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<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

Systematic, early rhythm control strategy for atrial fibrillation in patients with or without symptoms: the EAST-AFNET 4 trial

AIMS

Clinical practice guidelines restrict rhythm control therapy to patients with symptomatic atrial fibrillation (AF). The EAST-AFNET 4 trial demonstrated that early, systematic rhythm control improves clinical outcomes compared to symptom-directed rhythm control.

METHODS AND RESULTS

This prespecified EAST-AFNET 4 analysis compared the effect of early rhythm control therapy in asymptomatic patients (EHRA score I) to symptomatic patients. Primary outcome was a composite of death from cardiovascular causes, stroke, or hospitalization with worsening of heart failure or acute coronary syndrome, analyzed in a time-to-event analysis. At baseline, 801/2633 (30.4%) patients were asymptomatic [mean age 71.3 years, 37.5% women, mean CHA2DS2-VASc score 3.4, 169/801 (21.1%) heart failure]. Asymptomatic patients randomized to early rhythm control (395/801) received similar rhythm control therapies compared to symptomatic patients [e.g. AF ablation at 24 months: 75/395 (19.0%) in asymptomatic; 176/910 (19.3%) symptomatic patients, P = 0.672]. Anticoagulation and treatment of concomitant cardiovascular conditions was not different between symptomatic and asymptomatic patients. The primary outcome occurred in 79/395 asymptomatic patients randomized to early rhythm control and in 97/406 patients randomized to usual care (hazard ratio 0.76, 95% confidence interval [0.6; 1.03]), almost identical to symptomatic patients. At 24 months follow-up, change in symptom status was not different between randomized groups (P = 0.19).

CONCLUSION

The clinical benefit of early, systematic rhythm control was not different between asymptomatic and symptomatic patients in EAST-AFNET 4. These results call for a shared decision discussing the benefits of rhythm control therapy in all patients with recently diagnosed AF and concomitant cardiovascular conditions (EAST-AFNET 4; ISRCTN04708680; NCT01288352; EudraCT2010-021258-20).

Anticoagulation, therapy of concomitant conditions, and early rhythm control therapy: a detailed analysis of treatment patterns in the EAST - AFNET 4 trial

Aims

Treatment patterns were compared between randomized groups in EAST-AFNET 4 to assess whether differences in anticoagulation, therapy of concomitant diseases, or intensity of care can explain the clinical benefit achieved with early rhythm control in EAST-AFNET 4.

Methods and results

Cardiovascular treatment patterns and number of visits were compared between randomized groups in EAST-AFNET 4. Oral anticoagulation was used in >90% of patients during follow-up without differences between randomized groups. There were no differences in treatment of concomitant conditions between groups. The type of rhythm control varied by country and centre. Over time, antiarrhythmic drugs were given to 1171/1395 (84%) patients in early therapy, and to 202/1394 (14%) in usual care. Atrial fibrillation (AF) ablation was performed in 340/1395 (24%) patients randomized to early therapy, and in 168/1394 (12%) patients randomized to usual care. 97% of rhythm control therapies were within class I and class III recommendations of AF guidelines. Patients randomized to early therapy transmitted 297 166 telemetric electrocardiograms (ECGs) to a core lab. In total, 97 978 abnormal ECGs were sent to study sites. The resulting difference between study visits was low (0.06 visits/patient/year), with slightly more visits in early therapy (usual care 0.39 visits/patient/year; early rhythm control 0.45 visits/patient/year, P < 0.001), mainly due to visits for symptomatic AF recurrences or recurrent AF on telemetric ECGs.

Conclusion

The clinical benefit of early, systematic rhythm control therapy was achieved using variable treatment patterns of antiarrhythmic drugs and AF ablation, applied within guideline recommendations.

Early Rhythm Control Therapy in Patients with Atrial Fibrillation and Heart Failure

Supplemental Digital Content is available in the text.

Even on optimal therapy, many patients with heart failure and atrial fibrillation experience cardiovascular complications. Additional treatments are needed to reduce these events, especially in patients with heart failure and preserved left ventricular ejection fraction.

Cabins, castles, and constant hearts: rhythm control therapy in patients with atrial fibrillation

Recent innovations have the potential to improve rhythm control therapy in patients with atrial fibrillation (AF). Controlled trials provide new evidence on the effectiveness and safety of rhythm control therapy, particularly in patients with AF and heart failure. This review summarizes evidence supporting the use of rhythm control therapy in patients with AF for different outcomes, discusses implications for indications, and highlights remaining clinical gaps in evidence. Rhythm control therapy improves symptoms and quality of life in patients with symptomatic AF and can be safely delivered in elderly patients with comorbidities (mean age 70 years, 3–7% complications at 1 year). Atrial fibrillation ablation maintains sinus rhythm more effectively than antiarrhythmic drug therapy, but recurrent AF remains common, highlighting the need for better patient selection (precision medicine). Antiarrhythmic drugs remain effective after AF ablation, underpinning the synergistic mechanisms of action of AF ablation and antiarrhythmic drugs. Atrial fibrillation ablation appears to improve left ventricular function in a subset of patients with AF and heart failure. Data on the prognostic effect of rhythm control therapy are heterogeneous without a clear signal for either benefit or harm. Rhythm control therapy has acceptable safety and improves quality of life in patients with symptomatic AF, including in elderly populations with stroke risk factors. There is a clinical need to better stratify patients for rhythm control therapy. Further studies are needed to determine whether rhythm control therapy, and particularly AF ablation, improves left ventricular function and reduces AF-related complications.

Characteristic features of patients with multiple accessory pathways

Objective Only limited clinical and electrophysiological data concerning patients (pts) with multiple accessory pathways (MAP) in comparison to large control groups are available. The aim of our study was to analyse these data from the largest cohort of patients with multiple accessory pathways and a large control group. Method and results We analysed data from pts with MAP (group 1) and pts with a single accessory pathway (AP) (group 2) referred for radiofrequency catheter ablation (RFCA) at our tertiary centre. Group 1 consisted of 124 pts (M 62.10%, mean age 33.00 ± 5.26) with MAP and RFCA. Group 2 consisted of 376 pts (M 51.20%, mean age 35.87 ± 16.15) with a single accessory pathway and RF ablation. Group 1 exhibited a higher incidence of overt APs (P < 0.0001), Ebstein anomaly (P = 0.001), ventricular fibrillation (P = 0.012), antidromic atrioventricular re-entrant tachycardia (A AVRT) (P = 0.025) and male gender (P = 0.038). The mean age at the first documented atrioventricular re-entrant tachycardia (AVRT) episode was lower in pts with MAP than in pts with single APs: 16.79 ± 13.41 vs 20.84 ± 14.29, respectively (P = 0.001). Concealed accessory pathways (P < 0.0001) occurred more frequently in the control group. Group 1 had more right-lateral (P = 0.0001), mid-septal (P = 0.0001), left-posterior (P = 0.01), left-anterior (P = 0.013) and left-lateral localizations of AP (P < 0.037). Conclusions The MAP group included statistically significantly more men, Ebstein anomaly and overt APs. The mean age of the first episode of atrioventricular re-entrant tachycardia was lower in pts with MAP. Certain distribution patterns are apparent for single and MAP. Pts with MAP are at higher risk of VF and antidromic atrioventricular re-entrant tachycardia.

