Diagnostic accuracy of Apple Watch Series 6 recorded single-lead ECGs for identifying supraventricular tachyarrhythmias: a comparative analysis with invasive electrophysiological study.

BACKGROUND: The advancements in wearable technology have made the detection of arrhythmias more accessible. While smartwatches are commonly used to detect patients with atrial fibrillation, their effectiveness in the differential diagnosis of supraventricular tachycardias (SVT) lacks consensus. METHODS: A study was conducted on 47 patients with documented SVTs on a 12-lead ECG. All patients in the cohort underwent electrophysiology study with induction of SVT. A 6th generation Apple Watch was used to record ECG tracings during baseline sinus rhythm and during induced SVT. Cardiology residents and attending cardiologists evaluated these recordings to diagnose the differential diagnosis of SVT. RESULTS: The evaluation revealed 27 cases of typical atrioventricular nodal reentrant tachycardia (AVNRT), 11 cases of atrioventricular reentrant tachycardia (AVRT), and 9 cases of atrial tachycardia/atrial flutter (AT/AFL) among the induced tachycardias. Attending physicians achieved an accuracy of 66.0 to 76.6%, and residents demonstrated accuracy rates between 68.1 and 74.5%. Interrater reliability was assessed using Fleiss's Kappa method, resulting in a moderate level of agreement between residents (Kappa = 0.465, p < 0.001, 95% CI 0.30-0.63) and attendings (Kappa = 0.519, p < 0.001, 95% CI 0.35-0.68). The overall Kappa value was 0.417 (p < 0.001, 95% CI 0.34-0.49). CONCLUSIONS: Smartwatch recordings demonstrate moderate feasibility in diagnosing SVT when following a pre-specified algorithm. However, this diagnostic performance was lower than the accuracy obtained from 12-lead ECG tracings when blinded to procedure outcomes.

Left atrial functions in the early period after cryoballoon ablation for paroxysmal atrial fibrillation.

PURPOSE: In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after pulmonary vein isolation (PVI) procedure. Although previous studies have investigated the altered mechanical functions of the LA with radiofrequency (RF) ablation, changes in the LA functions in the early period after cryoablation (CB-2) have not been clearly demonstrated. This study aims to explore the early periodical changes in mechanical functions of the LA in patients with PAF who underwent CB-2 based ablation through the help of echocardiographic methods which contain Doppler and strain parameters. METHODS: Consecutive 77 patients (mean age: 57.5 ±  11.2; 57% men) with PAF underwent CB-2 were prospectively analyzed. All patients were in sinus rhythm before and after the procedure. The LA dimensions, the LA reservoir strain, the LA atrial contractile strain and the LA conduit strain and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure. RESULTS: Acute procedural success was achieved in all cases. No major complications were observed. LA reservoir strain and LA contractile strain showed significant recovery after the procedure. (28.3 ± 12.8 vs. 34.6 ± 13.8, p < .001 and -10.8 ± 7.9 vs. -13.9 ± 9.3, p = .014 respectively). No significant change was demonstrated in other echocardiographic parameters. CONCLUSION: Significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF.

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.

Intracardiac electrogram characteristics of intramural outflow tract ventricular arrhythmias.

BACKGROUND: Annotation of earliest depolarization which depends on maximum dV/dt of unipolar-electrograms and unipolar QS morphology identify site of origin for ventricular premature contractions (VPC). However, identification of unipolar QS morphology has limitations due to low spatial resolution. This study aims to compare electrogram characteristics at successful ablation site in patients with outflow tract (OT) VPC. METHODS: Local activation time (LAT), duration, and voltage data of each bipolar- and unipolar-electrogram at the successful ablation sites from the right ventricle OT (RVOT) and the left ventricle OT (LVOT) cases were analyzed. RESULTS: Forty-four of 60 (73%) of patients were ablated from RVOT and in 16/60 (27%) required ablation from both sides. All patients had acute VPC suppression. Bipolar-electrogram-QRS onset was earlier (36.4 ± 14.5 ms vs 26.3 ± 7.4 ms, p = 0.01), duration of bipolar-electrogram was shorter (56.9 ± 18.9 ms vs 78.9 ± 21.8 ms, p = 0.002), and bi-voltage amplitude was higher (3.2 ± 2.3 mV vs 1.4 ± 1.1 mV, p = 0.07) for patients with RVOT-only ablation. Mean bipolar-unipolar-electrogram difference was 4.4 ± 4.5 ms in the RVOT group vs 12.8 ± 4.9 ms in RVOT + LVOT group (p < 0.001). Unipolar QS morphology was recorded in 3.0 ± 3.9 vs 3.6 ± 1.8 cm2 in RVOT and RVOT + LVOT group, respectively (p = 0.41). Unipolar-electrogram revealed W pattern in 3/44 of RVOT vs 5/16 of RVOT + LVOT group, respectively (p = 0.01). In 18/60 (30%) of patients, unipolar QS was not identified at successful ablation site. CONCLUSION: QS in unipolar-electrogram was not a perfect predictor for successful ablation sites. Analysis of bipolar voltage amplitude and duration with bipolar-unipolar-electrogram time difference may identify presence of a deeper source.

