A model study of the effects of sodium conductance changes on the inducibility of cardiac reentrant activity

摘要

A decrease in sodium channel conductance has been traditionally associated with a reduction in the tissue excitability, and hence has been hypothesized to have an antiarrhythmic effect. Recently Starmer has proposed reduction in sodium conductance was not anti-arrhythmic but rather would increase the vulnerable period and hence would be proarrhythmic. We used a sophisticated model of cardiac tissue to examine this possibility. Our results support Starmer's hypothesis. Reducing sodium conductance by a factor of 35% increased the vulnerable period by roughly 30%, and a decrease to 50% increased the vulnerable period by approximately 45%.