Computer-aided training sensorimotor cortex functions in humans before the upper limb transplantation using virtual reality and sensory feedback

One of the biggest problems of upper limb transplantation is lack of certainty as to whether a patient will be able to control voluntary movements of transplanted hands. Based on findings of the recent research on brain cortex plasticity, a premise can be drawn that mental training supported with visual and sensory feedback can cause structural and functional reorganization of the sensorimotor cortex, which leads to recovery of function associated with the control of movements performed by the upper limbs. In this study, authors - based on the above observations - propose the computer-aided training (CAT) system, which generating visual and sensory stimuli, should enhance the effectiveness of mental training applied to humans before upper limb transplantation. The basis for the concept of computer-aided training system is a virtual hand whose reaching and grasping movements the trained patient can observe on the VR headset screen (visual feedback) and whose contact with virtual objects the patient can feel as a touch (sensory feedback). The computer training system is composed of three main components: (1) the system generating 3D virtual world in which the patient sees the virtual limb from the perspective as if it were his/her own hand; (2) sensory feedback transforming information about the interaction of the virtual hand with the grasped object into mechanical vibration; (3) the therapist's panel for controlling the training course. Results of the case study demonstrate that mental training supported with visual and sensory stimuli generated by the computer system leads to a beneficial change of the brain activity related to motor control of the reaching in the patient with bilateral upper limb congenital transverse deficiency.

Implantable cardioverter-defibrillator therapy in a 34-year-old patient with eating disorders and after the third sudden cardiac arrest

Eating disorders (ED) such as anorexia nervosa and bulimia are psychiatric diseases associated with the highest mortality rate of any other psychiatric disorders. More recently, long-term outcome studies with follow-up of over 20 years report a mortality of between 15% and 18% (Casiero and Frishman, Cardiol Rev 14(5), 227, 2006). The sudden death secondary to arrhythmias is often the cause of death in these patients (Casiero and Frishman, Cardiol Rev 14(5), 227, 2006). A case of life-threatening ventricular arrhythmia (VA) in a patient with ED is presented. Clinical records (cardiologic, psychiatric), electrocardiograms, echocardiogram, coronary angiogram, cardiac magnetic resonance, and endocrine diagnostics were performed. Finally a cardioverter-defibrillator (ICD) was implanted in the patient after her third cardiac arrest. An optimal approach to antiarrhythmic therapy in such patients is a real challenge for a cardiologist.

[Cardiac abnormalities in patients with myotonic dystrophy--preliminary results]

INTRODUCTION

Myotonic dystrophy (DM) is an inherited multisystem disorder associated with myotonia, progressive skeletal muscle weakness and atrophy, involvement of peripheral and central nervous system and sudden death likely due to atrioventricular block and/or ventricular arrhythmia.

AIM OF THE STUDY

to assess the type and degree of cardiac and neurological involvement in patients (pts) with DM.

MATERIALS AND METHODS

10 pts (6 male), in mean age of 35 +/- 13 years, treated for DM type I (DM1)--7 pts and type II (DM2)--3 pts. All pts underwent a neurological examination including muscle strength assessment as well as cardiac diagnostics including: standard and 48-hour ambulatory electrocardiogram, echocardiographic examination, magnetic resonance imaging (MRI) of the heart and late potentials assessment.

RESULTS

Muscle strength was moderately diminished (46-48 points in MRC sub score) in 3 pts with DM1 and mildly diminished (56-58 points in MRC sub score) in 2 pts with DM2. These patients showed clinical symptoms of myopathy. Cardiovascular examinations revealed: QRS duration above 110 ms in 5 pts, clinically significant supraventricular arrhythmia or atrioventricular block in 3 pts, focal myocardial fibrosis in 3 pts, asymmetric hypertrophy of inter-ventricular septum in 1 patient, presence of late potentials in 5 pts. We have not observed correlation between impaired muscle strength and cardiac abnormalities. However, most pronounced cardiac abnormalities were observed in 2 male DM1 patients with clinical symptoms of myopathy and lowest MRC score. At a mean follow up of 3.2 +/- 1.4 years none of the pts died.

CONCLUSIONS

Cardiac involvement in pts with myotonic dystrophy is frequent and is characterized by phenotypic heterogeneity. Detection of cardiac abnormalities may require extensive diagnostics. The most important is the assessment of ECG. Cardiac and neurological abnormalities vary in intensity between patients without close relationship to each other.

Interventional treatment of atrial fibrillation - contemporary methods and perspectives

Atrial fibrillation (AF) is estimated to affect nearly 3 million people around the world. It is the most common arrhythmia and its incidence increases with age. Catheter ablation is an interventional procedure performed to reduce the patient's AF burden when pharmacotherapy did not succeed in relieving the patient's symptoms. The ablation is most effective in paroxysmal AF; however, many techniques are being developed to make this procedure more eligible for patients with persistent arrhythmia. The most common AF ablation technique involves separating electric activity of the pulmonary veins from the left atrium. Over recent years, many novel and promising techniques were developed (e.g., balloon cryoablation, circular catheter ablation, laser ablation, robotic navigation, etc.), which may further improve AF ablation efficacy.

Attraction and repulsion of spiral waves by inhomogeneity of conduction anisotropy--a model of spiral wave interaction with electrical remodeling of heart tissue

Various forms of heart disease are associated with remodeling of the heart muscle, which results in a perturbation of cell-to-cell electrical coupling. These perturbations may alter the trajectory of spiral wave drift in the heart muscle. We investigate the effect of spatially extended inhomogeneity of transverse cell coupling on the spiral wave trajectory using a simple active media model. The spiral wave was either attracted or repelled from the center of inhomogeneity as a function of cell excitability and gradient of the cell coupling. High levels of excitability resulted in an attraction of the wave to the center of inhomogeneity, whereas low levels resulted in an escape and termination of the spiral wave. The spiral wave drift velocity was related to the gradient of the coupling and the initial position of the wave. In a diseased heart, a region of altered transverse coupling corresponds with local gap junction remodeling that may be responsible for stabilization-destabilization of spiral waves and hence reflect potentially important targets in the treatment of heart arrhythmias.

Catheter ablation of atrial fibrillation in patients with hypertrophic cardiomyopathy: atrial fibrillation type determines the success rate

BACKGROUND

Atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is generally associated with deterioration of the clinical status, functional capacity, and quality of life. It is also an independent risk factor for stroke and death. Studies evaluating the effectiveness of AF ablation in this cohort are relatively scant, have included relatively few patients, and their results are somewhat conflicting. Thus, the aim of this study was to assess the safety and efficacy of catheter ablation of AF in patients with HCM.

METHODS

Thirty patients (10 females; mean age 48.7 ± 11 years) with drug-refractory paroxysmal (n = 14), persistent (n = 7), or long-persistent (> 1 year; n = 9) AF were prospectively recruited into the study. Eleven patients were in New York Heart Association (NYHA) class I, 13 patients were in NYHA class II, and 6 patients were in NYHA class III. Mean atrial volume was 180 ± 47 mL, interventricular septum thickness was 20.5 ± 6.3 mm, and left atrial area was 29.8 ± 6.2 cm2. Ablation protocol was adjusted to the clinical and electrophysiological status of the patients. Pulmonary vein isolation and bidirectional cavo-tricuspid isthmus block were performed in all patients. In addition, left atrial linear lesions were created and complex fragmented atrial potentials were ablated in patients with persistent and long-persistent AF, as well as during repeated procedures.

RESULTS

At 12 months, stable sinus rhythm (SR) was present in 16 (53%) patients, significantly more frequently in patients with paroxysmal AF (71% in SR) compared to those with persistent (57.1% in SR) or long-persistent (22% in SR) AF. A significant reduction of AF burden was observed in 85.7% of patients with paroxysmal AF, 71.4% of patients with persistent AF, and 55.5% of patients with long-persistent AF. Single procedure success rate was 33% (10 patients), and repeat ablation procedures were performed in 13 patients. No periprocedural complications occurred. Thromboembolic events were noted in 2 patients with arrhythmia recurrence during the follow-up, including stroke in 1 patient and peripheral embolism in the other patient. In both these patients, heart failure worsening was observed during these events, and anticoagulation was inadequate in one of them. Five of 16 patients in whom stable SR was observed during the follow-up were off antiarrhythmic drug therapy at final evaluation. In the other 6 patients, antiarrhythmic drug therapy was continued due to ventricular arrhythmias. Successfully treated patients more often had paroxysmal AF (successful ablation: paroxysmal AF in 10 of 16 patients; unsuccessful ablation: paroxysmal AF in 4 of 14 patients; p = 0.009) and were younger (45 ± 11.5 years vs. 52.6 ± 9.2 years; p = 0.046). In addition, a trend toward a reduced need for cardioversion at the end of the procedure was also observed in these patients (3 patients in the successful ablation group vs. 8 patients in the unsuccessful ablation group; p = 0.056). In multivariate regression analysis, paroxysmal AF was the only independent predictor of a successful outcome.

