Accessory pathway localization with probabilistic density maps generated by a mobile application: Assessment of a full pre-excitation net-vector method

INTRODUCTION

Precise electrocardiographic localization of accessory pathways (AP) can be challenging. Seminal AP localization studies were limited by complexity of algorithms and sample size. We aimed to create a nonalgorithmic method for AP localization based on color-coded maps of AP distribution generated by a web-based application.

METHODS

APs were categorized into 19 regions/types based on invasive electrophysiologic mapping. Preexcited QRS complexes were categorized into 6 types based on polarity and notch/slur. For each QRS type in each lead the distribution of APs was visualized on a gradient map. The principle of common set was used to combine the single lead maps to create the distribution map for AP with any combination of QRS types in several leads. For the validation phase, a separate cohort of APs was obtained.

RESULTS

A total of 800 patients with overt APs were studied. The application used the exploratory data set of 553 consecutive APs and the corresponding QRS complexes to generate AP localization maps for any possible combination of QRS types in 12 leads. Optimized approach (on average 3 steps) for evaluation of preexcited electrcardiogram was developed. The area of maximum probability of AP localization was pinpointed by providing the QRS type for the subsequent leads. The exploratory data set was validated with the separate cohort of APs (n = 256); p = .23 for difference in AP distribution.

CONCLUSIONS

In the largest data set of APs to-date, a novel probabilistic and semi-automatic approach to electrocardiographic localization of APs was highly predictive for anatomic localization.

Ventricular Arrhythmias in Left Ventricular Assist Device Patients-Current Diagnostic and Therapeutic Considerations

Left ventricular assist devices (LVAD) are used in the treatment of advanced left ventricular heart failure. LVAD can serve as a bridge to orthotopic heart transplantation or as a destination therapy in cases where orthotopic heart transplantation is contraindicated. Ventricular arrhythmias are frequently observed in patients with LVAD. This problem is further compounded as a result of diagnostic difficulties arising from presently available electrocardiographic methods. Due to artifacts from LVAD-generated electromagnetic fields, it can be challenging to assess the origin of arrhythmias in standard ECG tracings. In this article, we will review and discuss common mechanisms, diagnostics methods, and therapeutic strategies for ventricular arrhythmia treatment, as well as numerous problems we face in LVAD implant patients.

Cryoballoon ablation without use of contrast for the treatment of paroxysmal atrial fibrillation

BACKGROUND

Cryoballoon ablation (CBA) for atrial fibrillation (AF) is usually preceded by demonstrating pulmonary vein (PV) occlusion using contrast. The aim of the study was to determine efficacy and safety of a simplified protocol for CBA performed without demonstrating PV occlusion and compare achieved results with conventional CBA.

METHODS

Paroxysmal AF patients undergoing a first-time CBA were prospectively included. In the non-contrast (NC) group CBA was performed using standardized protocol without demonstrating PV occlusion. In the conventional contrast (CC) group ablations were performed after confirmation of PV occlusion.

RESULTS

The NC and CC groups comprised 51 and 22 patients, respectively. PVI according to the group assignment was achieved in 34 (67%) and 21 (95.5%) patients from the NC and CC groups, respectively (p < 0.001). In the NC group, 184 (90%) out of 204 veins were isolated without venography. There were no differences between the NC and CC groups in terms of procedure duration (89.7 ± 22.6 vs. 90.0 ± 20.6 min; p = 0.7) and fluoroscopy time (15.3 ± 6.3 vs. 15 ± 4.5 min; p = 0.8). In the NC group, the use of contrast was significantly lower compared to the CC group (4.9 ± 10.1 vs. 19.4 ± 8.6 mL, p < 0.001). There were no serious adverse events in both groups. A 1-year freedom from AF was achieved in 73.5% and 71.5% of patients from the NC and CC groups, respectively (p = 1).

CONCLUSIONS

Cryoballoon ablation without demonstrating vein occlusion with contrast is safe and feasible. Proposed simplified approach enables isolation of the vast majority of pulmonary veins with a significant reduction in the amount of contrast used.

Association of left atrial enlargement and increased left ventricular wall thickness with arrhythmia recurrence after cryoballoon ablation for atrial fibrillation

BACKGROUND

Left atrial enlargement (LAE) predicts atrial fibrillation (AF) recurrence after cryoballoon-based pulmonary vein isolation (CB). Increased left ventricular wall thickness (LVWT) is pathophysiologically associated with LAE and atrial arrhythmias.

AIMS

To assess effect of increased LVWT on long-term outcomes of CB depending on coexistence of LAE.

METHODS

LAE was defined using either echocardiography ( > 48 cm³/m²) or multislice computer tomography (MSCT, ≥63 cm³/m²). Increased LVWT was echocardiographic septal/posterior wall thickness > 10 mm in males and > 9 mm in females. All patients achieved 2-year follow-up.

