Reply to entcheva: The impact of T-tubules on action potential propagation in cardiac tissue

Since our observation that T-tubules can fail to propagate action potentials in diseased hearts (1), our studies have focused on understanding the consequences of these electrical defects for local Ca2+ release (2) and force production (3). More recently, we have started to explore the causes of electrical defects (4), focusing on the presence of electrical conduction failures, seemingly associated with a local drop in membrane excitability (5). The methodology developed through our work has allowed us to quantitatively assess T-tubular conductivity, thus permitting evaluation of the efficiency of passive spread of voltage changes across the cardiac cell. Although these passive electrical properties have been discussed in our article in some detail (4), the implications of the findings at the tissue level have been not been adequately explored.