Pre- and post-procedural cardiac imaging (computed tomography and magnetic resonance imaging) in electrophysiology: a clinical consensus statement of the European Heart Rhythm Association and European Association of Cardiovascular Imaging of the European Society of Cardiology.

Imaging using cardiac computed tomography (CT) or magnetic resonance (MR) imaging has become an important option for anatomic and substrate delineation in complex atrial fibrillation (AF) and ventricular tachycardia (VT) ablation procedures. Computed tomography more common than MR has been used to detect procedure-associated complications such as oesophageal, cerebral, and vascular injury. This clinical consensus statement summarizes the current knowledge of CT and MR to facilitate electrophysiological procedures, the current value of real-time integration of imaging-derived anatomy, and substrate information during the procedure and the current role of CT and MR in diagnosing relevant procedure-related complications. Practical advice on potential advantages of one imaging modality over the other is discussed for patients with implanted cardiac rhythm devices as well as for planning, intraprocedural integration, and post-interventional management in AF and VT ablation patients. Establishing a team of electrophysiologists and cardiac imaging specialists working on specific details of imaging for complex ablation procedures is key. Cardiac magnetic resonance (CMR) can safely be performed in most patients with implanted active cardiac devices. Standard procedures for pre- and post-scanning management of the device and potential CMR-associated device malfunctions need to be in place. In VT patients, imaging-specifically MR-may help to determine scar location and mural distribution in patients with ischaemic and non-ischaemic cardiomyopathy beyond evaluating the underlying structural heart disease. Future directions in imaging may include the ability to register multiple imaging modalities and novel high-resolution modalities, but also refinements of imaging-guided ablation strategies are expected.

Unipolar voltage mapping in right ventricular cardiomyopathy: pitfalls, solutions and advantages.

AIMS: Endocardial unipolar and bipolar voltage mapping (UVM/BVM) of the right ventricle (RV) are used for transmural substrate delineation. However, far-field electrograms (EGMs) and EGM changes due to injury current may influence automatically generated UVM. Epicardial BVM is considered less accurate due to the impact of fat thickness (FT). Data on epicardial UVM are sparse. The aim of the study is two-fold: to assess the influence of the manually corrected window-of-interest on UVM and the potential role of epicardial UVM in RV cardiomyopathies. METHODS AND RESULTS: Consecutive patients who underwent endo-epicardial RV mapping with computed-tomography (CT) integration were included. Mapping points were superimposed on short-axis CT slices and correlated with local FT. All points were manually re-analysed and the window-of-interest was adjusted to correct for false high unipolar voltage (UV). For opposite endo-epicardial point-pairs, endo-epicardial bipolar voltage (BV) and UV were correlated for different FT categories. A total of 3791 point-pairs of 33 patients were analysed. In 69% of endocardial points and 63% of epicardial points, the window-of-interest needed to be adjusted due to the inclusion of far-field EGMs, injury current components, or RV-pacing artifacts. The Pearson correlation between corrected endo-epicardial BV and UV was lower for point-pairs with greater FT; however, this correlation was much stronger and less influenced by fat for UV. CONCLUSION: At the majority of mapping sites, the window-of-interest needs to be manually adjusted for correct UVM. Unadjusted UVM underestimates low UV regions. Unipolar voltage seems to be less influenced by epicardial fat, suggesting a promising role for UVM in epicardial substrate delineation.

The transmural activation interval: a new mapping tool to identify ventricular tachycardia substrates in right ventricular cardiomyopathy.

