Study to Assess Efficacy and Safety of SZC for the Management of High Potassium in Patients With Symptomatic HFrEF Receiving Spironolactone

INCLUSION CRITERIA * Adults aged ≥18 years * Potassium and estimated glomerular filtration rate (eGFR): * Cohort 1: sK+ 5.1-5.9 mEq/L at screening/study enrolment and eGFR ≥30 mL/min/1.73 m2; OR * Cohort 2: Normokalaemic (sK+ 3.5-5.0 mEq/L) at screening and 'at risk' of developing HK defined as any of the following: * Have a history of HK (sK+ \>5.0 mEq/L) within the prior 36 months and eGFR ≥30 mL/min/1.73 m2; or * sK+ 4.5-5.0 mEq/L and eGFR 30 to 60 mL/min/1.73 m2; or * sK+ 4.5-5.0 mEq/L, and age \>75 years * Symptomatic HFrEF (New York Heart Association \[NYHA\] class II-IV), which has been present for at least 3 months * Left ventricular ejection fraction (LVEF) ≤40% * Receiving angiotensin-converting enzyme inhibitor (ACEi), angiotensin II receptor blocker (ARB), or angiotensin receptor-Neprilysin inhibitor (ARNi) * Not on or on low-dose spironolactone or eplerenone (\<25 mg daily) * Receiving beta-blocker unless contraindicated EXCLUSION CRITERIA * Heart failure due to restrictive cardiomyopathy, active myocarditis, constrictive pericarditis, hypertrophic (obstructive) cardiomyopathy, or severe stenotic valve disease as a primary cause of HF * Current inpatient hospitalisation with unstable HF, defined as any of the following: * Systolic blood pressure \<95 mmHg during the 6 hours prior to screening. * Intravenous diuretic therapy during the 12 hours prior to screening. * Use of intravenous inotropic drugs during the 24 hours prior to screening. * Received mechanical…