Permanent pacing versus cardioneuroablation for cardioinhibitory vasovagal syncope.

BACKGROUND: We compared the efficacy and safety of cardioneuroablation (CNA) vs. permanent pacing (PM) for recurrent cardioinhibitory vasovagal syncope (CI-VVS). METHODS: One hundred sixty-two patients (CNA = 61, PM = 101), age 36 + 11 years) with syncope frequency of 6.7 ± 3.9/year were included in this multicenter study. All patients with CNA were provided by a single center, while patients with PM were provided by 4 other centers. In the CNA arm, an electroanatomic mapping guided approach was used to detect and ablate ganglionated plexus sites. Dual chamber rate drop response (RDR) or close loop stimulation (CLS) transvenous and leadless pacemakers were implanted using standard technique. The primary endpoint was freedom from syncope. RESULTS: Of 101 patients in the PM group, 39 received dual-chamber pacemaker implants with the CLS algorithm, 38 received dual-chamber pacemakers with the RDR algorithm, and 24 received a leadless pacemaker. At 1-year follow-up, 97% and 89% in the CNA and PM group met the primary endpoint (adjusted HR = 0.27, 95% CI 0.06-1.24, p = 0.09). No significant differences in adverse events were noted between groups. There was no significant association between age (HR:1.01, 95% CI 0.96-1.06, p = 0.655), sex (HR:1.15, 95% CI 0.38-3.51, p = 0.809), and syncope frequency in the past year (HR:1.10, 95% CI 0.97-1.25, p = 0.122) and the primary outcome in univariable analyses. CONCLUSIONS: After adjustment for patient characteristics, the medium-term syncope recurrence risk of CI-VVS patients who underwent CNA was similar to that of a population of patients undergoing pacemaker implantation with a similar safety profile.

Effects of obesity on arrhythmic events and survival in patients with an implantable cardioverter defibrillator.

Background    Studies have shown that increased body weight and obesity may be associated with an increased risk of arrhythmic events. The aim of this study was to evaluate the effect of obesity on the risk of arrhythmic events, hospitalization, and death in patients who received implantable cardioverter defibrillator (ICD) therapy for primary or secondary prevention.Material and Methods    A single-center, prospective, observational study was conducted. Patients with body mass index (BMI) <30 kg / m2 were classified as non-obese, and patients with BMI ≥30 kg / m2 were classified as obese. The primary endpoints were arrhythmic events and device interventions. The secondary endpoints were all-cause mortality, cardiac mortality, cardiac rehospitalization, and a composite endpoint of mortality and hospitalization.Results    Among a total of 340 patients, 78.2 % were male, and 22.1 % were obese. The mean age was 60.9 yrs. Ventricular tachycardia (VT) was more frequent in non-obese patients (HR 0.57, [CI] 0.38-0.87, p=0.009). All-cause mortality and cardiac mortality in all patients tended to be more frequent in non-obese (HR 2.71, [CI] 0.93-7.93, p= 0.069 for all-cause mortality; HR 3.29, [CI] 0.97-11.17, p=0.056 for cardiac mortality). In the subgroup analysis, VT, all-cause mortality, and cardiac mortality were more common for non-obese patients in primary prevention and ischemic heart failure (HF) groups.Conclusion    While VT was more frequent in non-obese patients, VF, ICD appropriate shock, inappropriate shock, and antitachycardia pacing were similar in obese and non-obese patients. All-cause mortality and cardiac mortality were more frequent in non-obese patients.

