Diagnostic Value of Different Noninvasive Criteria of Latent Myocarditis in Comparison with Myocardial Biopsy

Purpose: The aim of this study was to quantify the value of various clinical, laboratory, and instrumental signs in the diagnosis of myocarditis in comparison with morphological studies of the myocardium. Methods: In 100 patients (65 men, 44.7 ± 12.5 years old) with “idiopathic” arrhythmias (n = 20) and dilated cardiomyopathy (DCM; n = 80), we performed the following: 71 endomyocardial biopsies (EMB), 13 intraoperative biopsies, 5 studies of explanted hearts, and 11 autopsies with virus investigation (real-time PCR) of the blood and myocardium. Antiheart antibodies (AHA) were also measured as well as cardiac CT (n = 45), MRI (n = 25), and coronary angiography (n = 47). The comparison group included 50 patients (25 men, 53.7 ± 11.7 years old) with noninflammatory heart diseases who underwent open heart surgery. Results: Active/borderline myocarditis was diagnosed in 76.0% of the study group and in 21.6% of patients in the comparison group (p < 0.001). The myocardial viral genome was observed more frequently in patients in the comparison group than in the study group (65.0 and 40.2%; p < 0.01). We evaluated the diagnostic value of noninvasive markers of myocarditis. The panel of AHA had the greatest importance in the identification of myocarditis: sensitivity was 81.5%, and the positive and negative predictive values were 75.0 and 60.5%. This defined the diagnostic value of noninvasive markers of myocarditis and established a diagnostic algorithm providing an individual assessment of the likelihood of myocarditis development. Conclusion: AHA have the greatest significance in the diagnosis of latent myocarditis in patients with “idiopathic” arrhythmias and DCM. The use of a complex of noninvasive criteria allows the probability of myocarditis to be estimated and the indications for EMB to be determined.