Management of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC-endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society.

Electrical storm (ES) is a state of electrical instability, manifesting as recurrent ventricular arrhythmias (VAs) over a short period of time (three or more episodes of sustained VA within 24 h, separated by at least 5 min, requiring termination by an intervention). The clinical presentation can vary, but ES is usually a cardiac emergency. Electrical storm mainly affects patients with structural or primary electrical heart disease, often with an implantable cardioverter-defibrillator (ICD). Management of ES requires a multi-faceted approach and the involvement of multi-disciplinary teams, but despite advanced treatment and often invasive procedures, it is associated with high morbidity and mortality. With an ageing population, longer survival of heart failure patients, and an increasing number of patients with ICD, the incidence of ES is expected to increase. This European Heart Rhythm Association clinical consensus statement focuses on pathophysiology, clinical presentation, diagnostic evaluation, and acute and long-term management of patients presenting with ES or clustered VA.

Impact of cryoballoon application abortion due to phrenic nerve injury on reconnection rates: a YETI subgroup analysis.

AIMS: Cryoballoon (CB)-based pulmonary vein isolation (PVI) is an effective treatment for atrial fibrillation (AF). The most frequent complication during CB-based PVI is right-sided phrenic nerve injury (PNI) which is leading to premature abortion of the freeze cycle. Here, we analysed reconnection rates after CB-based PVI and PNI in a large-scale population during repeat procedures. METHODS AND RESULTS: In the YETI registry, a total of 17 356 patients underwent CB-based PVI in 33 centres, and 731 (4.2%) patients experienced PNI. A total of 111/731 (15.2%) patients received a repeat procedure for treatment of recurrent AF. In 94/111 (84.7%) patients data on repeat procedures were available. A total of 89/94 (94.7%) index pulmonary veins (PVs) have been isolated during the initial PVI. During repeat procedures, 22 (24.7%) of initially isolated index PVs showed reconnection. The use of a double stop technique did non influence the PV reconnection rate (P = 0.464). The time to PNI was 140.5 ± 45.1 s in patients with persistent PVI and 133.5 ± 53.8 s in patients with reconnection (P = 0.559). No differences were noted between the two populations in terms of CB temperature at the time of PNI (P = 0.362). The only parameter associated with isolation durability was CB temperature after 30 s of freezing. The PV reconnection did not influence the time to AF recurrence. CONCLUSION: In patients with cryoballon application abortion due to PNI, a high rate of persistent PVI rate was found at repeat procedures. Our data may help to identify the optimal dosing protocol in CB-based PVI procedures. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03645577?term=YETI&cntry=DE&draw=2&rank=1 ClinicalTrials.gov Identifier: NCT03645577.

The implantation of AV leadless pacemaker - a case report.

In early 2020 Food and Drug Administration (FDA) approved Micra AV - a new type of leadless pacemaker with atrioventricular synchrony, to treat patients with atrio-ventricular (AV) blocks. We describe one of the first in Poland case of a patient who was implanted with Micra AV pacemaker. CASE REPORT: A 38-year-old female patient was admitted to the clinic due to the 29-seconds event of a complete AV block without an escape rhythm and was implanted with a dual chamber pacemaker without any complications. After several months she was admitted again with suspicion of ventricular perforation by the pacemaker electrode and underwent a replacement procedure of both pacemaker's leads. Nevertheless, one week later the patient developed a fever with significantly elevated inflammatory markers. The blood cultures were negative but in the transesophageal echocardiography features of cardiac device-related infective endocarditis were observed. Empirical antibiotic therapy was administered, and the device was removed. The Heart Team qualified the patient for the implantation of a MicraTM AV leadless pacemaker. The procedure was performed without any complications and the device was implanted to the right ventricle. All parameters were correct, and the patient was discharged. CONCLUSIONS: Micra AV may be a feasible and safe option for young patients with paroxysmal AV block after device-related complications.

Upgrade from implantable cardioverter-defibrillator vs. de novo implantation of cardiac resynchronization therapy: long-term outcomes.

AIMS: To assess and compare long-term mortality and predictors thereof in de novo cardiac resynchronization therapy defibrillators (CRT-D) vs. upgrade from an implantable cardioverter-defibrillator (ICD) to CRT-D. METHODS AND RESULTS: Study population consisted of 595 consecutive patients with CRT-D implanted between 2002 and 2015 in a tertiary care, university hospital, in a densely inhabited, urban region of Poland [480 subjects (84.3%) with CRT-D de novo implantation; 115 patients (15.7%) upgraded from ICD to CRT-D]. In a median observation of 1692 days (range 457-3067), all-cause mortality for de novo CRT-D vs. CRT-D upgrade was 35.5% vs. 43.5%, respectively (P = 0.045). On multivariable regression analysis including all CRT recipients, the previously implanted ICD was an independent predictor for death [hazard ratio (HR) 1.58, 95% confidence interval (CI) 1.10-2.29, P = 0.02]. For those, who were upgraded from ICD to CRT-D, the independent predictors for all-cause death were as follows: creatinine level (HR 1.01, 95% CI 1.00-1.02, P = 0.01), left ventricular end-systolic diameter (HR 1.07, 95% CI 1.02-1.11, P = 0.002), New York Heart Association (NYHA) IV class at baseline (HR 2.36, 95% CI 1.00-5.53, P = 0.049) and cardiac device-related infective endocarditis during follow-up (HR 2.42, 95% CI 1.02-5.75, P = 0.046). A new CRT scale (Creatinine ≥150 µmol/L; Remodelling, left ventricular end-systolic ≥59 mm; Threshold for NYHA, NYHA = IV) showed high prediction for mortality in CRT-D upgrades (AUC 0.70, 95% CI 0.59-0.80, P = 0.0007). CONCLUSION: All-cause mortality in patients upgraded from ICD is significantly higher compared with de novo CRT-D implantations and reaches almost 45% within 4.5 years. A new CRT scale (Creatinine; Remodelling; Threshold for NYHA) has been proposed to help survival prediction following CRT upgrade.

Contemporary management of patients with syncope in clinical practice: an EHRA physician-based survey.

Syncope is a heterogeneous syndrome encompassing a large spectrum of mechanisms and outcomes. The European Society of Cardiology published an update of the Syncope Guidelines in 2018. The aim of the present survey was to capture contemporary management of syncope and guideline implementation among European physicians. A 23-item questionnaire was presented to 2588 European Heart Rhythm Association (EHRA) members from 32 European countries. The response rate was 48%, but only complete responses (n = 161) were included in this study. The questionnaire contained specific items regarding syncope facilities, diagnostic definitions, diagnostic tools, follow-up, and therapy. The survey revealed that many respondents did not have syncope units (88%) or dedicated management algorithms (44%) at their institutions, and 45% of the respondents reported syncope-related hospitalization rates >25%, whereas most (95%) employed close monitoring and hospitalization in syncope patients with structural heart disease. Carotid sinus massage, autonomic testing, and tilt-table testing were inconsistently used. Indications were heterogeneous for implanted loop recorders (79% considered them for recurrent syncope in high-risk patients) or electrophysiological studies (67% considered them in bifascicular block and inconclusive non-invasive testing). Non-pharmacological therapy was consistently considered by 68% of respondents; however, there was important variation regarding the choice of drug and device therapy. While revealing an increased awareness of syncope and good practice, our study identified important unmet needs regarding the optimal management of syncope and variable syncope guideline implementation.

Cardiac arrhythmias in the emergency settings of acute coronary syndrome and revascularization: an European Heart Rhythm Association (EHRA) consensus document, endorsed by the European Association of Percutaneous Cardiovascular Interventions (EAPCI), and European Acute Cardiovascular Care Association (ACCA).