RESULTS

Of 250 patients (median [interquartile range, IQR] age of 61 [49.0-67.3] years; 30% female) with AF (40% non-paroxysmal), 66.5% had hypertension, and 27.2% underwent redo procedure. MSCT was done in 76%. During follow-up of 24.5 (IQR, 6.0-31.00) months the clinical success rate was 72%, despite 46% of patients having arrhythmia recurrence. Arrhythmia recurrence risk was increased by LAE and increased LVWT (hazard ratio [HR], 1.801; P = 0.002 and HR, 1.495; P = 0.036; respectively). The highest arrhythmia recurrence (61.9% at 2 years) was among patients with LAE and increased LVWT (33.6% of patients); intermediate (41.8%) among patients with isolated LAE; and lowest among patients with isolated increased LVWT or patients without LAE or increased LVWT (36.8% and 35.2% respectively, P = 0.004). After adjustment for body mass index (BMI), paroxysmal AF, CHA₂DS₂-VASc score, clinically-significant valvular heart disease, and cardiomyopathy, patients with LAE and concomitant increased LVWT diagnosis had a 1.8-times increased risk of arrhythmia recurrence (HR, 1.784; 95% confidence interval [CI], 1.017-3.130; P = 0.043).

CONCLUSION

Joint occurrence of LAE and increased LVWT is associated with the highest rate of arrhythmia recurrence after CB for AF.

Artificial intelligence analysis of ECG signals to predict arrhythmia recurrence after cryoballoon ablation of atrial fibrillation

Introduction

Cryoballoon-based pulmonary vein isolation (CB) is an effective option for rhythm control in atrial fibrillation (AF). There have been multiple attempts to predict arrhythmia recurrence, but with moderate success.

Purpose

To use artificial intelligence (AI) deep electrocardiogram (ECG) analysis to predict arrythmia recurrence after CB.

Methods

In a single-center study of 250 consecutive pts (58.2±12.6 years, 30% female) treated with CB for AF (05.2017–04.2019), 60% had paroxysmal AF (PAF), 66.5% had hypertension, and 27.2% had a redo CB. Analyses included left atrial volume (LA vol: indexed for BSA and assed by angio-MSCT in 76% and the rest with echo), left ventricle ejection fraction (LVEF) and hypertrophy (LVH: septal/posterior wall thickness ≥11mm in ♂ and ≥10mm in ♀) along with 30s arrhythmia recurrence at 2-yr follow-up. Baseline 500Hz raw 12-lead digital ECG signals were analyzed by means of convolutional neural network (CNN) architecture that was taught to process the 12-channel ECG signal (XML). The transfer learning method of CNN parameters learned on a very large number of coded consecutive training ECG samples (n=1,000) was adopted to analyze current sample of ECG signals.

Results

Arrhythmia recurrence at 2-yrs was 46.0% (n=115). There was gradual increase in predictive performance being the lowest if only baseline clinical data were analyzed and the highest combing all baseline clinical data plus anatomical and functional parameters (Table 1: #1–#3). AI baseline ECG analysis alone offered predictive performance similar to that made upon analysis of all baseline clinical data or joint analysis of LA vol, LVH, and LVEF (Table 1: #4). AI results added substantially to predictive performance of models using baseline clinical data alone (#1 vs #5, p&lt;0.001) and joint analysis of baseline clinical plus LA vol, LVH and LVEF (#3 vs #6, p=0.0130) (Fig. 1).

Conclusions

Prediction of recurrence after CB using raw ECG data with deep AI analysis is feasible. Joint analysis of results of AI of baseline ECG and basic clinical data offers predictive performance similar to that made upon analysis of clinical data including advanced information on LA volume and LVH and function. AI analysis of baseline ECG adds significantly to models aimed at recurrent AF prediction.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): National Institute of Cardiology, Warsaw, Poland

The association between the acquisition of antibodies against Lyme disease and the risk of atrial arrhythmias

INTRODUCTION

The impact of Borrelia burgdorferi (BB) antibodies on cardiac arrhythmias in patients without the typical symptoms of Lyme disease (LD) is largely unknown.

OBJECTIVES

To assess the risk of atrial fibrillation (AF) and other atrial arrhythmias (AAs) in patients who tested positive for LD antibodies.

PATIENTS AND METHODS

We included consecutive patients referred for diagnosis and treatment of AAs without a history of erythema migrans or other symptoms of LD. The presence of BB antibodies (immunoglobulin (Ig) M and IgG) was assessed in each patient, and the diagnosis of cardiac arrhythmias was made.

