11 research outputs found
Mechanoelectrical feedback regulates the arrhythmogenic activity of pulmonary veins
BACKGROUND: Atrial fibrillation is commonly associated with dilated pulmonary veins. Stretch has been shown to have mechanoâelectrical effects. OBJECTIVE: To investigate whether stretch can increase the arrhythmogenic activity of the pulmonary veins. METHODS: The transmembrane action potentials were recorded from rabbit pulmonary veins before and after stretch (100 and 300â
mg). Gadolinium and streptomycin (stretchâactivated ion channel blockers) were each perfused into the pulmonary veins under a 300âmg stretch. RESULTS: Stretch (0, 100 and 300â
mg) force dependently increased the incidence of spontaneous activity (22%, 48% and 83%; p<0.05), mean (standard deviation (SD)) firing rates of spontaneous activity (1.7 (0.2), 2.1 (0.3) and 3 (0.2)â
Hz; p<0.05) and incidence of early postâdepolarisations (9%, 26% and 61%; p<0.05) and delayed postâdepolarisations (0%, 4% and 30%; p<0.05) in 23 pulmonary veins. In the seven preparations with spontaneous activity after the 300âmg stretch, gadolinium (1, 3 and 10â
ÎŒmol/l) decreased the incidence of spontaneous activity by 43%, 29% and 14%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1)â
Hz to 0.8 (0.4), 0.3 (0.1) and 0.1 (0.1)â
Hz, respectively (p<0.05). Streptomycin (10 and 40â
ÎŒmol/l) decreased the incidence of spontaneous activity by 71% and 29%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1)â
Hz to 1.6 (0.4) and 0.5 (0.3)â
Hz, respectively (p<0.05). CONCLUSION: Stretch is an important factor in the electrical activity of the pulmonary vein. Stretchâinduced arrhythmogenic activity of the pulmonary vein may contribute to the genesis of atrial fibrillation