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Myocarditis Presenting with Ventricular Arrhythmias: Role of Electroanatomical Mapping-Guided Endomyocardial Biopsy in Differential Diagnosis

2011; Linguagem: Inglês

10.5772/22123

Maurizio Pieroni, Costantino Smaldone, Fulvio Bellocci,

Cardiomyopathy and Myosin Studies

Myocarditis is defined as a disease characterized by myocardial inflammation associated with myocyte necrosis. It can be caused by infections, autoimmune response primarily affecting the myocardium or by systemic autoimmune or inflammatory disorders (Aretz et al., 1986). Viral infections are the most frequent cause and account for the vast majority of cases in North America and Europe (Cooper, 2009). Cardiac symptoms that develop during myocarditis may follow after a delay of days to weeks from the beginning of the pathological process; they are quite unspecific and include fatigue, dyspnoea, palpitations, malaise and atypical chest discomfort. Even the clinical cardiac signs may be vague in many patients and generally include cardiac murmurs, gallop rhythms and other signs of heart failure and sometimes pericardial rubs when the pericardium is also involved in the inflammatory process. Myocarditis is often associated with various types of ECG abnormalities (including bundle branch blocks, Q waves resembling those related to myocardial infarction, repolarization abnormalities and QRS prolongation) and rhythm disturbance such as atrio-ventricular blocks, supraventricular tachycardias and ventricular ectopies and tachycardias. Echocardiography may reveal overt systolic dysfunction or a reduction of peak systolic velocities at TDI; moreover, regional wall motion abnormalities and diastolic dysfunction may be found (Cooper, 2009; Feldman et al. 2000). Therefore, this disease should always be considered in patients who present with rapidly progressive cardiomyopathy, chest pain with ECG anomalies that mimic an acute coronary syndrome but with normal coronary arteries or idiopathic ventricular arrhythmias. Furthermore, in young people myocarditis may be frequently responsible for sudden cardiac death, particularly after strenuous physical exertion (Doolan et al., 2004; Corrado D et al. 2001). With this regard it should be highlighted that the recognition of myocarditis in patients presenting with aborted sudden death or major ventricular arrhythmias is actually challenging in everyday clinical practice, as the diagnosis may be difficult and may require the use of invasive procedures. Nevertheless, the detection of myocarditis in patients presenting with ventricular arrhythmias may have a pivotal importance, because the