Figure 1.
A. Electrical heterogeneity in superior vena cava (SVC) sleeve preparation. A: Action potentials (APs) recorded in an SVC sleeve preparation at a basic cycle length (BCL) of 1000 ms. AP1 shows a relatively short action potential duration (APD) and no phase 4 depolarization, whereas APs 2 and 3 display a longer APD, smaller amplitude and phase 4 depolarization, more accentuated in AP3 than AP2. B: Picture of endocardial (Endo) and epicardial surface of a SVC sleeve. AP recordings were obtained from Endo surface.