in at least two contiguous ECG leads when the QRS duration was <120 ms, or by >2 R’ or >2 notches in the R wave or nadir of S wave in at least two contiguous leads in the presence of a QRS duration >120 ms. CONCLUSIONS In patients with CS, presence of fQRS on ECG is associated with a greater extent of low-voltage and abnormal EGMs at endocardial voltage mapping. Figure 2 V1 V4 V2 V5 DISCLOSURES None pertinent to this study SOURCE OF FUNDING V3 V6 Supported in part by The Richard T. and Angela Clark Innovation Fund in Cardiac Electrophysiology and the F. Harlan Batrus Research Fund.