Accentuated vagal antagonism paradoxically increases ryanodine receptor calcium leak in long-term exercised Calsequestrin2 knockout mice

Our novel results suggest that long-term exercise in CASQ2-/- mice increases susceptibility to ventricular arrhythmias by accentuating vagal antagonism during β-adrenergic challenge, which prevents HR acceleration and exacerbates abnormal RyR2 Ca2+ leak in EX CASQ2-/- VCM.