Vaičiulytė, Ona Rūta

The aim - to examine several pts before and after restoration of sinus rhythm (SR) by radiofrequency ablation and determine the presence of multiple AV nodel pathways in pts with permanent atrial fibrilation (PAF). Material and methods 64 pts with PAF were involved in study. SR was restored for 19 pts by radiofrequency catheter ablation. For each pts in this group, 500 RR intervals were recorded at rest, during orthostasis, and during exercises. The number of peaks on the RR interval histogram (RR IH) was determined. The test was repeated next day after successful radiofrequency ablation. Results. The RR IH analysis in pts with PAF showed that there were three types of RR interval histograms: unimodal, bimodal and polymodal. A single peak RRIH was found in 45% of pts, 40% of pts had two peaks, and 15% of pts had three or more peaks. After ablation, ventricular rate, heart rate variability, and/or number of peaks decreased in all pts. This suggested the present of multiple AV nodal pathways during atrial fibrilation. According to our data, this method may prove to be useful in selecting pts with PAF who are considered as data, this method may prove to be useful in selecting pts with PAF who are consiudered as candidates for radiofrequency modification of AV nodal conductive as opposed to AV nodal ablation. Conclusions: The computer-based RR IHanalysis method in patients with atrial fibrilation is a non-invasive method useful for investigation of AV function, morphology, or clinical aspects.

Thermography (TG) is used as a contact free method for investigation of the myocardium ischemic injury. In coronary bypass surgery without artificial blood circulation it is important to know how cessation of blood supply affects the myocardium. In experiments on working heart, TG allows monitoring temperature at the desired point of the epicardium. The aim was to investigate relations between myocardial ischemia and temperature and to prove that the ischemic tissue and border zones can be determined by TG. Experiments were performed on mongrel dogs. In the areas of induced ischemia, ventricular surface thermograms (T) and electrograms (EG) were recorded. The obtained data showed that temperatures in ischemic area and border zone of myocardium were different from those in healthy myocardium. A detailed analysis of T of ischemic area showed that between ischemic and healthy myocardium a border zone is formed which is very important for arrhythmia genesis. The border zone is several millimeters wide, and its temperature is 1°C higher than in healthy myocardium. The curve of the dynamics of temperature measured at all points of the ischemic zone has been created. Correlation between myocardium temperatures and characteristics of EG of ischemic zones is shown. Conclusion. The data show that TG is an appropriate method for determination of ischemic area and border zone in ventricular myocardium. TG gives a possibility to evaluate functional status of myocardium in a contact free way and may be applied for determination of ischemic damage of myocardium during cardiosurgery.

Uždaviniai 2009 metams: 1. Išeminės širdies ligos diagnostikos klinikinių sprendimų palaikymo sistemos medicininių žinių banko pildymas naujomis žiniomis, gautomis iš intelektualios duomenų analizės bei kompleksiškumo įverčių. 2. Funkcinių mėginių analizės metodų kūrimas vertinant žmogaus organizmo kompleksiškumo kitimus. 3. Kompleksinių sistemų teorija pagrįstų metodikų adaptacija ir taikymas širdies funkcijos vertinimui analizuojant sinchroniškai registruotus įvairaus pobūdžio širdies elektrinius signalus. 4. Širdies kraujotakos atstatymo proceso vertinimui skirtų kompleksinių sistemų teorijos metodų kūrimas ir testavimas. 5. Algoritmų ir programų, skirtų ramybės EKG kompleksiškumo pereinamųjų procesų širdyje po intervencijų vertinimui kūrimas. 6. Širdies diastolinės funkcijos nepakankamumo vertinimas netiesinės analizės metodikomis. [...].

The aim is to compare peculiarities of heart rate variability and autonomic nervous control in patients with atrial fibrilation after restoration simus rhythm by electrical, medical cardioversion and catheter ablation. Atrial fibrillation was diagnosed in 80 patients. The study has shown that functional cardiovascular reserve and autonomic nervous system control in early period after recovery sinus rhythm of the patients with atrial fibrillation treated by medical cardioversion and catheter ablation were better expressed.

The evaluation of the monopolar epicardial electrogram parameters was used to detect and evaluate the ischemic injury of myocardium in experiments and clinic. Experimental data shows that prolongation of monopolar electrogram duration and elevation of ST and T amplitude are informative parameters for evaluation of ischemic injury of heart tissue.

The aim of the study was to evaluate the peculiarities of heart rate variability and autonomic nervous system regulation and to predict the changes in sinus rhythm after successful medical or electrical correction. 72 patients with atrial fibrillation before and after its correction have monitored. Atrial fibrillation during the first month after cardioversion occurred in 26,3 % of patients. Data analysis using computerized heart rhythm analysis showed a decreased heart rate variability in patients during atrial fibrillation and increased heart rate variability. These parameters are the markers which characterize the sinus rhythm maintenance.

The aim of the study to establish and compare the heart rate (HR) reactions to active orthostatic and deep inspiration tests (AO; DI) in patients with heart rate disorders. 500 RR intervals were recorded in the lying position, during AO, again in lying position, during DI and delay for ten second then two minutes after last test. There were determining the maximal heart rate values parameters in response to AO and in response to DI. Heart rate reaction to deep inspiration test sometimes might be an useful to evaluate heart rate autonomic regulation.