RESULTS

Of the 527 patients enrolled in the study, 292 (55%) were diagnosed with AAs, and we detected BB antibodies in 131 (24.8%) patients. Patients with serological history of Borrelia infection were older [55.6 (15.7) vs. 50.3 (18.6) years; p = 0.01], had a higher probability of developing AF or other supraventricular arrhythmias (SAs) (66.4% vs. 51.8%, p = 0.03), and had elevated levels of N-terminal-pro-brain natriuretic peptide (NT-proBNP) (58% vs. 47.5%; p = 0.04). We also found an interaction between the occurrence of AF and other SAs in patients BB antibodies and elevated NT-proBNP values, and the risk of AAs in these patients increased almost threefold (p = 0.01).  Conclusion: Our data indicated an association between exposure to Borrelia infection and the risk of AF and other AAs occurrence in patients with elevated levels of NT-proBNP, suggesting the need for a more efficacious diagnostic approach for patients with SAs, especially in LD-endemic regions.

A combination of quinidine/mexiletine reduces arrhythmia in dilated cardiomyopathy in two patients with R814W SCN5A mutation

SCN5A gene mutations are described in 2% of patients with dilated cardiomyopathy (DCM) and different rhythm disturbances, including multifocal ectopic Purkinje‐related premature contractions. Recent data indicate that sodium channel blockers are particularly effective monotherapy in carriers of the R222Q SCN5A variant. Our purpose is to describe the effectiveness of antiarrhythmic treatment in a family with genetically determined arrhythmogenic DCM associated with the R814W variant in the SCN5A gene. We examined a family with arrhythmogenic DCM (multifocal ectopic Purkinje‐related premature contractions phenotype, atrial tachyarrhythmias, automatism, and conduction disorders) and described antiarrhythmic treatment efficacy in heart failure symptoms reduction and myocardial function improvement. We found a heterozygotic mutation R814W in SCN5A by whole exome sequencing in the proband and confirmed its presence in all affected subjects. There were two sudden cardiac deaths and one heart transplantation among first‐degree relatives. The 58‐year‐old father and his 37‐year‐old daughter had full spectrum of symptoms associated with R814W SCN5A mutation. Both had implanted cardioverter defibrillator. In the father, adding mexiletine to quinidine therapy reduced ventricular arrhythmia (50–60% → 6–8% of whole rhythm) and reverted long‐standing atrial fibrillation to sinus rhythm. In the daughter, mexiletine and overdrive pacing were effective in ventricular arrhythmia reduction (25% → 0.01%). Because of a growing number of atrial fibrillation recurrences, a reduced dose of quinidine (subsequently flecainide) was added, resulting in arrhythmia significant reduction. In both cases, antiarrhythmic effectiveness correlated with clinical improvement. In SCN5A R814W‐associated DCM, a combination of Class I antiarrhythmics and overdrive pacing is an effective treatment of severe ventricular and atrial arrhythmias.

Positional sleep disordered breathing in patients with arrhythmia. Should we advise our patients to avoid supine position during sleep?

BACKGROUND

Sleep disordered breathing [SDB] is a well-known problem in patients with cardiovascular diseases. Around 50% of pts. with SDB present positional sleep disordered breathing [PSDB].

AIMS

The aim of this study was the investigation of the frequency of PSDB in patients with different forms of arrhythmias.

METHODS

We analyzed the presence of SDB in 53 pts. with diagnosed atrial fibrillation (paroxysmal or persistent), 88 pts. before ablation of ventricular ectopy and 110 pts. that had Holter monitoring due to the symptoms suggesting arrhythmia.

RESULTS

Finally, we could collect all the data in 243 pts. - 150 men 93 women. AHI < 15 was recorded in 136 (56%) pts., AHI > 15 in 107 (44%) pts. Moderate sleep disordered breathing was diagnosed in 59 (24%) pts. (AHI 15-30), severe sleep disordered breathing (AHI > 30) was recognized in 48 (20%) pts. In all of the analyzed groups, AHI in supine position was significantly higher than in nonsupine position. PSDB was recorded in 55% of pts. with AHI > 15 and in 29% of pts. (n = 14) with AHI > 30. Percentage of time in supine position was an independent factor related with the presence of at least moderate or severe sleep disordered breathing.

CONCLUSION

1. Moderate or severe SDB is recorded in 44% of pts. with arrhythmias, almost 50% of them have positional SDB. 2. Percent of time of sleeping in supine position has an important independent impact on the presence of SDB. 3. Big studies should be conducted to verify if avoidance of sleeping in supine position may improve clinical outcome.

CONDENSED ABSTRACT

Sleep disordered breathing SDB is a frequent problem of pts. with cardiovascular diseases. It may influence the prognosis. Moderate or severe SDB is recorded in 44% of pts. with arrhythmias, almost 50% of them have positional SDB. Percent of time of sleeping in supine position has an important independent impact on the presence of SDB. 3. Big studies should be conducted to verify if avoidance of sleeping in supine position may improve clinical outcome. What is new?

