A multicenter, randomized, controlled study in Sweden (n=110). This study consists of 2 phases: 1) open-label run-in within approximately 2 months, and 2) randomized, double-blinded and placebo-controlled treatment for 6 months.

The open-label phase, in turn, consists of three periods: up-titration (normally 1 - 2 weeks, and longer in some cases), correction (maximum 72 hours) and maintenance (4 - 7 weeks).

A multicenter, randomized, controlled study in Sweden (n=110). This study consists of 2 phases: 1) open-label run-in within approximately 2 months, and 2) randomized, double-blinded and placebo-controlled treatment for 6 months.

The open-label phase, in turn, consists of three periods: up-titration (normally 1 - 2 weeks, and longer in some cases), correction (maximum 72 hours) and maintenance (4 - 7 weeks).

Eligible study population:

1. >70 yrs.
2. Regardless of LVEF but EF measured within past 2 years. For HFpEF echo criteria defined by ≥2 of: LV wall thickness ≥ 12 mm; LV mass index (BSA indexed LVH): male >115 g/m2, female >95 g/m2; relative wall thickness ≥0.42; E/e' ≥15 in sinus rhythm (or > 11 in the setting of atrial fibrillation); tricuspid regurgitation velocity >2.8 m/s; Left atrial volume index >34 ml/m2.
3. GFR ≥ 20 mL/min/1,73 m².
4. NYHA II-IV.
5. On optimal treatment as per physician´s judgement including ACE/ARB/ARNI, beta blockers, SGLT2 inhibitor för HFrEF/HFmrEF, and SGLT2 inhibitors in HFpEF
6. Suboptimal treatment with MRA (defined as: no use or ≤ 25 mg daily
7. And one of following:

1) Prior hyperkalemia (S-K> 5.0 mmol/L or P-K> 4.8 mmol/L*) during MRA treatment within last 24 months, and current S-K ≤ 5.0 or P-K ≤ 4.8 mmol/L 2) Current S-K 4.5-5.0 mmol/L or P-K 4.3-4.8 mmol/L, and potential risk of hyperkalemia as indicated by eGFR 30-45 ml/min/1,73 m2 3) Current S-K 5.1-5.9 mmol/L or P-K 4.9-5.7 mmol/L

• Corresponding plasma K (P-K) level is 0.2 mmol lower than serum K(S-K). Hyperkalemia is defined as P-K > 4,8 mmol/L or S-K >5,0 mmol/L.

Detailed inclusion and exclusions are described in Clinical Trial Org (NCT 047809239)

Inclusion Criteria:

• 1. >70 yrs. 2. Regardless of LVEF but EF measured within past 2 years. For HFpEF echo criteria defined by ≥2 of: LV wall thickness ≥ 12 mm; LV mass index (BSA indexed LVH): male >115 g/m2, female >95 g/m2; relative wall thickness ≥0.42; E/e' ≥15 in sinus rhythm (or > 11 in the setting of atrial fibrillation); tricuspid regurgitation velocity >2.8 m/s; Left atrial volume index >34 ml/m2.

  3. GFR ≥ 20 mL/min/1,73 m². 4. NYHA II-IV. 5. On optimal treatment as per physician´s judgement including ACE/ARB/ARNI, beta blockers, SGLT2 inhibitor för HFrEF/HFmrEF, and SGLT2 inhibitors in HFpEF 6. Suboptimal treatment with MRA (defined as: no use or ≤ 25 mg daily 7. And one of following:

  1. Prior hyperkalemia (S-K> 5.0 mmol/L or P-K> 4.8 mmol/L*) during MRA treatment within last 24 months, and current S-K ≤ 5.0 or P-K ≤ 4.8 mmol/L

  2. Current S-K 4.5-5.0 mmol/L or P-K 4.3-4.8 mmol/L, and potential risk of hyperkalemia as indicated by eGFR 30-45 ml/min/1,73 m2

  3. Current S-K 5.1-5.9 mmol/L or P-K 4.9-5.7 mmol/L

     • Corresponding plasma K (P-K) level is 0.2 mmol lower than serum K(S-K). Hyperkalemia is defined as P-K > 4,8 mmol/L or S-K >5,0 mmol/L.

     Exclusion Criteria: