Comparing Left Atrial Low Voltage Areas in Sinus Rhythm and Atrial Fibrillation Using Novel Automated Voltage Analysis: A Pilot Study.

Background: Low voltage areas (LVAs) have been proposed as surrogate markers for left atrial (LA) scar. Correlation between voltages in sinus rhythm (SR) and atrial fibrillation (AF) have previously been measured via point-by-point analysis. We sought to compare LA voltage composition measured in SR to AF, utilizing a high-density automated voltage histogram analysis (VHA) tool in those undergoing pulmonary vein isolation (PVI) for persistent AF (PeAF). Methods: We retrospectively analyzed patients with PeAF undergoing de novo PVI. Maps required ≥ 1,000 voltage points in each rhythm and had a standardized procedure (mapped in AF then remapped in SR post-PVI). We created six anatomical segments (AS) from each map: anterior, posterior, roof, floor, septal and lateral AS. These were analyzed by VHA, categorizing atrial LVAs into 10 voltage aliquots 0 - 0.5 mV. Data were analyzed using SPSS v.26. Results: We acquired 58,342 voltage points (n = 10 patients, mean age: 67 ± 13 years, three females). LVA burdens of ≤ 0.2 mV, designated as "severe LVAs", were comparable between most AS (except on the posterior wall) with good correlation. Mapped voltages between the ranges of 0.21 and 0.5 mV were labeled as "diseased LA tissue", and these were found significantly more in AF than SR. Significant differences were seen on the roof, anterior, posterior, and lateral AS. Conclusions: Diseased LA tissue (0.21 - 0.5 mV) burden is significantly higher in AF than SR, mainly in the anterior, roof, lateral, and posterior wall. LA "severe LVA" (≤ 0.2 mV) burden is comparable in both rhythms, except with respect to the posterior wall. Our findings suggest that mapping rhythm has less effect on the LA with voltages < 0.2 mV than 0.2 - 0.5 mV across all anatomical regions, excluding the posterior wall.

Picking the Locked Door: Experiences and Techniques in Transseptal Puncture Post-Atrial Septal Defect Occlusion.

The management of atrial septal defects (ASDs) has been revolutionized by the advent of percutaneous transvenous occlusion devices. This case series describes techniques required to perform a transeptal puncture safely and effectively in patients postimplantation of an atrial septal defect occluder to facilitate catheter ablation of atrial arrhythmias. (Level of Difficulty: Intermediate.).

The impact of steerable sheath visualization during catheter ablation for atrial fibrillation.

AIMS: Incorporating a steerable sheath that can be visualized using an electroanatomical mapping (EAM) system may allow for more efficient mapping and catheter placement, while reducing radiation exposure, during ablation procedures for atrial fibrillation (AF). This study evaluated fluoroscopy usage and procedure times when a visualizable steerable sheath was used compared with a non-visualizable steerable sheath for catheter ablation for AF. METHODS AND RESULTS: In this retrospective, observational, single-centre study, patients underwent catheter ablation for AF using a steerable sheath that is visualizable using the CARTO EAM (VIZIGO; n = 57) or a non-visualizable steerable sheath (n = 34). The acute procedural success rate was 100%, with no acute complications in either group. Use of the visualizable sheath vs. the non-visualizable sheath was associated with a significantly shorter fluoroscopy time [median (first quartile, third quartile), 3.4 (2.1, 5.4) vs. 5.8 (3.8, 8.6) min; P = 0.003], significantly lower fluoroscopy dose [10.0 (5.0, 20.0) vs. 18.5 (12.3, 34.0) mGy; P = 0.015], and significantly lower dose area product [93.0 (48.0, 197.9) vs. 182.2 (124.5, 355.0) µGy·m2; P = 0.017] but with a significantly longer mapping time [12.0 (9.0, 15.0) vs. 9.0 (7.0, 11.0) min; P = 0.004]. There was no significant difference between the visualizable and non-visualizable sheaths in skin-to-skin time [72.0 (60.0, 82.0) vs. 72.0 (55.5, 80.8) min; P = 0.623]. CONCLUSION: In this retrospective study, use of a visualizable steerable sheath for catheter ablation of AF significantly reduced radiation exposure vs. a non-visualizable steerable sheath. Although mapping time was longer with the visualizable sheath, the overall procedure time was not increased.

Ablation Index Outcome in Redo Persistent Atrial Fibrillation Ablation: Results of a Short-Term Study.

Background: Ablation index (AI) is a novel catheter-based parameter that has improved the outcome and safety of radiofrequency (RF) ablation of pulmonary vein isolations (PVIs). This index incorporates contact force (CF) (g), time (s), and power (W) parameters. The role of AI in redo ablations for persistent atrial fibrillation (peAF) has not been fully investigated. Hence, the impact of AI on the success of the redo PVI during the short-term follow-up period is the aim of this study. Methods: A retrospective analysis of 39 consecutive patients who underwent redo PVI ablations for peAF was carried out between January 2016 and December 2018. Target values for AI were 500 - 550 for anterior and roof and 400 - 380 for posterior and inferior regions. We compared outcomes between AI-guided and catheter CF ablations (i.e., forced time integral (FTI) of more than 400 g/s) during a follow-up of 24 months. Results: Pulmonary vein reconnections at redo procedure were similar in both groups (P = 0.1). AF free burden period was non-significant (mean 15.53 ± 2.4 months in AI group vs. 15.22 ± 1.9 months in CF group, P = 0.79) at 24 months. The AI group demonstrated greater numbers of patients for whom anti-arrhythmic therapy could be de-escalated over 1 year (n = 11 (65%) in AI vs. n = 6 (27%) in CF, P = 0.02). Fewer patients underwent escalation of their anti-arrhythmic therapy (n = 2 (12%) in AI vs. n = 7 (32%) in CF, P = 0.15). The AI group trended towards a shorter procedure time (111.6 ± 27 min) compared to the CF group (133 ± 40 min) (P = 0.06). Other procedural details were comparable. Conclusion: Redo PVI interventions using AI lead to a significant de-escalation in medication during follow-up. Procedure time and radiation dose using AI tends to be shorter. Both techniques are safe with minimal complications.

Classification of Left Atrial Diseased Tissue Burden Determined by Automated Voltage Analysis Predicts Outcomes after Ablation for Atrial Fibrillation.

BACKGROUND: The burden and persistence of atrial fibrillation (AF) have been associated with the presence and extent of left atrial (LA) fibrosis. Recent reports have implicated an association between the extent of LA fibrosis and the outcome of pulmonary vein isolation (PVI). We aimed to analyse the value of an automated scar quantification method in the prediction of success following PVI. METHODS: One hundred and nine consecutive patients undergoing PVI for paroxysmal or persistent AF were included in our observational study with a 2-year follow-up. Prior to PVI, patients underwent high-definition LA electroanatomical mapping, and scar burden was quantified by automated software (Voltage Histogram Analysis, CARTO 3, Biosense Webster), then classified into 4 subgroups (Dublin Classes I-IV). Recurrence rates were analysed on and off antiarrhythmic drug therapy (AAD), respectively. RESULTS: The overall success rate was 74% and 67% off AAD at 1- and 2-year follow-up, respectively. Patients with Dublin Class IV had significantly lower success rates (p = 0.008, off AAD). Dublin Class IV (OR = 2.27, p = 0.022, off AAD) and the presence of arrhythmia in the blanking period (OR = 3.28, p = 0.001, off AAD) were the only significant predictors of recurrence. The use of AAD did not affect these results. CONCLUSIONS: We propose a classification of low voltage areas based on automated quantification by software during 3D mapping prior to PVI. Patients with high burden of low voltage areas (>31% of <0.5 mV, Dublin Class IV) have a higher risk of recurrence following PVI. Information gathered during electroanatomical mapping may have important prognostic value.

The Value of Voltage Histogram Analysis Derived Right Atrial Scar Burden in the Prediction of Left Atrial Scar Burden.