Distances between transseptal puncture site and anatomical landmarks

The aim of the study was to provide quantitative data and to look for new landmarks useful during transseptal puncture (TSP) using a fluoroscopy-guided approach. METHODS AND RESULTS: A total of 104 patients at mean age 57 ± 12 years, of whom 92% underwent pulmonary vein isolation, were analysed. Before TSP catheters were placed in the coronary sinus (CS) and His bundle region. A guidewire running from femoral vein through great veins was left loose in superior vena cava. Before TSP X-ray images were taken in right anterior oblique (RAO) 45° and RAO 53° projections. Locations posterior to TSP site in RAO were described with negative values and those anterior with positive values. The measured distances in millimeters were as follows: (a) between TSP site and posterior atrial wall (RAO 45 = -21 ± 7 mm; RAO 53 = -19 ± 6 mm (b) between TSP site and free guidewire (RAO 45 = -5 ± 4 mm, RAO 53 = -3 ± 4 mm (c) between TSP site and CS ostium (RAO 45 = 9 ± 6 mm; RAO 53 = 8 ± 5 mm (d) between TSP site and His region (RAO 45 = 29 ± 8 mm; RAO 53 = 30 ± 8 mm). We observed correlations between measured distances and age, body mass index and sizes of cardiac chambers. The distance between TSP site and the line projected by the guidewire running between great veins, measured in mid-RAO projections, was very small. CONCLUSION: The distances between TSP site and standard anatomical landmarks used during TSP vary with regard to age, physique and cardiac chamber dimensions. TSP site, as assessed in mid RAO, is in direct vicinity to the line projected by a guidewire running between the great veins.

Reduction of left ventricular mass, left atrial size, and N-terminal pro-B-type natriuretic peptide level following alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

Alcohol septal ablation (ASA) is an alternative to surgical treatment in patients with hypertrophic obstructive cardiomyopathy (HOCM). Through alcohol-induced necrosis, ASA leads to an increase in left ventricular outflow tract (LVOT) diameter and a decrease in LVOT pressure gradient.

AIM

We sought to assess the effect of ASA on left ventricular (LV) wall thickness and mass, left atrial (LA) size, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) level.

METHODS

The study cohort consisted of 50 patients with HOCM (30 in the ASA group, 20 in the optimal pharmacotherapy group [OPG]). Transthoracic echocardiography (TTE), cardiac magnetic resonance (CMR), and NT-proBNP level analysis were performed at baseline and at six months.

RESULTS

All parameters are presented as means. In the ASA group, the maximal LVOT pressure gradient decreased from 122.7 to 54.8 mmHg directly after ASA and to 37.2 mmHg after a further six months (p < 0.0001). The NT-proBNP level decreased from 2174.4 to 1103.4 pg/mL (p < 0.001). On TTE, the interventricular septum (IVS) thickness decreased to from 23.6 to 19.4 mm (p < 0.0001) and the lateral wall (LW) thickness decreased from 15.9 to 14.2 mm (p < 0.007). On CMR, basal IVS thickness decreased from 23.7 to 18.0 mm (p < 0.0001) and the LW thickness decreased from 13.2 to 12.2 mm (p = 0.02). IVS mass reduced from 108.9 to 91.5 g (-16%; p < 0.001). All of the above parameters remained unchanged in the OPG.

CONCLUSIONS

Successful ASA reduces LV hypertrophy and improves parameters of the LV overload, resulting in LV wall hy-pertrophy regression, and LA size and NT-proBNP level reduction. The above parameters may be as useful in assessing the efficacy of ASA as the LVOT gradient itself.

Ventricular fibrillation induced by radiofrequency energy delivery for premature ventricular contractions arising from the right ventricular outflow tract: is implantablecardioverterdefibrillator indicated?

INTRODUCTION    Inadvertently induced ventricular fibrillation (VF) by radiofrequency (RF) energy delivery for premature ventricular complexes (PVCs) is a rare phenomenon; nevertheless, it is crucial to assess long‑term risk of sudden cardiac death in these patients. OBJECTIVES    The aim of our study was to define the long‑term prognosis in patients with normal ejection fraction (EF), in whom VF was inadvertently induced by RF energy application during ablation of symptomatic idiopathic PVCs originating from the right ventricular outflow tract (RVOT). PATIENTS AND METHODS    Among over 20 000 RF catheter ablations performed at 5 tertiary centers (2008-2016), 6 patients (5 men) had VF induced by RF application to the RVOT. The mean (SD) age of patients was 35.2 (16.8) years. All patients had normal EF (≥60%). We analyzed the risk of malignant ventricular arrhythmias and assessed heart function during follow‑up. RESULTS    After ablation, baseline contrast‑enhanced magnetic resonance imaging was performed in 4 of the 6 patients; no area of late gadolinium enhancement was observed. One patient received an implantable cardioverter‑defibrillator (ICD). Exercise tests revealed only rare PVCs. All patients completedthe follow‑up (mean [SD] duration of follow‑up, 64.0 [34.9] months). All patients were alive, with no cases of syncope, documented ventricular tachycardia, or VF. The patient with an ICD received 2 inappropriate high‑voltage therapies. CONCLUSIONS    Patients with inadvertently induced VF via RF energy application during ablation of PVCs from the RVOT, who have normal left ventricular function and no electrocardiography abnormalities have good prognosis and low VF risk during long‑term follow‑up. Therefore, ICD placement seems to be not indicated for these patients.

