Cardio-fistular Recirculation in Patients With Chronic Heart Failure and Preserved Left Ventricle Ejection Fraction

Inclusion Criteria: * signed informed consent, * \> 18 years * maintenance ("chronic") hemodialysis, * native arteriovenous fistula, * arteriovenous fistula volume blood flow ≥1 l/min, * arteriovenous fistula volume blood flow / cardiac output ratio \< 0.3, * interdialysis weight gain \<5% of "dry" body weight, * sufficient hemodialysis dose (eKt/V \> 1.2), * chronic heart failure (NYHA I-II classes only), * preserved left ventricular ejection fraction (≥50%), * absence of arrhythmias (except first-degree atrioventricular block block), * absence of heart valve disease (except mitral regurgitation grade I-II), * absence of intradialysis hypo/hypertension * "long" interdialysis interval (3 days). Exclusion Criteria: * hypo/hypertension during or after hemodialysis, * arrhythmias (except first-degree atrioventricular block) after hemodialysis.