Figure 1. Heterogeneities in the appearance of the epicardial action potential second upstroke gives rise to fractionated epicardial electrogram (EG) activity in the setting of Brugada syndrome (BrS).
Left panel: Shown are right precordial lead recordings, unipolar and bipolar EGs recorded form the right ventricular outflow tract of a BrS patient (from Nademanee et al. (11), with permission). Right panel: ECG, action potentials from endocardium (Endo) and two epicardial (Epi) sites, and a bipolar epicardial EG (Bipolar EG) all simultaneously recorded from a coronary-perfused right ventricular wedge preparation treated with NS5806 (5 μM) and verapamil (2 μM) to induce the Brugada phenotype. Basic cycle length=1000 ms.