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The crista supraventricularis and septomarginal trabecula are common elements of the right ventricle, and determine many hemodynamic phenomena. The morphological analysis of both structures in regard to their mutual relations was the aim of this study. The study was carried out on the material of preserved human hearts--fetuses, children and adults. The size and development of the crista supraventricularis was carefully evaluated. The division of its lower part, and hence the possibilities of development of the septomarginal trabecula, was divided into five types (A, B, C, D and E). The most common was type B, containing two muscular trabeculae. The width of the crista varied 1/5-3/5 of the width of the interventricular septum. On the basis of this study, a conclusion of morphological unity of the septomarginal trabecula and crista supraventricularis was drawn.

The aim of this study was ultrasound evaluation of atherosclerotic plaque morphology in relation to the degree of coronary artery lumen narrowing in patients with ischaemic heart disease. Intravascular ultrasound was performed on 38 patients (30 men and 8 women) aged 35 to 77 (average age 60 +/- 11 years old) with symptoms of ischaemic heart disease. The structure of atherosclerotic plaques with a degree of lumen narrowing of < 50% (1st group) was distinctly different from the structure of plaques with a degree of lumen narrowing of 50-75% (2nd group, p = 0.0045) and the structure of plaques with a degree of lumen narrowing of >/= 75% (3rd group, p < 0.001). The incidence of soft plaques decreased, whereas the percentage of mixed and hard plaques increased gradually with the increase in the degree of artery lumen narrowing. Significant differences in the incidence of plaque calcification were observed between the groups evaluated with crosssections of different degrees of lumen narrowing (p = 0.0032). The smallest number of calcifications was discovered in the 1st group as compared to the 2nd (p = 0.0027) and the 3rd group (p = 0.0026). With a higher degree of lumen narrowing, a lower percentage of eccentric plaques and a higher percentage of concentric plaques were observed. There were more eccentric plaques and fewer concentric plaques in cross-sections of the 1 st group as compared to the 2nd group (p = 0.0056) and the 3rd group (p = 0.0018). A comparison between the 2nd and 3rd groups showed no significant difference in the incidence of eccentric or concentric plaques (p = 0.5). In conclusion, intravascular ultrasound evaluation revealed significant relationships between the structure, presence of calcifications and location of atherosclerotic plaques and the degree of artery lumen narrowing. The incidence of mixed, hard, calcified and concentric plaques increased, whereas the percentage of soft, non-calcified and eccentric plaques decreased gradually with the increase in the degree of artery lumen narrowing.

Unlabelled: In most papers atherosclerotic remodelling was assessed in one segment of each studied artery. Such mode of study makes impossible to investigate the homogeneity of the remodelling. The aim of the study was intravital assessment by means of intravascular ultrasonography (IVUS) of the incidence of positive and negative remodelling in coronary artery segments and verification of the hypothesis that remodelling is inhomogeneous within the same artery., Method: Remodelling was assessed quantitatively by IVUS (3.5 F; 20 MHz Visions Five-64 F/X catheters, Oracle In-Vision Imaging System, Endosonics Corp. USA) in 48 segments of 27 coronary arteries. On the base of the difference between total vessel area (TA) at lesion site and reference cross-section (plaque area < 35%) remodelling was classified as negative, positive or absent. In 13 arteries out of 27 studied arteries more than 1 segment was assessed, containing both cross-section with > 50% stenosis and reference cross-section., Results: Positive, negative and absent remodelling was observed in 54%, 29% and 17% of segments, respectively. The analysis revealed two different types of remodelling in 7 out of 13 arteries with several analysed segments. This finding demonstrates that remodelling is inhomogenous within the artery (p < 0.006)., Conclusions: Compensatory enlargement is the most common response of coronary arteries to atherosclerotic plaque development followed by negative remodelling and absence of remodelling. Not homogenous remodelling within the same artery suggests a prominent role of local factors in determining the type of response of the artery to plaque accumulation.

