Purpose. The aim of the experimental study was to study the effects of stereotaxic radioablation of various doses on the myocardium of the atria, ventricles and atrioventricular (AV) node in the long term (up to 6 months); as well as assessment of collateral damage during radioablation.

Material and methods. The research was carried out on 4 domestic pigs. The animals were 10-12 weeks old, the average weight was 30±2.7 kg. Linear accelerator «TrueBeam», Varian was used for the experiment. Animals were divided into groups according to the zones of planned radiation exposure: 1st animal AV node (dose 35 Gy), 2nd animal AV node and the apex of the left ventricle (LV) (dose 40/35 Gy, respectively), 3rd animal pulmonary veins (PV) and left atrium (dose 30 Gy), 4th AV node and free wall of the LV (dose 45/40 Gy). Under intravenous sedation with hemodynamic monitoring, contrast-based CT of the heart was performed to assess the degree of displacement of the heart chambers in one respiratory and cardiac cycle and to assess the anatomy of the chambers of the heart and adjacent organs. The allocation and the contouring of the target zones were carried out in 3 projections: axial, frontal and sagittal. For electrophysiological control, loop recorders were implanted in each animal. The average exposure time was 11±7 minutes. The long-term follow-up period was 6 months, followed by morphological examination of autopsy material.

Results. The average follow-up period after the experiment was 134.75±77.34 days. The electrophysiological effect of the ablation was achieved in cases of complete AV-block development. This effect was developed in 2 out of 3 animals, whose AV-node was exposed: 2nd animal 40 Gy on 108^th day of observation and 4th animal 45 Gy on 21^st day of observation. No cardiac arrhythmias were recorded in all cases. The results of macroand microscopic examination showed significant changes in the target zones. These areas had precise but uneven damage boundaries, which were within the planned ones (conformal exposure with a high degree of precision). The transmural nature of the changes was noted as well. Massive fields of fibrous tissue of various degrees of maturity (with a predominance of subepicardial localization) with focal hemorrhages of various ages and granulations were detected, which were surrounded by cardiomyocytes with coagulated and vacuolated cytoplasm.

Conclusion. The use of non-invasive stereotactic treatment of tachyarrhythmias has high prospects in modern arrhythmology as an alternative ablation method.

Purpose. Comparison of computer tomography (СT) contrast enhancement (CE) protocols for optimal visualization of cardiac chamber, definition it’s influence on results of non-invasive superficial cardiac mapping.

Materials and methods. The study included 93 patients with heart rhythm disorders who planned catheter ablation of arrhythmia. Noninvasive cardiac mapping was made for topical diagnostics. It includes multichannel ECG-registration and CT with intravenous СE (1st group monophasic (50 patients), 2nd group split-bolus (18 patients), 3rd group with pre-bolus (25 patients). Qualitative and quantitative (measurement of mean blood attenuation in four chambers, calculation of ventricular-myocardial contrast-to-noise ratio VM-LV и VM-RV for left ventricle (LV) and right ventricle (RV), respectively) parameters were compared between groups. Fusion of ECG and CT data was made semi-automatic with diagnostic complex «Amycard 01К».

Results. Regardless of CE technique was noted sufficient and homogeneous contrast attenuation of left atrium (LA) and LV (mean blood attenuation in LA more than 278 HU, LV 250 HU, VM-LV 0,582). Enhancement of right heart was insufficient with monophasic protocol, in most cases the average CT density was lower than 200 HU, VM-RV 0,256. Split-bolus protocol improves visualization of right atrium (RA) and RV (blood density in RA 258HU, RV 227HU, VM-RV 0,541), however there was heterogeneity of RA cavity because of artifacts from superior vena cava (VC) and unenhanced blood from inferior inferior VC. Using of pre-bolus increases contrast ratio between RA myocardium and blood due to increasing CT density of blood in inferior VC (blood density 294 HU). Quality of right ventricle CE was similar to 2nd group (blood density 264 HU, VM-RV 0,565).

Conclusion. CE protocols split-bolus and with pre-bolus improve visualization of right ventricle, supporting the high level enhancement of left heart. Protocol with pre-bolus is preferable for exact differentiation of right atrial endocardial contour.

