Return of spontaneous circulation and heart rhythm during the first analysis of the heart electrical activity

Introduction. Return of spontaneous circulation (ROSC) of a patient with cardiac arrest is the main goal of carrying out cardiopulmonary resuscitation.Aim. Evaluation of frequency of return of spontaneous circulation depending on the heart rhythms in the first moment of heart electrical activity.Material and methods. Analysis of 105 cases of sudden cardiac arrest in out-of-hospital conditions on the premises of Brzozow Emergency Medical Service from September 2016 to the end of February 2018. The data was collected from intervention medical cards and medical rescue procedure cards. Statistical analysis was carried out using STATISTICA software. Statistical significance was assumed to be p<0.05.Results. Sudden cardiac arrest in the analysed group applied to 62.9% of men. Return of spontaneous circulation was achieved only in 16 out of 105 cases (15.2%) of sudden cardiac arrest. The analysis has indicated that ROSC was successful among 66.67% of patients, who during the first analysis of the rhythm, represented cardiac arrest in VF/pVT, what constituted 75% of all ROSC cases in the analysed group. Comparison between ROSC and rhythm during the first evaluation of the rhythm showed statistical significance (p=0.00). Statistical significance was also shown in the relationship between ROSC and the average age of the patient (p=0.0155).Conclusions. Sudden cardiac arrest, when diagnosed in the first analysis of the rhythm VF/pVT, has bigger chances for return of spontaneous circulation than it has in other rhythms.

Interrelation between the number of ectopic foci and the chaoticity degree of ventricular fibrillation

Электрическая активность сердца при фибрилляции желудочков регистрируется на ЭКГ как хаотичное чередование разных по амплитуде и длительности возбуждений. Для количественного анализа этих показателей широко используются методы математического моделирования и теории хаоса. Цель исследования - использование методов математического моделирования для изучения взаимосвязи между степенью хаотичности процесса фибрилляции желудочков и количеством эктопических фокусов, функционирующих в миокарде желудочков. Электрическую активность сердца при фибрилляции желудочков моделировали суммой N-независимых импульсных потоков с различными амплитудно-частотными и фазовыми характеристиками. Степень хаотичности электрической активности сердца оценивали с помощью энтропии и фазовых портретов амплитуд фибриллярных осцилляций. Методом компьютерного моделирования рассчитывали теоретические зависимости степени хаотичности фибриллярных осцилляций от количества импульсных потоков. Результаты теоретических расчетов сопоставляли с результатами физиологических экспериментов, выполненных на крысах и собаках. Показано, что степень хаотичности фибриллярных осцилляций различна у крыс и собак и зависит от числа эктопических фокусов, функционирующих в миокарде желудочков. Для крыс были характерны двухочаговые типы моделей фибрилляции желудочков, для собак - многоочаговые (4-5 фокусов) типы моделей. Cardiac electrical activity during ventricular fibrillation shows on electrocardiogram as chaotic alternation of excitations different in amplitude and duration. Methods of mathematical modeling and the chaos theory are widely used for quantitative analysis of these irregularities. The aim of the present work was using methods of mathematical modeling to study the interrelation between the chaoticity degree of ventricular fibrillation and the number of myocardial ectopic pacemakers. Cardiac electrical activity during ventricular fibrillation was modeled as a sum of N independent pulse streams with various amplitude-frequency and phase characteristics. The chaoticity degree of heart electrical activity was estimated using entropy and phase portraits of fibrillar oscillations. Theoretical dependences between the chaoticity degree of ventricular fibrillation and the number of pulse streams were calculated using computer modeling. Results of computer experiments were compared with those of real physiological experiments on rats and dogs. The chaoticity degree of fibrillar oscillations was shown to be different in rats and dogs and dependent on the number of ectopic pacemakers functioning in the myocardium. Two-focal types of ventricular fibrillation models were characteristic of rats and multifocal (4-5 foci) types we characteristic of dogs.

Computerized electrocardiogram in agoutis (Dasyprocta prymnolopha Wagler, 1831) anesthetized with ketamine and midazolam

ABSTRACT: An electrocardiogram is a test that assesses heart electrical activity and is applied more frequently in the veterinary care of wild animals. The present study aimed to define the electrocardiogram pattern of agoutis (Dasyprocta prymnolopha Wagler, 1831) anesthetized with ketamine and midazolam. Eighteen clinically healthy agoutis (D. prymnolopha) were used from the Nucleus for Wild Animal Studies and Conservation (NEPAS) of the Federal University of Piauí, Brazil. The animals were chemically restrained with 5% ketamine hydrochloride at a dose of 15mg/kg and midazolam at a dose of 1mg/kg by intramuscular injection. Electrocardiogram tests were carried out by a computerized method with the veterinary electrocardiogram [Acquisition Model for Computer (ECG - PC version Windows 95) Brazilian Electronic Technology (TEB) consisting of an electronic circuit externally connected to a notebook computer with ECGPC-VET (TEB) software installed on the hard disc. In analysing the EKG results, significant differences were observed for QRS complex duration, PR and QT intervals and for R wave millivoltage between the genders; but we observed a significant influence of weight despite the gender. In the present experiment, the anaesthetic protocol was shown to be well tolerated by the agoutis, and no arrhythmias occurred during the time the animals were monitored. The reference values obtained should be used to better understand the cardiac electrophysiology of the species and for its clinical and surgical management.