Cardiac arrhythmias have troubled patients and fascinated physicians for centuries. The twentieth century was an era of progress, when the mechanism of cardiac disorders became more commonly recognised. Arrhythmias may be due to abnormalities of automaticity, to abnormalities of conduction, or to a combination of both. In order for re-entry to occur, an area of slowing conduction combined with unidirectional block must be present. Much investigation has centred on the underlying re-entry mechanisms of atrial flutter. In the light of these facts, it would seem that a close acquaintance with the detailed topography of the vena cava orifice (cavo), coronary sinus orifice (sinus) and the attachment of the septal leaflet of the tricuspid valve (tricupid) area could be of great interest, especially for invasive cardiologists. The research was conducted carried out on material consisting of 41 hearts of humans of both sexes from the age of 12 to 80 (6 female, 35 male). Classical macroscopic methods of anatomical evaluation were used. The following measurements were made: the shortest distance between the Eustachian valve and the attachment of the tricuspid valve on the left margin of the coronary sinus orifice (diameter 1), the distance between the attachment of the tricuspid valve and the inferior margin of the sinus orifice (diameter 2), the distance between the Eustachian valve and the attachment of the tricuspid valve on the right margin of the coronary sinus orifice (diameter 3), the distance between the inferior margin of the vena cava inferior and the attachment of the tricuspid valve (diameter 4) and, finally, the diameter between the attachment of the septal cusp of the tricuspid valve and the extemal border of the vena cava inferior (diameter 5). No correlation was found between the age and sex of the three groups of the material. The dimensions of the structure examined were similar in the three groups of hearts. In young adult hearts all the diameters measured ranged from 4 to 47 mm. The average diameters were, respectively: 15.02 mm (diameter 1), 8.97 mm (diameter 2), 17.27 mm (diameter 3), 26.87 mm (diameter 4), 36.42 mm (diameter 5). In the mature adult hearts all the diameters measured ranged from 8 to 45 mm; 18.19 mm (diameter 1), 10.54 mm (diameter 2), 19.95 mm (diameter 3), 28.90 mm (diameter 4), 39.63 mm (diameter 5). In the older adults hearts all the diameters measured ranged from 4 to 47 mm. The average diameters were, respectively: 15.65 mm (diameter 1), 8.70 mm (diameter 2), 7.25 mm (diameter 3), 26.80 mm (diameter 4), 35.85 mm (diameter 5). On the basis of our study we were able to conclude that the diameters of the cavo-sinus-tricuspid area were constant and did not differ significantly within the three (young, mature, old) adult groups examined.

The majority of anatomical structures within the heart during typical atrial flutters' ablation, right sided accessory pathway ablation or slow pathway ablation are invisible or blurred. Therefore it is very important to know in details interior right atrial structures during such procedures. In the neighborhood of coronary sinus orifice small concavity is visible. This area, called subthebesian fossa, is placed between the os of coronary sinus, the orifice of vena cava inferior and tricuspid annulus. The fossa is on the way of typical atrial flutters' reentrant circuit and is placed next to the isthmus area, which has become a target site for ablative therapy. Regarding the facts mentioned above we decided to examine the topography of this concavity in relation to neighboring structures. Research was conducted on material consisting of 45 human hearts of both sexes, from 19 to 71 years of age. The hearts came from patients whose death was not cardiologic in origin. The topography of the fossa was examined in relation to coronary sinus orifice (diameter A), vena cava inferior orifice (diameter B) and the attachment of the posterior leaflet of the tricuspid valve (diameter C). Besides we measured two perpendicular sizes in the inlet plane of the fossa. There were the longest size (diameter D) and the shortest size of the fossa (diameter E). We also defined deepness of the fossa (diameter F). Diameter A was from to 2 to 7mm (avg. 4.9 +/- 1.4 mm), diameter +/- from 2 to 8mm (avg. 4.0 +/- 1.6 mm) and diameter C from 5 to 9 mm (avg. 7.0 +/- 1.5 mm). The longest size in inlet plane of the concavity (diameter D) was from 12 to 18 mm (avg. 14.1 +/- 1.7 mm) and shortest size (diameter E) was from 7 to 14 mm (avg. 9.0 +/- 1.7 mm). The deepness of the fossa (diameter F) was from 2 to 7 mm (avg. 4.8 +/- 1.2 mm). The subthebesian concavity is inconstant anatomical structure, occurring in all forty five examined hearts (100%). The shape and sizes of the subthebesian fossa were variable in examined group of hearts. Our data suggest that differences in diameters between subthebesian fossa and neighboring structures may have clinical importance during ablation procedure.

