PROGNOSTIC VALUE OF PATHOLOGIC Q-WAVE AND TIME OF ITS APPEARANCE IN PATIENTS WITH MYOCARDIAL INFARCTION: COMPARISON STUDY

Aim. To evaluate short- and long-term prognosis of myocardial infarction (MI) depending on occurrence of pathologic Q-wave on ECG and time of its appearance.Material and methods. 616 patients with initial ST-elevated MI were included into the study — 254 women and 362 men, aged 62.1±11.2. All patients were split up three groups depending on occurrence of pathologic Q-wave on ECG and time of its appearance. First group consisted of 311 patients with early Q-wave (during first 6 hours from onset of MI symptoms). Second group consisted of 120 patients with late Q-wave (from 6 to 24 hours from onset of MI symptoms). Third group consisted of 185 patients with non-Q-wave MI.Results. The hospital lethality in the patients with early Q-wave was significantly higher than this in patients of the second and the third groups. However, we didn’t reveal significant differences between patients with late Q-wave and patients without Q-wave on ECG. The incidences of cardiac death (sudden death and fatal MI), non-fatal MI and hospitalization because of unstable angina was assessed during next two years. During the follow-up period patients of three groups had similar incidences of the non-fatal MI and hospitalization because of unstable angina. However, incidence of cardiac death was significantly higher in early Q-wave group in comparison with non-Q-wave group.Conclusion. Occurrence of pathologic Q-wave on ECG and time of its appearance should be taken into account to assessed short- and long-term prognosis of MI

THE PREVALENCE AND CLINICAL SIGNIFICANCE OF CARDIAC ARRHYTHMIAS

Arrhythmias are one of the most complex, insufficiently studied, and therefore one of the most urgent problems of modern cardiology. A wide spectrum of clinical manifestations of cardiac rhythm disorders (CRDs), their detection both in various diseases and in healthy people, necessitate the study of their prevalence in populations. In the majority of conducted epidemiological studies a single recording of electrocardiogram (ECG) was used. This is the most usable method for examination of large populations but a little informative for detecting arrhythmias. The small frequency of CRDs detected during ECG recording is due to the short duration of its registration. An increase in the duration of ECG recording (ECG recording for 2 minutes, continuous recording of 100 cardiocycles) leads to an increase in arrhythmias frequency. With a wide introduction in the practice of ECG monitoring by Holter as well as the use of individual recorders of electrocardiogram ("handheld ECG recording") data appeared indicating a much higher frequency of CRDs. Data obtained in numerous studies on the prevalence of arrhythmias are very contradictory and depend both on the characteristics of populations and on methodological approaches, which requires further epidemiological studies. At the same time, the main initiating point of such researches is the clinical significance of certain CRDs. However, if the clinical significance of ventricular tachyarrhythmias and atrial fibrillation does not currently cause any doubt, the clinical significance of extrasystoles is highly controversial, despite the high their prevalence, including this in prognostically unfavorable groups of patients. In recent years, the results of a number of studies have been published that allow to think about the adverse effects of both supraventricular and ventricular extrasystoles of the course of certain cardiovascular diseases. Very heterogeneous results of the performed studies, as well as data about the high clinical significance of individual CRDs, make further epidemiological studies in this field extremely urgent

The relationship of arrhythmias with structural and functional heart changes according to the echocardiography data in the adult population of the Arctic

Aim. To study the relationship of arrhythmias, registered by the electrocardiography (ECG) and ECG Holter monitoring, with the changes of the heart and disorders of its function detected by echocardiography in the adult population of the Arctic, living in unfavorable environmental conditions.Material and methods. Patients (n=348) of both sexes, aged 20 years and older, were randomly selected and examined. All participants were carried out ECG recording in 12 standard leads, Holter monitoring and transthoracic echocardiography.Results. Statistically significant associations between certain types of arrhythmias and echocardiographic changes were observed. There were revealed correlations of medium strength: between atrial fibrillation (AF), registered by ECG and dilatation of the left (r=0.3215) and right (r=0.3275) atrium; between AF, registered by Holter monitoring, and left ventricular (LV) systolic dysfunction (r=0.3216); between premature ventricular contractions, registered by Holter monitoring, and LV hypertrophy (r=0.3332).Conclusion. The аassociation between arrhythmias and structural and functional changes of the heart in individuals living in adverse climatic conditions were confirmed

