Inclusion Criteria:

• Age ≥ 18
• Known HF with impaired, midly-reduced or preserved LVEF
• Under guideline directed medical therapy for HF according to ESC Heart Failure Guidelines applicable at inclusion
• Previously followed (or included at hospital discharge) by remote monitoring allowing daily weight by connected scale (i.e. Careline®, Optified-self®, NewCard®, Implicity®)
• Under furosemide diuretic treatment ≥ 20mg/day for at least 30 days prior to inclusion
• Current unplanned hospitalization or unplanned/emergent consultation for acute/decompensation HF

Exclusion Criteria:

• Subject unable to express their consent and sign informed consent form
• Subject not covered by public health insurance
• Refusal to participate (absence of informed consent).
• Subject under guardianship, legal protection, or deprived of liberty.
• Pregnant or breastfeeding women.
• Subject under law protection and prisoners
• Women of child bearing potential, unless they are using an effective method of birth control (i.e. oral contraceptives, implantable contraceptives, injectable contraceptives, transdermal contraceptives, intrauterine devices, male or female condoms with spermicide, abstinence, or a sterile sexual partner)
• Subject unable to comprehend or adhere to the protocol and follow-up
• Concurrent participation in another interventional study.
• Chronic ventricular assist device or heart transplant patients.
• Acute heart failure from recent acute coronary syndrome (< 1 month).
• Severe chronic renal failure or dialysis (GFR < 20 ml/min).
• History of renal colic, hyperchloremic acidosis and wheat allergy (other than coeliac disease)
• Known severe hepatic insufficiency defined by a PTT < 50% or a Child-Pugh score C and/or a known (clinial or biological) supplemented adrenal insufficiency
• Intolerance to sulphonamides
• Hypersensitivity to the active substance (Acetazolamide) or to any of the excipients (Calcium carbonate, wheat starch, gelatine, magnesium stearate)
• Concomitant use of carbamazepine or quinidinics (hydroquinidine, quinidine)
• Low cardiac output syndrome/cardiogenic shock.
• Current use of acetazolamide or any other carbonic anhydrase inhibitor, including but not limited to topical ophthalmic formulations (e.g., brinzolamide, dorzolamide, methazolamide)
• Concomitant use of lithium, valproic acid and valpromide
• Current use of high-dose aspirin (>300 mg/day).

Non-randomization criteria (Criteria should be controlled before patients' randomization) :

• False alarm
• Time between alarm and randomization > 48h
• Subject who declines his participation
• Loss of study treatments or unable to take it at D0
• Hemodynamic instability justifying an urgent hospitalization
• If applicable, positive urine pregnancy test