Despite major therapeutic advances over the last decades, complex supraventricular and ventricular arrhythmias (VAs), particularly in the emergency setting or during revascularization for acute myocardial infarction (AMI), remain an important clinical problem. Although the incidence of VAs has declined in the hospital phase of acute coronary syndromes (ACS), mainly due to prompt revascularization and optimal medical therapy, still up to 6% patients with ACS develop ventricular tachycardia and/or ventricular fibrillation within the first hours of ACS symptoms. Despite sustained VAs being perceived predictors of worse in-hospital outcomes, specific associations between the type of VAs, arrhythmia timing, applied treatment strategies and long-term prognosis in AMI are vague. Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia that may be asymptomatic and/or may be associated with rapid haemodynamic deterioration requiring immediate treatment. It is estimated that over 20% AMI patients may have a history of AF, whereas the new-onset arrhythmia may occur in 5% patients with ST elevation myocardial infarction. Importantly, patients who were treated with primary percutaneous coronary intervention for AMI and developed AF have higher rates of adverse events and mortality compared with subjects free of arrhythmia. The scope of this position document is to cover the clinical implications and pharmacological/non-pharmacological management of arrhythmias in emergency presentations and during revascularization. Current evidence for clinical relevance of specific types of VAs complicating AMI in relation to arrhythmia timing has been discussed.

Peri-procedural routines, implantation techniques, and procedure-related complications in patients undergoing implantation of subcutaneous or transvenous automatic cardioverter-defibrillators: results of the European Snapshot Survey on S-ICD Implantation (ESSS-SICDI).

The aim of this European Heart Rhythm Association (EHRA) prospective snapshot survey is to assess peri-procedural practices, implantation techniques, and short-term procedure-related complications associated with implantation of subcutaneous implantable cardioverter-defibrillator (S-ICD) or transvenous implantable cardioverter-defibrillator (TV-ICD), across tertiary European electrophysiology centres. An internet-based electronic questionnaire concerning implantation settings, peri-procedural routines, techniques, personnel, complications, and patient outcomes was sent to the centres routinely implanting both TV-ICDs and S-ICDs. The centres were requested to prospectively include consecutive patients implanted with either TV-ICD or S-ICD during the 8-week enrolment period. Overall, 20 centres from 6 countries enrolled 429 consecutive patients. Subcutaneous implantable cardioverter-defibrillators (20%) compared with TV-ICD were implanted mainly under general anaesthesia (72% vs. 14%), in the surgical operation room settings (69% vs. 43%), with more frequent prophylactic antibiotic administration (82% vs. 91%), and post-implant defibrillation testing (85% vs. 7%, all P < 0.05). Feasibility (implantation duration of 45 min) and short-term complication rates (4%) were comparable for S-ICDs and TV-ICDs, but the spectrum of complications varied, despite different baseline characteristics of patients undergoing the S-ICD vs. TV-ICD implantation. This EHRA snapshot survey provides important insights into the implantable cardioverter-defibrillator implantation routines and patient outcomes. Our study showed differences between the S-ICD and TV-ICD implantation routines with respect to implantation settings, peri-procedural management, and pre-defined procedural endpoints. However, the comparable duration of S-ICD or TV-ICD implantation and similar rates of peri-procedural complications indicate that both devices can be routinely used in clinical practice.

The first successful implantation of an intravenous AAIR pacemaker into autologous extracardiac lateral tunnel Fontan in the child.

Patients with a single ventricle have complex anatomy that requires staged palliation which is usually the Fontan procedure. This procedure has undergone a lot of modifications to improve hemodynamics. Despite these efforts, sinus node dysfunction (SND) and bradyarrythmias are still common complications after Fontan operation, therefore there is a need of pacemakers implantation. Unfortunately, the most frequent technique of creating Fontan cannale - the extracardiac lateral tunnel makes the transvenous access to the atrium difficult or impossible to achieve. We report a case of successful implantation of an endocardial atrial lead for SND in patient with an extracardiac autologous Fontan tunnel.

The Incidence, Clinical Significance, and Treatment Effects of Depression in Cardiac Resynchronization Therapy Recipients.

OBJECTIVES: Chronic heart failure (HF) is associated with significantly increased prevalence of depression. The aim of the study was to assess the incidence and clinical impact of depression as well as the effectiveness of depression treatment in HF patients. METHODS: A prospective interventional trial included 285 consecutive cardiac resynchronization therapy recipients. Patients underwent a psychiatric examination at the time of implantation and then it was routinely repeated at 3, 6, and 12 months after the procedure, and every 6 months thereafter. One hundred and thirty-five (47.4%) patients with depression were included in the depression group, whereas the control group was comprised of 150 patients free of depression. Sixty-eight (50.4%) subjects received antidepressants (treated group), whereas the observational group had 67 (49.6%) depressed patients who refused to take antidepressants. RESULTS: Depression remission was achieved in 51 (75.0%) patients from the treated group. Long-term mortality and HF hospitalization rates were significantly higher in the depression group than in the control group (20.7 vs. 11.3% and 32.6 vs. 19.2%, respectively). However, remission from depression was associated with a 40% reduction in the relative risk of major adverse cardiac events (MACE). CONCLUSIONS: Patients with HF and concomitant depression are at higher risk of MACE compared with those free of depression. Effective antidepressant treatment may significantly improve long-term outcomes in this population.

