What is the emergency department (ED) management of a patient with hypertrophic obstructive cardiomyopathy (HOCM) presenting with acute chest pain, dyspnea, syncope, or rapid atrial fibrillation (AF)?

Emergency Department Management of HOCM

Immediate Stabilization and Critical Actions

For patients with HOCM presenting to the ED with acute symptoms, the priority is aggressive volume resuscitation for hypotension, avoidance of all vasodilators and inotropes, and initiation of beta-blockers while obtaining urgent echocardiography to confirm obstruction. 1

First 10 Minutes: Assessment and Monitoring

• Place patient on continuous cardiac monitoring with defibrillator immediately available 1
• Obtain 12-lead ECG within 10 minutes to exclude concurrent ACS or arrhythmias 1
• Assess for high-risk features: ongoing chest pain >20 minutes, severe dyspnea, syncope, hemodynamic instability 1
• Obtain urgent bedside echocardiogram to confirm LVOT gradient and assess severity of obstruction 2

Management by Presenting Syndrome

Acute Hypotension/Shock

Intravenous phenylephrine (or other pure vasoconstrictors without inotropic activity) is the recommended first-line agent for acute hypotension in HOCM, alone or combined with beta-blockers. 1

• Administer aggressive IV fluid boluses first—hypovolemia dramatically worsens LVOT obstruction 1
• AVOID all inotropes (dobutamine, dopamine, epinephrine) as they worsen obstruction 1
• If phenylephrine unavailable, use norepinephrine cautiously (has some beta-agonist activity) 3
• Consider emergency VA-ECMO for refractory cardiogenic shock as bridge to definitive septal reduction therapy 3

Chest Pain/Dyspnea

• Initiate non-vasodilating beta-blockers (metoprolol, atenolol, propranolol) titrated to maximum tolerated dose—this is Class I recommendation 1
• Target heart rate reduction to improve diastolic filling time and reduce myocardial oxygen demand 1, 4
• If beta-blockers ineffective or not tolerated, substitute with verapamil or diltiazem 1
• CRITICAL CAVEAT: Verapamil is potentially harmful in patients with severe dyspnea at rest, hypotension, or very high resting gradients (>100 mmHg) 1

Rapid Atrial Fibrillation

• Rate control with beta-blockers or diltiazem/verapamil (if hemodynamically stable and gradient <100 mmHg) 1
• Initiate immediate anticoagulation—life-long anticoagulation is indicated after first AF episode in HCM 5
• Avoid digoxin as it can worsen outflow obstruction through positive inotropy 1
• Consider urgent cardioversion if hemodynamically unstable 5

Syncope

• Assess for ventricular arrhythmias requiring ICD consideration 4, 5
• Evaluate for severe LVOT obstruction as cause 2
• Exclude concurrent ACS, pulmonary embolism, or other life-threatening causes 2

Medications to IMMEDIATELY Discontinue

Discontinue all vasodilators and medications that worsen dynamic obstruction: 1

• ACE inhibitors and ARBs (worsen obstruction through afterload reduction) 1
• Dihydropyridine calcium channel blockers (amlodipine, nifedipine) 1
• Nitrates (can cause catastrophic hypotension) 1
• Digoxin (positive inotrope worsens obstruction) 1
• High-dose diuretics (hypovolemia worsens obstruction) 1

Cautious Use of Diuretics

• Low-dose loop or thiazide diuretics may be considered for volume overload with high filling pressures 1
• Use extreme caution—excessive diuresis causes hypovolemia that dramatically worsens LVOT obstruction 1
• Intermittent dosing or chronic low-dose therapy preferred over aggressive diuresis 1

Disposition and Escalation

Admission Criteria

• All symptomatic HOCM patients with acute presentations require admission to monitored bed 1
• Hemodynamically unstable patients require ICU/CCU admission 1

Cardiology Consultation

• Immediate cardiology consultation for all acute HOCM presentations 1
• Discuss need for advanced therapies if symptoms persist despite optimal medical therapy 1

Septal Reduction Therapy Referral

• For patients with persistent severe symptoms (NYHA class III-IV) despite maximum medical therapy, refer to experienced HCM center for septal reduction therapy 1
• Surgical myectomy is preferred for younger patients, those with extreme hypertrophy (>30mm), or concurrent cardiac disease requiring surgery 1, 6
• Alcohol septal ablation is recommended for elderly patients or those with prohibitive surgical risk 1

Critical Pitfalls to Avoid

• Never give standard ACS treatment blindly—nitrates and morphine can cause catastrophic hypotension in HOCM 1
• Never use inotropes for hypotension—they worsen obstruction and can precipitate cardiovascular collapse 1
• Never aggressively diurese—hypovolemia is one of the most dangerous states in HOCM 1
• Verapamil in high-gradient patients (>100 mmHg) can be lethal—use only in stable patients with lower gradients 1
• Children <6 weeks should never receive verapamil—risk of life-threatening bradycardia and hypotension 1