The purpose of this study is to describe safety and efficacy of Dapaglifozin in adults patients with a systemic right ventricle (congenitally corrected transposition of the great arteries or transposition of the great arteries following arterial switch procedure) and impaired systolic function of the systemic right ventricle.

This is a prospective double arm study aiming to describe safety and efficacy of Dapaglifozin in adults patients with a systemic right ventricle (congenitally corrected transposition of the great arteries or transposition of the great arteries following arterial switch procedure) and impaired systolic function of the systemic right ventricle.

Dapagliflozin will be prescribed in a group of randomly selected patients in addition to the optimized medical therapy for heart failure with reduced ejection fraction.

Changes in quality of life indicators, symptoms, biohumoral markers, exercise capacity and echocardiographic parameters of systolic right ventricular function will be evaluated in comparison with the control group, which will continue standard heart failure therapy.

Inclusion Criteria:

• Age≥18years
• Optimal medical therapy or at least 3months
• Systemic right ventricle ejection fraction≤40%, assessed on echocardiography

Exclusion Criteria:

• Univentricular physiology
• Systolic blood pressure<90mmHg
• Glomerular filtration rate(GFR)<30ml/min