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[...]. Aim of the study. The purpose of the study was the evaluation the functional and structural changes undergoing in the cardiac intrinsic ANS of the sheep after the RFA of cardiac ganglionated plexuses of the left atrium during the 12-month follow-up. Study goals:1. Evaluation of basic HRV time (Heart rate, SDNN, RMSSD, pNN50, HRV TI) and frequency (HF, LF, VLF, LF/HF) domain parameter values for the sheep. 2. Perform the epicardial radiofrequency ablation in the LA at the PV roots of the sheep heart. 3. Evaluation of the cardiac intrinsic nervous system functional changes immediately after the procedure (2-3 days) and during the 12-month follow-up. 4. Evaluation of the structural changes of the cardiac intrisic ANS after the RFA in sheep heart. [...].

Fluorescent immunohistochemistry on the cardiac conduction system in whole mount mouse heart preparations demonstrates a particularly dense and complex network of nerve fibres and cardiomyocytes which are positive to the hyperpolarization activated cyclic nucleotide-gated potassium channel 4 (HCN4-positive cardiomyocytes) in the sinoatrial node region and adjacent areas around the root of right cranial vein. The present study was designed to investigate the morphologic and histochemical pattern of nerve fibres and HCN4-positive cardiomyocytes using fluorescent techniques and/or electron microscopy. Adrenergic and cholinergic nerve fibres together with HCN4-positive cardiomyocytes were identified using primary antibodies for tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), and the HCN4 channel respectively. Amid HCN4-positive cardiomyocytes, fluorescence and electron microscopy data demonstrated a dense distribution of nerve fibres immunoreactive for ChAT and TH. In addition, novel electron microscopy data revealed that the mouse sinoatrial node contained exclusively unmyelinated nerve fibres, in which the majority of axons possess varicosities with clear mediatory vesicles that can be classified as cholinergic. Synapses occurred without any clear terminal connection with the effector cell, i.e. these synapes were of "en passant" type. In general, the morphologic pattern of innervation of mouse HCN4-positive cardiomyocytes identified using electron microscopy corresponds well to the dense network of nerve fibres demonstrated by fluorescent immunohistochemistry in mouse sinoatrial node and adjacent areas. The complex and extraordinarily dense innervation of HCN4-positive cardiomyocytes in mouse sinoatrial node underpins the importance of neural regulation for the cardiac conduction system. Based on the present observations, it is concluded that the occurrence of numerous nerve fibres nearby atrial cardiomyocytes serves as a novel reliable extracellular criterion for discrimination of SA nodal cardiomyocytes using electron microscopy.

[...]. Aim of and objectives of the study. The aim of the study: to identify limits and innervation of the sinoatrial node in hearts of mice, rabbits and pigs. Objectives: 1. To examine the distribution of pacemaker cells within the right atrium. 2. To examine the density of innervation within the sinoatrial node. 3. To examine the distribution of neuronal somata within the sinoatrial node. 4. To examine neurochemical properties of neurons within the sinoatrial node. 5. To compare the morphology of neurons within the sinoatrial node. [...].

Darbo tikslas. Ištirti ir morfometriškai įvertinti dešiniojo prieširdžio ausytės miokardo nervinio rezginio sandaros pokyčių sąsają su miokardo išemija, širdies funkcinės būklės parametrais bei amžiumi. Ištirti 56 abiejų lyčių 20–94 metų žmonės. 39 tiriamieji priklausė sergančiųjų išemine širdies liga grupei. Jų amžiaus vidurkis – 63,83±15,67 metų. 17 žmonių priklausė kontrolinei grupei. Jų amžiaus vidurkis – 60,53±9,89 metų. Kontrolinę grupę sudarė mirusieji, kuriems, patologinio anatominio tyrimo duomenimis, nenustatyta kardialinė patologija, galėjusi sukelti širdies pažeidimą ar perkrovą. Sergančiųjų išemine širdies liga grupę sudarė ligoniai, kuriems atlikta aortos–vainikinių arterijų nuosruvio suformavimo operacija. Jiems buvo įvertintas vainikinių širdies arterijų stenozės laipsnis, pagrindiniai rodikliai, atspindintys prieširdžių dydį bei poinfarktinio rando susidarymą. Poinfarktiniai randai nustatyti 18 (46,2 proc.) ligonių, randų nerasta – 21 (53,8 proc.). Nervinio rezginio sandaros kiekybiniams pokyčiams vertinti atlikome morfometrinį tyrimą, kuriam buvo panaudoti neurohistocheminis ir vaizdo mikroskopinis metodai. Įvertinus morfometrinio bei klinikinių tyrimų duomenis, nustatėme, kad sergančiųjų išemine širdies liga nervinio rezginio struktūrų užimamas plotas yra 5,0±1,0 proc., jų perimetras – 10488±2134 μm, skaičius – 2698±981, o kontrolinės grupės tiriamųjų nervinio rezginio struktūrų užimamas plotas yra 6,0±1,4 proc., jų perimetras – 13008±4436 μm, skaičius – 3469±1511. Tiriamiesiems, kuriems buvo nustatytas poinfarktinis randas, nervinio rezginio struktūrų skaičius buvo mažesnis vidutiniškai 9,3 proc., užimamas plotas – 8,9 proc., perimetras – 9,7 proc., nei sergančiųjų išemine širdies liga, kuriems nebuvo rando [...]., The aim of this study was to investigate and evaluate morphometrically the relationship between changes in the structure of myocardial nerve plexus of the right atrium auricle and myocardial ischemia, parameters reflecting functional status of the heart, and age. A total of 56 females and males aged 20–94 years were investigated. Ischemic heart disease group consisted of 39 persons (their mean age was 63.83±15.67 years). The control group comprised 17 persons (the mean age was 60.53±9.89 years). Control group consisted of deceased persons who according to the pathologic and anatomic examination were not diagnosed with cardiac pathology leading to heart lesions or overload. Ischemic heart disease group consisted of patients who underwent aorta-coronary artery bypass grafting surgery. In ischemic heart disease group, degree of coronary artery stenosis was evaluated as well as the major indicators reflecting the size of atria and formation of postinfarction scar. After examination, postinfarction scars were found in 18 (46.2%) persons; no scars were found in 21 (53.8%) persons. Neurohistochemical method and video microscopy were employed for the evaluation of quantitative changes in the structure of the myocardial nerve plexus. In ischemic heart disease group, the structures of nerve plexus occupied 5.0±1.0% of the area, perimeter was 10 488±2134 mm, and number of the structures was 2698±981; the same parameters in the control group were 6.0±1.4%, 13 008±443 mm, and 3469±1511, respectively. In persons with postinfarction scar, the number of nerve plexus structures was lower by 9.3%, area by 8.9%, perimeter by 9.7% on average as compared to ischemic heart disease group without a scar. Regression analysis did not reveal any statistically significant correlation between the degree of coronary artery stenosis and quantitive parameters of nerve plexus (P>0.05) [...].

