Encoded byANK2, ankyrin-B (AnkB) is a multifunctional adapter protein critical for the expression and targeting of key cardiac ion channels, transporters, cytoskeletal-associated proteins, and signaling molecules. Mice deficient for AnkB expression are neonatal lethal, and mice heterozygous for AnkB expression display cardiac structural and electrical phenotypes. HumanANK2loss-of-function variants are associated with diverse cardiac manifestations; however, human clinical ‘AnkB syndrome’ displays incomplete penetrance. To date, animal models for human arrhythmias have generally been knock-out or transgenic overexpression models and thus the direct impact ofANK2variants on cardiac structure and functionin vivois not clearly defined. Here, we directly tested the relationship of a single humanANK2disease-associated variant with cardiac phenotypes utilizing a novelin vivoanimal model. At baseline, young AnkBp.E1458G+/+mice lacked significant structural or electrical abnormalities. However, aged AnkBp.E1458G+/+mice displayed both electrical and structural phenotypes at baseline including bradycardia and aberrant heart rate variability, structural remodeling, and fibrosis. Young and old AnkBp.E1458G+/+mice displayed ventricular arrhythmias following acute (adrenergic) stress. In addition, young AnkBp.E1458G+/+mice displayed structural remodeling following chronic (transverse aortic constriction) stress. Finally, AnkBp.E1458G+/+myocytes harbored alterations in expression and/or localization of key AnkB-associated partners, consistent with the underlying disease mechanism. In summary, our findings illustrate the critical role of AnkB inin vivocardiac function as well as the impact of single AnkB loss-of-function variantsin vivo.However, our findings illustrate the contribution and in fact necessity of secondary factors (aging, adrenergic challenge, pressure-overload) to phenotype penetrance and severity.