Background: A degree of reduction of heart rate (HR) and blood pressure (BP) values following beta-blocker administration has been shown to indicate beta-blockade effectiveness. Whether this parameter is also useful in the identification of patients with vaso-vagal syncope (VVS) who could benefit from beta-blocker therapy, has not yet been established., Aim: To analyse the usefulness of propranolol-induced acute changes in HR and BP in the prediction of the results of tilt testing (TT) in patients with VVS., Methods: The study group consisted of 37 patients with a history of at least two syncopal episodes in the past 6 months, in whom syncope was reproduced during TT. After positive baseline TT the patients were returned to supine position and were given intravenous propranolol. After 15 min supine rest the patients were tilted again using the same protocol as during the baseline test. Propranolol was considered effective when the result of the second (on drug) TT was negative or the time to syncope occurrence was longer than during baseline TT. During the whole procedure systolic BP (SBP), mean BP (MBP), diastolic BP (DBP) and HR were measured. These parameters were analysed in four different time-intervals: period I - between 13th and 15th minute of supine rest preceding the passive phase of TT, period II - between first and third minute of the passive TT, period III - following propranolol injection, between 13th and 15th minute of supine rest preceding second TT, and period IV - between first and third minute of second TT, either passive (if positive) or after NTG administration. Both, mean values and differences (Delta) in analysed parameters between various time-intervals (II-I, III-I, IV-II and IV-III) were taken into account., Results: Intravenous propranolol occurred effective in preventing syncope during second TT in 29/37 (78%) patients. The DeltaSBP, DeltaMBP and DeltaDBP values calculated from periods III and IV were significantly different between patients with or without protective effects of propranolol. The cut-off values which were computed to obtain the highest value of total predictive accuracy (the highest value of the sum of sensitivity and specificity) were -5 mmHg for DeltaSBP, -4 mmHg for DeltaMBP and -2 mmHg for DeltaDBP. A stepwise logistic regression analysis revealed that DeltaSBP of -5 mmHg or less had the highest value in the prediction of a positive response to propranolol, reaching a sensitivity of 72%, specificity of 88%, positive predictive value of 95% and negative predictive value of 48%., Conclusions: Propranolol-induced changes in blood pressure values may predict the effectiveness of beta-blockade in preventing syncope during second TT performed after intravenous infusion of propranolol. A drug-induced reduction in systolic blood pressure of less than 5 mmHg may identify those who will benefit from beta-blocker therapy.

One of the hypotheses put forward concerning the mechanism of vasovagal syncope is that the vagal afferent fibres are activated during vigorous contractions against a partly empty left ventricle. The aim of the study was to confirm this hypothesis by using 2D echocardiography during a head-up tilt test. The study was carried out on 39 patients (17 male, 22 female, age range 21-64 years), all with a history of recurrent syncope. The patients were examined using a 2D echo to measure the end-diastolic and end-systolic volume before the head-up tilt test after the Westminster protocol (45 min/60 grade) and every five minutes after tilting. T patients during head-up tilt test had a positive response and 32 proved negative. A reduction of both the end-diastolic and end-systolic volumes of the left ventricle was noticed. There was no significant difference in the degree of ejection fraction reduction. The difference in ejection fraction reduction between the two groups was similarly non-significant. It was also noticed that the patients with a positive response had more vigorous contractions than those with a negative test. The decision was therefore taken to use a different parameter for the left ventricle contraction, namely the LV posterior wall slope. As this parameter is partly dependent on time, its use in confirming the extremely vigorous nature of the contractions was considered appropriate. Only 6 patients were tested using this parameter. A tendency towards greater left ventricle posterior wall slope values, both before and during tilting was noticed in the group of patients with vasovagal reaction. Our data shows that vigorous contraction is probably less responsible for vasovagal syncope release than left ventricle volume reduction.

