Fragmentation of narrow QRS complex of sinus origin in patients with postinfarction cardiosclerosis as prognostic criterion for course of coronary heart disease

Fragmentation of a QRS complex is an ECG-phenomenon resulting from non-uniform activation of the ventricular myocardium in the background of cicatricial, fibrous changes. This indicator is associated with adverse outcomes (including the development of life-threatening arrhythmias, sudden death) in patients with various cardiovascular pathologies, including ischemic heart disease. Objective. To study the effect of fragmentation of a narrow sinus QRS complex on the frequency of visits to outpatient hospitals, hospitalization in cardiology hospitals, the frequency of implantation of ECS, recurrent heart attacks and deaths in patients with myocardial infarction in history. Assess the prognostic significance of the prevalence and different localization of QRS fragmentation. Material and methods. The study included 137 patients with postinfarction cardiosclerosis and CHF with preserved LV EF, who were hospitalized in the years 2013-2018. The main group (with QRS fragmentation) included 39 patients, the control group (without fragmentation) had 98 ones. The groups were comparable in age and sex. We analyzed the surface ECG in 12 leads using the following fragmentation criteria: notch R (S) or RSR notch in at least two leads corresponding to the same zone of origin with a QRS duration of less than 120 ms. Results. Total mortality (12 [30.8 %] vs 14 [14.3 %]) and the frequency of sudden death (5 [12.8 %] vs 3 [3.1 %]) were significantly higher in the group with QRS fragmentation. In cases with a fatal outcome, the median number of leads with QRS fragmentation was greater (5 vs 2; p < 0.001). With a favorable outcome in 96.3 % of cases, fragmentation was observed in the leads corresponding to only one of the walls of the left ventricle, with a fatal outcome in 25 % of cases (p < 0.001). The presence of fragmentation along the three walls was associated with an unfavorable outcome. In 75.0 % of the dead, fragmentation along the side wall was observed (p < 0.001). The frequency of visits to outpatient hospitals, the frequency of hospitalizations in the main group were significantly higher (p < 0.001). A direct statistically significant association of high closeness between the number of leads with QRS fragmentation and hospitalization rate was detected (r_xy = 0.77; p < 0.001). The risk of recurrent heart attack in the main and control groups was not significantly different. The chances of an ECS-implantation among patients with fragmentation were 20.1 times higher than in the control group (p < 0.001; OR: 20.1; 95 % Cl: 6.2-65.7). Among patients requiring installation of an ECS, fragmentation of the ventricular complex was on average encountered in a larger number of leads (p = 0.049). Fragmentation on the lower wall of the left ventricle was a factor that increased the chances of implanting an ECS by 18.7 times (p = 0.005; OR: 18.7; 95% Cl: 2.1-167.3). Findings. The presence of fragmentation of a narrow sinus QRS complex in two or more ECG leads in patients with post-infarction cardiosclerosis is associated with a significant increase in the frequency of visits to outpatient medical facilities and the frequency of hospitalizations; the frequency of arrhythmic events requiring the implantation of an ECS; an increase in overall mortality and the risk of sudden death, but not associated with a significant risk of recurrent heart attacks. With increase in number of assignments with fragmentation of QRS the frequency of hospitalizations increases. Fragmentation on the bottom wall increases the chances of installing an ECS, and fragmentation on the side wall is a marker of an unfavorable outcome.

QRS fragmentation, narrow QRS complex, ECG, lead, myocardial infarction, coronary heart disease, postinfarction cardiosclerosis, mortality, sudden death, hospitalization, ECS