CONCLUSIONS

Catheter ablation of AF in patients with HCM is an effective and safe therapeutic option, particularly in patients with paroxysmal AF. Effectiveness of ablation is significantly smaller in patients with persistent AF and even more so in those with long-persistent AF. Repeated procedures were often necessary. Continued antiarrhythmic drug therapy is often required due to a significant degree of atrial remodelling.

QRS complex widening as a predictor of appropriate implantable cardioverter-defibrillator (ICD) therapy and higher mortality risk in primary prevention ICD patients

BACKGROUND AND AIM

Effectiveness of implantable cardioverter-defibrillators (ICD) in patients with reduced left ventricular ejection fraction after myocardial infarction has been documented in large randomised trials. We analysed the predictive value of clinical factors at the time of implantation for adequate ICD interventions and mortality risk.

METHODS

We analysed 121 consecutive patients (15 women, 106 [88%] men; mean age 62 ± 10 years) with coronary artery disease in whom ICD was implanted for primary prevention between 2001 and 2007. Mean duration of follow-up was 876 ± 538 days.

RESULTS

Forty-four (36.4%) patients had adequate ICD interventions. In the Cox analysis, wider QRS complexes (hazard ration [HR] per each 10 ms increment: 1.13, confidence interval [CI] 1.039-1.229, p = 0.0045) and younger age at the time of ICD implantation (HR per each 10 year increment: 0.7, CI 0.5-0.9, p = 0.0081) were associated with a higher probability of adequate intervention. Wider QRS complexes were associated with a higher probability of electrical storm (HR 1.059, CI 1.014-1.045, p = 0.0002). During follow-up, 21 (17.4%) patients died. In the Cox analysis, wider QRS complexes (HR per each 10 ms increment: 1.123, CI 1.011-1.248, p = 0.0306 [in univariate analysis only]), older age at the time of implantation (HR per each 10 year increment: 1.7, CI 1.1-2.8, p = 0.0396) and higher NYHA class (HR 4.4, CI 1.7-11.5, p = 0.0022) were associated with increased mortality. Mortality was reduced by previous revascularisation (HR 0.3, CI 0.1-0.7, p = 0.006).

CONCLUSIONS

Patients with wider QRS complexes at the time of ICD implantation had a higher probability of adequate device intervention and mortality risk. QRS complex widening was also associated with a higher incidence of electrical storm.

[Wide spectrum of arrhythmias, with inductions and terminations of atrio-ventricular replica-nodal tachycardia by automaticity during successful radiofrequency ablation of long anterogradely slow conducting atrio-fasciculo-ventricular accessory pathway]

Mahaim syndrome is still a challenge. The specific characteristics of the pathway, the fact that it seldom occurs, and ambiguities about the pathophysiology and nomenclature make it, for electrophysiologists, still difficult to ablate. We present a case of a patient with anterogradely slow conducting accessory pathway, which has been effectively ablated although M potential was not observed nor was a mechanical conducting block of the accessory pathway. The accessory pathway showed a wide spectrum of electrophysiological characteristics of the "AV node physiology" including inductions and terminations of atrio-ventricular replica-nodal tachycardia by local automaticity, not only during electrophysiological study, but during successful application. The accessory pathway presented signs of two types of pseudo Mahaim fibers: atrio-fascicular and slow conducting atrio-ventricular connection.