LEFT ATRIAL FUNCTION: MODERN ASSESSMENT METHODS AND CLINICAL SIGNIFICANCE

Assessment of the left atrial (LA) function is important aspect of comprehensive cardiovascular system estimation. Many cardiac diseases make an impact to LA work either by direct affect on myocardium or hemodynamic condition changing. It is considered, LA and left ventricle diastolic pressure is interrelated, thus without mitral valve disease LA expanding is a sign of LV filling pressure augmentation. Examination of LA size and function by analysis of atrial reservoir, conduit, and booster pump can predict cardiovascular outcomes in patients with cardiomyopathy, ischemic heart disease and valvular heart disease. The last two decades gave new technologies to accurate and comprehensive LA mechanics estimation, in the first place related to tissue Doppler imaging. Atrial strain and strain rate obtained using two-dimensional speckle-tracking echocardiography have proved to be feasible and reproducible techniques to evaluate LA mechanics.In physiological settings, LA is a highly expandable chamber with relatively low pressures. However in the presence of acute and chronic injury, LA wall stretches. LA stretching is a hallmark of structure changing with myocardial fibrosis and has influence on LA strain and strain rate. LA strain estimation could be useful in the prediction of sinus rhythm restoration and maintenance after cardioversion and catheter ablation. Low values of global longitudinal LA strain indicate irreversible LA remodeling and are related to the atrial fibrillation progression from paroxysmal to permanent forms. The most interesting in these circumstances is the potential contribution of echocardiography to thromboembolic risk stratification in atrial fibrillation and invasive procedures such as atrial ablation. Therefore, at present, the main task is to understand the ways of clinical application of data  obtained during the LA study

Diastolic function of the left ventricle in patients with cardiomyopathy and low ejection fraction: the role of torsion in left bundle branch block

Influence of left bundle branch block (LBBB) on left ventricle (LV) diastolic function and mechanisms of LV torsion remains underestimated.Aim. To study the relationship of LV diastolic function and LV torsion in patients with cardiomyopathy and LBBB in comparison with patients with cardiomyopathy and normal intraventricular conduction.Material and methods. Patients with cardiomyopathy (n=74) and LV ejection fraction <40% were included into the study and divided in two groups with narrow QRS complex and LBBB (the mean QRS duration = 153 ms). Echocardiography was performed in all patients with hemodynamic indices detection, and myocardium strain and torsion estimation.Results. The patients with LBBB showed less twisting, than patients without LBBB (3.24±3.35° and 5.87±3.83°, respectively, p=0.013914), but significant diastolic function differences between groups were absent. Despite the lack of difference in heart remodeling indices, subgroup of patients with LV rigid body rotation showed significantly less LV twisting and changes in pulmonary vein flow related to LV high end diastolic pressure. In the rigid body rotation group systolic left atrial filling fraction was 32.3±8.07%, whereas in the group with a physiological counter-rotation - 53.1±10.1% (p=0.000226). Potential reason of these findings was interventricular dyssynchrony. Deviation of time interval to peak myocardial systolic velocity between opposite basal segments in group with LBBB and anomalous LV rotation was more (63.3±35.1 ms) than this in group with LBBB and physiological LV rotation (8.0±17.9 mc, p=0.015922). This finding suggests that LV rigid body rotation in patients with LBBB may reflect a more pronounced mechanical dyssynchrony.Conclusion. LBBB has complex negative influence on process of LV electric activation and contraction which results in deterioration of LV twisting, mechanical dyssynchrony and deterioration of diastolic function. In disorders of intraventricular conduction and local contractility, assessment of pulmonary vein flow, possibly, more precisely reflects diastolic function status