An unexpected route of temporary pacing lead.

Congenital anomalies of the venous system including superior (SVC) and inferior vena cava are not uncommon. Failure of certain vessels embryogenesis results in numerous caval variations and anomalies. Anomalies of systemic venous circulation are frequently seen in patients with congenital heart disease and are sometimes incidentally recognized. However, these are usually without significant clinical implications, detection of these anomalies is necessary to avoid diagnostic pitfalls and for planning vascular interventions. We present a rare caval anomaly, a left-sided IVC with hemiazygos continuation to left SVC and coronary sinus.

The impact of the clinical diagnosis on the vagal response and heart rate after ganglionated plexus ablation.

BACKGROUND: Ganglionated plexi (GP) ablation may be associated with improved syncope or arrhythmia-free survival arrhythmia patients with vasovagal syncope (VVS) and atrial fibrillation (AF), respectively. We aimed to compare the characteristics of vagal response (VR) and clarify the effect on heart rate after GP ablation based on clinical diagnosis. METHODS: A total of 83 consecutive patients undergoing GP ablation were divided following two groups: (1) GP ablation for VVS (VVS group, n = 43) and (2) GP ablation in addition to pulmonary vein isolation (AF group, n = 40). We examined VR characteristics during RF ablation and high frequency stimulation, respectively, in the VVS and AF groups. To evaluate immediate and long-term heart rate response, a standard 12-lead ECG was obtained at baseline at 24 h after ablation and at the last follow-up visit. RESULTS: In the VVS group, the superior and inferior left atrial GPs were the most common GP sites at which a VR was observed. No VR was seen during radiofrequency application in the superior and inferior right atrial GPs in the VVS group. On the contrary, VR was more prevalent in the right-sided GPs during high-frequency stimulation in the AF group. VR was observed during ablation in only one patient with AF. Although the heart rate increased significantly after ablation in both groups, the effect was more prominent and durable in the VVS group. CONCLUSIONS: The autonomic response during GP ablation is different in VVS compared to AF, suggesting that VVS and AF may represent distinct forms of autonomic hyperactivity.

Stand-alone Focal Impulse and Rotor Modulation (FIRM) ablation versus second-generation cryoballoon pulmonary vein isolation for paroxysmal atrial fibrillation.

INTRODUCTION: Focal Impulse and Rotor Modulation (FIRM) guided catheter ablation aiming at stable rotors has been investigated as a treatment option in patients with atrial fibrillation (AF). The objective of this study was to compare the safety and efficacy of FIRM-guided ablation with second-generation cryoballoon pulmonary vein isolation (CB2-PVI) in paroxysmal AF. METHODS: Consecutive patients (n = 22, mean age 60 ± 11 years, 59.1% of males) who were treated with a stand-alone FIRM-guided ablation were included in this retrospective single-center study. Procedural data and arrhythmia-free survival at 12 months were compared with n = 86 consecutive patients (mean age 62 ± 13 years, 62.4% of males) who received de-novo CB2-PVI. RESULTS: Median procedure duration was significantly longer in the FIRM group than in the CB2-PVI group (152 [IQR 120-176] minutes vs. 122 [110-145] minutes; p = .031). One patient (1.2%) in the CB2-PVI group and five patients (22.7%) in the FIRM group had vascular access complications. Atrial tachyarrhythmias recurred in 15 patients in the FIRM group and 11 in the CB2-PVI group. Kaplan-Meier estimation of single-procedure arrhythmia-free survival at 12 months was 25% (95% confidence interval [CI] 6%-44%) in the FIRM group and 87% (95% CI 78%-96%) in the CB2-PVI group (p < .001). Repeat ablations were performed in 14/20 (70.0%) patients in the FIRM group and in 12/85 (14.1%) in the CB2-PVI group (p < .001). CONCLUSION: De novo ablation of AF using FIRM-guided AF ablation results in shorter arrhythmia-free survival after 12 months compared to CB2-PVI and a need for repeat ablation in the majority of patients to achieve stable sinus rhythm.

