Determination of persistent heart rhythm disorders predictors in military combatants with severe myocarditis

Abstract

The aim – to study heart rhythm and conduction disturbances in different localization and distribution of myocardial lesions in combatants with severe myocarditis based on the results of a 6-month follow-up.
Materials and methods. 46 male military personnel with a severe course of acute myocarditis (AM) with a reduced ejection fraction (EF) of the left ventricle (LV) (≤ 40 %) with an average age of (35,1±2,4) years were examined. Examinations were carried out in the 1st month after the onset of symptoms of myocarditis and after 6 months of observation. The diagnosis of myocarditis and the severe course of the disease were established on the basis of the Recommendations for the diagnosis and treatment of myocarditis of the All-Ukrainian Association of Cardiologists of Ukraine. All patients underwent for 24-hour ECG monitoring with analysis of the frequency and spectrum of rhythm and conduction disturbances and cardiac magnetic resonance (CMR) imaging with contrast analysis of the topography of the lesion and counting the number of LV segments affected by inflammatory changes and LV segments with the presence of late gadolinium enhancement (LGE).
Results and discussion. When comparing the results of heart MRI with the data of daily ECG monitoring, a clear association of the presence of frequent ventricular extrasystoles (VE) and paroxysms of non-sustained ventricular tachycardia (NSVT) with the localization of LGE in the interventricular septum (IS) was established – among patients with LGE lesions at the onset of AM more than in a third (37.0 %) had frequent VE, and NSVT paroxysms, which increase the risk of developing life-threatening ventricular arrhythmias, were detected in 25,9 % of cases. After 6 months of observation in the presence of LGE in the IS, the frequency of detection of frequent VE and NSVT paroxysms was also significantly higher compared to other localization of the lesion and amounted to 20,0 and 13,3 %, respectively. With the help of correlation analysis, an associative relationship was revealed between the presence of LGE in the IS and the presence of frequent VE and NSVT paroxysms in the debut of myocarditis – r=0.73 (р<0.01) and r=0.66 (р<0,01) respectively, and also after 6 months of observation – r=0.65 (р<0.01) and r=0.59 (р<0.05), respectively. According to the results of the multivariate regression analysis, predictors of frequent VE persistence after 6 months were: LVEF ≤30 %; LV end-diastolic volume index ≥105 ml/m2; presence of inflammatory changes in ≥5.0 LV segments; presence of LGE in ≥4.0 LV segments and its presence in the IS, determined in the 1st month from the onset of the disease. The predictors NSVT paroxysms persistence after 6 months were the same factors with the exception of LV EF, and, according to the value of the β coefficient (β=1.302; p<0.001), the most significant contribution was the presence of LGE in the IS.
Conclusions. In combatants with severe myocarditis, the presence of late gadolinium enhancement in the interventricular septum is an additional risk factor for the persistence of frequent ventricular extrasystoles and paroxysms of non-sustained ventricular tachycardia during 6 months, while the presence of late gadolinium enhancement in the posterior and lateral walls of the left ventricle has no reliable relationship with the presence of rhythm and conduction disorders. On the basis of multivariate regression analysis, predictors of frequent ventricular extrasystoles and paroxysms of non-sustained ventricular tachycardia persistence were established in combatants with myocarditis.