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OBJECTIVE: The aim of the study was to evaluate the influence of the number of electrocardiogram (ECG) leads on the diagnostic value of TCRT (spatial QRS-T angle) parameter (12 standard ECG leads and 61 surface ECG leads were used). The TCRT parameter, which describes the spatial QRS-T angle, is a useful indicator of the risk of ventricular tachycardia (VT) and sudden cardiac death (SCD). It is usually calculated from standard 12 leads ECG. METHODS: The TCRT parameter was calculated from the three virtual orthogonal leads obtained by singular value decomposition of the averaged ECG signals. Sensitivity and specificity of TCRT parameter in identifying VT patients were tested on two groups of patients after myocardial infarction: 13 non - VT patients and 30 VT patients. Additionally 17 healthy volunteers were studied as a control group. RESULTS: Mean value (+/-SD) of TCRT parameter calculated for 61 leads was -0.80+/-0.27 for VT patients and 0.27+/-0.46 for non VT patients. For 12 standard leads TCRT mean value was -0.80+/-0.22 for VT patients and 0.27+/-0.49 for non VT patients. Sensitivity for VT patients was 87% (61 leads) and 83% (12 leads). Specificity in non-VT group was 100% for both lead sets. CONCLUSIONS: Results of the study show distinct differences in the TCRT parameter values between VT patients and non VT patients for both lead sets. The sensitivities of the TCRT parameter obtained for 61 leads and for 12 standard leads were comparable. [ABSTRACT FROM AUTHOR]

Background: There is some disagreement concerning the minimal value of the interval between components of double potentials (DPs interval) that allows distinguishing complete and incomplete block in the cavotricuspid isthmus (CTI)., Objectives: To assess clinical utility of the relationship between atrial flutter cycle length (AFL CL) and the DPs interval., Methods: Ablation of the CTI was performed in 87 patients during AFL (245 ± 40 ms). Subsequently, DPs were recorded during proximal coronary sinus pacing at sites close to a gap in the ablation line and after achievement of complete isthmus block., Results: We noted strong correlation between AFL CL and the DPs interval after achievement of isthmus block (r = 0.73). The mean DPs interval was 95.3 ± 18.3 ms (range 60-136 ms) and 123.3 ± 24.3 ms (range 87-211 ms) during incomplete and complete isthmus block, respectively (P < 0.001). When expressed as a percentage of AFL CL, this interval was 35.7 ± 3.5% AFL CL (range 28-40.2%) and 50.4 ± 6.9% AFL CL (range 39-72%) during incomplete and complete isthmus block, respectively (P < 0.001). A cutoff value of 40% of AFL CL identified CTI block with 96.7% sensitivity and 100% specificity., Conclusions: The interval between DPs after achievement of block in the CTI correlates with AFL CL. The DPs interval expressed as a percentage of AFL CL allows better distinguishing between complete and incomplete isthmus block compared to standard method based on milliseconds. The DPs interval below 40% of AFL CL indicates sites close to a gap in the ablation line., (©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.)

Background: Atrial fibrillation (AF) in WPW syndrome occurs earlier and is more common than in the general population., Aim: To evaluate the predisposing factors for the first episode of AF in patients with WPW., Methods: We analysed data on 930 patients (510 males, 420 females) with WPW treated in our centre during 1988-2007. AF was diagnosed in 236 patients (25% - 161 males, 75 females, aged 36 +/- 15 years). The AF group was divided into two subgroups - patients with AF and atrio-ventricular reentrant tachycardia (AVRT), and patients with AF only. The analysis included subjects' age and gender, the presence of AVRT, the number and properties of accessory pathways, left ventricular ejection fraction (LVEF) and concomitant cardiovascular diseases., Results: The groups did not differ in terms of concomitant diseases and LVEF. In the whole group of patients with AF, arrhythmia occurred earlier in men than in women (34 +/- 14 vs. 40 +/- 15 years of age, p = 0.013). In the subgroup with AF and AVRT, AF was documented earlier compared to patients with AF only (34 +/- 15 vs. 41 +/- 15 years of age, p = 0.0072). AVRT was more common in patients with AF compared to those without AF (69 vs. 53%, p < 0.001). In the whole group of 930 patients, AF was observed more often in patients with overt pre-excitation compared to concealed WPW (29 vs. 12%, p < 0.001)., Conclusions: In patients with WPW syndrome, AF occurs earlier in patients with AVRT compared to patients with AF and without documented AVRT, earlier in men compared to women, and is more common in patients with overt WPW.

