Cardiac Electrophysiological Alterations in Heart/Muscle-Specific Manganese-Superoxide Dismutase-Deficient Mice: Prevention by a Dietary Antioxidant Polyphenol

Figure 2

Effects of chronic AP intake on effective refractory period (ERP) and vulnerability to ventricular tachycardia (VT) and ventricular fibrillation (VF) during burst ventricular pacing in control and H/M-Sod2 ^−/− mice. (a) Representative ECG records during burst ventricular pacing observed in a control mouse (upper panel) and H/M-Sod2 ^−/− mouse (lower panel). Note that ventricular tachycardia was induced by burst pacing (30 basic stimuli at a 100 ms interval followed by 5 premature stimuli at an interval of ERP + 2 ms) in the H/M-Sod2 ^−/− mouse but not in the control mouse. (b) Ventricular ERP measured in control and H/M-Sod2 ^−/− mice with and without AP treatment. Control, 𝑛=7, control + AP, 𝑛=10, H/M-Sod2 ^−/−, 𝑛=13, H/M-Sod2 ^−/− + AP, 𝑛=11. Values are mean ± SEM, ***𝑃<0.001, *𝑃<0.05. (c) Incidence of VT or VF induced by burst pacing in control and H/M-Sod2 ^−/− mice with and without AP treatment. ***𝑃<0.001, *𝑃<0.05. Note that chronic intake of AP significantly lessened the prolongation in ERP and decreased the incidence of VT or VF induction in H/M-Sod2 ^−/− mice.

(a)

(b)

(c)