Invasive Electrophysiological Study Research Articles

Management of arrhythmia recurrence in patients with pulmonary vein stenosis following atrial fibrillation ablation.

Arrhythmia recurrence is a common clinical problem in patients with pulmonary vein stenosis (PVS) following catheter ablation of atrial fibrillation. The study sought to analyse the management of arrhythmia recurrence in patients with PVS. Retrospective analysis was performed on 29 patients with high-degree PVS. Follow-up contained clinical visits, Holter-electrocardiogram recordings and invasive pulmonary vein (PV) angiography and electrophysiological studies. Arrhythmia recurrence was observed in 18 patients (62%) after PVS formation. Fifteen of 18 patients (83.3%) with and 1 of 11 patients (9.1%) without arrhythmia recurrence had electrical PV reconnection (P = 0.0003). In 14 of 16 patients repeat pulmonary vein isolation (PVI) was conducted (radiofrequency ablation in 12 and cryoballoon ablation in 2 cases). Repeat PVI was successful in all PVs in nine patients and incomplete in five patients (failed attempt in two patients with stent implantation, no attempt in three patients with stenotic PVs). Freedom from arrhythmia recurrence was estimated at 56.3% [95% confidence interval (CI) 36.4-72.0%] after 24 months. At the end of the follow-up, complete PVI was documented in 19 of 23 patients (82.6%) with stable sinus rhythm and in 2 of 6 patients with arrhythmia recurrence (33.3%) (P = 0.0335). The Kaplan-Meier estimate of recurrence-free survival of restenosis after interventional PVS treatment was similar in patients without and with repeat ablation [75.6% (95% CI 57.0-94.3%) and 67.0% (95% CI 43.2-90.7%) after 500 days, P = 0.77]. Pulmonary vein reconnection is the major driver of arrhythmia recurrence in PVS patients. Repeat PVI is feasible and does not lead to progression of PVS or restenosis if the procedure is carefully performed.

Arrhythmias and fasciculoventricular pathways in patients with Danon disease: A single center experience.

Danon disease is a rare X-linked storage disorder characterized by hypertrophic cardiomyopathy leading to arrhythmias and heart failure. A preexcitation pattern on electrocardiogram (ECG) has been described in these patients, however, invasive studies to distinguish between Wolff-Parkinson-White syndrome syndrome and fasciculoventricular pathways (FVP) are limited. The purpose of this study was to delineate the electrophysiological cardiac abnormalities in patients with Danon disease and to describe the presence of FVP in this population. We performed a retrospective study of all patients with a confirmed diagnosis of Danon disease presenting to a single center from May 2005 to May 2018. Baseline demographics, clinical characteristics, ECG findings, and electrophysiology study (EPS) results were collected. Ten patients with Danon disease (30% male, average age 17.4 years) were identified. Seven patients (70%) had tachyarrhythmias including five with atrial arrhythmias and six with nonsustained ventricular tachycardia. Preexcitation pattern on ECG was found in four (40%) patients. Of these, two underwent an EPS which confirmed the presence of an FVP. One patient underwent an adenosine challenge which supported a FVP. Implantable cardioverter defibrillator was placed in five patients for primary prevention with no patients receiving an appropriate discharge. Over a follow-up of 5.3 years, five underwent heart transplantation. This study reports a high incidence of FVP in patients with Danon disease and preexcitation. It underscores an alternate etiology of preexcitation in this population which can potentially be diagnosed without invasive EPS testing. Future multicenter studies are needed to expand this experience.

Validation of a novel automated signal analysis tool for ablation of Wolff-Parkinson-White Syndrome.

