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Fig. 2. Echocardiographic examination demonstrated diffuse LV and RV hypokinesis with moderate dilation of both ventricles, severe biventricular systolic dysfunction (LV ejection fraction 20%, RV FAC 20%, moderate mitral regurgitation, relevant tricuspid regurgitation), mild diffuse pericardial effusion, bilateral pleural effusion, apical thrombus in the LV.
In the first 24 hours following admission to CCU the patient developed two episodes of ventricular fibrillation, resolved without sequelae with external CPR and biphasic external DC shock (200 and 120 J, respectively) and was put on i.v. magnesium and amiodarone. Cardiac CMR was not performed because of electrical and hemodynamic instability. On the second day of admission, complete right and left heart catheterization was performed. Coronary angiography excluded any coronary artery pathology.
Can we make the final diagnosis based on the above cited results and what are the possible etiologies of this severe non-ischemic biventricular failure?
If not, which additional examination would you recommend?
What do you predict will be the clinical outcome in this patient?
Question 1: Can we make the final diagnosis based on the above cited results and what are the possible etiologies of this severe non-ischemic biventricular failure?
Answer: We can’t make the final diagnosis. The exclusion of coronary artery disease provides relevant information, although an ischemic etiology was unlikely given the female gender, the relatively young age, the absence of atherosclerosis risk factors, and the normal troponin levels. The ECG pattern with microvoltages could indicate extreme obesity, pericardial effusion, myocarditis, myxedema, amyloidosis or other metabolic or storage disorders. The patient was not obese, had normal coronary arteries, normal lab tests concerning thyroid function and hematological profile. In our patient the mild pericardial effusion could be responsible for the ECG changes, but pericardial effusion may simply reflect heart failure and/or a concomitant myopericarditis.
The association with a possible gastroenteritis at presentation may also indicate Enteroviral infection and viral myocarditis. However, there was no fever, negative viral serology (lack of IgM positivity for common cardiotropic viruses) (1-4). Alternatively a viral infection might have triggered acute cardiac failure in an asymptomatic idiopathic dilated cardiomyopathy. Additional information could have been provided by cardiac MRI, e.g. presence or absence of oedema and/or late gadolinium enhancement (LGE), distribution of LGE (5), but this could not be performed due to electrical and hemodynamic instability. Anyhow, the final differential diagnosis of viral (virus–positive) or immune-mediated (virus-negative) acute or chronic myocarditis could only be based upon endomyocardial biopsy (1-4, 6). An endomyocardial biopsy could also rule out myocarditis and establish the diagnosis of idiopathic dilated cardiomyopathy or of other rare causes of myocardial disease, e.g. cardiac amyloidosis or giant-cell myocarditis (7). SLE may give cardiovascular involvement, but it is often asymptomatic, or secondary to kidney and lung SLE involvement. SLE myocarditis and post-myocarditis DCM may occur, but they are less common than pericarditis, endocarditis, vasculitis or atherosclerotic SLE-associated coronary artery disease. The patient did not have any clinical or diagnostic feature in keeping with the 1997 update of the American College of Rheumatology classification criteria (ACR97) for systemic lupus erythematosus (SLE) (8). In addition, endomyocardial biopsy (see below) disclosed another histopathological entity.
Question 2: If not, which additional examinations would you recommend?
Answer: This is a case of new-onset heart failure of <2 weeks duration associated with a dilated left (and right) ventricle with hemodynamic compromise, as well as of new-onset heart failure of 2 weeks to 3 months duration associated with a dilated left (and right) ventricle with new-onset ventricular arrhythmia not responsive to usual care within 1 to 2 weeks. Thus there are 2 Class I indications for performing an endomyocardial biopsy according to the American Heart Association, the American College of Cardiology and the European Society of Cardiology Scientific Statement on the role of Endomyocardial Biopsy (7). The two most likely causes of heart failure are a severe myocarditis process, possibly giant cell myocarditis and an end-stage idiopathic dilated cardiomyopathy.
Our patient underwent right ventricular endomyocardial biopsy, with classical histology, immunohistochemistry, molecular detection of common cardiotropic viruses by polymerase chain reaction (PCR) in myocardial tissue and on blood, and serum testing for anti-heart autoantibodies (AHA) (3,4,6). Endomyocardial biopsy showed (Figure 2) massive diffuse lymphomonocytic infiltrate with extensive myocyte necrosis and frequent giant cells, mild subendocardial fibrosis. The findings were indicative of giant cell myocarditis. PCR was negative for enterovirus, influenza A and B, Cytomegalovirus, Ebstein-Barr virus, Herpes-virus, Herpes virus 6, Adenovirus, Parvovirus B19. AHA test was strongly positive for organ-specific anti-heart autoantibodies (6). The final diagnosis was of a virus-negative, autoimmune giant cell myocarditis with biventricular involvement.
Figure 2. Endomyocardial biopsy diagnostic for Giant cell Myocarditis. Hematoxylin eosin stain, original magnification 60X. Note the inflammatory cell infiltrate characterized by lymphomonocytes, eosinophils, and giant cell (arrow) associated to myocardial damage. In the insert immunohistochemical staining with giant cell positivity for the macrophage marker CD68.
Question 3: What do you predict will be the clinical outcome in this patient?
Answer: The patient had severe biventricular dilatation and dysfunction, 2 episodes of aborted cardiac arrest in the absence of reversible causes, hemodynamic instability and an histological diagnosis of virus-negative, autoimmune giant cell myocarditis that has per se a dismal prognosis. Female gender, biventricular dysfunction at presentation, severe right and left ventricular dysfunction and giant cell myocarditis are all negative prognostic features in myocarditis (6). Immunosuppressive therapy is mandatory once the diagnosis of virus-negative, autoimmune giant cell myocarditis is established and may defer or prevent heart transplantation (8). The patient was put on triple immunosuppressive therapy with methylprednisolone, azathioprine and cyclosporine on top of standard heart failure therapy and of i.v. inotropic support. On day 7 from diagnosis due to hemodynamic instability on medical therapy she was also put on ExtraCorporeal Membrane Oxygenation (ECMO) as a bridge to heart transplant, underwent urgent transplant listing and was successfully transplanted after 18 days. She is alive and well at 10 months post-transplantation, but at the last surveillance endomyocardial biopsy giant cell myocarditis was found to relapse in the absence of cardiac symptoms or dysfunction on echocardiography on the transplanted heart. Therefore, immunosuppression was intensified and the patient has been scheduled for an early follow-up biopsy. The possibility to relapse in the target transplanted organ is a typical feature of organ-specific autoimmune conditions, such as virus-negative giant cell myocarditis (9), but this event is usually successfully managed with intensified immunosuppression.
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