Fig. 9.

The changes in contraction frequency elicited by AST-C I and AST- III were weakly correlated with one another, as were the changes in frequency elicited by AST-C II and AST-C III. However, in both cases, correlation coefficients are low (<0.2) and significant scatter exists. No significant correlation was seen between the changes in contraction frequency elicited by AST-C I and AST-C II. Graphs of the responses of the same individuals to each pair of peptides are graphed, and fitted with a linear correlation; n = 53 hearts. A: AST-C I vs. AST-C II (Pearson correlation, r² = 0.068, P = 0.059). B: AST-C I vs. AST-C III (Pearson correlation, r² = 0.086, P = 0.033). C: AST-C II vs. AST-C III (Pearson correlation, r² = 0.156, P = 0.003).