We describe a case of persistent atrial tachycardia/flutter in a 19-year old female with corrected transposition of great arteries (ccTGA) and dual inlet left ventricle (DILV), treated with surgical palliative operations. The arrhythmia became persistent and symptomatic with dyspnea and severe cyanosis. During the EP study, the right atrial isthmus-dependent reentry was identified. In electroanatomical maps large areas of low voltage and electrical silence were localised. Due to these areas of slow conduction the isthmus dependent arrhythmia had long CL. Linear RF applications closed the isthmus, resulting in flutter termination. During 3 months of follow-up the patient remained free of arrhythmia.

We present a case of a 16-year-old girl with AVNRT with 1:1 or 2:1 conduction from the atria to ventricles which was perceived by the patient as two different types of palpitations.

We present a case of 67-year-old patient with recurrent persistent atrial macroreentry after surgical removal of left atrial myxoma. The macroreentry was cavo-tricuspid isthmus dependent with a pseudo-atypical atrial flutter morphology and variable cycle lengths between 290 and 340 ms.

Background: Pseudo-Mahaim (AP-M) fibers are a rare variant of atrioventricular (AV) accessory pathways. Atriofascicular and atrioventricular accessory connections are characterized by slow conduction and decremental properties. Dual physiological AV node pathways, slow and fast, are observed in a large number of patients with AP-M. Therefore, there is substrate for AV nodal reentrant tachycardia (AVNRT) in addition to antidromic AV reentrant tachycardia (AVRT) with left bundle branch block (LBBB)-like morphology. Other arrhythmia such as atrial fibrillation (AF) or atrial flutter (AFL) and ventricular fibrillation (VF) are also observed. We analysed the occurrence of arrhythmias in a group of patients with AP-M treated in our department., Methods: We evaluated 27 patients (12 women) aged 14-53 years (mean age 25.6 years) with AP-M. The clinical course in these patients, in particular with regard to the occurrence of arrhythmias, was analysed. Patients with dual AV node properties were compared to patients without such findings., Results: We found dual AV node properties in 18 patients (Group 1), while 9 patients had fast pathway only (Group 2). Twenty-six patients presented with AVRT, 2 patients with AVNRT, 3 patients with AF, 1 patient with AT, 2 patients with AFL, and 3 patients with VF. In 2 patients, AP-M were seen in an atypical area. In one patient, the pathway connected the right atrium with the left ventricle (septal region), and in the other patient it connected the left atrium with the left ventricle (left anterior region)., Conclusions: The majority of AP-M was right-sided. Two thirds of patients with AP-M had anatomical substrate for AVNRT (fast/slow pathway AV node). VF or asystole occurred in 10% of patients.

We describe a case of a 44-year old man with recurrent atrial arrhythmias (atrial ectopy, atrial tachycardia and fibrillation) originating from the vein of Marshall (VoM). Stress, exertion and isoproterenol increased frequency and duration of highly symptomatic arrhythmia paroxysms. In 2002 he underwent two sessions of RF ablation. In the area of the left inferior pulmonary vein ostium (LIPV) and along the course the VoM, spiky, firing potentials were recorded. Ablation of the VoM region induced high frequency focal firing (CL approximately 200 ms) with 1: 1 VoM-->LA conduction. Before sinus rhythm return, a gradual increase of conduction of VoM-->LA block was observed. During the second session residual breakthroughs were recorded. During 5 years of follow-up the patient remained free from arrhythmia without antiarrhythmic drugs.