AIMS: In right ventricular cardiomyopathy (RVCM), intramural scar may prevent rapid transmural activation, which may facilitate subepicardial ventricular tachycardia (VT) circuits. A critical transmural activation delay determined during sinus rhythm (SR) may identify VT substrates in RVCM. METHODS AND RESULTS: Consecutive patients with RVCM who underwent detailed endocardial-epicardial mapping and ablation for scar-related VT were enrolled. The transmural activation interval (TAI, first endocardial to first epicardial activation) and maximal activation interval (MAI, first endocardial to last epicardial activation) were determined in endocardial-epicardial point pairs located <10 mm apart. VT-related sites were determined by conventional substrate mapping and limited activation mapping when possible. Nineteen patients (46 ± 16 years, 84% male, 63% arrhythmogenic right ventricular cardiomyopathy, 37% exercise-induced arrhythmogenic remodelling) were inducible for 44 VT [CL 283 (interquartile range, IQR 240-325)ms]. A total of 2569 endocardial-epicardial coupled point pairs were analysed, including 98 (4%) epicardial VT-related sites.The TAI and MAI were significantly longer at VT-related sites compared with other electroanatomical scar sites [TAI median 31 (IQR 11-50) vs. 2 (-7-11)ms, P < 0.001; MAI median 65 (IQR 45-87) vs. 23 (13-39)ms, P < 0.001]. TAI and MAI allowed highly accurate identification of epicardial VT-related sites (optimal cut-off TAI 17 ms and MAI 45 ms, both AUC 0.81). Both TAI and MAI had a better predictive accuracy for VT-related sites than endocardial and epicardial voltage and electrogram (EGM) duration (AUC 0.51-0.73). CONCLUSION: The transmural activation delay in SR can be used to identify VT substrates in patients with RVCM and predominantly hemodynamically non-tolerated VT, and may be an important new mapping tool for substrate-based ablation.

Accuracy of electroanatomical mapping-guided cardiac radiotherapy for ventricular tachycardia: pitfalls and solutions.

AIMS: To analyse and optimize the interobserver agreement for gross target volume (GTV) delineation on cardiac computed tomography (CCT) based on electroanatomical mapping (EAM) data acquired to guide radiotherapy for ventricular tachycardia (VT). METHODS AND RESULTS: Electroanatomical mapping data were exported and merged with the segmented CCT using manual registration by two observers. A GTV was created by both observers for predefined left ventricular (LV) areas based on preselected endocardial EAM points indicating a two-dimensional (2D) surface area of interest. The influence of (interobserver) registration accuracy and availability of EAM data on the final GTV and 2D surface location within each LV area was evaluated. The median distance between the CCT and EAM after registration was 2.7 mm, 95th percentile 6.2 mm for observer #1 and 3.0 mm, 95th percentile 7.6 mm for observer #2 (P = 0.9). Created GTVs were significantly different (8 vs. 19 mL) with lowest GTV overlap (35%) for lateral wall target areas. Similarly, the highest shift between 2D surfaces was observed for the septal LV (6.4 mm). The optimal surface registration accuracy (2.6 mm) and interobserver agreement (Δ interobserver EAM surface registration 1.3 mm) was achieved if at least three cardiac chambers were mapped, including high-quality endocardial LV EAM. CONCLUSION: Detailed EAM of at least three chambers allows for accurate co-registration of EAM data with CCT and high interobserver agreement to guide radiotherapy of VT. However, the substrate location should be taken in consideration when creating a treatment volume margin.

Myocardial calcification is associated with endocardial ablation failure of post-myocardial infarction ventricular tachycardia.

AIMS: In patients with post-myocardial infarction (post-MI) ventricular tachycardia (VT), the presence of myocardial calcification (MC) may prevent heating of a subepicardial VT substrate contributing to endocardial ablation failure. The aims of this study were to assess the prevalence of MC in patients with post-MI VT and evaluate the impact of MC on outcome after endocardial ablation. METHODS AND RESULTS: In 158 patients, the presence of MC was retrospectively assessed on fluoroscopy recordings in seven standard projections obtained during pre-procedural coronary angiograms. Myocardial calcification, defined as a distinct radiopaque area that moved synchronously with the cardiac contraction, was detected in 30 patients (19%). After endocardial ablation, only 6 patients (20%) with MC were rendered non-inducible compared with 56 (44%) without MC (P = 0.033) and of importance, 8 (27%) remained inducible for the clinical VT [compared with 9 (6%) patients without MC; P = 0.003] requiring therapy escalation. After a median follow-up of 31 months, 61 patients (39%) had VT recurrence and 47 (30%) died. Patients with MC had a lower survival free from the composite endpoint of VT recurrence or therapy escalation at 24-month follow-up (26% vs. 59%; P = 0.003). Presence of MC (HR 1.69; P = 0.046), a lower LV ejection fraction (HR 1.03 per 1% decrease; P = 0.017), and non-complete procedural success (HR 2.42; P = 0.002) were independently associated with a higher incidence of VT recurrence or therapy escalation. CONCLUSION: Myocardial calcification was present in 19% of post-MI patients referred for VT ablation and was associated with a high incidence of endocardial ablation failure.

