Morphological and electrocardiographic criteria for myocardial fibrosis and atrial fibrillation

Abstract

Background. The formation of myocardial fibrosis is the leading mechanism for occurrence of atrial fibrillation. In this regard, an attempt to prevent development of myocardial fibrosis and its treatment is pathogenetically expedient. In recent years, there have been reports on the early diagnosis of myocardial fibrosis using electrocardiography (ECG). Therefore, in order to understand the clinical significance of myocardial fibrosis, it is necessary to compare morphological and ECG parameters. The purpose of the work was to study the morphological and electrocardiographic parallels of atrial myocardial fibrosis in atrial fibrillation. Material and methods. The study included 64 autopsy protocols and case histories of women with ECG-documented atrial fibrillation, which divided into three groups. Group 1 included 20 autopsy protocols for women who died at the age of 27-43 years. Group 2 included 21 autopsy protocols for women who died at the age of 47-52 years. Group 3 included 23 autopsy protocols for women who died at the age of 54-68 years. For histological examination, material taken from the left atrium, right atrium, and Bachmann’s bundle. The type of myocardial fibrosis histologically assessed; the prevalence of fibrosis assessed in points (from 0 to 4 points), the area of fibrosis was assessed as a percentage. Results. It has been established that the area of myocardial fibrosis in atrial fibrillation increases with age. At the age of 27-43 years, the fibrosis area is 17.8%, 47-52 years old - 24.3%, and at 54-68 years old - 26.1%. It was found that myocardial fibrosis in atrial fibrillation slows down the conduction of excitation through the atria. The width of the atrial wave (P) at the age of 27-43 years is 137.1±1.7 ms, by the age of 47-52 years it increases by 7.2% (p<0.001), and by the age of 54-68 years by 13.8% (p<0.001). Atrial myocardial fibrosis was shown to be associated with P wave width (p<0.001), P wave dispersion (p<0.001) and P wave second phase width in lead V1 on ECG (p<0.001). Conclusions. Received data shows a close relation between the morphological structure and ECG signs of atrial myocardial fibrosis in atrial fibrillation.

Keywords

• myocardial fibrosis
• atrial fibrillation
• fibrotic remodeling of the myocardium