Rationale and current perspective for early rhythm control therapy in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia and an important source for mortality and morbidity on a population level. Despite the clear association between AF and death, stroke, and other cardiovascular events, there is no evidence that rhythm control treatment improves outcome in AF patients. The poor outcome of rhythm control relates to the severity of the atrial substrate for AF not only due to the underlying atrial remodelling process but also due to the poor efficacy and adverse events of the currently available ion-channel antiarrhythmic drugs and ablation techniques. Data suggest, however, an association between sinus rhythm maintenance and improved survival. Hypothetically, sinus rhythm may also lead to a lower risk of stroke and heart failure. The presence of AF, thus, seems one of the modifiable factors associated with death and cardiovascular morbidity in AF patients. Patients with a short history of AF and the underlying heart disease have not been studied before. It is fair to assume that abolishment of AF in these patients is more successful and possibly also safer, which could translate into a prognostic benefit of early rhythm control therapy. Several trials are now investigating whether aggressive early rhythm control therapy can reduce cardiovascular morbidity and mortality and increase maintenance of sinus rhythm. In the present paper we describe the background of these studies and provide some information on their design.

[12-year follow-up of a patient after successful ablation of incessant fascicular tachycardia with biventricular heart failure and severe sinus node dysfunction]

We present a case of a 14 year-old boy with a incessant fascicular tachycardia with retrograde conduction and tachycardiomyopathy. Verapamil, adenosine, lignocaine and repeated cardioversions were unsuccessful in termination of tachycardia. Amiodarone however caused sinus node dysfunction and temporary electrode pacing had to be used. The patient underwent successful radiofrequency catheter ablation in the area of the left posterior fascicle. Because of ventricular extrasystoles (with QRS morphology resembling that of fascicular VT) the patient underwent second ablation which significantly reduced the number of ventricular beats. The course of subsequent 12-year follow-up was uneventful.

Spiral wave breakup in excitable media with an inhomogeneity of conduction anisotropy

Many conditions remodel the heart muscle such that it results in a perturbation of cells coupling. The effect of this perturbation on the stability of the spiral waves of electrochemical activity is not clear. We used the FitzHugh-Nagumo model of an excitable medium to model the conduction of the activation waves in a two-dimensional system with inhomogeneous anisotropy level. Inhomogeneity of the anisotropy level was modeled by adding Gaussian noise to diffusion coefficients corresponding with lateral coupling of the cells. Low noise levels resulted in a stable propagation of the spiral wave. For large noise level conduction was not possible due to insufficient coupling in direction perpendicular to fibers. For intermediate noise intensities, the initial wave broke up into several independent spiral waves or waves circulating around conduction obstacles. At an optimal noise intensity, the number of wavelets was maximized-a form of anti-coherent resonance was obtained. Our results suggest that the inhomogeneity of conduction anisotropy may promote wave breakup and hence play an important role in the initiation and perpetuation of the cardiac arrhythmias.

[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.

[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.

[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.

[Sixty four-slice computed tomography unmasked unexpected source of atrial arrythmias--a case report]

We describe a 23-year-old man with drug refractory, left atrial arrhythmias (paroxysmal atrial tachycardia, runs, pairs and single extra beats) in the area of remnant of left upper pulmonary vein ostium (in fact, this vein). The superior drained into vena innominata/vena cava superior. The patient underwent three unsuccessful catheter ablations in another center. Computed tomography scan of left atrium and pulmonary veins revealed this rare congenital anomaly. This information was crucial to perform successful ablation in the area of remnant and distinguish left atrial appendage from the remnant area. During 6 month follow-up the patient remained free of arrhythmia.

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.