Ablation of atrial tachyarrhythmias late after surgical correction of tetralogy of Fallot: long-term follow-up

BACKGROUND

After the surgical correction of tetralogy of Fallot, surgical scars and natural obstacles form pathways capable of supporting an atrial tachyarrhythmia (AT). Radiofrequency (RF) ablation is effective, although the few studies published on this topic had relatively short follow-up periods.

AIM

The aims of the study were to evaluate the acute and long-term effects of RF ablation of AT and examine the charac-teristics of arrhythmia recurrence.

METHODS

Tetralogy of Fallot patients (n = 16, age 44.7 ± 10.7 years) referred for ablation of ATs, appearing 25.7 ± 9.6 years after repair, were studied.

RESULTS

Twenty-five ATs were ablated, including 16 cavo-tricuspid isthmus atrial flutters (CTI-AFLs) and nine intraatrial reentrant tachycardia (IART). In one patient with paroxysmal atrial fibrillation (PAF), pulmonary vein isolation was also performed. Ten patients had permanent, and six had paroxysmal arrhythmia prior to the first ablation. Four patients had PAF. Regardless of the type of first ablated arrhythmia, all 16 patients required CTI-AFL ablation. The effectiveness of the first RF ablation reached 88%. The acute efficacy of RF ablation was 100% for CTI-AFL and 78% for IART. Long-term follow-up was possible in 15 out of 16 patients (mean follow-up 68.8 ± 36.6 months). Four patients were free of sustained arrhythmia, nine (60%) had AF. After the last RF ablation, an episode suggestive of CTI-AFL/IART was documented only in one patient.

CONCLUSIONS

Ablation of CTI-AFL/IART in tetralogy of Fallot patients is safe and effective. AF was observed in most patients during the long-term follow-up. Regardless of the type of the first ablated arrhythmia, all patients required CTI-AFL ablation.

Ablation of Macro-Re-Entrant Atrial Arrhythmia Late after Surgical Aortic Valve Replacement

BACKGROUND

Re-entrant atrial arrhythmias are common in patients after cardiac surgery. To date, however, no studies have reported the safety and efficacy of radiofrequency (RF) ablation of macro-re-entrant atrial arrhythmias in a unique, homogeneous group of patients after surgical replacement of the aortic valve and single right atriotomy.

METHODS

Among over 4,000 RF catheter ablations performed at the authors' center between 2008 and 2014, eight patients (seven males, one female; mean age 55.1 ± 19.9 years) after aortic valve replacement (AVR) and without history of any other cardiosurgical procedures were identified with documented macro-re-entrant atrial arrhythmia. The mechanism of macro-re-entrant arrhythmia was analyzed, as well as the safety and efficacy of RF ablation in a group of patients after AVR and single right atrial free wall atriotomy.

RESULTS

The average time from surgery to RF catheter ablation was 11.3 ± 11.3 years (range: 4-35 years). In five patients with permanent arrhythmia, entrainment mapping proved these arrhythmias to be cavotricuspid isthmus- dependent, in three patients with paroxysmal atrial arrhythmia cavotricuspid isthmus-dependent atrial flutter was induced during the electrophysiological study. Intra-atrial re-entrant tachycardia was neither recorded nor induced in any patient. Successful ablation of cavotricuspid isthmus is defined as the termination of arrhythmia, and bidirectional block in cavotricuspid isthmus was achieved in all patients. A long-term follow up, based on a seven-day Holter monitoring, was conducted in all patients, with a mean observation time of 40.1 ± 28.6 months after the procedure. Among the patients, ablated arrhythmia (cavotricuspid isthmusdependent atrial flutter) recurred in one patient, atrial fibrillation occurred in three patients, and an atrial tachycardia in one patient.

CONCLUSIONS

In the presented series of patients, cavotricuspid isthmus-dependent atrial flutter was shown to be the mechanism of post-cardiosurgical macro-re-entrant clinical arrhythmia in all subjects. Atrial fibrillation was frequently observed among those patients during follow up.

Atrial tachycardia ablation in patients with a functional single ventricle after the Fontan surgery

BACKGROUND

Atrial tachyarrhythmias are a leading source of morbidity and mortality after Fontan-type procedures and antiarrhythmic drug therapy is often ineffective in these patients.

AIM

To evaluate short- and long-term outcomes of radiofrequency current ablation for atrial tachycardia (AT) in patients after the Fontan procedure, and to report clinical, electrophysiological and electroanatomical characteristics of these arrhythmias.