The typical atrial flutter is the most common supraventricular tachycardia with reentrant circuit. This tachyarrythmia is based on macroreentry wave going around established anatomic landmarks. The reentry in the inferior right atrial wall passes through narrow isthmus, which is the goal for ablative therapy. The isthmus area is bordered anteriorly by the tricuspid valve and posteriorly by the inferior vena cava, coronary sinus, and eustachian ridge. Near to this area we can find anatomical structure, which can be very important during arising, perpetuation and curing of atrial flutter. The concavity, so-called subthebesian fossa, is on the way of typical atrial flutters' reentrant circuit. Regarding the facts mentioned above we decided to examine the morphology and the arrangement of the muscle fibres in this fossa. Research was conducted on material consisting of 70 human hearts of both sexes from the age of 34 to 72 years. 50 hearts came from patients whose death was not cardiologic in origin. 20 hearts came from humans in whose common atrial flutter was confirmed. We observed the arrangement of muscle fibres in the area of subthebesian fossa. Besides we measured the size and deepness of the subthebesian fossa in both groups of hearts. We found that regular arrangement of muscle fibres within subthebesian fossa was present in 23 healthy human hearts (46%) and 7 cases (35%) of hearts with atrial flutter. The irregular arrangement of muscle fibres was observed in 27 hearts (54%) of control group and 13 hearts (65%) with dysrrhythmia. The thickness of the right atrial wall within the subthebesian fossa was very thin in 8 normal hearts (16%) and in 5 dysrrhythmic hearts (25%). The sizes of examined structure were variable in both groups of hearts, and are presented in the table. It seems that the subthebesian concavity can be the substrate for reentrant circuit during atrial flutter, and there could be such special arrangement of muscle fibres, which allows for microreentrant circuit to arise in this area.

The atria are highly complex multidimensional structures composed of a heterogeneous branching network of subendocardial muscular bundles. The relief of the inner part of the right atrium includes the crista terminalis as well as multiple pectinate muscles that bridge the thinner atrial free walls and appendages. However, a handful of studies have focused attention on the role of the naturally occurring complexities of the atrial subendocardial muscle structures in the mechanisms of cardiac arrhythmias. In accordance with the facts mentioned above, it was decided to examine the morphology and topography of the external interatrial junctions and related structures in order to define the possible anatomical basis of impulse propagation in focal atrial fibrillation. Research was conducted on material consisting of 15 human hearts of both sexes (female--6, male--9) from 18 to 82 years of age. In addition we were concerned, on the basis of the history and electrocardiograph tracings, that none of the patients had shown focal and non-focal type of atrial fibrillation. The classic macroscopic methods of anatomical evaluation were used. The walls of the atria were prepared via a stereoscopic microscope, the pericardium and fatty tissue were eliminated from the surface of the atria, visualising muscle fibres linking both of the atria, and the beginnings and the endpoints of fascicles in the right and left atrium were estimated. The structure, large muscle bundle, was present in all examined hearts. The muscle fascicle was descending from the anterior wall of the right atrium just below the orifice of the superior vena cava. The fascicle, running towards the left atrium, divided into two branches, one of which joined with the superior fascicle from the posterior wall and created one running above the interatrial septum and infiltrating into the wall of the left atrium on its superior surface between the superior pulmonary veins. The other branch of the anterior fascicle was running across the anterior wall of the atria and it penetrated into the left atrium muscle in the region of the inferior pole of the left auricle outlet. On the posterior wall of the atria three types of interatrial fascicles were distinguished: unifascicular, bifascicular and trifascicular. The bifascicular type was the most frequent configuration (9 cases--60.0%), in 5 cases it was trifascicular (33.3%) and finally the unifascicular configuration was observed in just 1 heart (6.7%). On the basis of our study we can conclude that the external interatrial fascicles are the constant structure of the heart, although they may have a variable morphology. Those structures could be responsible for physiological conduction between the atria and may play an important role in patients with atrial fibrillation.