BackgroundIn previous pilot work we demonstrated that a novel automated signal analysis tool could accurately identify successful ablation sites during Wolff-Parkinson-White (WPW) ablation at a single center.ObjectiveWe sought to validate and refine this signal analysis tool in a larger multi-center cohort of children with WPW.MethodsA retrospective review was performed of signal data from children with WPW who underwent ablation at two pediatric arrhythmia centers from 2008–2015. All patients with WPW ≤ 21 years who underwent invasive electrophysiology study and ablation with ablation signals available for review were included. Signals were excluded if temperature or power delivery was inadequate or lesion time was < 5 seconds. Ablation lesions were reviewed for each patient. Signals were classified as successful if there was loss of antegrade and retrograde accessory pathway (AP) conduction or unsuccessful if ablation did not eliminate AP conduction. Custom signal analysis software analyzed intracardiac electrograms for amplitudes, high and low frequency components, integrated area, and signal timing components to create a signal score. We validated the previously published signal score threshold 3.1 in this larger, more diverse cohort and explored additional scoring options. Logistic regression with lasso regularization using Youden’s index criterion and a cost-benefit criterion to identify thresholds was considered as a refinement to this score.Results347 signals (141 successful, 206 unsuccessful) in 144 pts were analyzed [mean age 13.2 ± 3.9 years, 96 (67%) male, 66 (45%) left sided APs]. The software correctly identified the signals as successful or unsuccessful in 276/347 (80%) at a threshold of 3.1. The performance of other thresholds did not significantly improve the predictive ability. A signal score threshold of 3.1 provided the following diagnostic accuracy for distinguishing a successful from unsuccessful signal: sensitivity 83%, specificity 77%, PPV 71%, NPV 87%.ConclusionsAn automated signal analysis software tool reliably distinguished successful versus unsuccessful ablation electrograms in children with WPW when validated in a large, diverse cohort. Refining the tools using an alternative threshold and statistical method did not improve the original signal score at a threshold of 3.1. This software was effective across two centers and multiple operators and may be an effective tool for ablation of WPW.

Management of Asymptomatic Wolff-Parkinson-White Pattern by Pediatric Electrophysiologists

To determine the present-day approach of pediatric cardiac electrophysiologists to asymptomatic Wolff-Parkinson-White (WPW) pattern and to contrast to both published consensus statements and a similar survey. A questionnaire was sent to 266 Pediatric and Congenital Electrophysiology Society physician members in 25 countries; 21 questions from the 2003 survey were repeated, with new questions added regarding risk stratification and decision making. We received 113 responses from 13 countries, with responders having extensive electrophysiology experience (median 15years [IQR 8.5-25years]). Only 12 (11%) believed that intermittent pre-excitation and 37 (33%) that sudden loss of pre-excitation on exercise test were sufficient evidence of accessory pathway safety to avoid an invasive electrophysiology study. Optimal weight for electrophysiology study was 20kg (IQR 18-22.5kg), and 61% and 58% would then ablate all right-sided or left-sided accessory pathways, respectively, regardless of electrophysiological properties, whereas only 23% would ablate all septal accessory pathways (P<.001). Compared with 2003, respondents were more likely to consider inducible arrhythmia (77% vs 26%, P<.001) as sufficient indication alone for ablation. In the context of recent literature regarding the reliability of risk-stratification tools, most operators are now performing electrophysiology study for asymptomatic Wolff-Parkinson-White regardless of noninvasive findings. Many will then proceed to default ablation of all accessory pathways distant from critical conduction structures.

Intravenous antazoline, a first-generation antihistaminic drug with antiarrhythmic properties, is a suitable agent for pharmacological cardioversion of atrial fibrillation induced during pulmonary vein isolation due to the lack of influence on atrio-venous conduction and high clinical effectiveness (AntaEP Study).