METHODS

We retrospectively analysed data obtained in 8 patients (5 males, 3 females) after the Fontan procedure who underwent ablation for AT between 2002 and 2013. In order to compare the clinical impact of arrhythmia before and after ablation, we used the modified arrhythmia score, ranging from 0 (no arrhythmia activity) to 12 (very severe arrhythmia). In all patients, electroanatomical mapping using the CARTO system was performed, allowing semiquantification of low-voltage (< 0.5 mV) areas and scars.

RESULTS

Seven patients had an atriopulmonary connection and 1 patient had an extracardiac conduit. The mean patient age was 9.4 ± 3.1 years at the time of the Fontan procedure and 26.2 ± 4.6 years at the time of the first ablation. A total of 18 ablations were performed with no complications, 1 to 4 (median 2.5) procedures per patient. In patients who had more than 1 ablation, the mean time from the first to the last procedure was 34.8 months (range 1-64 months). In individual patients, 1 to 4 (median 2.5) different ATs were observed, with the mean tachycardia cycle length of 334 ± 95 ms. In 6 patients, low-voltage area (< 0.5 mV) comprised 25-50% of the right atrium, and in two others it comprised 10-25% and < 10% of the right atrium, respectively. Seven procedures were fully successful (ablation of all ATs), 7 were partially successful (ablation of only some AT, including clinical arrhythmia, but not of all ATs) and 4 were unsuccessful (failed ablation of clinical AT). The mean procedural, fluoroscopy and ablation times were 176 ± 54.6, 13.7 ± 5.7 and 21.7 ± 11.9 min, respectively. Freedom from arrhythmia during the mean follow-up of 58.6 ± 46 months (range 11-127 months) since the last procedure was obtained in 4 patients. The median arrhythmia score after the last ablation was significantly reduced compared to baseline (4.5 vs. 8; p < 0.05).

CONCLUSIONS

Catheter ablation of AT in patients after the Fontan procedure is safe but its acute and long-term efficacy is limited. Due to complex and extensive substrate, along with complex anatomy, recurrences are frequent and patients may require repeat ablation procedures. Suppression of arrhythmia is associated with an improved clinical status of the patients.

[Parahisian atrial tachycardia or atrioventricular nodal reentrant tachycardia with tendon of Todaro breakthrough?]

We present a case of a 61 year-old woman with tachycardia originating close to the His bundle where radiofrequency (RF) ablation may bear potential risk of atrioventricular (AV) block. In this case report we discuss the possibility of a AV nodal reciprocating tachycardia with tendon of Todaro breakthrough. Patient was safely and effectively treated with RF catheter ablation.

Relationship between cycle length of typical atrial flutter and double potential interval after achievement of complete isthmus block

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.

[Ortodromic atrio-ventricular reentrant tachycardia with functional left bundle branch block morphology - differential diagnosis of wide complex tachycardia based on case report]

We present a case of 18 year-old man, without structural heart disease, who suffered from regular and irregular palpitations. ECG was normal during sinus rhythm, and showed LBBB morphology during tachycardia (220/min). Programmable pacing from CS induced sustained atrial fibrillation with normal and wide QRS (LBBB-like, RBBB-like) and minimal RR interval 270 ms. We found and ablate concealed left free wall accessory pathway. During 1-year observation patient stayed asymptomatic.

Predictors of successful defibrillation threshold test during CRT-D implantation

BACKGROUND

The assessment of defibrillation energy requirement (DER) is a standard practice during cardioverter-defibrillator (ICD) implantation. It is recommended to assure that the energy at least 10 J below the maximal energy deliverable by the implanted device successfully converts the induced ventricular fibrillation (VF). The cardiac resynchronisation therapy with defibrillator (CRT-D) recipients are at increased risk of developing serious complications due to repeated VF induction.

AIM

To define the prevalence of high DER among CRT-D recipients and to determine the factors which allow to obtain defibrillation safety margin.

METHODS

We examined all patients who underwent CRT-D implantation between June 2006 and June 2009 in our institution. The verification of the DER required at least one termination of the induced VF with the energy at least 10 J below the maximal energy deliverable by the implanted device.

RESULTS

The CRT-D was implanted in 65 patients. The first defibrillation test was successful in 57 (88%) patients. In the remaining 8 patients (12%), the defibrillation test was unsuccessful. These patients required system revision: reprogramming shocking polarity (2), reversing polarity and adjusting waveform (3), lead repositioning (1) and adding a subcutaneous lead (2). The use of high output devices (maximal energy > 30 J) and dual-coil leads was associated with a significantly (p < 0.05) lower rate of high DER, although high DER occurred in one patient implanted with the high output device. There was a correlation between the probability of successful defibrillation and renal function. It was less likely to obtain successful defibrillation safety margin in patients with creatinine > 175 micromol/L. During the follow up, ventricular tachyarrhythmia detected in the VF detection zone occurred in 13 (20%) patients, including two patients, who required system modification during implantation. In both cases, VF was terminated by the first defibrillation with the maximal energy of the implanted devices.