We present a case of 53-year-old patient who experienced paroxysms of wide QRS complex tachycardia at a rate of 150 bpm and LBBB morphology 6 years after inferior myocardial infarction and CABG. Anamnesis and morphology of tachycardia could suggest ventricular tachycardia. However during electrophysiological study we observed AVRT with LBBB and "regularly irregular" AVRT with normal QRS complex and changing entrance to the AV node (through slow and fast pathway). In this paper we present our approach and try to explain why the tachycardia using concealed bypass tract appeared so late in life.

We present a case of a 19-year-old patient with incessant arrhythmias originating from the right upper pulmonary vein (RUPV) presenting as frequent premature beats, automatic rhythms mimicking sinus rhythm (SR) and pulmonary vein tachycardias. Morphology of P' wave resembled sinus P wave due to relatively short distance of the ectopic focus from the sinus node. Occasionally, when discharges from the focus were relatively slow (800-500 ms) and regular it was mimicking sinus rhythm. Activation preceding P' wave during arrhythmia was recorded in RUPV as well as in superior vena cava. In this paper we discuss our approach that allowed localising the arrhythmogenic focus in the RUPV. After isolation of the RUPV sinus rhythm was restored with tachycardia at a cycle length of 320 ms continuing in the isolated vein.

We present a case of a 17-year-old patient in whom recurrent bradycardia and syncope episodes were present. During the pathological bradycardia incessant runs of irregular tachycardia from the region of atrial extension of AV node were observed. The bradycardia runs were due to advanced functional AV nodal block. The patient was qualified for pacemaker implantation and antiarrhythmic treatment by his GP. Successful ablation of atrial tachycardia revealed that SA and AV node properties were in the normal range; therefore no pacemaker implantation was needed.

Recent studies have demonstrated spatio-temporal organisation in atrial fibrillation (AF), with a highest dominant frequencies (DF) at pulmonary veins ostia (PVo). We present a case of 58-year-old woman with AF evaluated by spectral frequency analysis. Simultaneous recordings at each veno-atrial junction and coronary sinus were obtained. Sequential fast Fourier transforms (FFT) of digitalized signals were performed. FFT profiles were analysed to determine DF. Low DF recorded at right inferior PVo suggested no contribution to AF process. Ablation of high DF PVo and low DF SVC with nonuniform anisotropic conduction resulted in AF termination and good clinical outcome in 1-year follow-up.

The selective ablation of the recurrent ventricular tachycardia (VT) in a 75-year old patient after extensive inferior myocardial infarction (24 years ago), with low ejection fraction was performed. In 1995 the cardioverter-defibrillator was implanted due to recurrent, symptomatic VT. The coronary angiography in 1995 and in 2006 revealed the occlusion of the right coronary and the circumflex arteries. One year after implantation, he had electrical storm caused by proarrhythmic effect of amiodarone with prolongation of QT/QTc interval. During follow up episodes of VT (approximately 5/year) were successfully terminated by ATP and rarely by cardioversion. Recently, the patient was admitted to the hospital because of the very frequent (25/day) episodes of slow (500-560 ms), sustained ventricular tachycardia. The pharmacological treatment was unsuccessful. CARTO mapping and entrainment pacing revealed VT circuit around mitral annulus. A few applications at the paraseptal part of the mitral isthmus terminated VT, which was no longer inducible. During following days there were no VTs requiring ICD interventions.

We present a case of a 19-year old man with minor Ebstein's anomaly, intermittent long QT interval and WPW syndrome in whom atrial fibrillation, degenerating into ventricular fibrillation was the first symptom. QRS complex morphologies during atrial fibrillation revealed the presence of three accessory pathways (septal, right inferior paraseptal and antero-inferior). Immediately after resuscitation the patient was treated with amiodarone, which resulted in a significant prolongation of QT interval to 700 ms. After RF ablation of accessory pathways patient remains asymptomatic during 6-month follow up, however QTc interval is about 500 ms.

