Study: NCT01973335

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Combination therapy with acetazolamide and low-dose loop diuretics
Description: * Patients receive 500 mg of intravenous acetazolamide immediately after randomization, with 250 mg intravenous acetazolamide administered on each consecutive day in the morning for as long as the patient is considered volume overloaded by his/her treating cardiologist.~* Patients receive 2 mg of intravenous bumetanide immediately after randomization, with 1 mg intravenous bumetanide administered on each consecutive day in the morning for as long as the patient is considered volume overloaded by his/her treating cardiologist.~* If diuresis \<1,5 L while the patient is still considered volume overloaded by his/her treating cardiologist, the dose of acetazolamide is maintained at 500 mg and the dose of bumetanide is maintained at 2mg.~In case of therapy-refractory congestion, treatment is at the discretion of the treating physician, but addition of chlorthalidone 50 mg PO is recommended by the investigators as a first-line option.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Combination therapy with acetazolamide and low-dose loop diuretics
Description: * Patients receive 500 mg of intravenous acetazolamide immediately after randomization, with 250 mg intravenous acetazolamide administered on each consecutive day in the morning for as long as the patient is considered volume overloaded by his/her treating cardiologist.~* Patients receive 2 mg of intravenous bumetanide immediately after randomization, with 1 mg intravenous bumetanide administered on each consecutive day in the morning for as long as the patient is considered volume overloaded by his/her treating cardiologist.~* If diuresis \<1,5 L while the patient is still considered volume overloaded by his/her treating cardiologist, the dose of acetazolamide is maintained at 500 mg and the dose of bumetanide is maintained at 2mg.~In case of therapy-refractory congestion, treatment is at the discretion of the treating physician, but addition of chlorthalidone 50 mg PO is recommended by the investigators as a first-line option.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: High-dose loop diuretics
Description: * Patients receive the double of their daily maintenance dose of oral loop diuretics converted to mg bumetanide as an intravenous bolus after randomization.~* Patients continue to receive this dose daily on the next 3 days divided between two administrations with at least a 6 h interval for as long as they are considered volume overloaded by the treating cardiologist.~* If diuresis \<1,5 L while the patient is still considered volume overloaded by the treating cardiologist, the dose of bumetanide is doubled.~In case of therapy-refractory congestion, treatment is at the discretion of the treating physician, but addition of chlorthalidone 50 mg PO is recommended by the investigators as a first-line option.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: High-dose loop diuretics
Description: * Patients receive the double of their daily maintenance dose of oral loop diuretics converted to mg bumetanide as an intravenous bolus after randomization.~* Patients continue to receive this dose daily on the next 3 days divided between two administrations with at least a 6 h interval for as long as they are considered volume overloaded by the treating cardiologist.~* If diuresis \<1,5 L while the patient is still considered volume overloaded by the treating cardiologist, the dose of bumetanide is doubled.~In case of therapy-refractory congestion, treatment is at the discretion of the treating physician, but addition of chlorthalidone 50 mg PO is recommended by the investigators as a first-line option.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Upfront therapy with oral spironolactone
Description: Patients randomized to this group receive oral spironolactone (25mg) immediately after randomization and in the morning of each subsequent day unless the serum potassium level is \>5 mmol/L.~Note: Investigators and treating physicians are blinded to treatment allocation for this arm, but no matching placebo is provided, so patients are not.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Upfront therapy with oral spironolactone
Description: Patients randomized to this group receive oral spironolactone (25mg) immediately after randomization and in the morning of each subsequent day unless the serum potassium level is \>5 mmol/L.~Note: Investigators and treating physicians are blinded to treatment allocation for this arm, but no matching placebo is provided, so patients are not.