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Background: The three-dimensional electroanatomic mapping (EAM) system allows performing catheter ablation (CA) without fluoroscopy in patients with premature ventricular contractions (PVCs). The right ventricle outflow tract (RVOT) location is favorable for performing zero-fluoroscopy CA. Non-RVOT zero-fluoroscopy CA is a challenging procedure. The study aimed to evaluate the efficacy and safety of zero-fluoroscopy CA using the EAM in patients with PVCs from RVOT and non-RVOT., Methods: Completely zero-fluoroscopy CA of PVCs guided by EAM was performed in 107 patients with PVCs. 54 patients underwent zero-fluoroscopy RVOT CA. The remaining 53 patients underwent zero-fluoroscopy non-RVOT CA. Demographic and clinical baseline characteristics, procedure parameters, and follow-up were obtained from medical records. Primary outcomes were the acute and the permanent success rate (12-month follow-up), complications, and procedure time., Results: There were no significant differences between groups regarding baseline characteristics. Acute procedural success was achieved in 52 patients (94,44%) in the RVOT zero-fluoroscopy CA group and in 45 patients (86,54%) in the non-RVOT zero-fluoroscopy CA group (ns). A long-term success rate was achieved in 50 patients (90,74%) in the RVOT zero-fluoroscopy CA group and in 44 patients (84,62%) in the non-RVOT zero-fluoroscopy CA group (ns). The median procedure time was 80.5 minutes in the RVOT group and 90 minutes in the non-RVOT group (ns). There were two complications in the non-RVOT group (ns)., Conclusions: There were no differences in procedure time efficacy and safety zero-fluoroscopy ablation between RVOT and non-RVOT locations. Non-fluoroscopy CA of PVCs is a feasible, safe, and efficient procedure.

Background: Atrial fibrillation (AF) in patients with Wolff-Parkinson-White (WPW) syndrome is potentially life-threatening as it may deteriorate into ventricular fibrillation. The aim of this study was to assess whether the emergency medical team members are able to diagnose AF with a rapid ventricular response due to the presence of atrioventricular bypass tract in WPW syndrome., Methods: The study group consisted of 316 participants attending a national congress of emergency medicine. A total of 196 questionnaires regarding recognition and management of cardiac arrhythmias were distributed. The assessed part presented a clinical scenario with a young hemodynamically stable man who had a 12-lead electrocardiogram performed in the past with signs of pre-excitation, and who presented to the emergency team with an irregular broad QRS-complex tachycardia., Results: A total of 71 questionnaires were filled in. Only one responder recognized AF due to WPW syndrome, while 5 other responders recognized WPW syndrome and paroxysmal supraventricular tachycardia or broad QRS-complex tachycardia. About 20% of participants did not select any diagnosis, pointing out a method of treatment only. The most common diagnosis found in the survey was ventricular tachycardia/broad QRS-complex tachycardia marked by approximately a half of the participants. Nearly 18% of participants recognized WPW syndrome, whereas AF was recognized by less than 10% of participants., Conclusions: Members of emergency medical teams have limited skills for recognizing WPW syndrome with rapid AF, and ventricular tachycardia is the most frequent incorrect diagnosis.

