ST-Segment Elevation and Fractionated Electrograms in Brugada Syndrome Patients Arise From the Same Structurally Abnormal Subepicardial RVOT Area but Have a Different Mechanism.
BACKGROUND
Brugada syndrome (BrS) is characterized by a typical ECG pattern. We aimed to determine the pathophysiologic basis of the ST-segment in the BrS-ECG with data from various epicardial and endocardial right ventricular activation mapping procedures in 6 BrS patients and in 5 non-BrS controls.


RESULTS
In 7 patients (2 BrS and 5 controls) with atrial fibrillation, an epicardial 8×6 electrode grid (interelectrode distance 1 mm) was placed epicardially on the right ventricular outflow tract (RVOT) before video-assisted thoracoscopic surgical pulmonary vein isolation. In 2 other BrS patients, endocardial, epicardial RV (CARTO), and body surface mapping was performed. In 2 additional BrS patients, we performed decremental preexcitation of the RVOT before endocardial RV mapping. During video-assisted thoracoscopic surgical pulmonary vein isolation and CARTO mapping, BrS patients (n=4) showed greater activation delay and more fractionated electrograms in the RVOT region than controls. Ajmaline administration increased the region with fractionated electrograms, as well as ST-segment elevation. Preexcitation of the RVOT (n=2) resulted in ECGs that supported the current-to-load mismatch hypothesis for ST-segment elevation. Body surface mapping showed that the area with ST-segment elevation anatomically correlated with the area of fractionated electrograms and activation delay at the RVOT epicardium.


CONCLUSIONS
ST-segment elevation and epicardial fractionation/conduction delay in BrS patients are most likely related to the same structural subepicardial abnormalities, but the mechanism is different. ST-segment elevation may be caused by current-to-load mismatch, whereas fractionated electrograms and conduction delay are expected to be caused by discontinuous conduction in the same area with abnormal myocardium.
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Judith N
JN
Ten Sande
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Ruben
R
Coronel
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Chantal E
CE
Conrath
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Antoine H G
AH
Driessen
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Joris R
JR
de Groot
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Hanno L
HL
Tan
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Koonlawee
K
Nademanee
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Arthur A M
AA
Wilde
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.).
Jacques M T
JM
de Bakker
From the Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam (J.N.t.S., R.C., C.E.C., A.H.G.D., J.R.d.G., H.L.T., A.A.M.W., J.M.T.d.B., P.F.H.M.v.D.); Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands (J.N.t.S., J.M.T.d.B.); L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Université Bordeaux Segalen, Bordeaux, France (R.C.); and Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.). p.f.vanDessel@amc.uva.nl j.n.tensande@amc.uva.nl.
Pascal F H M
PF
van Dessel
D000200:Action Potentials; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D018780:Body Surface Potential Mapping; D053840:Brugada Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D016022:Case-Control Studies; D017115:Catheter Ablation / Q000379:methods; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D004699:Endocardium / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011667:Pulmonary Veins / Q000503:physiopathology / Q000601:surgery; D020775:Thoracic Surgery, Video-Assisted; D016278:Ventricular Function, Right
Brugada syndrome; activation delay; electrophysiology; mpping