Atrioventricular nodal reentry tachycardia base on reentry circulation in nodal-perinodal area. The radical treatment of choice is radiofrequency ablation. Procedure approached from the anterior-superior (fast) region sufficient a few seconds of energy delivery for success, however this can result in A-V block. The possibility that arrhythmias substrate may lie very superficially (success of ablation) and damage the normal structures (complication) in the perinodal region must be considered. In order to confirm this hypothesis we examined the autopsy material of 100 normal hearts, both sexes from 18 to 105 years of age (control) and 50 hearts with A-V total block 45-95 years of age (block). We paid attention to the morphology of the nodal artery (NA), atrial inputs (AI) and transitional inputs (TI). It was observed that NA at the level of the central fibrous body was positioned in 94% in the central and in 6% in the inferior part of Koch's triangle. It was removed from the endocardium 3-6 mm in control and 2-5 mm in block group respectively (NS). In the perinodal area we distinguished AI that directly joined the A-V compact node: superficial (right part of the interatrial septum) or deep (left part). The former occurred in 100% of controls and in 80% of block groups (NS), and the latter in 80% of control group and in 34% in block respectively (p < 0.05). The real substrate of arrhythmia in anterior-superior region lies very superficially and far from the conduction tissue; NA in examined hearts was lying deep beneath the endocardium; ablation close to the node could result in A-V block.

About 25% of accessory pathways (AP) run via "posteroseptal" space (PSS). There are three approaches for ablation of these pathways: from the right atrium, from the left atrium or from the ventricle and coronary sinus (CS). However in some cases AP is too far from all of them. Catheterisation of the middle cardiac vein (MCV) seems to be the only chance for successful ablation. Our aim was to evaluate the topography of the MCV in PSS. Classical anatomical investigation was carried out on the autopsy material of 98 consecutive human hearts (42 F, 56 M; age 57 +/- 21 yrs). It was supported by transverse section performed under coronary sinus. Regions just behind the atrioventricular septum and behind the cavities were respectively classified as "septal", right (RP) and left posterior (LP). Between them right (RPS) and left posteroseptal areas (LPS) were present. At the posterior view of the heart the angle between CS and MCV ranged from 75 to 90 degrees in 62% of hearts, 60-75 degrees in 18%, 30-60 degrees in 10% and 90-130 degrees in 10%. In 16% MCV ran via the "septal" region, 59%--LPS, 10%--RPS, 10%--RP and 5%--LP. At the ostium of 58% MCV a valve was observed, however there was no trouble with insertion of the 6F catheter into it. We concluded that it is possible to insert the 6F catheter into MCV, which makes it possible to perform ablation of epicardial postero-inferior accessory pathways. The origin of MCV is usually located in the left "posteroseptal" region and runs towards the left side of the posterior wall.

