Figure 3: HF Hearts Have Slower Calcium Reuptake Kinetics, Which Is Prevented by RDN

(A) Representative calcium transients at 333-ms pacing cycle length from CTL, HF, and HF+RDN hearts are shown. Calcium transients are expressed as F/F0 (fluorescence level [F] normalized to diastolic fluorescence level [F0]). The decay portion of the calcium transient (from 30% to 90% of decline phase) is marked as a red curve, and is fit to a single exponential function whose time constant, τ, is used to measure calcium decay. (B) Summary data of time constant tau (τ) and calcium transient amplitude for all the groups are shown. The mean time constant τ is larger in HF hearts than CTL hearts, reflecting a slower calcium decay rate or a slower calcium reuptake. However, the mean time constant τ is smaller in HF+RDN hearts than HF hearts, suggesting RDN improves calcium reuptake in HF. The calcium transient amplitude is also significantly smaller in HF hearts than CTL hearts. RDN significantly increases calcium transient amplitude in HF hearts (HF+RDN). Data represent mean ± SD; *p < 0.05 HF versus CTL group. #p < 0.05 HF+RDN versus HF group. Abbreviations as in Figure 1.