The prognostic value of J-wave pattern for recurrence of ventricular tachycardia after catheter ablation in patients with myocardial infarction.

BACKGROUND: J-waves and fragmented QRS (fQRS) on surface ECGs have been associated with the occurrence of ventricular tachyarrhythmias. Whether these non-invasive parameters can also predict ventricular tachycardia (VT) recurrence after radiofrequency catheter ablation (RFCA) is unknown. Of interest, patients with a wide QRS-complex have been excluded from clinical studies on J-waves, although a J-wave like pattern has been described for wide QRS. METHODS: We retrospectively included 168 patients (67 ± 10 years; 146 men) who underwent RFCA of post-infarct VT. J-wave pattern were defined as J-point elevation ≥ 0.1 mV in at least two leads irrespective of QRS width. fQRS was defined as various RSR` pattern in patients with narrow QRS and more than two R wave in those with wide QRS. The primary endpoint was VT recurrence after RFCA up to 24 months. RESULTS: J-wave pattern and fQRS were present in 27 and 28 patients, respectively. Overlap of J-wave pattern and fQRS was observed in nine. During a median follow-up of 20 (interquartile range 9-24) months, 46 (27%) patients had VT recurrence. Kaplan-Meier curves revealed that both J-wave pattern and fQRS were associated with VT recurrence. Multivariate Cox regression analysis demonstrated that the presence of J-wave pattern (hazard ratio [HR] 2.84; 95% confidence interval [CI] 1.45-5.58; P = .002) and greater number of induced VT (HR 1.29; 95% CI 1.15-1.45; P < .001) were the independent predictors of VT recurrence. CONCLUSIONS: A J-wave pattern-but not fQRS-is independently associated with an increased risk of post-infarct VT recurrence after RFCA irrespective of QRS width. This simple non-invasive parameter may identify patients who require additional treatment.

The harm of delayed diagnosis of arrhythmogenic cardiac sarcoidosis: a case series.

AIMS: Cardiac sarcoidosis (CS) is a known cause of ventricular tachycardia (VT). However, an arrhythmogenic presentation may not prompt immediate comprehensive evaluation. We aimed to assess the diagnostic and disease course of patients with arrhythmogenic cardiac sarcoidosis (ACS). METHODS AND RESULTS: From the Leiden VT-ablation-registry, consecutive patients with CS as underlying aetiology were retrospectively included. Data on clinical presentation, time-to-diagnosis, cardiac function, and clinical outcomes were collected. Patients were divided in early (<6 months from first cardiac presentation) and late diagnosis. After exclusion of patients with known causes of non-ischaemic cardiomyopathy (NICM), 15 (12%) out of 129 patients with idiopathic NICM were ultimately diagnosed with CS and included. Five patients were diagnosed early; all had early presentation with VTs. Ten patients had a late diagnosis with a median delay of 24 (IQR 15-44) months, despite presentation with VT (n = 5) and atrioventricular block (n = 4). In 6 of 10 patients, reason for suspicion of ACS was the electroanatomical scar pattern. In patients with early diagnosis, immunosuppressive therapy was immediately initiated with stable cardiac function during follow-up. Adversely, in 7 of 10 patients with late diagnosis, cardiac function deteriorated before diagnosis, and in only one cardiac function recovered with immunosuppressive therapy. Six (40%) patients died (five of six with late diagnosis). CONCLUSION: Arrhythmogenic cardiac sarcoidosis is an important differential diagnosis in NICM patients referred for VT ablation. Importantly, the diagnosis is frequently delayed, which leads to a severe disease course, including irreversible cardiac dysfunction and death. Early recognition, which can be facilitated by electroanatomical mapping, is crucial.

Arrhythmia exacerbation after post-infarction ventricular tachycardia ablation: prevalence and prognostic significance.