Implantation of transvenous devices is a widespread procedure in clinical cardiology. It is well known that the presence of the electrodes in the cardiovascular system can induce fibrosis or fibrous adhesions between them and cause tricuspid regurgitation. Moreover there are suggestions that the placement of the electrode in the tricuspid orifice may also play a role in the development of tricuspid insufficiency because of the thickening of reactive leaflets and the impairment of their mobility in morphological studies. There are no papers regarding the topography of the electrode in the right ventricle judged by means of transthoracic echocardiography. Moreover in literature we did not meet reports comparing the localisation of the lead on the tricuspid valve function. Therefore we decided to describe the detailed topographic relations between the lead and the structures of the right ventricle in a larger population and we compared the influence of the lead location for tricuspid valve function. Research was carried out on a group of 86 patients (52 M, 34 F), with a mean age of 64.7 +/- 14.9 years with permanent cardiac pacemaker or implantable cardioverter-defibrillator (ICD). On the basis of echocardiograms performed we assessed the position of the lead regarding the tricuspid valve leaflets or commissure, and judged the course of the lead beneath the tricuspid valve level. Moreover special attention was focused on the placement of the tip of the electrode. We qualified its position into three categories: apex of the right ventricle, right ventricle outflow tract, and "para-apex" position. The degree of the tricuspid valve insufficiency was assessed by means of semiquantitative method based on the Color-flow Doppler echocardiography. We measured the extension and the area of the tricuspid regurgitant jet using four-gradual scale. We compared the topography of the lead at the level of the valve with its function by means of the presence and degree of its regurgitation. We stated that in 35% of cases the pacing lead was located at the level of the anterior leaflet of the tricuspid valve, in 23% at the level of the septal leaflet and in 12% at the posterior one. Besides in 10% the electrode was placed between the leaflets just over the commissures. On the other hand in the remaining 20% the lead was positioned centrally in the right atrioventricular orifice without adherence to any leaflet. Next we assessed the course of the lead beneath the tricuspid valve level and stated that most frequently (45%) it run just across the centre of the right ventricle, and in other cases was lying along the interventricular septum (in 39% of cases) or along the anterior wall of the right ventricle (in 16%). The tip of the lead was positioned exactly in the apex of the right ventricle in 74%, in the right ventricular outflow tract in 9% and in 17% its position was "para-apical". We did not see any statistically significant differences between the presence and intensification of valve regurgitation and topography of the lead. We concluded that at the level of the tricuspid valve the lead was positioned in the anteroseptal part of tricuspid annulus and the proper apical position of the electrode's tip occurred in approximately 75% of cases. Localisation of the electrode at the level of the tricuspid orifice does not influence its insufficiency as detected by Doppler echocardiography.

Permanent cardiac pacing is a method of choice in the treatment of specific arrhythmias and conduction disturbances. Clinical studies show that cardiac performance diminished at the site of impulse spreading. It determines local hypotrophy below the position of the pacing lead (early electric activation) with hypertrophic changes in the opposite lying myocardium (late electric activation). It seems that morphological changes, especially research by intravital methods, so relevant in permanent pacing to today's invasive cardiologist, are not understood in full. In connection with this we decided, on the basis on the echocardiographic examination, to evaluate in detail the morphology of the right ventricle and atrium in patients with permanent pacing. Research was carried out on a group of 124 patients (68 males, 56 females) from 40-93 years of age (avg. 68 +/- 14 yrs): 86 patients had implanted pacemakers or AICD (group I), the control group consisted of 38 patients with other cardiac diseases without any pacemaker devices (group II). We measured echocardiographically the following diameters: end-diastolic and systolic diameters of the right ventricle/atrium in short and long axis, diameter of the tricuspid orifice valve and calculated area of the tricuspid orifice based on a special formula. Regarding the morphometric parameters of the right ventricle and right atrium, we confirmed that all diameters of group I were overshooting in correlation to group II. Those differences, such as RVd-short and -long, RVs-long, RVinflow, RA-long and -short, TRId, were statistically significant. Regarding the area of the tricuspid orifice (TRIa), we did not observe any changes in the two examined groups. We concluded that patients with implanted devices have changes in the morphometric parameters of the right ventricle, atrium and orifice, but they do not depend on the duration of pacemaker implantation.

The structure of the heart has been the subject of many observations since the beginnings of medical research. The first information regarding the existence of the conduction system of the heart was described by Purkinje and regarding the a-v node by Tawara. From the history regarding this structure it seems that this special system, so relevant to today's invasive cardiologist, is not understood in full. With regards to the interventional electrophysiology on the basis of histological study we decided to evaluate in detail the morphology and the topography of the various portions of the a-v junction. In order to confirm this hypothesis we made observations on the autopsy material of 100 normal human hearts, both sexes from 16 weeks of foetal life to 105 years of age, in which no pathological changes or inborn faults were found. Sections were done containing the heart's septum, stained using Masson's method with Goldner's modification. This research proves that the atrioventricular junction is a stable structure occurring in all hearts, undergoing involutionary changes with age, in which two main parts can be differentiated: the node and the bundle. The morphology of the node is very complex, because it is composed of three zones: the prenodal, the perinodal and the main, differing in cell structure and position. The topography of the node is generally stable, as it lies in the interatrial septum and always above the septal leaflet of the tricuspid valve. The structure of the bundle, in contrast to the node, is more stable and consists of the following parts: the penetrating, the non-branching and the branching. Its topography is also stable, as it lies in the membranous septum, mainly below the septal cusp of the tricuspid valve.