Can we rely on machines? Device-detected atrial high rates correspond well with atrial arrhythmias in cardiac resynchronization recipients.

AIMS: The aim of the study was to verify in what proportion of patients, device-detected atrial high rate (AHR) episodes are indeed atrial arrhythmias (AAs). We investigated also the reasons for inappropriate arrhythmia classification and assessed if patients with misdiagnosed arrhythmias have distinct characteristics that would help to identify them. METHODS AND RESULTS: The study population consisted of 304 consecutive patients implanted with cardiac resynchronization therapy defibrillators (CRT-Ds) and subsequently monitored via remote monitoring for a median follow-up (FU) of 30.5 months. Intracardiac electrograms of every recorded AHR episode were assessed and classified (AA vs. no AA) by two experienced cardiologists. During FU, 14 386 episodes of AHR were recorded and classified in 176 (57.9%) patients. In 89.2% of them, these episodes were true AA (94% atrial fibrillation, 62% de novo). The reasons for AHR misdiagnosis were atrial far-field signals (89.5%) and noise (10.5%). The mean per cent of day spent in AHR (54.9 vs. 5.86%; P < 0.001) and the occurrence of periods with low CRT pacing (82.8 vs. 55%; P = 0.003) were significantly higher in AA subjects than in those with misdiagnosed AHR. Episode duration of properly detected AHRs was longer than that of misdiagnosed AHRs. Higher per cent of time spent in AHR was an independent marker of appropriate arrhythmia detection [adjusted hazard ratio (HR) 1.04; P = 0.023]. CONCLUSION: Nearly two-thirds of CRT-D patients had AHR episodes within 2.5 years after implantation. Almost 90% of AHRs were indeed AA. Misdetections were caused by far-field sensing or noise. A two-step diagnostic algorithm (>9% of time spent in AHRs and episode duration >36 s) allowed for proper detection of AA with a high hit-rate and specificity.

Stroke prevention strategies in patients with atrial fibrillation and heart valve abnormalities: perceptions of 'valvular' atrial fibrillation: results of the European Heart Rhythm Association Survey.

The purpose of this European Heart Rhythm Association (EHRA) Survey was to assess the perceptions of 'valvular' atrial fibrillation (AF) and management of AF patients with various heart valve abnormalities in daily clinical practice in European electrophysiology (EP) centres. Questionnaire survey was sent via the Internet to the EHRA-EP Research Network Centres. Of the 52 responding centres, 42 (80.8%) were university hospitals. Choosing the most comprehensive definition of valvular AF, a total of 49 centres (94.2%) encountered a mechanical prosthetic heart valve and significant rheumatic mitral stenosis, 35 centres (67.3%) also considered bioprosthetic valves, and 25 centres (48.1%) included any significant valvular heart disease, requiring surgical repair in the definition of valvular AF. Only three centres (5.8%) would define valvular AF as the presence of any (even mild) valvular abnormality. None of the centres would use non-vitamin K antagonist oral anticoagulants (NOACs) in AF patients with mechanical prosthetic valves, only 5 centres (9.8%) would use NOACs in patients with significant mitral stenosis, 17 centres (32.7%) would consider the use of NOACs in patients with bioprosthetic valves, and 21 centres (41.2%) would use NOACs in patients with a non-recent transcatheter valve replacement/implantation, while 13 centres (25.5%) would never consider the use of NOACs in AF patients with even mild native heart valve abnormality. Our survey showed marked heterogeneity in the definition of valvular AF and thromboprophylactic treatments, with the use of variable NOACs in patients with valvular heart disease other than prosthetic heart valves or significant mitral stenosis, indicating that this term may be misleading and should not be used.

