Search
giant cell myocarditis
Epidemiology:
- rare
- annual incidence 0.13/100,000 persons
- tends to occur in younger adults & middle-aged persons
- 4th or 5th decade of life [2]
- affects men & women equally
Pathology:
- T-cell mediated autoimmune process
- myocarditis
- widespread inflammatory infiltrates
- multinucleated giant cells, eosinophils, & lymphocytes causing myocardial necrosis
- myocardial fibrosis, scarring
- with or without noncaseating granulomas [2]
Clinical manifestations:
- often quickly progressive
- median survival of 6 months after symptom onset [2]
- congestive heart failure
- heart block (5%) [2]
- ventricular arrhythmias
- palpitations
- sustained ventricular tachycardia (50%)
- less commonly, it can mimic an acute myocardial infarction
- syncope
Laboratory:
- complete blood count
- eosinophils in blood may show eosinophilia
Special laboratory:
- electrocardiogram
- low voltage
- ventricular arrhythmia
- heart block
- bifascicular block or left bundle-branch block [2]
- endomyocardial biopsy is needed to establish a diagnosis
- myocardial involvement typically patchy
- a negative biopsy does not rule out giant cell myocarditis
- sensitivity of endomyocardial biopsy is 69%
- repeat biopsy can increase yield to 80-93%
Radiology:
- myocardial perfusion imaging
- no coronary artery obstruction
- cardiac magnetic resonance imaging (MRI)
- subendocardial involvement in giant-cell myocarditis
- right ventricular side of basal interventricular septum is involved in cardiac sarcoidosis [2]
Complications:
- sometimes fatal; death or heart transplantation 89% [2]
- sudden cardiac death uncommon
- other autoimmune diseases, including myasthenia gravis, inflammatory bowel disease & thyroiditis are common
Differential diagnosis:
- cardiac sarcoidosis
Management:
- combination immunosuppression:
- 2-3 drugs including cyclosporine, prednisone, azathioprine, mycophenolate mofetil, or muromonab
- presence of eosinophils in diseased myocardium may be associated with greater responsiveness to immunosuppressive therapy
- may increase long-term survival [2]
- implantable cardioverter-defibrillator (ICD)
- even when left ventricular systolic dysfunction is mild
- cardiac transplantation
- inotropic agents & mechanical support as a bridge to cardiac transplantation
- acute rejection is higher with giant-cell myocarditis than with dilated cardiomyopathy (16% vs 5%) [2]
- 5-year survival rate of 71% [1]
- 1, 5, & 10 years after transplantation are 94%, 82%, & 68%, respectively [2]
- recurrence of giant-cell myocarditis in cardiac-transplant recipients occurs in 20-25%, but may respond to an increase in immunosuppression
General
myocarditis
References
- Jani SM, Nallamothu BK, Cooper LT, Smith A, Fazel R.
Beating, Fast and Slow.
N Engl J Med 2017; 377:72-78. July 6, 2017
PMID: 28679100
http://www.nejm.org/doi/full/10.1056/NEJMcps1608688
- Rothaus C
A Man with Cardiomyopathy and Ventricular Tachycardia.
NEJM REsident 360. April 25, 2018
https://resident360.nejm.org/content_items/a-man-with-cardiomyopathy