Antazoline is a first-generation antihistaminic drug used primarily in eye drop formulations. When administered intravenously, antazoline displays antiarrhythmic properties resulting in a rapid conversion of recent-onset atrial fibrillation (AF) to sinus rhythm (SR). The aim of the study was to assess the influence of antazoline on atrio-venous conduction and other electrophysiological parameters in patients undergoing AF ablation. An experimental prospective study. Patients scheduled for the first-time AF ablation, in SR and not on amiodarone were enrolled. Atrio-venous conduction assessment and invasive electrophysiological study (EPS) were performed before and after intravenous administration of 250mg of antazoline. In case of AF induction during EPS, antazoline was administered until conversion to SR or a cumulative dose of 300mg. We enrolled 14 patients: 13 (93%) men, mean age 63.4 (59.9-66.8) years, mean CHA2 DS2 -VASc score 1.6 (1.0-2.2). Antazoline was administered in a mean dose 257.1 (246.7-267.6) mg. Pulmonary vein potentials and atrial capture during pulmonary vein stimulation were present before and after the administration of antazoline. Wenckebach point and atrial conduction times did not change significantly, but atrio-ventricular node effective refractory period improved-324.7 (275.9-373.5) ms vs 284.3 (256.2-312.4) ms, P=0.02. Antazoline was effective in all 5 (100%) cases of AF induction during EPS. There were no serious adverse events. Due to the lack of influence on atrio-venous conduction and high clinical effectiveness, antazoline may be suitable for pharmacological cardioversion of AF occurring during AF ablation.

Comparison of Electrophysiologic Profiles in Pediatric Patients with Incidentally Identified Pre-Excitation Compared with Wolff-Parkinson-White Syndrome

The rising utilization of screening electrocardiograms has resulted in increased incidental identification of ventricular pre-excitation in pediatric patients. We compared accessory pathways of incidentally identified pre-excitation to Wolff-Parkinson-White Syndrome (WPW) with the aim to identify factors important in preprocedural counseling and planning. This single-center, retrospective study of patients ≤18 years without congenital heart disease identified 227 patients diagnosed with pre-excitation and referred for invasive electrophysiology study between 2008 and 2017. WPW Syndrome was diagnosed in 178 patients, while 49 patients had incidental identification of pre-excitation. Anterograde conduction of incidentally identified accessory pathways was not clinically different between the two cohorts at baseline or upon isoproterenol infusion. However, the proportion of accessory pathways meeting high-risk criteria was significantly lower than in patients diagnosed with WPW, 12% versus 28% (p < 0.05). Retrograde conduction at baseline of incidentally diagnosed accessory pathways was slower with a median block cycle length 365 milliseconds (IQR 260 to 450) versus 290 milliseconds (IQR 260 to 330, p < 0.01). In the incidentally identified cohort, right-sided, paraHisian, and fascicular pathways were more common with fewer attempted ablations (71% vs 94%, p < 0.001) and lower success rate (91% vs 97%, p < 0.001). A binomial logistic regression analysis further indicated patients incidentally identified with pre-excitation were associated with having lower rates of inducible supraventricular tachycardia, atrial fibrillation, and ablations performed, in addition, to having right-sided pathways. In conclusion, as patients with incidentally identified pre-excitation present more frequently for consideration of invasive electrophysiology study, these results impact procedural approaches, technical considerations, patient counseling, and outcome expectations.

AN INCIDENTAL FINDING OF ABRUPT BASAL SEPTAL DYSKINESIS IDENTIFIED BY SPECKLE TRACKING IMAGING: THINK WOLFF-PARKINSON-WHITE

The localization of accessory pathways in Wolf-Parkinson-White (WPW) syndrome patients is usually through an invasive electrophysiology (EP) study with no rule for 2-D echocardiography in current practice. A 31-year-old female with no significant history presented with 3 day history of fever and

Characteristics of dynamic electrocardiogram, heart rate variability, and electrophysiological study in a Chinese population with vasovagal syncope