Decreasing time between first diagnosis of paroxysmal atrial fibrillation and cryoballoon ablation positively affects long-term consequences.

BACKGROUND: Patients with atrial fibrillation (AF) usually experience a worsening of their AF burden over time. We aimed to investigate timing of pulmonary vein isolation (PVI) by cryoballoon (CB-2) after the first clinical diagnosis of AF on ablation-related outcomes. METHODS: A total of 132 consecutive patients with paroxysmal AF undergoing PVI by CB-2 were included in the study. The patients were retrospectively sorted into two groups to evaluate differences in AF recurrence risk associated with early ablation (n = 89), defined as within 365 days of first AF diagnosis, and late ablation (n = 365), defined as > 365 days after first AF diagnosis. AF-free survival during follow-up was compared between groups. RESULTS: Although mean procedure times were comparable between groups, mean fluoroscopy times were lower in the early ablation group. For the whole study group, median (interquartile range) time from AF diagnosis to first ablation was 4.0 (2.0-11.3) months [3.0 (1.0-4.0) vs 14.0 (12.0-22.5) months in the early and late ablation groups, respectively]. Median follow-up for the whole population was 12.0 (12.0-18.0) months, and after the blanking period, 14 (10.6%) patients had arrhythmia recurrence (2 in the early and 12 in the late ablation groups). In the univariable Cox regression analysis and propensity score adjusted penalized Cox regression analysis, there was a significant association between delay in ablation time and AF recurrence (unadjusted hazard ratio = 7.74, 95% CI 2.26-40.1, p < 0.001, adjusted hazard ratio = 7.50, 95% CI 2.23-38.6, p < 0.001). CONCLUSION: Delays in treatment with CB-2 ablation may negatively affect AF-free survival rates among patients with paroxysmal AF.

Catheter Ablation for Atrial Fibrillation in Patients ≤30 Years of Age.

Pulmonary vein (PV) automaticity is an established trigger for paroxysmal atrial fibrillation (PAF), making PV isolation (PVI) the cornerstone of catheter ablation. However, data on triggers for atrial fibrillation (AF) and catheter ablation strategy in very young patients aged <30 years are sparse. A total of 51 young patients (mean age 24.0 ± 4.2 years, 78.4% men) with drug-refractory PAF underwent electrophysiology (EP) study and ablation at 5 EP centers. None of the patients had structural heart disease or family history of AF. EP study induced supraventricular tachycardia (SVT) in 12 patients (n = 12, 23.5%): concealed accessory pathway mediated orthodromic atrioventricular reentrant tachycardia in 3 patients, typical atrioventricular nodal reentrant tachycardia in 6 patients, left superior PV tachycardia in 1 patient, left atrial appendage tachycardia in 1 patient, and typical atrial flutter in 1 patient. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure, except for the patient with atrial flutter who received cavotricuspid isthmus ablation in addition to PVI. Remaining patients underwent radiofrequency (n = 15, 29.4%) or second-generation cryoballoon-based PVI (n = 24, 47%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-hour Holter-electrocardiogram at 3, 6, and 12 months after ablation, or additional Holter-electrocardiogram was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode >30 seconds after a 3-month blanking period. A total of 2 patients with atrioventricular nodal reentrant tachycardia, 1 with left atrial appendage tachycardia, experienced AF recurrence within the first 3 months and received PVI. After the 3-month blanking period, during a median follow-up of 17.0 ± 10.1 months, 44 of 51 patients (86.2%) were free of ATA recurrence. In the PVI group, 33 of 39 patients (84.6%) experienced no ATA recurrence. In conclusion, SVT substrate is identified in around a quarter of young adult patients with history of AF, and targeted ablation without PVI may be sufficient in the majority of these patients. PVI is needed in the majority and is safe and effective in this population.

The benefit of cardioneuroablation to reduce syncope recurrence in vasovagal syncope patients: a case-control study.