Introduction: Targeted treatment of atrial fibrillation (AF) involves circumferential isolation of all pulmonary veins (PV) or isolation of electrical connections within their ostia. Only in some cases are the real localisation and number of triggering foci, the anatomy of venous ostia as well as the form of AF (paroxysmal, persistent, chronic, primary or secondary) taken into consideration., Aim: To compare the results of selective electrical isolation (1-3 PV ostia or ablation of a single focus in other veins or atrium) versus isolation of all pulmonary veins., Methods: RF ablation was performed in eighty patients (51 men, 29 women) with symptomatic, drug-refractory AF. Fifty-nine patients had paroxysmal AF (PAF), 16 persistent (AFpers), and 5 chronic AF (AFchro). Selective ablation was carried out in those patients who had detectable AF triggers during sinus rhythm -- supraventricular extrasystolic beats (SVEB) of 1 to 3 morphologies (group I). Extended ablation -- isolation of all 4-5 PV -- was performed in patients with multiple SVEB morphologies and heterogeneous electrical connections within all PV (group II). Group I consisted of 60 patients (22 females) aged 46+/-14 years, whereas group II comprised 20 patients (7 females) aged 52+/-13 years. In 24 patients (18 from group I and 6 from group II) with concomitant typical atrial flutter, an ablation line in the cavo-tricuspid isthmus was also performed. Long-term results were assessed 17+/-15.6 (4-105) months after the procedure based on routine ECG, ambulatory 24-hour ECG monitoring, clinical evaluation and regular phone calls. In patients with PAF, left atrial diameter <4.2 cm and evidence of successful ablation, antiarrhythmic agents were withheld. In patients with AFpers and AFchro, antiarrhythmic drugs were discontinued 3 to 6 months after successful ablation., Results: Complete procedural success was achieved in 61 (76%) patients, and significant clinical improvement was observed in another 9 (11%) patients. Effective ablation significantly improved quality of life. In group I the procedure was entirely successful or a marked improvement was reported (single, transient palpitation episodes and/or atrial tachyarrhythmias lasting up to 30 seconds) in 54 (90%) patients. Among 48 (80%) patients with complete success, 25 (42%) did not receive any antiarrhythmic drugs during follow-up, 12 (20%) with arterial hypertension received beta-blockers, and 11 (18%) continued beta-blocker + class I antiarrhythmic drug. In another 6 (10%) patients a significant clinical improvement in arrhythmia control was observed. In Group II the procedure was fully effective or a significant improvement was observed in 16 (80%) patients. Among 13 (65%) patients with complete success, 5 (25%) did not require any antiarrhythmic drugs, 4 (20%) who had hypertension continued beta-blockers, and another 4 (20%) continued beta-blocker + I class antiarrhythmic drug. A significant clinical improvement of arrhythmia control was observed in another 3 (15%) patients., Conclusions: In patients with a limited number of triggering foci and limited AF substrate, selective ablation effectively eliminates AF with a low risk of complications. Detailed electrophysiological assessment (standard ECG, 12-lead Holter ECG monitoring and endocardial mapping) allows precise identification of this group of patients. In patients with chronic and persistent AF benefits occur with some delay which is associated with a delayed reversal of atrial remodelling.

We present a case of a 15-year old girl in whom supraventricular tachycardia (SVT) with rSr' pattern in lead V1 and the QRS width of less than 110 ms, suggesting typical slow-fast AVNRT, was the presenting arrhythmia. During sinus rhythm no preexcitation was observed. Considerable variability of the tachycardia cycle length (240-370 ms), attributable to the presence of the fast and slow nodal pathways, was also observed. However, during the electrophysiological study only orthodromic atrio-ventricular reciprocating tachycardia with the left-sided superior accessory pathway as the retrograde limb was documented. Thus, rSr' pattern was due to incomplete right bundle branch block. We describe how the correct diagnosis and the site of the atrial insertion of the accessory pathway could be inferred from the careful analysis of the P' wave morphology during the tachycardia.

Lef atrial thrombus formation during ablation of atrial fibrillation carries the risk of thrombo-embolic complications. We describe a case of a 55 year old male in whom thrombus formation was detected by intracardiac echocardiography. Thrombus was safely removed by aspiration into transseptal sheath.

