Global deletion of potassium channel Kv1.5 causes biventricular heart failure

Background: Heart failure (HF) is a chronic disease with high morbidity and mortality among older populations. Chronic HF ultimately affects both the right (RV) and left (LV) ventricles and often presents with extra-cardiac outcomes including pulmonary hypertension (PH). Study of biventricular failure and its extra-cardiac consequences has been challenging in pre-clinical models, suggesting new models may be beneficial to uncover new mechanisms of disease. Potassium channels are implicit regulators of vascular tone and are strongly but independently associated with PH and LV dysfunction. Aim: We hypothesized that deletion of the potassium rectifier channel Kv1.5 would cause biventricular HF, thus representing a new model from which to understand ventricle-specific mechanisms of HF. Methods and Results: We used a model of global vasoconstriction by genetic deletion of potassium rectifier channel Kv1.5 (Kv1.5 KO). Male and female mice were studied at middle age (12-13 months) as this is when HF risk begins to increase with age. In response to Kv1.5 KO, both the LV and RV experienced elevated afterload. While Kv1.5 KO mice developed RV systolic dysfunction with hypertrophy and fibrosis, the LV developed mild hypertrophy and diastolic dysfunction. Consistent with biventricular remodeling, Kv1.5 KO mice also displayed higher liver and lung weights and exercise intolerance. Conclusion: Deletion of Kv1.5 causes systemic and pulmonary vasoconstriction with distinct outcomes in the LV and RV. This model of biventricular dysfunction may be useful for studying extra-cardiac consequences of HF and understanding ventricle-specific mechanisms of disease.