Background: Obstructive sleep apnoea (OSA) and atrial fibrillation (AF) are two conditions highly prevalent in the general population. OSA is known to cause haemodynamic changes, oxidative stress, and endothelial damage, and therefore promote vascular and heart remodelling which results in AF triggering and exacerbation. Coexistence of OSA and AF influences the course of both diseases, and therefore should be taken into consideration in patient management strategy planning., Aim: To assess the prevalence of OSA in Polish AF patients, and to describe the clinical characteristics of patients with concomitant OSA and AF., Methods: We enrolled into the study 289 consecutive patients hospitalised in a tertiary, high-volume Cardiology Department with a primary diagnosis of AF. In addition to standard examination, all patients underwent an overnight sleep study to diagnose OSA, which was defined as apnoea-hypopnoea index (AHI) ≥ 5 per hour., Results: After applying exclusion criteria, the final analysis covered 266 patients (65.0% male, mean age 57.6 ± 10.1 years). OSA was present in 121 (45.49%) patients. Patients with OSA were older (59.6 ± 8.0 vs. 56.0 ± 11.4 years; p = 0.02), had higher body mass index (BMI; 30.9 ± 5.4 vs. 28.7 ± 4.4 kg/m²; p < 0.01) larger neck size (41.2 ± 3.8 vs. 39.3 ± 3.3 cm; p = 0.0001) and waist circumference (108.5 ± 13.1 vs. 107.7 ± 85.4 cm; p < 0.0001) than patients without OSA. There were no significant differences between the groups in terms of systolic and diastolic blood pressure or history of comorbidities (p > 0.05). OSA patients were less likely than non-OSA patients to have paroxysmal AF (62.0% vs. 75.9%; p = 0.02). Dividing newly diagnosed OSA patients according to the disease severity showed that mild OSA (AHI ≥ 5/h and < 15/h) was present in 27.82% of the study population, moderate OSA (AHI ≤ 15/h and ≥ 30/h) in 13.16% of patients, and severe OSA (> 30/h) in 4.51% of patients. No significant differences in terms of comorbidities and anthropometric features were seen between mild and moderate, between moderate and severe, and between mild and severe OSA., Conclusions: OSA is highly prevalent in patients with AF in the Polish population, and affects approximately half of the patients. OSA patients are more likely to be older, have higher BMI, and greater waist and neck circumference. Persistent AF is the most common form of the arrhythmia in patients with OSA, while patients without OSA are more likely to have paroxysmal AF.

Background: The aims of the study are 1) to assess antiarrhythmic prophylaxis efficacy during the first 2 months after radiofrequency ablation (ARF) due to AF; 2) to define risk factors for early AF recurrence (EAFR) after ARF; 3) to determine the long-term follow-up results and risk factors for late AF recurrence (LAFR)., Methods: A total number of 210 consecutive patients who had undergone ARF due to AF were analyzed. Patients were randomized into three groups: Group 1 (G1), without any anti-arrhythmic drug (AAD); Group 2 (G2), with amiodarone or sotalol; Group 3 (G3), with last ineffective AAD. The study was designed to analyze two periods: short-term observation, the first 2 months after ARF; and at least 2 years of long-term follow-up., Results: After 2 months, clinical data were collected from 171 patients (123 males, mean age of 50.3 years; persistent AF in 19.8%; lone AF in 36.6%). Sinus rhythm (SR) was maintained in 84 (49.1%) patients; 35 (20.4%) patients presented with a single episode of AF, 39 (23%) patients experienced a reduction in number of AF episodes, and 13 (7.5%) patients showed no improvement. No predisposing factor for early recurrence was found. After a mean follow-up of 55 months, clinical data were collected in 137 patients, of which 47 (34%) maintained SR. Those more likely to sustain SR were: males (82.9% vs. 62.2%; p = 0.018), younger patients (44.8 ± 12.7 vs. 52.5 ± 9.9; p = 0.0001), patients with smaller left atrium diameter (4.05 ± ± 0.49 cm vs. 4.25 ± 0.51 cm; p = 0.04), and those without any AF recurrence during the first 2 months after ARF (78.7% vs. 35.6%; p < 0.0001). In the multivariable analysis, the independent risk factors for LAFR were hypertension (p < 0.001) and persistent AF (p = 0.014)., Conclusions: Antiarrhythmic prophylaxis does not affect the number of AF recurrences during the first 2 months after ablation. SR maintenance during a blanking period after AF ablation is a positive prognostic factor in long-term follow-up. Persistent AF and hypertension are independent risk factors for late AF recurrence after pulmonary vein isolation.