BACKGROUND: Adequate and effective therapy for resistant vasovagal syncope patients is lacking and the benefit of cardioneuroablation (CNA) in this cohort is still debated. The aim of this study is to assess the long-term effect of CNA versus conservative therapy (CT) in a retrospectively followed cohort. METHODS: A total of 2874 patients underwent head-up tilt test (HUT) and 554 (19.2 %) were reported as positive, with VASIS type 2B response or > 3 s asystole in 130 patients. After exclusion of 29 patients under 18 years and over 65 years of age, 101 patients were included final analysis. Fifty-one patients (50.4%) underwent CNA and 50 (49.6%) patients received CT. After propensity score matching, 19 pairs of patients were successfully matched. The recurrence rate of syncope was compared between groups. RESULTS: During a median follow-up of 22 months (IQR, 13-35), syncope was seen in 12 (11.8%) cases. In the 19 propensity-matched patients, recurrent syncope was observed in 8 patients in the CT group and in 2 patients in the CNA group, respectively. In mixed effect Cox regression analysis, CNA was associated with less syncope recurrence risk at follow-up (HR 0.23, 95% CI 0.03-0.99, p = 0.049). The 4-year Kaplan-Meier syncope free rate was 0.86 (95% CI, 0.63-1.00) for CNA group and 0.50 (95% CI, 0.30-0.82) for CT group in the matched cohort. CONCLUSIONS: In highly selected patients with HUT-induced cardioinhibitory response, CNA is associated with a significant reduction in syncope recurrence during follow-up when compared to CT.

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.

Procedural and short-term results of electroanatomic-mapping-guided ganglionated plexus ablation by first-time operators: A multicenter study.

INTRODUCTION: Single-center observational studies have shown promising results with fragmented electrogram (FE)-guided ganglionated plexus (GP) ablation in patients with vagally mediated bradyarrhythmia (VMB). We aimed to compare the acute procedural characteristics during FE-guided GP ablation in patients with VMB performed by first-time operators and those of a single high-volume operator. METHODS AND RESULTS: This international multicenter cohort study included data collected over 2 years from 16 cardiac hospitals. The primary operators were classified according to their prior GP ablation experience: a single high-volume operator who had performed > 50 GP ablation procedures (Group 1), and operators performing their first GP ablation cases (Group 2). Acute procedural characteristics and syncope recurrence were compared between groups. Forty-seven consecutive patients with VMB who underwent FE-guided GP ablation were enrolled, n = 31 in Group 1 and n = 16 in Group 2. The mean number of ablation points in each GP was comparable between groups. The ratio of positive vagal response during ablation on the left superior GP was higher in Group 1 (90.3% vs. 62.5%, p = .022). Ablation of the right superior GP increased heart rate acutely without any vagal response in 45 (95.7%) cases. The procedure time was longer in group 2 (83.4 ± 21 vs. 118.0 ± 21 min, respectively, p < .001). Over a mean follow-up duration of 8.0 ± 3 months (range 2-24 months), none of the patients suffered from syncope. CONCLUSION: This multi-center pilot study shows for the first time the feasibility of FE-guided GP ablation across a large group of procedure-naïve operators.

Why is the Tilt Table Test Still Useful to Define who Should or Should Not Get A Pacemaker with Vasovagal Syncope?

The the tilt table test (TTT )has been used identify appropriate candidates for pacing in the majority of randomized trials. However, in recent years, it has been claimed-based largely on International Study on Syncope of Uncertain Etiology (ISSUE) studies-that the TTT demonstrates only a weak correlation with the mechanism documented by implantable loop recorder (ILR) at the time of syncope and thus confounds the correct diagnosis. Thus, cardiac pacing was supported in patients with recurrent vasovagal syncope (VVS) in whom clinically relevant asystole had been documented by ILR. In the present Editorial, we tried to discuss potential role of TTT in diagnostic workflow of VVS based on current data.

Filtering electrocardiogram: Music, math, and ST-elevation myocardial infarction.

Clinicians should have a basic understanding of the working principle of the instruments they use to avoid potential pitfalls caused by post-processing of the acquired biological signals. An electrocardiogram (ECG) is no exception; many different errors can arise during the acquisition or the processing of the ECG data, which may result in dangerous misdiagnoses. We present a case where the use of an inappropriate high-pass filter led to a false diagnosis of ST-elevation myocardial infarction. In addition, this report discusses the basic mechanisms of this frequently overlooked phenomenon and methods to avoid it.