Internal Medicine Resident University of British Columbia Vancouver, British Columbia, Canada
Case background: BACKGROUND Myocarditis is a rare but life-threatening complication of autoimmune disease. Fulminant cases demand early recognition, hemodynamic support, and tissue diagnosis. Endomyocardial biopsy (EMB) is the gold standard but carries procedural risks, especially in unstable patients. We describe two cases of fulminant myocarditis in ulcerative colitis (UC) – one eosinophilic, one giant cell – both requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO), complicated by EMB-induced tamponade and right ventricular (RV) perforation. These cases highlight diagnostic, therapeutic, and procedural challenges in immune-mediated myocarditis.
CASE 1: GIANT CELL MYOCARDITIS A 57-year-old female with UC (post-ileostomy), primary sclerosing cholangitis, and other comorbidities presented with two months of exertional and positional chest pain. ECG showed anterior ST-elevation with reciprocal changes and RBBB. High-sensitivity troponin I (hs-cTnI) was 613 ng/L. CT pulmonary angiogram ruled out PE.
Coronary angiography revealed normal coronaries. Transthoracic echocardiography (TTE) showed LVEF 45–55% with inferoposterior hypokinesis. Symptoms resolved by day 3, and she was discharged with presumed coronary vasospasm.
Ten days later, she re-presented with chest pain, dyspnea, and orthopnea. POCUS showed reduced LVEF. Repeat ECG showed similar ST changes; hs-cTnI and BNP had increased to 1153 ng/L and 923 pg/mL. Angiography again showed normal coronaries. Repeat TTE showed LVEF < 25% with severe global hypokinesis. Suspecting fulminant myocarditis, she was admitted, started on IV methylprednisolone, and underwent EMB via right internal jugular approach, and under ultrasound guidance.
EMB was complicated by hemopericardium, PEA arrest, requiring emergent VA-ECMO and surgery for clot evacuation, and patch repair of RV puncture. Histopathology confirmed giant cell myocarditis (GCM) with necrosis, mixed infiltrate, and multinucleated giant cells. She was transferred to a transplant center and started on calcineurin inhibitor and induction with antithymocyte globulin. With no improvement, she was urgently listed for transplant and received a new heart within days, with excellent neurologic and functional recovery.
CASE 2: EOSINOPHILIC MYOCARDITIS A 58-year-old male with UC on vedolizumab presented with two days of dyspnea, fevers, and malaise. On arrival: hypotensive (89/51 mmHg), bradycardic (HR 60), tachypneic, hypoxemic, and examining wet and cold.
POCUS showed biventricular dysfunction. ECG revealed complete heart block with junctional escape, evolving to accelerated idioventricular rhythm and anterior ST-elevation. hs-cTnI was 16,761 ng/L; NT-proBNP >35,000; with evidence of severe multi-organ hypoperfusion.
Coronary angiography showed diffuse narrowing suggestive of vasospasm. Following VA-ECMO initiation, coronaries normalized. Transesophageal echo showed LVEF 15% with global hypokinesis and RV dysfunction. He was started on pulse methylprednisolone and underwent EMB via left femoral access and under fluoroscopy guidance, similarly, complicated by tamponade and RV rupture requiring surgical patch repair.
Histopathology showed eosinophilic myocarditis (EM) with eosinophilic and histiocytic infiltrate and necrosis. No granulomas, vasculitis, or giant cells were seen. EGPA was ruled out by serology, imaging, and absence of systemic features. Two of four biopsy fragments were diagnostic, raising concern for sampling error and missed GCM.
After 7 days of IV steroids, he had precipitous recovery and was successfully weaned off VA-ECMO. Repeat echo showed normalization of biventricular function. He remained stable off inotropes with preserved end-organ function.
Management Challenges: THE ROLE – AND RISK – OF ENDOMYOCARDIAL BIOPSY IN FULMINANT MYOCARDITIS Guidelines, including the 2021 AHA/ACC scientific statement, give a Class I recommendation for EMB in patients with new-onset heart failure < 2 weeks with hemodynamic compromise – criteria met by both patients. Yet these cases reveal the real-world challenges of biopsy in critically ill myocarditis patients.
Both developed life-threatening complications – cardiac tamponade and RV free wall rupture – following EMB. While biopsy is indispensable for subtype identification and guiding therapy, these outcomes raise a key question: how can we minimize EMB risk?
Risk contributors include: • Anatomical site: The RV free wall is a common target due to accessibility but is especially vulnerable in inflamed myocardium. • Imaging technique: Echo or fluoroscopy guidance is standard; real-time visualization may avoid fragile areas. • Multidisciplinary backup: High-risk biopsies require surgical contingency planning and coordination.
These cases illustrate the paradox: those who most need a biopsy often face the greatest procedural danger. Early biopsy by experienced teams in surgical-capable centers is critical.
THE CENTRAL ROLE OF TISSUE DIAGNOSIS IN GUIDING MYOCARDITIS MANAGEMENT Despite similar presentations – fulminant biventricular failure and shock – histological findings radically altered management.
Case 1: Giant Cell Myocarditis (GCM) Biopsy showed giant cells and myocyte necrosis, confirming GCM, a subtype with median survival < 3 months without aggressive therapy. The patient received immediate triple immunosuppression and was listed for urgent transplant, which she later underwent. This escalation hinged entirely on biopsy – there are no reliable clinical or imaging markers for GCM.
Case 2: Eosinophilic Myocarditis (EM) Biopsy revealed eosinophilic infiltration without granulomas or giant cells. This raised the question of primary EM versus secondary causes (e.g., EGPA, HES), with vastly different management implications.
An expedited multidisciplinary workup followed: • Rheumatology investigated systemic vasculitis and ANCA status. • Hematology assessed for clonal eosinophilia, including molecular testing. • Pathology confirmed primary, non-clonal EM after detailed review.
The patient responded rapidly to steroids alone – no further immunosuppression needed.
Why it matters: Biopsy does more than confirm myocarditis – it directs therapy and determines urgency: • GCM requires immediate immunosuppression and transplant planning. • EM demands workup for systemic disease and may avoid over-treatment.
Without tissue, both patients might have received inappropriate or delayed therapy. EMB remains central to precise, individualized care.
CONCLUSION AND TAKEAWAYS These cases provide several high-yield clinical lessons: 1. Endomyocardial biopsy is essential in fulminant myocarditis – both for diagnosis and to guide immunosuppressive therapy and transplant planning. This aligns with Class I guideline recommendations. 2. Biopsy in this setting is high risk. Procedural strategies (e.g., avoiding RV free wall, using imaging guidance, involving surgical backup) should be considered standard. 3. Timing matters: early biopsy, before deterioration, may reduce procedural risk and expedite definitive management. 4. Histology changes everything: despite similar clinical pictures, tissue diagnosis led to divergent therapies – full immunosuppression and transplant in one, steroids and recovery in the other.