CONCLUSIONS

High DER occurred in a significant number of CRT-D recipients. There is a correlation between high DER and impaired renal function. The use of high output devices significantly decreases the number of patients who required system modification in order to obtain an adequate defibrillation safety margin.

[Radiofrequency ablation of ventricular arrhythmia from the non-coronary cusp]

There is a close anatomical relationship between the non-coronary aortic cusp (NCC) and sites where His bundle (HB) is recorded in the right ventricle (RV). We describe a patient with frequent premature ventricular beats originating near HB. Arrhythmia was successfully ablated from the NCC although local electrogram preceded QRS in NCC and His area. When RV mapping reveals an earliest ventricular activation in the HB region, mapping in the right coronary cusp and NCC should be done to identify the area of arrhythmia origin.

Ablation of severe drug-resistant tachyarrhythmia during pregnancy

AIMS

The goal of this study was to describe mapping and ablation of severe arrhythmias during pregnancy, with minimum or no X-ray exposure. Treatment of tachyarrhythmia in pregnancy is a clinical problem. Pharmacotherapy entails a risk of adverse effects and is unsuccessful in some patients. Radiofrequency ablation has been performed rarely, because of fetal X-ray exposure and potential maternal and fetus complications. GROUP AND METHOD: Mapping and ablation was performed in 9 women (age 24-34 years) at 12-38th week of pregnancy. Three had permanent junctional reciprocating tachycardia, and 2 had incessant atrial tachycardia. Four of them had left ventricular ejection fraction < or =45%. One patient had atrioventricular nodal reciprocating tachycardia requiring cardioversion. Three patients had Wolff-Parkinson-White syndrome. Two of them had atrial fibrillation with ventricular rate 300 bpm and 1 had atrioventricular tachycardia 300 bpm. Fetal echocardiography was performed before and after the procedure.

RESULTS

Three women had an electroanatomic map and ablation done without X-ray exposure. The mean fluoroscopy time in the whole group was 42 +/- 37 seconds. The mean procedure time was 56 +/- 18 minutes. After the procedure, all women and fetuses were in good condition. After a mean period of 43 +/- 23 months follow up (FU), all patients were free of arrhythmia without complications related to ablation either in the mothers or children.

CONCLUSION

Ablation can be performed safely with no or minimal radiation exposure during pregnancy. In the setting of malignant, drug-resistant arrhythmia, ablation may be considered a therapeutic option in selected cases.

Predictors of the atrial fibrillation occurrence in patients with Wolff-Parkinson-White syndrome

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.

Technical and practical aspects of remote monitoring of implantable cardioverter-defibrillator patients in Poland - preliminary results

BACKGROUND

The aim of remote monitoring of implantable cardioverter-defibrillators (ICD) is to increase the patient's safety by early detection of technical or medical malfunctions and decrease the number of follow-up visits.

AIM

To evaluate the feasibility and reliability of internet-based home monitoring of ICD recipients in Poland.

METHODS

Twenty-seven patients with ICD with remote monitoring options were evaluated; 20 (74%) patients had a single chamber ICD, 6 (22%) patients had a dual chamber ICD and one had an ICD with a resynchronisation therapy option. Medical and technical events reported by the remote monitoring system as well as interruptions in monitoring longer than 14 days were analysed.

RESULTS

The patients were followed for 12.7 +/- 10.5 months. Two of them died because of heart failure (6 and 13 months after ICD implantation, respectively). The remote monitoring system reported medical events in 13 (48%) patients. In total, we received 32 event reports (from 1 to 19 per patient, mean 2.6) which were generated due to the detection of ventricular tachycardia (VT) (17 events in 9 patients), ventricular fibrillation (VF) (9 episodes in 6 patients), ineffective defibrillation with the maximal energy (5 reports in 3 patients) and supraventricular tachycardia in the VT detection window (1). Two patients had more than 3 VT/VF episodes during 24 h. There were no reports on technical abnormalities of the ICD system. Interruptions in home monitoring longer than 14 days occurred in 5 (18.5%) patients and lasted 2 to 14 weeks (mean 2.8 +/- 7.1). The longest break was caused by the patient's stay abroad. The remaining interruptions were caused by: journeys (5 episodes), hospitalisations (4), and a temporary stay in a place without sufficient GSM coverage (3). During the follow-up period there were no interruptions in monitoring caused by transmitter or ICD failure. All data received by the home monitoring system were confirmed during the follow-up visits.

CONCLUSION

Remote monitoring of ICD recipients in Poland does not present technical difficulties and enables early detection of serious events in ICD patients.

