What is the best initial step in managing a 68-year-old man with progressive shortness of breath, orthopnea, hypertension, type 2 diabetes mellitus, and a history of myocardial infarction, presenting with jugular venous distension, pitting edema, and impaired oxygen saturation?

Management of Acute Heart Failure in a Patient with History of Myocardial Infarction

The best initial step in managing this 68-year-old man with acute heart failure is to administer IV diuretics (furosemide) while simultaneously providing supplemental oxygen to maintain oxygen saturation above 90%. 1, 2

Clinical Assessment and Diagnosis

This patient presents with classic signs and symptoms of acute heart failure:

• Progressive shortness of breath for 3 days
• Orthopnea and paroxysmal nocturnal dyspnea
• Jugular venous distension (10 cm above sternal angle)
• S3 gallop and laterally displaced apical impulse
• Bilateral crackles at lung bases
• Peripheral edema (2+ pitting in ankles)
• Tachycardia (102/min) and tachypnea (24/min)
• Oxygen saturation of 93% on room air

These findings, combined with his history of hypertension, diabetes mellitus, and previous myocardial infarction, strongly suggest acute decompensated heart failure, likely precipitated by dietary nonadherence (recent salt intake).

Immediate Management Algorithm

1. Position patient upright to reduce work of breathing

2. Administer supplemental oxygen to maintain SaO₂ >95% 2

   • The ACC/AHA guidelines recommend oxygen supplementation for patients with pulmonary congestion to achieve arterial saturation >90% (Class I recommendation, Level of Evidence C)

3. Administer IV loop diuretics 2, 3

   • Furosemide 40 mg IV given slowly (over 1-2 minutes)
   • If inadequate response within 1 hour, may increase to 80 mg IV
   • The ACC/AHA guidelines recommend diuretics for patients with pulmonary congestion and volume overload (Class I recommendation, Level of Evidence C)

4. Consider IV nitrates if blood pressure remains elevated 2

   • Indicated with SBP >100 mmHg (patient's current SBP is 158/92 mmHg)
   • Start with low dose and titrate as needed
   • Contraindicated if hypotension develops

Secondary Diagnostic Steps

After initiating the above treatments, proceed with:

1. Chest X-ray to confirm pulmonary congestion and rule out alternative diagnoses 1

   • This is crucial for establishing a baseline and guiding therapy

2. 12-lead ECG to assess for ischemia, arrhythmias, or conduction abnormalities that may be contributing to heart failure 2

3. Laboratory studies:

   • Cardiac biomarkers (troponin)
   • Electrolytes, BUN/creatinine
   • Brain natriuretic peptide (BNP)

4. Echocardiography to assess ventricular function and rule out mechanical complications 2

Important Considerations and Pitfalls

• Avoid beta-blockers or calcium channel antagonists in patients with acute heart failure and signs of low cardiac output 2

• Monitor respiratory status closely as patients with severe pulmonary edema may require non-invasive positive pressure ventilation if they don't respond to initial therapy 2

• Watch for worsening renal function with diuretic therapy, especially in this patient with diabetes who may have underlying nephropathy 2

• Consider the possibility of acute coronary syndrome as a precipitant of heart failure, particularly given the patient's history of previous MI and diabetes 2, 4

• Assess volume status carefully before aggressive diuresis, though this patient clearly shows signs of volume overload 2

The European Society of Cardiology guidelines emphasize that immediate interventions for acute heart failure should include positioning the patient upright, administering oxygen, and initiating IV diuretics, with consideration of IV nitrates if blood pressure allows 1. The patient's clinical presentation with orthopnea, jugular venous distension, and peripheral edema strongly indicates volume overload requiring prompt diuresis 3.