Background: Atrial fibrillation (AF) is the most frequent sustained supraventricular tachyarrhythmia. Radiofrequency (RF) ablation is one of the options used to prevent the recurrence of AF. Despite thorough studies, the relation between left atrial (LA) size and the results of RF ablation remains controversial., Aim: To estimate the relation between LA size assessed by echocardiography and the AF recurrence rate after pulmonary vein isolation (PVI)., Methods: Our analysis comprised 175 AF patients subjected to PVI between June 2011 and March 2012. Inclusion criteria comprised: symptomatic AF with no reversible cause, and age < 70, LA < 5.5 cm (anteroposterior). PVI was performed with a 4-mm non-irrigated catheter or irrigated catheter and circular mapping catheter (electroanatomic mapping with LocaLisa or CARTO systems). Recurrence was defined as any atrial tachyarrhythmia episode that lasted more than 30 s after three months of blanking period. Standard echocardiographic post-ablation anteroposterior LA measurements were performed with additional parameters such as systolic and diastolic LA area and volume (on sinus rhythm)., Results: The analysis included 198 procedures performed in 175 patients. Median follow-up time was 17 months. Median age was 56 years. After the first procedure, AF recurred in 88 (52.4%) patients. Efficacy after the last procedure was 55.2% (43.5% for persistent AF and 59.7% for paroxysmal AF). No significant relation between any of the LA parameters and the recurrence rate was found. Cox univariate and multivariate analysis revealed only very early AF recurrence as a prognostic factor for AF recurrence in the long term., Conclusions: In patients with AF, no relation could be observed between the recurrence rate after PVI and the echocardiographic LA measurement parameters.

Background: Radiofrequency (RF) catheter ablation is a first-line therapy for patients withdrug-refractory atrial fibrillation (AF). Complete isolation of electrical potentials at the ostium of pulmonary vein (PV) is a challenging procedure. There are different techniques and devicesused for PV isolation (PVI). The objective of this study was to evaluate the efficacy and safety of PV ablation catheter (PVAC)., Methods: A total of 67 consecutive patients with paroxysmal and persistent AF were treated with the PVAC. The patients' information were obtained from clinical charts. Follow-up was obtained by one day Holter monitoring at 2, 4, 6, 8, 10 and 12 months after ablation and ECG registration if any symptoms or arrhythmia occurred., Results: The median follow-up duration was 16 months (IQR: 12-20 months). In the population which was available at follow-up (n = 60), 22 (36.7%) patients were in sustained sinus rhythm (SR) without anti-arrhythmic drugs (AAD). Overall 26 (43.3%) patients were in sustained SR with and without AAD. In the paroxysmal AF group, after a single PVAC ablation procedure (n = 39), 19 (48.7%) patients had sustained SR without AAD. In the persistent AF group (n = 15), after the single PVAC ablation, 2 (13.3%) patients had sustained SR without AAD., Conclusions: PVI with PVAC is a safe procedure with 48.7% efficacy in patients with paroxysmal AF. The efficacy of PVAC in patients with persistent or long-standing persistent AF is not acceptable.

Background: Electrical storm (ES) is a life-threatening condition requiring prompt and effective therapy. This may be achieved by the use of catheter ablation., Aim: To assess safety and efficacy of catheter ablation in patients with ES., Methods: We performed 28 ablation procedures from February 2006 to May 2010 due to ES in 24 patients (21 men, 3 women, aged 62.5 ± 7.8 years). Eighteen patients had a history of myocardial infarction, 2 - dilated cardiomyopathy, 2 - hypertrophic cardiomyopathy (one also had myocardial infarction), 1 - spongiform cardiomyopathy, 1 - heart failure after aortic valve replacement and 1 - myocarditis. The mean value of ejection fraction was 27.3 ± 6.5% (15-40%). Procedures were performed using the CARTO system. Two patients after an endocardial map had also epicardial mapping performed and one of these patients underwent epicardial cryoablation. The other one underwent a radiofrequency catheter ablation., Results: During the follow-up period of 27.8 ± 15.9 months 16 (66%) patients had no ventricular tachycardia (VT)/ventricular fibrillation (VF) episodes. Sporadic VT episodes were observed in 3 patients. Recurrence of ES occurred in 3 (12%) patients and 3 (12%) patients died during the follow-up due to the progression of heart failure., Conclusions: 1. Ablation of ventricular arrhythmias in the course of ES in patients with organic heart disease is safe and effective, and probably improves their prognosis. 2. After ablation, some patients have adequate interventions of implantable cardioverter-defibrillator due to progression of the disease. 3. The method does not prevent haemodynamic mortality.