Pacemaker lead extraction is the treatment of choice in infectious complications regarding implantation procedure. The purpose of this study was to estimate the safety of the extraction in relation to the morphological changes of the pacing electrode. Research was carried out on materials consisting of 60 human hearts from 45 to 95 years of age (average 63 +/- 15 yrs), with VVI or DDD pacing (pacing duration 84 +/- 26 months) fixed in a formalin solution. Classical macroscopic anatomical methods were applied. In 44 hearts (73.3%) from the investigated group the posterior tricuspid leaflet was thickened only, and in 24 of these hearts the process regarded not only posterior leaflet but also the septal one and especially commissure between them. In 52 hearts (86.6%) inflammatory reaction spread also to the neighbouring part of the electrode. The length of the neointima-inflammatory tissue ranged from 4 to 8 mm (average 5 +/- 2 mm). On the tip of the electrode in the right ventricle cavity in 56 hearts (93.3%) we observed that endocardial leads were surrounded by fibrous thickening, and partially covered by endocardial tissue. We concluded that from the anatomical point of view the extraction of the pacing electrode seems to be questionable, especially in long-term permanent pacing. The experimental traction shows that only recently implanted electrodes were removed without any complications and in others with fraction of the tip, myocardial tissue avulsion or such removal was not successful at all.

The anatomy of the conduction system of the heart so relevant in the contemporary invasive cardiology is not fully understood. It has turned out that ablation procedures bring new information as to its structure and function, but in some cases can result in complete a-v block. Atrioventricular nodal artery located within the nodal-perinodal tissue can probably be damaged during the ablation procedures. Therefore, we decided to explore in detail the morphology and the topography of the atrioventricular nodal artery in healthy humans and in patients with clinical traits of a-v conduction disturbances requiring permanent pacing. The microscopic study was carried out on 30 normal human hearts specimens (17 F, 3 M) from 17 to 86 years of age, and on 20 hearts with conduction disturbances (11 F, 9 M) from 39 to 85 years of age. We found that the number of the atrioventricular node arteries is different and independent of the extent that induces block causing conduction disturbances. The topography of the artery in perinodal zone was consistent in normal hearts, yet in hearts with conduction disturbances we observed about 2% of deviations in its location. It might be the reason for generation of iatrogenic complications after invasive cardiological procedures. The morphology revealed changes in 50% of the examined hearts and their vessel walls, which was declared to be connected with ageing. This correlated with certain stages of atherosclerosis as well as hypertension characteristic of elderly patients. We observed that in 33% of hearts from control group small parietal thrombi were detected and in 60% of paced group respectively. Hence, it seems that the procedures in perinodal zone should be performed in its proximal part because of a minor probability of direct and indirect (through nodal artery) damage of the atrioventricular structure of the junction.

Unlabelled: Permanent cardiac pacing is a widely applied procedure in invasive cardiology. The aim of our study was the analysis of the localisation of the tip of the pacemaker lead and its course in the right ventricle. Research was carried out on a group of 12 patients (5F, 7M), from 40 to 93 years of age (average 70 +/- 15 yrs) with permanent cardiac pacing or implantable cardioverter-defibrillator (ICD). Subsequent echocardiographic views were applied: an apical four chamber view, a subcostal one and a parasternal right ventricular inflow tract view. At the level of the tricuspid annulus the electrode was positioned: the anterior leaflet--41.7% (5 pts), the anteroseptal commissure 25% (3 pts), the posterior leaflet 8.3% (1 pt) and the septal one--8.3% (1 pt). In 16.7% (2 patients) the lead was positioned centrally in the right atrioventricular orifice. Regarding the further positioning of the electrode in the ventricle, in 41.7% (5 pts) the leads were placed along the interventricular septum, in 16.7% (2 pts) along the anterior wall of right ventricle and in 41.7% (5 pts) across the centre of the right ventricle. The tip of the lead was positioned in the apex of the right ventricle in 83.4% (10 pts). In the remaining 16.7% (2 pts) the position was not apical--in 1 patient the anterior wall of the right ventricle and in 1 patient the interventricular septum. In the VVI pacing mode the electrode did not lie on the interventricular septum. In contrast to this in 80% of patients (4 pts) having the DDD pacing mode the lead was situated on the interventricular septum on its course downwards to the ventricle., Conclusions: 1) On the level of the leaflets of the tricuspid valve the lead most often was positioned at the level of the anterior leaflet and the anteroseptal commissure. 2) Most patients had an apical localisation of the tip of the lead. 3) Differences between morphological and echocardiographic studies are related to the intravital and the two-dimensional character of echocardiography, and probably to the small population of the group examined.