AIMS: Catheter ablation is an effective treatment for post-infarction ventricular tachycardia (VT). However, some patients may experience a worsened arrhythmia phenotype after ablation. We aimed to determine the prevalence and prognostic impact of arrhythmia exacerbation (AE) after post-infarction VT ablation. METHODS AND RESULTS: A total of 1187 consecutive patients (93% men, median age 68 years, median ejection fraction 30%) who underwent post-infarction VT ablation at six centres were included. Arrhythmia exacerbation was defined as post-ablation VT storm or incessant VT in patients without prior similar events. During follow-up (median 717 days), 426 (36%) patients experienced VT recurrence. Events qualifying as AE occurred in 67 patients (6%). Median times to VT recurrence with and without AE were 238 [interquartile range (IQR) 35-640] days and 135 (IQR 22-521) days, respectively (P = 0.25). Almost half of the patients (46%) who experienced AE experienced it within 6 months of the index procedure. Patients with AE had had longer ablation times during the ablation procedures compared to the rest of the patients (median 42 vs. 34 min, P = 0.02). Among patients with VT recurrence, the risk of death or heart transplantation was significantly higher in patients with than without AE (hazard ratio 1.99, 95% CI 1.28-3.10; P = 0.002) after adjusting for age, gender, ejection fraction, cardiac resynchronization therapy, post-ablation non-inducibility, and post-ablation amiodarone use. CONCLUSION: Arrhythmia exacerbation after ablation of infarct-related VT is infrequent but is independently associated with an adverse long-term outcome among patients who experience a VT recurrence. The mechanisms and mitigation strategies of AE after catheter ablation require further investigation.

Optimizing ablation duration using dormant conduction to reveal incomplete isolation with the second generation cryoballoon: A randomized controlled trial.

INTRODUCTION: Efficacy of cryoballoon ablation depends on balloon-tissue contact and ablation duration. Prolonged duration may increase extracardiac complications. The aim of this study is to determine the optimal additional ablation duration after acute pulmonary vein isolation (PVI). METHODS: Consecutive patients with paroxysmal AF were randomized to three groups according to additional ablation duration (90, 120, or 150 seconds) after acute PVI (time-to-isolation). Primary outcome was reconnection/dormant conduction (DC) after a 30 minutes waiting period. If present, additional 240 seconds ablations were performed. Ablations without time-to-isolation <90 seconds, esophageal temperature <18°C or decreased phrenic nerve capture were aborted. Patients were followed with 24-hour Holter monitoring at 3, 6, and 12 months. RESULTS: Seventy-five study patients (60 ± 11 years, 48 male) were included. Reconnection/DC per vein significantly decreased (22%, 6% and 4%) while aborted ablations remained stable (respectively 4, 5, and 7%) among the 90, 120, and 150 seconds groups. A shorter cryo-application time, longer time-to-isolation, higher balloon temperature and unsuccessful ablations predicted reconnection/DC. Freedom of atrial fibrillation was, respectively, 52, 56, and 72% in 90, 120, and 150 seconds groups ( P = 0.27), while repeated procedures significantly decreased from 36% to 4% ( P = 0.041) in the longer duration group compared to shorter duration group (150 seconds vs 90 seconds group). In multivariate Cox-regression only reconnection/DC predicted recurrence. CONCLUSION: Prolonging ablation duration after time-to-isolation significantly decreased reconnection/DC and repeated procedures, while recurrences and complications rates were similar. In a time-to-isolation approach, an additional ablation of 150 seconds ablation is the most appropriate.

Impact of left atrial box surface ratio on the recurrence after ablation for persistent atrial fibrillation.