Background: Cryoballon isolation of the pulmonary veins has recently emerged as a promissing technique for ablation of atrial fibrillation (AF)., Aim: To present our initial experience in cryoballon isolatin of the pulmonary veins in patients with AF., Methods: Eight patients (5 males; age 59+/-2 years) with AF: 2 with persistent and 6 with paroxysmal (5 of them after unsuccessful RF ablation) with >or=6 month follow-up after the procedure were included. One patient after myocardial infarction was treated with primary angioplasty with stent implantation. Another one had biatrial pacemaker. The procedure was performed with cryobaloon with 28 mm diameter (Arctic Front--Cryocath). After transseptal puncture mapping of the pulmonary vein ostia was performed with Lasso catheter (Johnson and Johnson). At each pulmonary vein ostium with pulmonary vein potentials 2 cryoapplications of 300 s duration was performed. Correct balloon placement before cryoapplication was checked using contrast injection into the pulmonary veins. During cryoapplication in the right pulmonary vein ostia permanent pacing of the phrenic nerve 30 beats per minute was performed to prevent its paralysis. After cryoapplications in all veins remapping with Lasso catheters was performed. In the absence of pulmonary vein potentials the procedure was finished, otherwise next cryoapplications were performed. During follow-up ECG was performed if any palpitations occurred, and 24-hour Holter monitoring was performed 1, 2 ,4, 6, 8, 10 and 12 months after the procedure. A 2-month blanking period after the procedure was used. The lack of symptomatic AF and the absence of AF>30 s on Holter ECG monitoring were defined as successful procedure. An improvement was defined as reduction of frequency/duration of AF paroxysm and reduction of the EHRA index>or=1., Results: During 8 procedures isolation of 31 pulmonary vein was performed. Procedure duration was 3.5+/-0.85 h, fluoroscopy time--33.55+/-15.44 min, and total cryoapplication time--38.33+/-4.1 min. There were no complications. After the follow-up of 8.5+/-0.99 months 6 (75%) patients were free from arrhythmia, including the patient after myocardial infarction and one patient with permanent AF prior ablation. In another patient an improvement was observed (EHRA score II/III to I) whereas in one patient with permanent AF the procedure was unsuccessful., Conclusion: Cryoballoon ablation of pulmonary vein ostia is effective and safe, and can be an alternative to RF ablation. Easier procedure technique make possible shortening of the learning curve and increase the number of treated patients.

