Figure 4: HF Hearts Have an Increased Susceptibility to Ca-ALT, Which Is Prevented by RDN

(A) Representative calcium transient tracings at 333-ms and 130-ms pacing cycle length from CTL, HF, and HF+RDN hearts are shown. Significant calcium transient alternans (Ca-ALT) is seen in the HF heart (middle panel), but not in the CTL (upper panel), and HF+RDN (lower panel) hearts. (B) Summary data demonstrating the relationship of PR and Ca-ALT from CTL, HF, and HF+RDN hearts are shown. In HF hearts, more Ca-ALT is observed at each PR tested, and HF produces a leftward shift in Ca-ALT to PR relationship, which is prevented by RDN (HF+RDN). *p < 0.05 HF versus CTL group. #p < 0.05 HF+RDN versus HF group. L = large calcium transient; S = small calcium transient; other abbreviations as in Figures 1 and 2.