Objectives: The goal of this study was to describe the mapping and ablation of polymorphic ventricular tachycardia (VT) after myocardial infarction (MI)., Background: The initiating mechanisms of polymorphic VT after MI have not been reported., Methods: Five patients (four males; age 61 +/- 7 years) with recurrent episodes of polymorphic VT after anterior MI (left ventricular ejection fraction 32 +/- 7%) despite revascularization and antiarrhythmic drugs were studied. All patients demonstrated frequent ventricular premature beats (PBs) initiating polymorphic VT. Pace mapping and activation mapping were used to identify the earliest site of PB activity. The presence of a Purkinje potential preceding PB defined its origin from the Purkinje network. Electroanatomic voltage mapping was performed to delineate the extent of MI., Results: The PBs were observed in all cases to arise from the Purkinje arborization in the MI border zone. These PBs were right bundle-branch block in all five patients, with morphologic variations in the limb leads in four; one also had a left bundle-branch block morphology. The coupling interval of the PB to the preceding QRS complex demonstrated significant variations (320 to 600 ms). During PB, the Purkinje potential at the same site preceded the QRS complex by 20 to 160 ms and was associated with different morphologies. Repetitive Purkinje activity was documented during polymorphic VT. Splitting of Purkinje activity and Purkinje to muscle conduction block were also observed. Ablation at these sites eliminated all PBs. At 16 +/- 5 months follow-up using defibrillator memory interrogation, no patient has had recurrence of arrhythmia., Conclusions: The Purkinje arborization along the border-zone of scar has an important role in the mechanism of polymorphic VT in patients after MI. Ablation of the local Purkinje network allows suppression of polymorphic VT.

Background: Atrial fibrillation (AF) in patients with WPW syndrome may be a life-threatening arrhythmia., Aim: To identify risk factors of AF and their prognostic significance in patients with WPW syndrome., Methods: Clinical and electrophysiological parameters of 239 patients with WPW syndrome, who underwent successful RF ablation, were analysed using logistic regression and multivariate analysis. One hundred eight patients had no history of AF whereas the remaining 81 patients had previous spontaneous AF episodes. Long-term follow-up data (mean 29+/-23 months, range 1-99 months) were available in 136 patients (87 without AF and 49 with AF)., Results: Patients with AF were significantly older, more frequently of male gender and had more often a history of syncope than patients without AF. There were two peaks of AF occurrence - in the third and in the fifth decade of life. Fourteen patients had a history of ventricular fibrillation - 11 patients with AF vs 3 patients without AF (p=0.0016). Patients with a history of AF were more prone to AF induced during electrophysiological study and had less frequently concealed accessory pathways., Conclusions: Age, gender and a history of syncope are the independent risk factors of AF in patients with WPW syndrome. Anterograde conduction via accessory pathway is of major importance in the development of AF. RF ablation of an accessory pathway should be performed early because the risk of the procedure is small and there is an increasing risk of AF with ageing.

Background: Arrhythmogenic right ventricular dysplasia (ARVD) is characterised by fatty and fibrous infiltration of myocardial muscle. Clinical symptoms include dangerous cardiac arrhythmias and heart failure in the advanced form of the disease. ARVD is genetically determined in at least 50% of cases and is characterised by a marked variability of clinical presentation within one family., Aim: To assess the prevalence of the familial form of ARVD in Poland, the mode of inheritance and the risk of sudden cardiac death as well as heart failure development in asymptomatic patients, in whom ARVD was detected during family screening., Methods: 211 relatives of 40 patients with ARVD were examined. Thirty two families were identified in which at least two members had the disease. The analysed parameters included family history, physical examination, ECG, echocardiography and magnetic resonance., Results: Abnormalities of the right ventricle and/or cardiac arrhythmias suggesting ARVD were found in 71 subjects (mean age 32.4 years). In 28 cases ARVD was diagnosed. From this group, one patient had aborted sudden death. In the remaining 43 subjects a borderline form of the disease was detected. Of this group, one patient died suddenly. The degree of morphological changes in cardiac muscle correlated with patients' age., Conclusions: 1. The familial form of ARVD is frequent in Poland. 2. ARVD is inherited in an autosomal dominant mode. 3. Sudden cardiac death may be the first symptom of the disease, even in subjects with borderline ARVD. 4. ARVD is a progressive disease. Concomitant left ventricular involvement is not rare and probably represents a late stage of the disease.