Background: The aim of this study was to evaluate the reliability of pacemaker diagnostic function in diagnosing ventricular arrhythmias., Methods: We compared the occurrence of ventricular ectopic beats in 51 simultaneous 24-hour electrocardiogram (ECG) recordings and pacemaker event counters printouts. The diagnostic function of a pacemaker allowed also for a qualitative assessment in 38 patients. In these cases, the occurrence of complex forms of ventricular arrhythmias was cross-checked for accelerated ventricular rhythms together with ventricular tachycardia, and triplets and couplets. The detection of at least one type of complex ventricular form of arrhythmia, diagnosed by both methods, was considered as an agreement between the methods., Results: The results of ventricular ectopic beat counts differed significantly between the methods. In three (6%) patients, the results were consistent; in 20 (39%) the pacemaker underestimated results; in 28 (55%) they were overestimated. When more liberal criteria of agreement were applied, clinically significant differences were observed in 24 (47%) patients; in seven (29%) patients the count made by the pacemaker was lowered; and in 17 (71%) it was overestimated. Ventricular tachycardias were recorded in 24-hour ECG in eight patients. In three, they were identified by the pacemaker diagnostic function. In five, the pacemaker did not recognize tachycardia (because of its frequency being below 120/min). In nine, tachycardia was recognized falsely. The sensitivity in ventricular tachycardia diagnosis by pacemaker diagnostic function was 38%, specificity - 70%, the value of a positive result - 25%, negative - 81%., Conclusions: The evaluation of ventricular arrhythmias by pacemaker cannot serve as the only reliable diagnostic method of arrhythmias. The presence of a large number of sequences that may correspond to ventricular arrhythmia or failure to sense, should result in verification via 24-hour ECG monitoring.

Background: Ablation of atrial fibrillation (AF) can be difficult and time-consuming. Systems facilitating catheter navigation may be helpful., Aim: To compare the efficacy of the LocaLisa system with the conventional mapping/ablation approach to radiofrequency (RF) ablation of AF., Methods: Group 1, consisting of 64 patients (48 male; aged 51.5+/-10.6 years), underwent segmental isolation of the pulmonary veins with the Lasso catheter and the LocaLisa system. Group 2, consisting of 64 patients (44 male, aged 51.4+/-11.0 years), had RF ablation guided by means of a conventional fluoroscopy-based approach. Clinical and procedural data were analysed., Results: Nine patients from group 1 and three patients from group 2 had persistent AF. In group 1 the mean number of isolated veins was 3.98+/-0.96, while in group 2 - 4.0+/-0.95 (NS). In group 1 cavotricuspid isthmus lines were created in four patients and lines in the roof of the left atrium in two patients. One patient needed slow pathway ablation. In group 2 six patients had ablation of the cavotricuspid isthmus and a line was created at the roof of the left atrium in one patient. Two patients had ectopic activity ablated in the crista terminalis. Procedure times were 131.6+/-40.3 and 170.0+/-56.5 min (p <0.0001) and fluoroscopy times were 16.93+/-9.7 and 35.66+/-12.7 min (p <0.0001) for groups 1 and 2, respectively. Long-term efficacy of RF ablation was similar in both groups (for example, complete success was achieved in 59% of patients using LocaLisa and 50% without using this system, NS)., Conclusions: The LocaLisa navigation system makes it possible to shorten both the duration of the procedure and the total fluoroscopy time during ablation of AF.

A patient with a 6-year history of drug-resistant, recurrent arrhythmias (AT/AFL, single SVEBs, pairs and series) developed arrhythmogenic cardiomyopathy. Conduction block between coronary sinus (CS) and atria caused periodical change of tachycardia's rate. Successful RF ablation performed in the middle of CS at a place of spike potentials of a 284 ms CL. During a 6-years follow-up after ablation, ejection fraction increased from 38 to 59% and the quality of life improved significantly.

Progress in the field of clinical and experimental electrophysiology helps us to elucidate connections between clinical problems and genetic cellular abnormalities. So far four genes have been discovered to be responsible for inherited forms of atrial fibrillation. Several polymorphisms in genes encoding angiotensinogen, connexin 40 and subunits of potassium channels (KCNE1) have been disclosed to correlate with this disease. On the other hand genetic background of preexcitation, atrio-ventricular nodal reentry tachycardia and ventricular tachycardias need further studies. More research is also needed to assess the efficacy of pharmacogenetic treatment methods for atrial fibrillation.

A case of a 64-year-old male diagnosed with remote inferior myocardial infarction (MI), is presented. Electrophysiological examination revealed the presence of an accessory pathway with a negative delta wave in inferior leads mimicking pathological Q wave. Differential diagnosis of pathological Q waves is discussed.