BACKGROUND: The posterior wall of the left atrium (LA) is a well-known substrate for atrial fibrillation (AF) maintenance. Isolation of the posterior wall between the pulmonary veins (box lesion) may improve ablation success. Box lesion surface area size varies depending on the individual anatomy. This retrospective study evaluates the influence of box lesion surface area as a ratio of total LA surface area (box surface ratio) on arrhythmia recurrence. METHODS: Seventy consecutive patients with persistent AF (63 ± 11 years, 53 men) undergoing computed tomography (CT) imaging and ablation procedure consisting of a first box lesion were included in this study. Box lesion surface area was measured on electroanatomical maps and total LA surface area was derived from CT. Patients were followed with 24-h electrocardiography and exercise tests at 3, 6, and 12 months after AF ablation. Arrhythmia recurrence was defined as any AF/atrial tachycardia (AT) beyond 3 months without antiarrhythmic drugs. RESULTS: During a median follow-up of 13 (interquartile range = 10-17) months, 42 (60%) patients had AF/AT recurrence. Multivariate Cox proportional regression analysis showed that a larger box surface ratio protected against recurrence (hazard ratio [HR] = 0.81; 95% confidence interval [CI] = 0.690-0.955; P = 0.012). Left atrial volume index (HR = 1.01 [0.990-1.024, P = 0.427] and a history of mitral valve surgery (HR = 2.90; 95% CI = 0.970-8.693; P = 0.057) were not associated with AF recurrence in multivariate analysis. CONCLUSION: A larger box lesion surface area as a ratio of total LA surface area is protective for AF/AT recurrence after ablation for persistent AF.

Whole human heart histology to validate electroanatomical voltage mapping in patients with non-ischaemic cardiomyopathy and ventricular tachycardia.

Aims: Electroanatomical voltage mapping (EAVM) is an important diagnostic tool for fibrosis identification and risk stratification in non-ischaemic cardiomyopathy (NICM); currently, distinct cut-offs are applied. We aimed to evaluate the performance of EAVM to detect fibrosis by integration with whole heart histology and to identify the fibrosis pattern in NICM patients with ventricular tachycardias (VTs). Methods and results: Eight patients with NICM and VT underwent EAVM prior to death or heart transplantation. EAVM data was projected onto slices of the entire heart. Pattern, architecture, and amount of fibrosis were assessed in transmural biopsies corresponding to EAVM sites. Fibrosis pattern in NICM biopsies (n = 507) was highly variable and not limited to mid-wall/sub-epicardium. Fibrosis architecture was rarely compact, but typically patchy and/or diffuse. In NICM, biopsies without abnormal fibrosis unipolar voltage (UV) and bipolar voltage (BV) showed a linear association with wall thickness (WT). The amount of viable myocardium showed a linear association with both UV and BV. Accordingly, any cut-off to delineate fibrosis performed poorly. An equation was generated calculating the amount of fibrosis at any location, given WT and UV or BV. Conclusion: Considering the linear relationships between WT, amount of fibrosis and both UV and BV, the search for any distinct voltage cut-off to identify fibrosis in NICM is futile. The amount of fibrosis can be calculated, if WT and voltages are known. Fibrosis pattern and architecture are different from ischaemic cardiomyopathy and findings on ischaemic substrates may not be applicable to NICM.

Incidence and predictors of dormant conduction after cryoballoon ablation incorporating a 30-min waiting period.

AIMS: Electrical reconnection after pulmonary vein (PV) isolation is associated with atrial fibrillation (AF) recurrence. Reconnection may already develop within a 30 min waiting period and may only occur as dormant conduction (DC) revealed by adenosine infusion. This study determines incidence and predictors of DC after cryoballoon ablation incorporating a 30 min waiting period and the effect of treating this 'late' DC on 1 year AF-recurrence. METHODS AND RESULTS: Consecutive patients scheduled for a first ablation were prospectively included. Intravenous adenosine was administered 30 min after PV isolation to unmask DC (adenosine+). Additional applications were performed to abolish DC. Atrial fibrillation recurrence was evaluated after 3, 6, and 12 months with ECG and 24 h Holter recordings. Results were compared with a prior group of consecutive patients that underwent cryoablation without DC testing (adenosine-). The adenosine+ group consisted of 36 patients (78% male, 61 ± 10 years, paroxysmal AF 86%). ***Dormant conduction was found in 42% of patients (15/36) and 14% of PVs (20/143). Multivariate analysis showed that PV isolation during the first freeze independently reduced DC risk (OR = 0.064, P < 0.01). After 12 ± 1 months, 11 (83%) of adenosine+ patients had no AF-recurrences, compared with 37 (60%) of adenosine- patients (n = 62, 70% male, 59 ± 11 years, 90% paroxysmal AF, P = 0.02). Ablation with DC treatment independently reduced the risk of AF-recurrence (OR = 0.26, P = 0.02). CONCLUSION: Incorporating a 30-min waiting period after cryoballoon ablation increases the incidence of DC compared with previous results. Absence of PV isolation during the first freeze is associated with an increased risk of late DC. Treatment of this DC seems to improve outcome.