Objective. The epicardiac neural ganglia of the adult human heart are distributed in the seven neural ganglionated subplexuses. The aim of the present investigation was to determine the distribution of the epicardiac ganglia in human fetuses of different age, because intrinsic cardiac nervous system of the human fetus has not been enough investigated so far. Material and methods. In the present study seventeen human fetus hearts were investigated, in which epicardiac neural ganglionated plexus was visualized by histochemical method for acetylcholinesterase. Results. Analysis of the total hearts preparations showed that: (1) the epicardiac neural ganglionated plexus of the fetus at fifteen weeks of gestation has already differentiated into seven ganglionated subplexuses, structure of which is typical for the adult human heart; (2) the epicardiac plexus of fetuses at 15–40 weeks of gestation contains on average 865±40 epicardiac ganglia, that may widely range in number from 644 to 1193; (3) the largest number of the neural ganglia is concentrated on the posterior surface of both atria, where up to 76% of all ganglia maybe located; (4) the difference between the number of epicardiac ganglia in the human fetuses at the early (15–25 weeks) and late (26–40 weeks) stages of fetogenesis is not statistically significant (p>0.05). In conclusion, both the distribution and the number of the epicardiac ganglia of fetuses ranging from 15 to 40 weeks of gestation are not age-dependent but varied substantially from heart to heart.

The present study was performed in order to determine morphological agerelated changes of the human intracardiac ganglia. Paraffin sections of 40 ganglia from infants, adult and aged human hearts were stained with Picro-Mallory method. The ganglia area, nerve cell (with clearly visible nucleolus) area, neuron soma long axis length, perimeter, area of neuronal nuclei and neuron soma form factor were measured with the aid of computer images analyzing program “Sigma Scan Pro 5.0”. Also, the neuronal density and the area occupied by nerve cells per ganglion section were calculated. The relative frequency of satellite cells, in close contact with nerve cell soma, was estimated. Based on the data of this study, we concluded that the area of ganglia, neurons and their nuclei increased with age. Neuronal packing density significantly decreased, but the area occupied by nerve cells within the ganglia decreased non-significantly. Satellite cells were more numerous nearby ganglion neurons from infant hearts. Shape factor of neurons was stable between the groups. In conclusion, the present study confirms significant differences in the morphology of the intrinsic cardiac ganglia with age.

The aims of present study were to verify the topography of the intracardiac nerve subplexuses (INS) by using electrophysiological methods, its relations with sinoatrial (SA) node function and to investigate possibility of selective surgical SA node denervation. Fifteen mongrel dogs of either sex weighing 8 to 15 kg were used for electrophysiological studies. Both cervical vagosympathetic trunks were isolated and crushed by tight ligatures. Nervus subplexuses destructions were performed by cryocoagulation in three zones located around the right superior vena cava: ventral, lateral and dorsal. The sinus rhythm, SA node function recovery time, AV node conductivity, AV node and atrial effective refractory period were measured. Five experiments in each of three zones were performed. Experimental data show that destruction of the epicardial nerves has different effect on electrophysiological parameters. After destruction of the anterior zone of the right atrium the sinus rhythm decreased on an average by 11.6%; SA node function recovery time prolonged by 7.2%; AV node conductivity decreased by 13.1%; AV node effective refractory period prolonged by 12.9% and atrial effective refractory period, by 10.9 %. Measurements of electrophysiological parameters after intravenous injection of atropine sulphate show that sinus rhythm decreased on an average by 23.4%; SA node function recovery time increased by 9.1%; the conductivity of AV node decreased by 10.2%; AV node effective refractory period prolonged by 15.4% and atrial effective refractory period, by 13.2%. [...].