Impedance cardiography (ICG) enables the non-invasive, reproducible, beat-to-beat estimation of stroke volume (SV) changes, and the measurement of the absolute values of the ejection time (ET) and pre-ejection period (PEP), which allows the indirect evaluation of cardiac contractility. The miniaturised, Holter-type impedance cardiography device with built-in one channel of ECG called ReoMonitor, was constructed. The system allows the long-term, beat-to-beat, automatic evaluation of SV, ET, PEP and heart rate. The measurements obtained by ReoMonitor were verified using on echocardiographic method in supine and tilted positions. A high correlation coefficient (r=0.83) was calculated between the measurements collected using both methods. Speech or vigorous movement distinctly lowered the percentage of properly recognised cardiac cycles (during daytime: 20-80%, during the night: 75-90%). However, during exercise testing on a cycloergometer the quality of recordings was good. The following clinical applications of a system are presented: a) evaluation of hemodynamical abnormalities caused by arrhythmia events, b) vasovagal syncope diagnosis, and c) optimisation of atrio-ventricular delay during dual-chamber pacing.

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.

The tendon of Todaro, found in the right atrium of the heart, has considerable clinical importance in the fields of both cardiac surgery and invasive cardiology. The goal of this study was to examine the occurrence and degree of development of the tendon of Todaro in humans. Research was conducted on material consisting of 160 human hearts of both sexes from the age of 14 Hbd to 87 years of age. Classical anatomical methods were used and histological sections were prepared from 100 hearts of various age groups stained with Masson's method in Goldner's modification. The tendon of Todaro occurred in all examined hearts. In foetal hearts, in the area typical of the course of the tendon of Todaro, a very well-developed, white structure was observed, convexed into the lumen of the atrium. Histologically, this was young fibrous tissue with a characteristically large number of fibroblasts. Evenly in infants and newborns, a visible convex structure was also observed extending into the lumen of the right atrium, however, to a lesser degree than in foetuses. In the group of hearts of young adults, it was also possible to follow the course of the tendon of Todaro macroscopically. However, the older the heart was, the less the convex was visible, and in older adults it was completely invisible. In histological sections, it was observed that with ageing the number of connective tissue cells decreased, and fibres forming the lining increased. In the hearts of older adults the tendon of Todaro formed very small ribbons of connective tissue. Histologically, only small numbers of cellular elements were noticed. In the adult heart the examined tendon was located the deepest and did not connect to the endocardium. We can conclude that the tendon of Todaro is a stable structure, occurring in all examined hearts even when it is not macroscopically visible. Due to the morphological changes that affect the tendon of Todaro in human ontogenesis, for the cardiac surgeon, its relevance as an important topographical structure in the hearts of older adults is minimal.

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.

The case of a 35 year-old patient with recurrent, sustained atrioventricular nodal reentry tachycardia (AVNRT)--type slow/fast--refractory to group IA, IC, II, IV antiarrhythmic agents is presented. The maximum rate of the tachycardia was 280/min. During the antiarrhythmic treatment with group IA, IC and IV agents the tachycardia rate was 230/min. The effective refractory period (ERP) of the slow pathway was 200 ms in antegrade direction. ERP of the fast pathway was 260 ms in antegrade and 210 ms in retrograde direction. Ablation of the slow pathway was performed with radiofrequency energy (device HAT 200 S manufactured by Osypka GMBH, catheter Cereblate No 6). The total ablation time was 96 s, maximal temperature of the effective ablation time was 51 centrigrades. Total energy delivered was 2316 J. The ablation caused neither atrioventricular conduction block nor any damage to the heart structure other than the slow conduction pathway. After the ablation there are no evidence of conduction through the slow pathway. Conduction in anterograde and retrograde direction occurs through the fast pathway. No AVNRT were observed. After ablation the patient has no antiarrhythmic treatment.