Outcomes of a single centre registry of patients with ischaemic heart disease, qualified for an RF ablation of ventricular arrhythmia after ICD intervention

BACKGROUND AND AIM

Reduction of ICD interventions improves the quality of life and possibly reduces mortality. Ablation reduces ICD interventions in patients with ablatable arrhythmia, but its effectiveness needs to be proven for patients with coronary artery disease (CAD) regardless of the type of arrhythmia. Our study was designed to address this issue, but it had to be terminated due to recruitment problems. The reasons for early termination are described in this paper.

METHODS

Patients with CAD and implanted ICD, who within the past three months survived an episode of VT/VF, were selected for this study. Patients were to be randomised for ablation or pharmacotherapy. A group of 209 patients was screened between June and December of 2007.

RESULTS

Out of 209 patients, 39 (18.7%) had appropriate ICD therapy during the last three months and were potentially eligible for the trial. Out of 39 patients, 34 could not be randomised, due to the presence of exclusion criteria (n-25) or consent refusal (n-9). Previous ablation (n-10), left ventricular thrombus (n-3) or presence of mitral or aortic artificial valve (n-3) were the most frequent exclusion criteria. During follow-up of 12 months one patient required ablation due to frequent ICD discharges. From the five randomised patients, two were randomised to ablation and three to the pharmacotherapy arm.

CONCLUSIONS

1. Ablation might not be suitable as a routine treatment for all patients with ICD interventions, as a significant group prefers not to undergo RF ablation as a routine treatment or there are contraindications for the ablation. 2. There are obstacles in prospective and randomised evaluation of the role of ablation in patients with CAD and ICD interventions, which are related both to patients' medical conditions and to patients' will. These limitations should be taken into account when designing further studies.

[Pseudo atypical atrial flutter or atrial tachycardia dependent on complex substrate in a patient with univentricular heart after palliative operations - mapping and ablation]

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.

[Radiofrequency ablation of long standing persistent atrial fibrillation and post-incisional macroreentrant right atrial tachycardia in patient with advanced biventricular heart failure--case raport]

We present a case of a 54 year old male with a long-standing atrial fibrillation (AF) who was scheduled for cardiac transplantation due to the progression of heart failure. Previous treatment included pacemaker implantation, mitral valvuloplasty, a-v node modification using RF ablation, and pharmacological therapy. This time the patient underwent complex AF ablation which consisted of pulmonary vein isolation, mitral and left atrial roof line creation, cavo-tricuspid isthmus ablation and ablation of complex fractionated atrial electrograms, which resulted in restoration of sinus rhythm. Because of the right atrial post-incisional tachycardia the patient underwent second ablation session. This complex invasive approach occurred successful. The patient remains in sinus rhythm with improved left ventricular function and better NYHA class over a 12-month follow-up.

[Successful ablation of left atrial flutter with a single RF application in a patient after atrial fibrillation ablation - when is it possible?]

We describe a case of a 49-year-old patient with left atrial flutter after atrial fibrillation ablation. Left atrium activation map (CARTO) and entrainment mapping revealed local reentry on the posterior wall of the left atrium, close to the proximal coronary sinus. Arrhythmia was terminated with a single RF application and remained noninducible. However, after 6-weeks follow-up patient presented with a roof line and mitral isthmus - dependent atrial flutters which were successfully ablated.

[Sotalol prevents atrio-ventricular tachycardia but not atrial fibrillation with rapid ventricular response in a patient wiht WPW syndrome]

We present a case of 23-year-old male with the Marfan syndrome multiple accessory pathways and atrio-ventricular reentry ant tachycardia (AVRT) as well as atrial fibrillation (AF). Sotalol was partially effective for AVRT, however, it did not prevent AF, RF ablation cured all arrythmias. This case shows that sotalol can attenuate AVRT recurrences, however, it does not prevent rapid conduction via accessory pathways during AF.

[Right atrial flutter or tachycardia?]

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.

The clinical course and risk in patients with pseudo-Mahaim fibers

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.

[Coronary venoplasty during the implantation of the cardiac resynchronisation device--a case report]

We describe a case of a 76-year-old patient with advanced block in the His-Purkjnie system, who underwent implantation of a cardioverter-defibrillator with cardiac resynchronisation therapy. Complete heart block occurred during the insertion of the coronary sinus cathether. The implantation of the left ventricular (LV) lead was impossible due to difficult anatomy of the coronary venous system. The right ventricular pacing caused the further prolongation of the QRS duration and exacerbation of heart failure symptoms. Thus, the LV lead was successfully implanted during the second procedure after the balloon venoplasty of the lateral cardiac vein. The biventricular pacing was successful during 4 months follow-up.

[The vein of Marshall as a source of various types of atrial arrhythmias, including adrenergic paroxysmal atrial fibrillation--successful catheter ablation]

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.

[Wide QRS complex tachycardia in a patient after inferior myocardial infarction and CABG -- the role of electrophysiological study and RF ablation]

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.