An easy-to-use, operator-independent, clinical model to predict the left vs. right ventricular outflow tract origin of ventricular arrhythmias.

AIMS: To identify clinical characteristics able to predict a left ventricular outflow tract (LVOT) origin in outflow tract ventricular arrhythmias (OTVAs). METHODS AND RESULTS: We included 117 consecutive patients (training sample) with successful radiofrequency ablation of OTVA in one centre. A predictive model for LVOT origin was obtained using clinical data. The model was prospectively validated in a second population (testing sample) of 143 patients from two additional centres. In training sample, mean age was 54 ± 17 years, 72 patients (61%) were male, and 63 (54%) had cardiovascular risk factors. Sixty (51%) patients had LVOT origin. Independent predictors for LVOT origin were the presence of hypertension [odds ratio (OR) 2.17, confidence interval (CI) 0.91-6.20, P = 0.09], male gender (OR 4.83, 95% CI 1.89-12.33, P < 0.001), and age >50 years (OR 4.46, 95% CI 1.57-12.7, P = 0.005). A simple score was constructed with these three variables to predict LVOT origin (mean predicted probability of 15% for score 0, 26% for score 1, 60% for score 2, and 87% for score 3, P < 0.001) and reached 80% sensitivity and 75% specificity. The score was validated in the testing sample and was not inferior to previously described electrocardiogram algorithms. CONCLUSION: Patients currently referred for OTVA ablation are older, more frequently men, and with a higher probability for LVOT origin than previously described. A LVOT origin is associated with the presence of hypertension, male gender, and older age, and can be anticipated by using a simple clinical score.

Excellent Outcomes After First-Line Ablation in Post-MI Patients With Tolerated VT and LVEF >35.

BACKGROUND: Post-myocardial infarction (MI) patients with ventricular tachycardia (VT) are considered at risk for VT recurrence and sudden cardiac death (SCD). Recent guidelines indicate that in selected patients catheter ablation should be considered instead of an implantable cardioverter-defibrillator (ICD). OBJECTIVES: This study aimed to analyze outcomes of patients referred for VT ablation according to left ventricular ejection fraction (LVEF), tolerance of VT, and acute ablation outcome. METHODS: Post-MI patients without prior ICD undergoing VT ablation at a single center between 2009 and 2022 were included. Patients who presented with tolerated VT and who had an LVEF >35% were offered catheter ablation as first-line therapy. ICD implantation was offered to all patients but was subject to shared decision according to clinical presentation, LVEF, and ablation outcome. RESULTS: Eighty-six patients (mean age 69 ± 9 years, 84% male, mean LVEF 41 ± 9%) underwent VT ablation. In 66 patients, LVEF was >35%, of whom 51 had tolerated VT. Of these 51 patients, 37 (73%) were rendered noninducible. In 5 of 37 noninducible and in 11 of 14 inducible patients, an ICD was implanted. During a median follow-up of 40 months (Q1-Q3: 24-70 months), 10 of 86 patients had VT recurrence. The overall mortality was 27%, and 1 patient with ICD died suddenly. Among the 37 patients (none on antiarrhythmic drugs) with LVEF >35%, tolerated VT, and noninducibility, no SCD or VT recurrence occurred. Among the 14 patients with LVEF >35%, tolerated VT, and inducibility after ablation, no SCD occurred, but VT recurred in 29%. CONCLUSIONS: Post-MI patients with LVEF >35%, tolerated VT, and noninducibility after ablation have an excellent prognosis. Deferring ICD implantation seems to be safe in these patients.

Management of cardiac emergencies in women: a clinical consensus statement of the Association for Acute CardioVascular Care (ACVC), the European Association of Percutaneous Cardiovascular Interventions (EAPCI), the Heart Failure Association (HFA), and the European Heart Rhythm Association (EHRA) of the ESC, and the ESC Working Group on Cardiovascular Pharmacotherapy.