[Incessant septal tachycardia eliminated by RF applications from right and left atrium]

We present a case of a 29-year-old woman who suffered from incessant atrial tachycardia (AT) leading to tachycardia-induced cardiomyopathy. Based on classical mapping of the right and left atria the focus of AT was localised in the inter-atrial septum area. The RF applications from the right atrium stopped AT for some seconds. Applications from the left atrium terminated AT definitively. The patient has been free from symptoms of arrhythmia and heart failure for seven years.

[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.

[Glass of water or ablation? - episodes of malignant atrial tachyarrhythmias during swimming in a lake in a woman with overt Wolff-Parkinson-White syndrome and benign palpitations for several decades of life]

We present a case of a 41 year old woman with overt Wolff-Parkinson-White syndrome (WPW) and benign palpitations for over four decades of life who suffered from a malignant atrial tachyarrhythmias (typical atrial flutter concomitant with left atrial fibrillation) during swimming in a lake. Loading dose of amiodarone increased frequency of attacks of sustained AVRT. In spite of treatment with amiodarone, effective refractory period of accessory pathway was still short. After ablation of accessory pathway, during five years of follow-up, there was no arrhytmia recureence.

[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.

Deleterious effect of unintentional pacing from the middle cardiac vein in a patient with congenitally corrected transposition of the great arteries and ventricular septal defect. The beneficial effect of cardiac resynchronization therapy after heart surgery

This report presents a case of a 31-year-old male with congenitally corrected transposition of the great arteries, ventricular septal defect (VSD) and complete heart block who was admitted to our institution because of an exacerbation of heart failure after pacemaker implantation. The ECG and chest radiograph revealed that the ventricular lead was placed in the middle cardiac vein. After cardiosurgical procedure (VSD closure and atrioventricular valves replacement), the clinical symptoms of heart failure were still present. They diminished while the patient was on escape rhythm (40-70 bpm). Therefore, the previously implanted leads were removed and the transvenous, biventricular system was implanted, which resulted in a significant clinical improvement.

['Weak' and 'strong' palpitations in a girl with atrioventricular nodal reentrant tachycardia--a case report]

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.

Electrical remodelling of the left and right atria due to rheumatic mitral stenosis

AIMS

To characterize the atrial remodelling in mitral stenosis (MS).

METHODS AND RESULTS

Twenty-four patients with severe MS undergoing commissurotomy and 24 controls were studied. Electrophysiological evaluation was performed in 12 patients in each group by positioning multi-electrode catheters in both atria to determine the following: effective refractory period (ERP) at 10 sites at 600 and 450 ms; conduction time; conduction delay at the crista terminalis (CT); and vulnerability for atrial fibrillation (AF). P-wave duration (PWD) was determined on the surface ECG. In the remaining 12 patients in each group, electroanatomic maps of both atria were created to determine conduction velocity and identify regions of low voltage and electrical silence. Patients with MS had larger left atria (LA) (P < 0.0001); prolonged PWD (P = 0.0007); prolonged ERP in both LA (P < 0.0001) and right atria (RA) (P < 0.0001); reduced conduction velocity in the LA (P = 0.009) and RA (P < 0.0001); greater number (P < 0.0001) and duration (P< 0.0001) of bipoles along the CT with delayed conduction; lower atrial voltage in the LA (P < 0.0001) and RA (P < 0.0001); and more frequent electrical scar (P = 0.001) compared with controls. Five of twelve with MS and none of the controls developed AF with extra-stimulus (P = 0.02).

CONCLUSION

Atrial remodelling in MS is characterized by LA enlargement, loss of myocardium, and scarring associated with widespread and site-specific conduction abnormalities and no change or an increase in ERP. These abnormalities were associated with a heightened inducibility of AF.

[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.

[Ablation of right ventricular tachycardia with a bizarre QRS complex--a case report]

We describe a case of a 77-year-old patient with recurrent, symptomatic ventricular tachycardia with a bizarre QRS complex originating from the right ventricle lateral wall. The small region of slow conduction was the critical substrate for initiation and maintenance of ventricular tachycardia, confirmed by a successful one RF application.

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.