The relationship between the structural features of postinfarction myocardium and cardiac arrhythmias

Background. Transformation of the morphology of the post-infarction myocardium changes the electrical characteristics of the heart muscle, increasing the risk of life-threatening arrhythmias. Objective . The aim of the study was to compare the structural and electrical features of the heart muscle in post-infarction patients. Design and methods. The study participants were 105 (85.4 %) patients who had suffered an MI, aged 56.7±8.4 years. Six months after the MI, the patients underwent cardiac magnetic resonance imaging (MRI) (GE SIGNA Voyager tomograph, GE HealthCare, USA) with the introduction of a contrast agent — gadoteric acid. Six and 12 months after the MI, the patients underwent multi-day electrocardiogram monitoring (MMEKG) for 72 hours. Results. According to MMEKG, unstable paroxysms of VT were registered in 9 (6.8 %) patients. Frequent (>30/h) ventricular extrasystoles (VE) were correlated with the percentage of scar zone — r=0.679 (p=0.0101), the mass of the heterogeneous zone — r=0.721 (p=0.00951). An association was established between polymorphic VE with the presence of areas of microvascular obstruction r=0.812 (p=0.0095) and intramyocardial hemorrhage r=0.798 (p=0.0114). Most parameters of autonomic regulation and heart rate turbulence showed a moderate negative relationship with the scar mass. According to the data of univariate regression analysis, risk markers of unstable VT were established: scar zone mass, end-diastolic size, turbulence slope, SDNN variability parameter. Conclusion. Predictors of unstable runs of ventricular tachycardias within 12 months after myocardial infarction are the mass of the scar zone, the values of the left ventricular end-diastolic diameter, the values of the turbulence slope and the SDNN variability parameter.