In this new Clinical Problem-Solving article, a 67-year-old man presented to the emergency department with chest pain that had begun earlier that day and had progressed over a period of several hours. The pain was substernal and nonradiating, and it did not change with position or food intake.
Although the detection of pulmonary edema on radiography often indicates an acute rise in left-sided filling pressures or acute lung injury, radiographic detection of cardiomegaly suggests a myocardial condition that has been present for weeks to months.
• What are etiologies of acute biventricular heart failure?
Potential causes of acute biventricular failure include myocardial ischemia, a mechanical complication caused by a recent myocardial infarction, acute regurgitant valvular lesions, an acute aortic syndrome (e.g., aortic dissection, intramural thrombus, or penetrating ulcer), or acute myocarditis. Consideration must be given to other acute cardiomyopathic processes, including infectious, drug-mediated, toxic, infiltrative, autoimmune, and metabolic cardiomyopathies.
• What is the epidemiology and typical presentation of giant-cell myocarditis?
First described more than 100 years ago, giant-cell myocarditis is an extremely rare, idiopathic, and frequently fatal condition. There have been approximately 300 reported cases; estimates based on autopsy data suggest that the incidence of giant-cell myocarditis is between 0.007% and 0.051%. Before the diagnostic and therapeutic advances made in the past 30 years, giant-cell myocarditis was diagnosed only at autopsy. A presentation with new heart failure is typical of giant-cell myocarditis. Most patients with giant-cell myocarditis are between 30 and 50 years of age, whereas our patient was 67 years of age. In addition, ventricular tachycardia and heart block are often found in patients with giant-cell myocarditis. Although autoimmune conditions do not occur frequently enough to be considered typical of giant-cell myocarditis, they are present in one fourth of cases, and their presence should increase the suspicion of giant-cell myocarditis.
Morning Report Questions
Q: What is the recommended treatment of giant-cell myocarditis?
A: Immunosuppressive therapy should be initiated immediately; the preferred regimen includes intravenous administration of high-dose glucocorticoids and a calcineurin inhibitor or another therapy directed at T cells. Even with early, aggressive immunosuppressive therapy, however, the median survival of patients with giant-cell myocarditis is less than a year. Mechanical circulatory support is often the only option for patients with giant-cell myocarditis and hemodynamic compromise. Although placement of a left ventricular assist device alone may be adequate in patients with isolated left ventricular dysfunction, patients with clinically significant right heart failure or hemodynamically significant ventricular arrhythmias that cannot be controlled require biventricular assist devices or a total artificial heart as a bridge to cardiac transplantation.
Q: What is the prognosis of giant-cell myocarditis?
A: A rapidly downhill course despite appropriate treatment of heart failure further differentiates giant-cell myocarditis from other disorders. Timely diagnosis facilitates early initiation of appropriate therapy. Unlike most forms of myocarditis, giant-cell myocarditis may respond to immunosuppressive therapy. Although immunosuppression has not been shown to improve left ventricular function, multicenter case series have shown higher rates of transplantation-free survival among patients receiving immunosuppressive therapy as a result of a reduction in ongoing inflammatory injury to the ventricle. Median transplantation-free survival among patients with giant-cell myocarditis is on the order of 3 months without immunosuppressive therapy, and it extends to approximately 12 months with cyclosporine or multiagent immunosuppressive therapy. Approximately 30% of patients die within several weeks after presentation.