title: Increased inducibility of ventricular tachycardia and decreased heart rate variability in a mouse model for type 1 diabetes: effect of pravastatin.
abstract: Although a reduction in the high-frequency (HF) component of heart rate variability (HRV) is a major complication of diabetes and a risk factor for sudden death, its relationship to ventricular tachycardia (VT) is unknown. We developed a mouse model for the study of VT and its relationship to changes in HRV in the Akita type 1 diabetic mouse. Programmed ventricular stimulation of anesthetized mice demonstrated that Akita mice were more inducible for VT compared with wild-type mice: 78.6% versus 28.6% (P = 0.007). Optical mapping of perfused hearts demonstrated multifocal breakthroughs that occasionally gave rise to short-lived rotors consistent with focal initiation and maintenance of VT. Treatment of Akita mice with pravastatin, which had been previously shown clinically to decrease ventricular ectopy and to increase HRV, decreased the inducibility of VT: 36.8% compared with 75.0% with placebo treatment (P = 0.022). The HF fraction of HRV was reduced in Akita mice (48.6 ± 5.2% vs. 70.9 ± 4.8% in wild-type mice, P = 0.005) and was increased compared with placebo treatment in pravastatin-treated mice. Pretreatment of Akita mice with the muscarinic agonist carbamylcholine or the β-adrenergic receptor blocker propranolol decreased the inducibility of VT (P = 0.001). In conclusion, the increased inducibility of focally initiated VT and reduced HF fraction in Akita mice were partially reversed by both pravastatin treatment and pharmacologic reversal of parasympathetic dysfunction. In this new animal model for the study of the pathogenesis of VT in type 1 diabetes, pravastatin may play a role in the prevention of VT by attenuating parasympathetic dysfunction.
authors.affiliation: Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts;
authors.forename: Mohammad
authors.initials: M
authors.lastname: Rajab
authors.forename: Hongwei
authors.initials: H
authors.lastname: Jin
authors.forename: Charles M
authors.initials: CM
authors.lastname: Welzig
authors.forename: Alfred
authors.initials: A
authors.lastname: Albano
authors.forename: Mark
authors.initials: M
authors.lastname: Aronovitz
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ho-Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Mark S
authors.initials: MS
authors.lastname: Link
authors.forename: Sami F
authors.initials: SF
authors.lastname: Noujaim
authors.forename: Jonas B
authors.initials: JB
authors.lastname: Galper
mesh_terms: D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D004195:Disease Models, Animal; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D017035:Pravastatin / Q000494:pharmacology* / Q000627:therapeutic use; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000503:physiopathology*
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D017035:Pravastatin
keywords: secondary effects of diabetes; statins; type 1 diabetes; ventricular tachycardia