Cardiac emergencies in women, such as acute coronary syndromes, acute heart failure, and cardiac arrest, are associated with a high risk of adverse outcomes and mortality. Although women historically have been significantly underrepresented in clinical studies of these diseases, the guideline-recommended treatment for these emergencies is generally the same for both sexes. Still, women are less likely to receive evidence-based treatment compared to men. Furthermore, specific diseases affecting predominantly or exclusively women, such as spontaneous coronary dissection, myocardial infarction with non-obstructive coronary arteries, takotsubo cardiomyopathy, and peripartum cardiomyopathy, require specialized attention in terms of both diagnosis and management. In this clinical consensus statement, we summarize current knowledge on therapeutic management of these emergencies in women. Key statements and specific quality indicators are suggested to achieve equal and specific care for both sexes. Finally, we discuss several gaps in evidence and encourage further studies designed and powered with adequate attention for sex-specific analysis.

Incidence of Atrial Fibrillation After Radiofrequency Catheter Ablation for Atrial Tachycardia in Congenital Heart Disease.

BACKGROUND: Atrial tachycardia (AT) and atrial fibrillation (AF) coexist in 30% of congenital heart disease (CHD) patients. Successful atrial tachycardia catheter ablation (ATCA) might prevent AF. Data on new-onset AF after ATCA in CHD is scarce. OBJECTIVES: This study aimed to evaluate the incidence of new-onset AF after ATCA and to assess clinical characteristics associated with new-onset AF after ATCA in CHD. METHODS: CHD patients referred for ATCA to 3 European centers were included. New occurrence of AF was defined as electrocardiographic documentation of AF after any ATCA procedure in patients without history of AF. RESULTS: In 277 CHD patients (median age 37 years [Q1, Q3: 23, 49 years], 58% men, 59 [21%] simple, 111 [40%] moderate, and 107 [39%] complex CHD), AF occurred in 25 patients (9%) a median of 8 months (Q1, Q3: 4, 27 months) after ATCA. New-onset AF was persistent in the majority of the patients (17 of 25 [63%]). Patients with new-onset AF were older (44 years [Q1, Q3: 29, 55 years] vs 36 years [Q1, Q3: 23, 49 years]; P = 0.009) and more frequently had simple CHD (13 of 25 [52%] vs 46 of 252 [18%], respectively; P < 0.0001). Acute ATCA success rates were similar in patients with and without AF (52% vs 48%; P = 0.429). Simple CHD was an independent predictor of new-onset AF during follow-up. CONCLUSIONS: In our large cohort of patients with congenital heart disease, new-onset AF after ablation for AT occurred in only 9% of the patients. AF occurred without AT recurrence and was persistent in the majority of patients.

Validation of a prediction model for early reconnection after cryoballoon ablation.

BACKGROUND: We previously developed an early reconnection/dormant conduction (ERC) prediction model for cryoballoon ablation to avoid a 30-min waiting period with adenosine infusion. We now aimed to validate this model based on time to isolation, number of unsuccessful cryo-applications, and nadir balloon temperature. METHODS: Consecutive atrial fibrillation patients who underwent their first cryoballoon ablation in 2018-2019 at the Leiden University Medical Center were included. Model performance at the previous and at a new optimal cutoff value was determined. RESULTS: A total of 201 patients were included (85.57% paroxysmal AF, 139 male, median age 61 years (IQR 53-69)). ERC was found in 35 of 201 included patients (17.41%) and in 41 of 774 veins (5.30%). In the present study population, the previous cutoff value of - 6.7 provided a sensitivity of 37.84% (previously 70%) and a specificity of 89.07% (previously 86%). Shifting the cutoff value to - 7.2 in both study populations resulted in a sensitivity of 72.50% and 72.97% and a specificity of 78.22% and 78.63% in data from the previous and present study respectively. Negative predictive values were 96.55% and 98.11%. Applying the model on the 101 patients of the present study with all necessary data for all veins resulted in 43 out of 101 patients (43%) not requiring a 30-min waiting period with adenosine testing. Two patients (2%) with ERC would have been missed when applying the model. CONCLUSIONS: The previously established ERC prediction model performs well, recommending its use for centers routinely using adenosine testing following PVI.