Quality of life in cardiac resynchronization recipients: association with response and impact on outcome.

BACKGROUND: The prognostic impact of improvement in health-related quality of life (QoL) and its relation to response in cardiac resynchronization therapy (CRT) recipients remains unknown. AIM: To assess the correspondence between response to CRT and improvements in QoL and to verify if a change in QoL after pacing influences outcome in CRT patients. METHODS: Ninety-seven participants of the Triple-Site Versus Standard Cardiac Resynchronization Therapy Trial (TRUST CRT) randomized trial, in New York Heart Association class III-IV, QRS width ≥ 120 ms, left ventricular ejection fraction ≤ 35%, and significant mechanical dyssynchrony were included. Subjects filled out the Minnesota-QoL questionnaire prior to and 6 months after CRT with defibrillator (CRT-D) implantation. Data on major adverse cardiac events (MACEs: death, heart failure hospitalization, heart transplant) collected within the next 2.5 years and adjudicated blindly constituted the censoring variables. RESULTS: Within the first 6 months of resynchronization QoL improved in 81%, while worsening in 19% of patients. Clinical response, but not the echocardiographic one, was associated with improved QoL. During subsequent 2.5 years MACEs occurred in 37% of patients (23% died). Subjects without QoL improvement were significantly (both P < 0.05) more prone to experience MACE (61% vs 32%) and die (44% vs 18%) within the follow-up. Unimproved QoL increased the probability of future MACE by 2.7 times (95% confidence intervals [CI]: 1.26-5.83; P = 0.01) and death by 3.2 times (95% CI: 1.23-8.32; P = 0.02) independently from clinical and echocardiographic response. CONCLUSIONS: Clinical response, but not the echocardiographic one, was associated with improved QoL in CRT recipients. These preliminary data suggest that lack of improvement in QoL after CRT was associated with a strongly unfavorable prognosis, regardless of functional or echocardiographic response. Our results merit further studies with a larger number of patients.

Predictors of ventricular tachyarrhythmia in patients with implantable cardioverter-defibrillator and non-ischemic systolic heart failure.

BACKGROUND: The benefit derived from implantable cardioverter-defibrillators (ICD) in subjects with non-ischemic systolic HF (NICM) is less well-established. AIM: The study aimed to determine the incidence, predictors, and prognostic impact of ventricular arrhythmias in patients with ICD and NICM. METHODS: The study sample included 377 consecutive patients with ICD or cardiac resynchronization cardioverter-defibrillators (CRT-D, 74% of patients) and NICM implanted and monitored remotely in a university hospital. RESULTS: During the median (interquartile range [IQR]) follow-up of 1645 (960-2675) days, sustained ventricular arrhythmia occurred in 92 patients (24.4%). Of those, ventricular fibrillation (VF), ventricular tachycardia (VT), and both VT and VF occurred in 10 (10.9%), 72 (78.3%), and 10 (10.9%) patients, respectively. Patients with vs. those without ventricular arrhythmia differed concerning sex, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF), post-inflammatory etiology, atrial fibrillation/flutter occurrence, and supraventricular arrhythmia (SVT) other than AF/AFL during follow-up. In multivariable Cox regression, LVEDD (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.003-1.09; P = 0.03), AF/AFL (HR, 1.86; 95% CI, 1.21-2.85; P = 0.004), and SVT (HR, 1.77; 95% CI, 1.10-2.87; P = 0.02) were independent predictors of sustained VT, while AF/AFL (HR, 1.65; 95% CI, 1.07-2.56; P = 0.02) was independent predictor of VF. All-cause mortality in patients with VT/VF was significantly higher than in subjects without sustained ventricular arrhythmias (35.9% vs. 22.4%; P = 0.01). CONCLUSIONS: Ventricular arrhythmia occurred in every fourth patient with NICM and ICD during 4.5 years of observation and was associated with significantly worse prognosis than in subjects free of VT/VF. Higher LVEDD, atrial fibrillation/atrial flutter, and supraventricular tachycardia flag patients at risk of ventricular arrhythmia.

Implantation feasibility, procedure-related adverse events and lead performance during 1-year follow-up in patients undergoing triple-site cardiac resynchronization therapy: a substudy of TRUST CRT randomized trial.

