1. From the Arrhythmia Clinical Unit of Heart Institute (InCor) (M.I.S., C.F.P., S.L., D.H., F.D., C.H., E.S.); Post-Graduate Course of the Cardiology and Pneumology Department (A.C.V.); and Experimental Laboratory (E.P.) and Laboratory of Pathology (V.D.A.), Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil, and Department of Medicine and Biomedical Engineering, University of Virginia Medical School, Charlottesville, VA (S.M.).