Aim. Blood pressure (BP) determination in atrial fibrillation (AF) patients remains challenging due to its high inter-measurement variability. The novel methodology of precise beat-to-beat BP determination may be used to guide the hypotensive therapy selection and adjustment, but along with that provides additional opportunity for the investigation of hemodynamics in patients with chronic AF.

Material and method. The study sample consisted of 60 patients with the main diagnosis of grade II-III arterial hypertension; 30 of those were on sinus rhythm and 30 had chronic non-valvular AF. In all patients HR was within the limits recommended for left ventricular ejection fraction of >40%. Beat-to-beat systolic, diastolic, and pulse BP (SBP, DBP, and PBP, respectively) assessment at each heart beat within 15 minute interval was performed with “Kardiotekhnika-SAKR” system (NAO “Incart”, St.Petersburg, Russia).

Results. Mild RR-interval variations, observed on sinus rhythm, resulted in insignificant SBP, DBP, and PBP fluctuations. More prominent RR-interval irregularity, typical for AF, is accompanied by more significant SBP, DBP, and PBP deviations. As mean SBP of each patient was taken for 1,0, “normal” SBP (≥0,9) was seen in RR-intervals of 754±58 msec; “markedly decreased” (<0,9) in 619±66 msec; “prominently decreased” (<0,8) in 527±86 msec; “severely decreased” (<0,7) in 489±38 msec. For DBP (mean DBP of each patient was taken for 1,0) “normal” DBP (<1,1) was seen in RR-intervals of 758±63 msec; “markedly increased” (>1,15) in 587±38 msec; “prominently increased” (>1,2) in 566±38 msec; “severely increased” (>1,2) in 539±41 msec. For PBP (mean PBP of each patient was taken for 1,0) “normal” PBP (≥0,75) was seen in RR-intervals of 770±58 msec; “markedly decreased” (<0,75) in 561±40 msec; “prominently decreased” (<0,5) in 520±33 msec; “severely decreased” (<0,25) in 510±52 msec. Proportion of heart beats with insufficient efficacy according to PBP level (sum of “markedly”, “prominently”, and “severely” decreased) was 16,4±5,1% with prominent individual deviations (5,9-25,7%). Mean range of RR-interval providing to “marked” PBP decrease was 147±26 msec, also with significant individual variations 55-235 msec.

Conclusions. Beat to beat BP measurement is characterized by high level of accuracy. In addition to mean SBP and DBP, their beat-to-beat fluctuations can be determined, which might be significant in irregular rhythm. This might help in selection of individualized anti-hypertensive therapy. The study has shown that along with RR-intervals shortening the number of hemodynamically insufficient heart beats increased, which manifested by SBP decrease, DBP increase, resulting in decrease of PBP. However, this general consistent pattern masks the individual differences of heart rhythm structure in AF. This method can help to determine the optimal HR for each individual patient with AF.

Aims. To determine the role of the prevalence of low-voltage areas in the occurrence of arrhythmia recurrence after interventional treatment of atrial fibrillation (AF).

Methods. The study included 38 patients with paroxysmal (52.6%) and persistent (47.4%) forms of AF who underwent interventional treatment of AF using high-density electroanatomical mapping (at least 10,000 EGM points). Analysis of electroanatomical maps was performed after the completion of the ablation procedure. The area of the low-voltage zones was measured manually. Then, the areas of all regions of low-voltage activity were summed up; the resulting value was expressed as a percentage of the total surface area of the left atrium (LA).

Results. The observation period was 12.8±3.2 months. Based on the results of endocardial mapping, all patients were divided into 2 groups according to the prevalence of low-voltage areas in the LA. The first group included patients with an area of low-voltage zones less than 5% of the total surface of the left atrium, and the second with an area of low-voltage areas of more than 5% of the total surface of the left atrium. The patients of the first group had a lower LA volume compared to patients from the second group, with mean values of 119.87±16.35 ml and 154.57±33.23 ml, respectively (p=0.007). In the first group, AF recurrence was recorded in one patient after catheter treatment, in the second group in 5 patients.

Conclusion. Common areas of low-voltage activity in the left atrium, detected by high-density mapping before the procedure for catheter treatment of AF, are a predictor of arrhythmia recurrence after interventional treatment.

