[Cardio-Ankle Vascular Index and Subclinical Peripheral Atherosclerosis in Patients With Stable Coronary Artery Disease].

AIM: To study relationship between cardio-ankle vascular index (CAVI) and subclinical manifestations of noncoronary atherosclerosis in patients with stable ischemic heart disease (IHD). MATERIAL AND METHOD: We included into this study 511 patients with IHD examined within framework of a register of patients before aorto-coronary bypass surgery. CAVI was determined using VaSera-1000 device. RESULTS: We distinguished 2 groups of patients: (1) with abnormal (≥ 9.0, n = 128) and (2) normal (< 9.0, n = 383) CAVI. Group 1 compared with group 2 had high mean age (p = 0.02), comprised more women (p = 0.0016), hypertensive patients (p = 0.0061), patients with three vessel coronary disease, and patients with stenoses in carotid arteries. Multiple logistic regression analysis revealed independent association between elevated arterial stiffness and age. Elevated arterial stiffness was found in 25% of group 1 patients. Abnormal CAVI was associated with increased intima-media thickness and stenoses of carotid arteries but not with presence of stenoses in arteries of lower extremities.

[Role of multidetector computed tomography and stress- echocardiography in assessment of risk of cardiological complications of non-cardiac surgery].

AIM: to compare results of coronary angiography with data of multi-slice computed tomography (MSCT) - angiography, and analyze rate of detection of hemodynamically significant coronary artery lesions during preoperative examination of patients. MATERIAL AND METHODS: We analyzed case histories of 92 patients (median age 59 years) examined prior to surgery on non-coronary vessels or for exclusion of ischemic heart disease. All patients were subjected to selective coronary angiography (CA) and MSCT - angiography. According to results of CA we formed 2 groups - with coronary artery stenoses >70% (n=55, group 1) and <70% (n=37, group 2). In 46 patients (50%) dobutamine stress echocardiography was performed for detection of concealed coronary insufficiency. RESULTS: CA revealed hemodynamically significant stenoses >70% (>50% in left main coronary artery) in 91 of 324 arteries. MSCT angiography detected stenosis >50% in 184 of 324 arteries; in 148 patients results of MSCT were confirmed by presence of hemodynamically significant stenoses at coronary angiography (sensitivity 86%). Absence of lesions or presence of stenoses <50% were noted at MSCT in 368 arteries; in 345 cases this was confirmed by coronary angiography (predictive value of negative result 94%, specificity 91%). Result of dobutamine stress echocardiography was positive in 41% of patients in group 1 and in 20% - of group 2 (<0.001). Sensitivity of stress echocardiography for detection of significant stenoses was 41%, specificity - 80%, negative predictive value - 14%. CONCLUSION: Diagnostic value of MSCT for detection of coronary artery stenoses >70% have better sensitivity, specificity, negative and positive predictive value of compared with stress echocardiography. Results of this study confirm value of MSCT angiography for diagnosis of coronary atherosclerosis and allow to recommend it as a screening method for detection hemodynamically significant coronary artery involvement before extracardiac surgery.

Phase singularities and filaments: simplifying complexity in computational models of ventricular fibrillation.

In the whole heart, millions of cardiac cells are involved in ventricular fibrillation (VF). Experimental studies indicate that VF is sustained by re-entrant activity, and that each re-entrant wave rotates around a filament of phase singularity. Filaments act as organising centres, and offer a way to simplify and quantify the complex spatio-temporal behaviour observed in VF. Where a filament touches the surface of fibrillating myocardium re-entrant activity can be observed, however the behaviour of filaments within bulk ventricular myocardium is difficult to observe directly using present experimental techniques. Large scale computational simulations of VF in three-dimensional (3D) tissue offer a tool to investigate the properties and behaviour of filaments, and the aim of this paper is to review recent advances in this area as well as to compare recent computational studies of fibrillation in whole ventricle geometries.

[Dynamics of the excitable media with two interacting pacemakers]. / Dinamika vozbudimykh sred s dvumia vzaimodeistvuiushchimi peismeikerami.

A general model of the nonlinear interaction of two impulse systems was developed, which describes some types of cardiac arrhythmias. Phase locking phenomena were studied with consideration for refractoriness time. The phenomena of tongue splitting and the overlapping of the major synchronization regions were revealed. The results obtained make it possible to predict the behavior of excitable systems with two pacemakers depending on the type and intensity of their interaction and on the initial phase difference.