Background: Little is known about characteristics of dynamic electrocardiogram (DCG), heart rate (HR) variability (HRV), and invasive electrophysiological study (EPS) in the presence, pattern, and stage of vasovagal syncope (VVS) during head-up tilt test (HUTT). The present study aims to explore predictive value of these tests for HUTT outcomes with underlying mechanisms. Subjects and Methods: This retrospective study consecutively enrolled 519 patients with VVS from January 2007 to December 2017. Parameters of DCG, HRV, and EPS were evaluated according to the presence, pattern, and stage of syncope during HUTT. Results: Mixed pattern was the predominant subtype of VVS, and vasodepressor patients had a positive response earlier than in cardioinhibitory patients. Compared with negative group, positive group with mixed and cardioinhibitory patterns had significantly slower maximal HR and mean HR all day, at daytime, nighttime, and each hour point. No significance was observed in parameters of HRV between negative and positive groups. There was no significant difference in HR, spectral power components, and time-domain variables among syncopal patterns and syncopal stages. Positive group had longer durations of A-H interval, sinus node recovery time, Wenckebach point, and Wenckebach 2:1 point than negative group. There was a significant difference only in sinus node recovery time among syncopal patterns as well as A-H interval among syncopal stages. Conclusion: DCG-derived HR and EPS properties rather than 24-h HRV may be used to predict positive responses, but they could not predict syncopal patterns and syncopal stages.

Electrophysiological properties of asymptomatic children and adolescents with the Wolff-Parkinson-White electrocardiographic pattern

Optimal management in asymptomatic children and adolescents with the Wolff-Parkinson-White (WPW) electrocardiographic pattern is still debatable. The aim of this retrospective study was to evaluate the electrophysiological properties of asymptomatic children and adolescents with WPW. The medical records and procedural data of asymptomatic children and adolescents with the WPW electrocardiographic pattern who underwent invasive electrophysiological study (EPS) and catheter ablation between April 2012 and April 2018 were evaluated. In all, 149 consecutive, asymptomatic children and adolescents with WPW who underwent EPS were retrospectively investigated. In 39 (26.2%) of the patients, a shortest pre-excited R-R interval of ≤250 ms during atrial fibrillation or an accessory pathway effective refractory period of ≤270 ms was found. A total of 39 patients with high-risk antegrade conduction and 45 patients with inducible orthodromic atrioventricular re-entrant tachycardia underwent catheter ablation. In addition, 14 patients underwent catheter ablation due to family preference. High-risk antegrade conduction properties are exhibited by more than one-quarter of asymptomatic children and adolescents with WPW. Ablation should be considered as a first-line therapy in asymptomatic children and adolescents with high-risk WPW.

Role of QRS Fragmentation for Risk Stratification in Adults With Tetralogy of Fallot.

BackgroundPatients with tetralogy of Fallot (TOF) remain at risk for cardiovascular events despite successful repair. Some of the current risk stratification tools require advanced imaging and invasive studies, and hence are difficult to apply to routine patient care. A recent study showed that QRS fragmentation (QRS‐f) is predictive of mortality in patients with TOF. The current study aims to validate this result by assessing whether severity of QRS‐f could predict all‐cause mortality in a different TOF population.Methods and ResultsThe authors reviewed the Mayo Adult Congenital Heart Disease database for patients with TOF who had ECG from 1990–2017. QRS‐f was defined as notches in QRS complex in ≥2 contiguous leads on ECG, not related to bundle branch block, and classified as none, mild (≤3 leads), moderate (4 leads), or severe (≥5 leads). Of 465 patients (age 37±14 years) in the study, QRS‐f was present in 161 (35%): mild (n=43, 9%), moderate (n=77, 17%), and severe (n=41, 9%). There were 55 deaths (12%) during 13.6±8.2 years of follow‐up. Severity of QRS‐f remained an independent predictor of all‐cause mortality after adjustment for other ECG parameters, patient demographics, and atrial and ventricular arrhythmia (hazard ratio, 1.74 per class; 95% confidence interval, 1.08–2.93 [P=0.041]).ConclusionsThe presence of severe QRS‐f may be used as complementary data to the usual clinical indices to determine whether interventions such as invasive electrophysiology study should be performed in patients with nonsustained ventricular tachycardia or to proceed with pulmonary valve replacement in patients with severe pulmonary regurgitation with ventricular volumes below the guideline‐directed threshold for intervention.

