EM Command Center / Cardiovascular Emergencies • 3 min read • 2 sections

Infective Endocarditis & Valvular Emergencies

Comprehensive emergency protocol for infective endocarditis (IE) and acute mechanical valvular failure. Details the Modified Duke Criteria, distinguishing acute vs. subacute endocarditis, hemodynamic collapse from acute native and prosthetic valvular disruption, bedside echocardiographic features, and emergency empiric antimicrobial regimens.

Resuscitation Quick Ribbon (First 2 Minutes)

High-Acuity

Resus:Draw 3 sets of blood cultures from separate venipuncture sites over 30-60 minutes BEFORE starting antibiotics in stable patients; do not delay antibiotics in septic shock.

Empiric IV Antibiotics (Native Valve):Vancomycin 15-20 mg/kg IV q8-12h + Ceftriaxone 2 g IV q24h (or Ampicillin-sulbactam 3 g IV q6h).

Empiric IV Antibiotics (Prosthetic Valve < 1 year):Vancomycin + Gentamicin (1 mg/kg IV q8h) + Rifampin (300 mg PO/IV q8h).

Acute Aortic / Mitral Regurgitation:Flash pulmonary edema + refractory cardiogenic shock; start IV Nitroprusside / Nicardipine for afterload reduction + Dobutamine; IABP is STRICTLY CONTRAINDICATED in aortic regurgitation.

Prosthetic Valve Thrombosis:New muffled click + shock; urgent transesophageal echocardiogram (TEE); emergently consult cardiothoracic surgery for re-operation or slow-infusion low-dose tPA.

Bottom-Line Clinical Pearl

Acute aortic regurgitation presents with cardiogenic shock, flash pulmonary edema, and a soft, deceptively brief diastolic murmur with a narrow pulse pressure. Unlike chronic aortic insufficiency, classic peripheral signs (wide pulse pressure, water-hammer pulse) are ABSENT due to early ventricular equilibration.

1. Modified Duke Criteria for Infective Endocarditis

Definite endocarditis requires 2 Major criteria, 1 Major + 3 Minor, or 5 Minor criteria:

Category	Duke Criteria Components	Diagnostic Specifics
Major Criteria 1: Blood Cultures	Typical IE microorganisms from 2 separate blood cultures: S. aureus, Viridans streptococci, S. gallolyticus (bovis), HACEK group, or Enterococcus OR persistently positive blood cultures (> 12h apart) OR single positive blood culture for Coxiella burnetii (Q fever).	Blood cultures are positive in > 90-95% of cases unless pre-treated with antibiotics.
Major Criteria 2: Endocardial Involvement	Positive Echocardiogram: Oscillating intracardiac mass/vegetation on valve or supporting structures, abscess, new partial dehiscence of prosthetic valve, or new valvular regurgitation (worsening or changing of pre-existing murmur not sufficient).	Transesophageal Echocardiography (TEE) is gold standard (sensitivity > 90-95% vs. 60-70% for TTE); mandatory for prosthetic valves.
Minor Criteria (5 Total)	1. Predisposition (prosthetic valve, prior IE, IVDU, congenital heart disease) 2. Fever (temperature >= 38.0 C / 100.4 F) 3. Vascular phenomena (major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, ICH, conjunctival hemorrhages, Janeway lesions) 4. Immunologic phenomena (glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor) 5. Microbiologic evidence (positive culture not meeting major criteria)	Janeway lesions: Non-tender erythematous macules on palms/soles (microabscesses). Osler nodes: Tender subcutaneous nodules on finger/toe pads (immune complexes). Roth spots: Retinal hemorrhages with pale centers.

2. Acute Native & Prosthetic Valvular Failure

Valvular Pathology	Etiologies & Mechanisms	Clinical Presentation & Murmur	Hemodynamic Management
Acute Aortic Regurgitation	Infective endocarditis (leaflet perforation/vegetation), Stanford Type A aortic dissection, chest trauma	Sudden flash pulmonary edema, cardiogenic shock. Murmur is SOFT, LOW-PITCHED, and SHORT in early diastole (due to rapid LV pressure equilibration). Absence of wide pulse pressure.	Afterload reduction (IV Nitroprusside) + inotropic support (Dobutamine). INTRA-AORTIC BALLOON PUMP (IABP) IS STRICTLY CONTRAINDICATED (worsens regurgitation and causes arrest). Emergent surgery.
Acute Mitral Regurgitation	Papillary muscle rupture (post-inferior MI, RCA territory), chordae tendineae rupture (myxomatous disease), IE	Sudden catastrophic pulmonary edema, hypotension, harsh holosystolic apical murmur radiating to axilla (may be soft if severe low output)	Afterload reduction (Nitroprusside) + Dobutamine. IABP is BENEFICIAL here (reduces afterload and augments forward flow). Emergent surgery.
Prosthetic Valve Thrombosis	Subtherapeutic anticoagulation in mechanical valve (INR < 2.0-2.5), pannus ingrowth	Muffled/absent prosthetic metallic click, new regurgitant murmur, refractory pulmonary edema, shock	Stat TTE/TEE and fluoroscopy. Cardiothoracic surgery consult for emergent valve replacement OR slow-infusion tPA (25 mg IV over 6 hours).

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