Aim. Aim of our study was the assessment of autonomic nervous system (ANS) modulation by assessment of heart rhythm variation (HRV) using Holter monitoring after single second generation cryoballoon ablation (CBA) for paroxysmal atrial fibrillation (AF).

Methods. Patients who underwent the CBA for paroxysmal AF were include in this study. At the baseline the Holter monitoring after withdrawal of antiarrhythmic therapy (AAT) with assessment of HRV: SDNN, RMSSD, ln LF, ln LH, LH/HF, mean, minimal and maximal beats per minute (BPM) was perform. Follow-up was based on outpatient clinic visits at 3, 6, and 12 months including Holter monitoring.

Results. Among 80 patients underwent CBA, HRV was assessed in 55 patients (65.5% male, age median 61 years, 97.7% of pulmonary vein have been successful isolated). One year after CBA all HRV parameters and the mean, minimal and maximal BPM was significantly different from baseline parameters (p<0.05). In the AF recurrence group ln LF was lower at 3-, 6and 12-month visits (p<0.05) and minimal HR was higher at 3 months (median 58 vs 55.5, p=0.033). Multivariate analysis demonstrated that early recurrence of AF was independent predictor of AF recurrence after CBA (HR 7,44, 95% CI 2,19-25,25, р=0,001).

Conclusion. Our study demonstrated that CBA leads to modulation of ANS which persists for at least 12 months. The early recurrence of AF was only predictor of AF recurrence after CBA.

Aim. To study and compare the lesions characteristics of laser energy in heart ex vivo and in experimental large animals.

Materials and methods. For the ex vivo experiment a pig heart was obtained from a local slaughterhouse. Laser applications were applied using power 15-30 W in the left and right ventricles 5-50 seconds in duration. Immediately after ablation, examination was performed to determine myocardial damage characteristics at each point. In the experimental study, 7 sheep were included, laser applications were performed under fluoroscopic control in the right atrium with power 10, 15 and 20 W, 10-25 s; in the right ventricle 20, 25 and 30 W for 10-40 s; and in the left ventricle 20, 25 and 30 W for 20-40 s. The animals were euthanized and macroscopic examination of laser lesions was performed.

Results. A total of 27 laser applications were performed on the heart ex vivo, all lesions were visualized as white spots on the endocardial surface. The maximum lesion depth was 9 mm achieved when using 20 W /50 s, the maximum lesion diameter was 6 mm, when using 25 W /40 s. The minimum lesion diameter and depth were observed when using 30 W /5 s, 2x1 mm. A total of 48 laser applications were performed in experimental animals, in one experimental animal was observed a transmural lesion in the right atrium when using 15 W /20 s. In 3 out of 7 experimental animals, transmural lesions were observed in the right ventricle when using 20 W /30 s; 20 W /40 s and 30 W /10 s. In the left ventricle, transmural lesions were observed in 2 animals, using 15 W /20 s and 20 W /40 s. In the ex vivo study, there was a strong positive correlation between ablation energy and lesion depth (R=0.91, P<0.05) and lesion volume (R=0.73, P<0.05); while there was no such statistical correlation in vivo.

Conclusions. Laser ablation 15-20 W for 15-40 s seems to be optimal for achieving the deepest lesions in the atrium and ventricular myocardium. In our small pilot study with fiberoptic catheter ablation on a beating heart there was no correlation between energy delivered and the depth and volume of necrotic myocardium.

Assessment of the quality of life in patients with cardiac arrhythmias using questionnaires is increasingly becoming the subject of clinical studies. However, there are no uniform criteria and standard norms for assessing the quality of life. Each questionnaire has its own criteria and assessment scale. This review presents the main general questionnaires that have been used in world practice to assess the quality of life in cardiology and arrhythmology. Special questionnaires are considered, which are used to clarify the parameters of the quality of life of interest in cardiac arrhythmias. Particular attention is paid to the assessment of this indicator in patients with ventricular arrhythmias.

A clinical case report of late diagnosis (in relation to clinical manifestation) of the classic phenotype of Fabry disease in patient with cardiac involvement: phenocopy of hypertrophy cardiomyopathy, cardiac arrhythmias and conduction abnormalities.