Use of aVR and Jastrzębski algorithms in the classification of wide complex tachycardia in dogs – a preliminary study

IntroductionVentricular rhythm disturbances are a common pathology in human and veterinary medicine. In humans, the algorithmic approach is used to differentiate wide QRS complex tachycardia. The most commonly used are the aVR and Brugada algorithms as well as the ventricular tachycardia (VT) score developed by Jastrzębski and coworkers. In veterinary medicine, no such algorithms are available and the only parameter used to describe VT abnormalities is the duration of the QRS complexes. The aim of this analysis was determining whether human medicine algorithms for VT are applicable in veterinary medicine to differentiate wide QRS complex tachycardia in dogs.Material and MethodsA retrospective analysis was performed on 11 dogs of both sexes and various breeds and age diagnosed with VT. The diagnosis was based on ambulatory ECG, further established based on the reaction to lidocaine or adenosine or an invasive electrophysiological study.ResultsOf the 11 tracings passed through the aVR algorithm, 10 met the VT criteria. The most common criterion was the Vi/Vt ratio (8 out of 11 tracings). Based on the VT score, seven out of eight dogs had a high probability of VT.ConclusionRetrospective analysis of ECGs by aVR and VT score indicates that the applied algorithms may be useful in differentiating wide QRS complex tachycardia as a quick, easy, and non-invasive alternative to cardiac electrophysiology.

Ventricular Arrhythmias in the Patient with a Structurally Normal Heart.

Ventricular arrhythmias (VAs) are among the most common cardiac rhythm disturbances encountered in clinical practice. Patients presenting with frequent ventricular ectopy or sustained ventricular tachycardia represent a challenging and worrisome clinical scenario for many practitioners because of concerning symptoms, frequent associated acute hemodynamic compromise, and the adverse prognostic implications inherent to these cases. While an underlying structural or functional cardiac abnormality, metabolic derangement, or medication toxicity is often readily apparent, many patients have no obvious underlying condition, despite a comprehensive diagnostic evaluation. Such patients are diagnosed as having an idiopathic VA, which is a label with specific implications regarding arrhythmia origin, prognosis, and potential for pharmacologic and invasive management. Further, a subset of patients with otherwise benign idiopathic ventricular ectopy can present with polymorphic ventricular tachycardia and ventricular fibrillation, adding a layer of complexity to a clinical syndrome previously felt to have a benign clinical course. Thus, this review seeks to highlight the most common types of idiopathic VAs with a focus on their prognostic implications, underlying electrophysiologic mechanisms, unique electrocardiographic signatures, and considerations for invasive electrophysiologic study and catheter ablation. We further address some of the data regarding idiopathic ventricular fibrillation with respect to the heterogeneous nature of this diagnosis.

Therapy Of Cardiac Arrhythmias In Children: An Emerging Role Of Electroanatomical Mapping Systems

Cardiac arrhythmias are challenging diseases in childhood. Most of them in pediatric subjects (90.2%) are atrioventricular reentrant tachycardias and atrioventricular nodal reentrant tachycardias. The standard 12-lead ECG is a highly accurate diagnostic tool but an invasive electrophysiological study is often required. The main concern about this kind of procedures is their invasive nature and the need of radiations, so antiarrhythmic agents are currently the first line therapy. However, they often show side effects and can be insufficient for the rate control. We performed a systematic research on Embase and PubMed. We found 563 articles and selected the most representative 50. Management of cardiac arrhythmias could be very difficult in several scenarios, especially in children with body weight <15 kg and age <4 years. In general, pediatric subjects show a cumulative risk of malignancy greater than adults, having greater life expectancy. On this basis the guiding principle during radiation delivery in electrophysiological procedures is "as low as reasonably achievable" (acronym: ALARA). The development of 3-dimensional (3D) electroanatomical mapping systems allowed significant reduction of exposure. The most recently reported experiences demonstrate safety and feasibility of fluoroless ablation in the most common arrhythmias in children, even in challenging conditions. The first reasonable approach in cardiac arrhythmias involving younger patients seems to be pharmacological. However antiarrhythmic drugs pose problems both in terms of side effects and often have poor efficacy. Expertise in electrophysiological techniques is constantly increasing and the development of new technologies allow us to encourage the use of electroanatomical mapping systems in order to reduce the radiation exposure in children undergoing to catheter ablation, especially for accessory pathways.

