Pavol Švorc

By Pavol Svorc, Alexander Marossy, Pavol Svorc, Jr., Sona Gresova, Marek Buzga and Benjamin L. Fulton

Part of the book: Cardiac Arrhythmias

By Pavol Svorc, Ivana Bacova, Pavol Svorc, Jr., Monika Novakova and Alexander Marossy

Part of the book: Cardiac Arrhythmias

By Pavol Svorc

The design and development of experimental, in vivo, chronobiological animal models may help reveal some of the relationships between circadian rhythms and biological functions. In vivo experiments require the use of appropriate anesthesia, which should be selected according to their particular effect on the organism. The aim of study was to review the status of acid-base balance and ion concentration in arterial blood under common used general anesthesias in experiments in dependence on the light-dark (LD) cycle in spontaneously breathing rats. The experiments were performed using 3- to 4-month-old pentobarbital(P)-, ketamine/xylazine(K/X)-, and zoletil(Z)-anesthetized female Wistar rats after a 4-week adaptation to an LD cycle (12 h light and 12 h dark). We concluded that P anesthesia disturbs LD dependence of acid-base balance compared to K/X and Z anesthesia, but LD differences in plasma ion concentrations are disturbed under all type of general anesthesia. P anesthesia is not the most appropriate type of anesthesia in rat chronobiological experiments. It eliminated LD differences and also produces a more acidic environment, more pronounced hypercapnia and hypoxia than K/X and Z anesthesias. This should be taken into account because the altered internal environment may affect the activity of systems whose functions are primarily dependent on acid-base balance.

Part of the book: Circadian Rhythm

By Pavol Svorc

Part of the book: Autonomic Nervous System

By Pavol Švorc

Part of the book: Chronobiology

By Pavol Svorc Jr and Pavol Svorc

The aim was to evaluate the current state of the autonomic nervous system (ANS) activity under general anesthesia using heart rate variability (HRV) in dependence on the light-dark (LD) cycle in healthy, sexually mature, spontaneously breathing, zoletil-anesthetized (30 mg/kg) Wistar rats of both sexes after a 4-week adaptation to an LD cycle (12 h:12 h). The animals were divided into four experimental groups according to sex and light period (n = 20 each). RR interval duration, spectral power at very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF), total spectral power of HRV, and the LF/HF ratio were analyzed. Sympathetic and baroreceptor activity was decreased, and parasympathetic activity was increased in both sexes and in both light periods. Regarding sex differences, HRV was significantly lower in females versus males in the light period. In the dark period, females exhibited higher HRV than males. Regarding LD differences, in females, HRV was lower in the light versus the dark period, unlike males, in which HRV was higher in the dark versus the light period of the rat regimen day. Sex differences in the activity of the ANS were apparent in rats, persisted under general anesthesia, and were dependent on the LD cycle.

Part of the book: Autonomic Nervous System

By Pavol Svorc Jr and Pavol Svorc

General anesthesia is an established and well-known factor with a significant impact on cardiac parameters, which can be a problem in the final evaluation of changes in the individual electrophysiological myocardial parameters after various interventions. The present chapter provides a composite review of published data on electrocardiographic parameters (heart rate, PR interval, P wave duration, P wave amplitude, QRS complex, QT and QTc interval duration, and R wave and T wave amplitude) for in vivo rat experiments under general anesthesia from 130 articles, which were retrieved from a search of the Web of Science database, for articles published mainly between 2000 and 2021. ECG parameters reported as baseline or control values were summarized, and averages with ranges were calculated. It is important to be cautious in interpreting the results of such studies and discussions addressing the mechanisms underlying a given type of arrhythmia, it is important to acknowledge that initial ECG parameters may already be affected to some extent by general anesthesia as well as by sex and the time of day the experiments are performed. Although it is not an original research work, researchers working with rats in the laboratory, who routinely perform anesthesia, can use this as a reference to look into while analyzing their data.

Part of the book: Novel Pathogenesis and Treatments for Cardiovascular Disease