Research was conducted on material consisting of 45 fetal, newborn, infant and adult human hearts. False tendons in fetal, newborn and infant hearts were made up of mainly heart muscle tissue. False tendons of the tendon attachment to the interventricular septum. These false composed of muscle tissue and connective tissue in various proportions. Most of the connective tissue was observed in this age group in the area of the tendin attachment to the interventricular septum. These false tendons turned out to be very richly vascularized. In some of them, elements of the conductive system was confirmed, being an extension of the left branch of the bundle of His. This may confirm the role of false tendons in heart arrhythmias.

Research was conducted on material consisting of 180 fetal, newborn, infant, and adult hearts of various ages. Upon opening of the left ventricle the frequency of occurrence as well as the morphology of the false tendons were examined in this heart chamber. Special attention was paid to false tendons running through the ventricular lumen. It was determined that these elements occur with similar frequency, accounting for about 40% of hearts, in all examined age groups. In fetal hearts, the greatest number of false tendons in the ventricular lumen ran between the interventricular septum and the exterior ventricular wall, finding its attachment generally just below the base of the papillary muscle. In newborn, infant and adult hearts the greatest number of false tendons connected the interventricular septum with the posterior papillary muscle.

A new model of the atrioventricular junction was developed by Anderson et al, of which each element has clinical significance and requires more specific research into its morphology and topography. Observations were carried out on materials consisting of 200 human hearts of both sexes of various ages (from 16 weeks of fetal life to 97 years of age). Histological slides were stained by Masson's method in Goldner's modification. It was concluded that the atrioventricular node consisted of two layers in all groups of examined hearts: cells of the compact area and transitional cells. With age, these cells change their morphology, especially in the transitional layer. Morphologically, within the atrioventricular bundle were differentiated. The topography of the atrioventricular node is dependent on the age of the examined heart. As much as in human adults it is found entirely within the triangle of Koch, in fetal and children's hearts its elements of its left branch were found in the false chordae tendinae of the left ventricle. The above observations suggest that in the case of younger hearts the triangle of Koch does not represent an absolute margination for the elements of the conductive system of the heart, which in the case of cardiac surgical procedures and ablations can in some percent, be the cause of iatrogenic complications.

The material consists of 50 human hearts without either pathological changes or congenital malformations. Macroscopic and microscopic methods were applied. Histological specimens were stained alternatively with hematoxylin-eosin and according to van Giesson and Masson. In each heart the tendon of Todaro was dissected from its portion situated between the inferior vena cava and coronary sinus up to central part of the membranous septum (Fig. 1). The hearts were divided into 3 groups according to age: fetuses (20 hearts), infants (15) and adults (15) (Table I). In all hearts of fetuses and infants the tendon of Todaro was found to be a well-developed cylindrical structure covered with endocardium. In histologic specimens the tendon was s solid structure well-separated from other tissues (Fig. 3, Fig. 4). In hearts of adults (17-45 years old) the tendon of Todaro was less evident. However, in histological specimens it was present as a compact connective tissue band (Fig. 2). In hearts of subjects older than 50, the endocardium of this area was not elevated and not distinguishable even by palpation. The connective tissue band was formed by rather dissipated fibres, poorly separated from surrounding structures. As a result of our study one may conclude that the tendon of Todaro is present in each human heart. It is well-developed in hearts of fetuses and infants. Later it diminishes gradually becoming almost inconspicuous in old subjects.