Cardiac electrophysiology catheters for electrophysiological assessments of the lower urinary tract-A proof of concept ex vivo study in viable ureters.

To explore the feasibility of minimally invasive catheter-based electrophysiology studies in the urinary tract. This is a well-known method used in cardiology to investigate and treat arrhythmias. We developed an experimental platform which allows electrophysiological recordings with cardiac catheters and conventional needle electrodes in ex vivo pig ureters. The action potential was triggered by a stimulating electrode. We considered 13 porcine ureters (freshly collected and harvested in organ bath), 7 of which were used to optimize the setup and define the stimulation parameters; we performed the recordings in the remaining six ureters. The electrical propagation of the generated action potential was tracked with multiple sensing electrodes, from which propagation directions, velocities, refractory periods, and pacing thresholds were extracted. We recorded propagating electrical activity in four ureters using needle electrodes and in two ureters using cardiac catheters. Propagation velocities for forward direction (from kidney to bladder) derived by the two methods were similar (15.1 ± 2.6 mm/s for cardiac catheters, 15.6 ± 2.3 mm/s for needle recordings). Pacing thresholds, activation patters, and refractory times were provided for the ureteric smooth muscle. Retrograde propagations and corresponding velocities were also observed and measured. This study is a proof-of-concept showing that electrical activity can be measured "from the inside" of urinary cavities using catheters and that obtained results are comparable with the more invasive needle recordings. Catheter-based electrophysiology may allow, in the clinical setting, for: i) a more differentiated understanding of urological disorders such as overactive bladder and ii) new therapeutic approaches (e.g., targeted tissue ablation).

Abstract 108: Molecular and Electrophysiologic Characterization of Obesity Mediated Atrial Fibrillation in Mc4r-KO Mice

Background: Although a causal relationship between obesity and atrial fibrillation (AF) has recently been established, the underlying pathophysiological mechanisms remain unclear. Emerging evidence supports reduced cardiac Na + channel expression and current (I Na ) as one potential contributing mechanism. Mutations in the melanocortin-4 receptor ( MC4R ) gene are the most common monogenic form of obesity in humans. Objective: We used a genetic Mc4r-knockout, KO mouse model of obesity to test the hypothesis that obesity increases susceptibility to AF by modulating the cardiac Na + channel. Method: Invasive electrophysiology studies and patch clamping of membrane potentials were performed in mice between 4-6 months of age to evaluate the molecular and whole-animal electrophysiologic phenotype. Results: Mc4r-KO mice were significantly heavier than wild-type lean controls. Pacing induced AF in 100% of Mc4r-KO mice, and 25% in controls; AF burden was more in Mc4r-KO mice than control mice. We showed that the expression of the cardiac Na + channel, I Na , and atrial action potential duration was reduced in Mc4r-KO mice. Furthermore, the oxidative stress biomarker F2-isoprostanes levels were elevated in MC4r-KO when compared to controls and these levels along with AF burden were reduced after 2 weeks of mitochondrial antioxidant (Mito-TEMPO) administration. Conclusion: We showed that mice with genetic susceptibility to obesity are not only more prone to develop AF but that this risk is mediated in part by modulation of the cardiac Na + channel and increased oxidative stress. These findings may have important implications for the management of obesity-mediated AF in humans.

