What are the initial pharmacological treatments for acute severe heart failure?

Initial Pharmacological Treatment for Acute Severe Heart Failure

Intravenous loop diuretics are the cornerstone of initial therapy for acute severe heart failure, with an immediate starting dose of 20-40 mg IV furosemide (or equivalent) for diuretic-naïve patients, or at least double the home oral dose for those already on chronic diuretic therapy. 1

Immediate First-Line Therapy: Loop Diuretics

Dosing Strategy

• Door-to-diuretic time should not exceed 60 minutes 2
• For new-onset acute heart failure or patients not on chronic diuretics: 20-40 mg IV furosemide (or equivalent: 0.5-1 mg bumetanide; 10-20 mg torasemide) 1
• For patients already on chronic oral diuretics: Initial IV dose should be at least equivalent to (or double) the oral home dose 1, 2
• Maximum recommended dose: <100 mg in first 6 hours and <240 mg in first 24 hours 1, 2
• In severe renal impairment, doses up to 400-1000 mg/day may be required 2, 3

Administration Method

• Either intermittent boluses OR continuous infusion are equally acceptable - no mortality difference exists between these approaches 1
• The DOSE trial demonstrated no superiority of continuous infusion over intermittent boluses 4
• However, recent data suggests continuous infusion may achieve greater decongestion but with potentially poorer outcomes 5

Monitoring Response (Critical Within First 6 Hours)

• After 2 hours: Spot urinary sodium should be ≥50-70 mmol/L 2, 4
• After 6 hours: Urine output should be ≥100-150 mL/hour 2, 4
• Weight loss target: 0.5-1.5 kg in 24 hours or 3-5 L urine output 4
• Continuously monitor: symptoms, urine output, renal function, and electrolytes 1, 6

Escalation for Inadequate Response

• If targets not met: Double the original dose 2, 4
• Add combination diuretic therapy early (within first 24-48 hours if inadequate response) 2, 4
• Acetazolamide 500 mg IV once daily is particularly effective when baseline bicarbonate ≥27 mmol/L (use only first 3 days) 2
• Thiazide-type diuretic or spironolactone may be added for diuretic resistance 1, 6

Blood Pressure-Guided Additional Therapy

For Hypertensive Acute Heart Failure (SBP >90 mmHg)

• IV vasodilators should be considered as initial therapy alongside diuretics to improve symptoms and reduce congestion 1
• Vasodilators provide symptomatic relief in patients with SBP >90 mmHg without symptomatic hypotension 1
• Monitor blood pressure frequently during vasodilator administration 1

For Hypotensive Acute Heart Failure (SBP <90 mmHg)

• Inotropic agents may be considered ONLY in patients with symptomatic hypotension or signs of hypoperfusion 1
• Options include: dobutamine, dopamine, levosimendan, or phosphodiesterase III inhibitors (milrinone) 1, 7
• Inotropic agents are NOT recommended unless the patient is symptomatically hypotensive or hypoperfused due to safety concerns (increased mortality risk) 1
• Continuous ECG and blood pressure monitoring is mandatory when using inotropes due to arrhythmia and ischemia risk 1

For Cardiogenic Shock

• Vasopressor therapy (norepinephrine preferably) may be considered when shock persists despite inotropic support 1
• Immediate transfer to tertiary care center with 24/7 cardiac catheterization and mechanical circulatory support capability 1

Critical Supportive Measures

Respiratory Support

• Oxygen to achieve SpO2 ≥95% (≥90% in COPD patients) 1
• Non-invasive positive pressure ventilation (NIV) with PEEP should be considered early in patients with respiratory distress, as it reduces intubation rates and may reduce mortality 1
• CPAP or pressure support with PEEP (5-7.5 cmH2O, titrated up to 10 cmH2O) 1

Adjunctive Pharmacotherapy

• Morphine 2.5-5 mg IV boluses may be considered for severe dyspnea, restlessness, or anxiety (monitor respiration closely) 1
• Thromboembolism prophylaxis (LMWH) is recommended in all patients without contraindications 1

Common Pitfalls to Avoid

• Do NOT withhold or discontinue evidence-based disease-modifying therapies (ACE inhibitors, beta-blockers, etc.) unless hemodynamic instability or clear contraindications exist 1
• Avoid NSAIDs and COX-2 inhibitors - they worsen heart failure and increase hospitalization risk 1
• Avoid potassium-sparing diuretics during initial ACE inhibitor therapy 1
• High-dose diuretics (>120 mg/day furosemide) are associated with prolonged hospital stay and poorer outcomes 5
• Do NOT discharge patients with residual congestion - this is associated with poor prognosis and high readmission rates 2