INTRODUCTION: This substudy was to assess implantation feasibility and long-term safety of triple-site resynchronization therapy (CRT) in a series of consecutive patients included in a randomized trial. METHODS AND RESULTS: One hundred consecutive patients enrolled into Triple-Site Versus Standard Cardiac Resynchronization Therapy Randomized Trial were analyzed. Eligibility criteria included NYHA class III-IV, sinus rhythm, QRS ≥ 120 milliseconds, left ventricular ejection fraction ≤35%, and significant mechanical dyssynchrony. Patients were randomized in a 1:1 ratio to conventional or triple-site CRT with defibrillator-cardioverter. After 12 months of resynchronization 30% of patients with conventional resynchronization and 12.5% with triple-site CRT were in NYHA functional class III or IV (P < 0.05). Implantation of triple-site systems was significantly longer (median 125 minutes vs 96 minutes; P < 0.001), with higher fluoroscopic exposure, especially in patients with very enlarged left ventricle or pulmonary hypertension. Implantation success-rate was similar in the triple-site and conventional group (94% vs 98%; P = NS); however, additional techniques had to be used in a greater proportion of the triple-site patients (33.3% vs 16%; P < 0.05). Long-term lead performance tests revealed significantly higher pacing threshold and lower impedance in the triple-site group. The 1-year incidence of serious, CRT-related adverse events was similar in triple-site and conventional group (20.8% vs 30%; P = NS). CONCLUSIONS: Triple-site CRT is associated with more pronounced functional improvement than standard resynchronization. This form of pacing is equally safe and feasible as the conventional CRT. However, triple-site procedure is more time-consuming, associated with higher radiation exposure and the need to use additional techniques. Triple-site resynchronization is associated with less favorable electrical lead characteristics.

Quality of life in patients with a subcutaneous vs. transvenous implantable cardioverter-defibrillator.

BACKGROUND: The implantable cardioverter-defibrillator (ICD) and subcutaneous ICD (S-ICD) are well-accepted life-saving devices for treating potentially lethal ventricular arrhythmia, but little is known about quality of life (QoL) in patients with S-ICD and ICD. AIMS: Our study aimed to compare QoL in patients with S-ICD and ICD. METHODS: All consecutive patients who had S-ICD implanted between October 2015 and September 2021 were included in the study. A cohort of transvenous ICD (TV-ICD) patients was matched to S-ICD subjects by sex, age, indications for the device, and type of prevention. All patients were requested to fulfill two standardized questionnaires to assess QoL: 36-Item Short Form Health Survey (SF-36) and Minnesota Living with Heart Failure Questionnaire (MLHFQ) 6 months after device implantation. RESULTS: Patients with S-ICD (n = 49) and TV-ICD (n = 49) did not differ regarding baseline characteristics. There were no statistically significant differences between S-ICD and TV-ICD subgroup, both for mental and physical QoL assessed in SF-36 and MLHFQ (all P = NS). The median MLHFQ total score was 24 (9-41) for S-ICD and 28 (14-43) for TV-ICD (P = 0.83). The median total score for the SF-36 questionnaire was 62.5 (29-86) vs. 59 (38-77) for S-ICD and TV-ICD, respectively (P = 0.78). CONCLUSIONS: Quality of life after device implantation does not differ significantly between the groups of patients with subcutaneous and conventional implantable cardioverter-defibrillator.

Phrenic Nerve Injury During Cryoballoon-Based Pulmonary Vein Isolation: Results of the Worldwide YETI Registry.

BACKGROUND: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce. METHODS: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible. RESULTS: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 10 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was -49±8°C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months. CONCLUSIONS: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03645577. Graphic Abstract: A graphic abstract is available for this article.

Radiofrequency catheter ablation as a treatment option in a patient with hypoplastic left heart syndrome and atrial flutter after Fontan operation-Case report.

We report a 15-year-old male with hypoplastic left heart syndrome (HLHS) after Fontan operation with recurrent, drug-resistant atrial tachycardia. With the use of electro-anatomical mapping system (EnSite) an atrial flutter (AFl) with reentry activation around the tricuspid valve was diagnosed. Successful radiofrequency catheter ablation (RFCA) was performed.