Guidance of Intra-Operative Ventricular Tachycardia Ablation during LVAD Implantation with Pre-operative Cardiac MRI

Introduction Ventricular tachycardia (VT) is common in ischemic cardiomyopathy (ICM). Ablation maybe required to reduce ICD shocks and improve the quality of life. Preoperative VT mapping is an invasive electrophysiologic study prior to the surgery which heart failure patients may not tolerate. Substrate modification is usually done in an open epicardial approach during LVAD implantation. Non-invasive mapping techniques have not been described before. In this case pre-operative cardiac magnetic resonance (CMR) imaging was used to plan VT scar mapping and guide intra-operative cryoablation that was done while performing LVAD implantation. Case Report 69-year-old man with ICM (ejection fraction of 23%) and biventricular cardioverter-defibrillator (ICD). He has history of VT, four ablations, and on mexiletine and amiodarone. He had VT-related syncope terminated with anti-tachycardia pacing (ATP). ICD interrogation showed 15 appropriate shocks and >100 ATP therapies since the device implantation 6 months prior. In hospital he had slow monomorphic VT (slow cycle length 650 msec) with left bundle-branch morphology and superior axis positive in AVR. Milrinone was started for cardiogenic shock (cardiac index of 1.81 L/min/m2). He was not a transplant candidate so he was scheduled for destination therapy LVAD. Before the procedure he had sustained monomorphic VTs refractory to ATP requiring ICD shock. Cardiac MRI showed large chronic infarct with marked remodeling and transmural delayed enhancement in the inferoseptal, inferior, and inferolateral segments at the base a mid-ventricular portions of the left ventricle (LV) extending into the inferior aspect of the apical LV. Six myocardial segments equivalent was involved with transmural infarct. We decided to do an intra-operative VT ablation during LVAD implantation. Intraoperatively the LVAD ring was anchored to the apex with sutures. LV incision was made, and cryoablation of the inferoseptal towards inferolateral wall was performed using Cryo3 cryoICE catheter. Corresponding to the scar on MRI ablation lesions were created and the lesions were overlapping (from 3 to 9 o'clock position). The incision site was also cryoablated with a total of ten cryoablations. Conclusion This is the first case to use cardiac MRI for preoperative VT mapping and did correspond to the lesions seen intra-operatively. This is a novel non-invasive mapping tool for heart failure patients undergoing surgical cryoablation . At 1 month follow up the patient has had 68 episodes of non-sustained VT, and 8 episodes of VT, successfully treated with ATP.

From early beginnings to elaborate tools: contribution of German electrophysiology to the interventional treatment of cardiac arrhythmias : The German Cardiac Society welcomes ESC in Munich 2018.

Catheter ablation evolved from the early days of cardiac electrophysiology (EP), in which invasive electrophysiological studies were mainly a tool to find the correct diagnosis and to evaluate the most effective anti-arrhythmic drug for the patient. Today, catheter ablation is the most effective treatment option for patients suffering from supraventricular and ventricular arrhythmias. The understanding of cardiac arrhythmias and treatment strategies improved because of physicians and scientists from all over the world. The work of German cardiologists led to new achievements in the field of cardiac EP and catheter ablation. In this article, we summarize selective contributions of German EP centres in the field.

Prognostic Value of Atrial Fibrillation Inducibility in Patients Without History of Clinical Atrial Fibrillation.

During invasive electrophysiological studies (EPS), atrial fibrillation (AF) can be induced in patients without a history of AF. However, the prognostic value is not well evaluated in this population. Our aim was to investigate whether AF inducibility in those patients is associated with future clinical episodes of AF; whether non-inducibility is predictive of freedom from new-onset AF and finally, to examine clinical factors associated with inducibility. Medical records from patients undergoing EPS between the years 2011 and 2014 were analysed retrospectively with 62 patients matching our inclusion criteria. Patients were divided into subgroups according to their inducibility status and underwent follow-up. Patients were assessed by a structured telephone interview, data from the further treating physicians and ECG recordings. AF was inducible in 19 patients ("induction group") and not inducible in the remaining 43 ("control group"). Inducibility was associated with a higher age (p=0.002), lower GFR (p=0.002), higher CHAD2S2-VASc score (p=0.004) and diagnosis of mitral (p=0.014), tricuspid (p=0.017) and pulmonary (p=0.026) valve insufficiency. Three months after EPS, 89.5% of all inducible patients were free of diagnosed AF, in contrast to 100% of those without inducibility (p=0.031). At three years, no significant difference was left (p=0.162). AF inducibility was found more often in an older population with cardiac comorbidities. While inducibility was associated with an increased rate of diagnosed new-onset clinical AF in the months after testing, non-inducibility seemed to be associated with freedom from AF at least in the short to medium term. However, there was no significant difference in the long term follow-up.

Heart rate variability parameters in children with ventricular preexcitation.

The autonomic nervous system has a regulatory effect on cardiac electrophysiology and arrhythmogenesis. We aimed to assess cardiac autonomic status using heart rate variability (HRV) parameters in children with ventricular preexcitation. The electrocardiography, Holter monitoring, transesophageal electrophysiological study (TEEPS), and invasive electrophysiological study (EPS) results of ventricular preexcitation patients obtained over a 7-year period in our clinic were evaluated. According to the TEEPS results, patients' accessory pathway conduction was classified as adverse (n = 40) or nonadverse (n = 25). The HRV parameters of patients were compared according to tachycardia inducibility that assessed by TEEPS and EPS. Also, HRV parameters were compared in patients with adverse and nonadverse pathway conduction. Further, the HRV parameters of preexcitation patients were compared with those of healthy controls. LF/HF, the best measure of sympathovagal balance, was statistically higher in patients with adverse conduction than in patients without adverse conduction and controls (P=0.001). The LF/HF ratio was higher in ventricular preexcitation patients with inducible tachycardia than those without in EPS (P=0.001). In addition, the LF/HF ratio was higher in symptomatic ventricular preexcitation patients than asymptomatic ones (P=0.001). No difference in HRV parameters was found between preexcitation patients and controls. Autonomic tonus in patients with ventricular preexcitation may affect accessory pathway conduction properties, tachycardia inducibility, and symptomology. The indicator of sympathovagal balance, LF/HF ratio, increased in ventricular preexcitation patients with inducible tachycardia and those that were symptomatic.

Utility of Invasive Electrophysiology Studies in Patients With Severe Aortic Stenosis Undergoing Transcatheter Aortic Valve Implantation

Permanent pacemaker (PPM) implantation remains common after transcatheter aortic valve implantation (TAVI). Invasive electrophysiology studies (EPSs) may reduce PPM implantation rates by identifying patients who do not require long-term pacing. At our institution, a new strategy in which patients with equivocal indications for pacing underwent EPSs to determine the need for PPM implantation was adopted. We compared baseline demographics, TAVI procedural details, and outcomes in patients without any conduction disturbance after TAVI, patients with new PPM implantation, and patients with EPS ± new PPM implantation. After exclusion for preexisting PPMs, of a total of 614 consecutive TAVI patients, 117 (19.1%) required new PPM implantation for unequivocal pacing indications, and 95 (15.5%) underwent EPSs. Of those patients who underwent EPSs, 28 (29.5%) required PPM implantation and 67 (70.5%) did not. The overall rate of new PPM implantation was higher for self-expanding versus balloon-expandable valves (34.0% vs 19.9%, p = 0.0011). PPM implantation increased intensive care and hospital length of stay compared with patients without any conduction disturbance (10.7 ± 8.3 vs 8.5 ± 6.4 days, p = 0.003). A negative EPS did not prolong length of stay. There were no significant differences in 30-day and 1-year mortality between groups. In conclusion, among TAVI patients with new-onset conduction disturbance, EPS is a safe strategy to identify those who require PPM implantation and those in whom PPMs can be avoided.