INTRODUCTION: Growing evidence suggests that fibrotic changes can be observed in atrial fibrillation (AF) in both atria. Quantification of the scar burden during electroanatomical mapping might have important therapeutic and prognostic consequences. However, as the current invasive treatment of AF is focused on the left atrium (LA), the role of the right atrium (RA) is less well understood. We aimed to characterize the clinical determinates of the RA low-voltage burden and its relation to the LA scaring. METHODS: We have included 36 patients who underwent catheter ablation for AF in a prospective observational study. In addition to LA mapping and ablation, high-density RA bipolar voltage maps (HD-EAM) were also reconstructed. The extent of the diseased RA tissue (≤0.5 mV) was quantified using the voltage histogram analysis tool (CARTO®3, Biosense Webster). RESULTS: The percentage of RA diseased tissue burden was significantly higher in patients with a CHA2DS2-VASc score ≥ 2 (p = 0.0305), higher indexed LA volume on the CTA scan and on the HD-EAM (p = 0.0223 and p = 0.0064, respectively), or higher indexed RA volume on the HD-EAM (p = 0.0026). High RA diseased tissue burden predicted the presence of high LA diseased tissue burden (OR = 7.1, CI (95%): 1.3-38.9, p = 0.0145), and there was a significant correlation of the same (r = 0.6461, p < 0.0001). CONCLUSIONS: Determining the extent of the right atrial low-voltage burden might give useful clinical information. According to our results, the diseased tissue burden correlates well between the two atria: the right atrium mirrors the left atrium.

Quantitative assessment of left atrial scar using high-density voltage mapping and a novel automated voltage analysis tool.

PURPOSE: Left atrial (LA) fibrosis plays an important role in the pathogenesis and perpetuation of atrial fibrillation (AF). It may be identified by bipolar voltage (BiV) mapping, but quantification of fibrosis which previously relied on visual estimation of scar has been shown to be inaccurate. Our aim was to use a novel automated voltage histogram analysis (VHA) tool to quantify LA scar burden accurately in patients with AF. METHODS: LA voltage was assessed in 100 consecutive patients undergoing first pulmonary vein isolation (PVI) for paroxysmal or persistent AF using a circular multielectrode catheter to create high-density LA BiV maps which were analysed using the VHA tool after the procedure. RESULTS: High-density electro-anatomic maps took 10 min to create and contained a median of 1049 points. The VHA algorithm accurately quantified the burden of Diseased LA Tissue (≤ 0.5 mV) and Dense LA Scar (≤ 0.2 mV) with a median of 17.8% and 3.5% respectively. A quartile classification was applied based on diseased LA tissue burden. Patients in class IV with the highest diseased LA burden were older (p < 0.0001), more likely female (p = 0.0095), had higher CHA2DS2-VASc scores (p = 0.0024) and were more likely to have persistent rather than paroxysmal AF (p = 0.0179) than those in classes I-III. CONCLUSIONS: The VHA algorithm is able to quantify percentage surface area voltage rapidly and according to preset ranges for the first time. The algorithm offers the potential for classification of patients undergoing AF ablation into different classes of diseased LA burden, which may have diagnostic, therapeutic and prognostic implications.

Ventricular Tachycardia Storm After Standard Radiofrequency Pulmonary Vein Isolation.

BACKGROUND The occurrence of ventricular arrhythmias (VAs), particularly premature ventricular complexes, following pulmonary vein isolation (PVI) is a documented phenomenon, but monomorphic scar-related ventricular tachycardia (VT) following PVI is an unusual phenomenon. In this case report, we present a case of new-onset VA after radiofrequency PVI in a patient with no prior history of sustained VTs. CASE REPORT Our patient was a 69-year-old man with a history of symptomatic persistent atrial fibrillation, with an apparently structurally normal heart with subtle regional wall motion abnormalities. He underwent radiofrequency directed pulmonary vein isolation ablation. On the night of an uneventful procedure, the patient for the first time experienced a sustained ventricular tachycardia that exacerbated into a VT storm. Each arrhythmia was terminated by cardioversion due to hemodynamic instability. Antiarrhythmic treatment with lidocaine was initiated immediately. The patient settled from sustained ventricular arrhythmia and received further ablation to monomorphic ventricular tachycardia. CONCLUSIONS The incidence of ventricular ectopics after PVI ablation has been previously described, but a sustained monomorphic ventricular storm has not been reported before with RF ablation. We attribute the pathophysiology to an increase in myocardial excitability and/or ventricular autonomic modulation. This is a very rare phenomenon, but any subtle imaging abnormality before planning RF-PVI should be taken into consideration.

First experience with zero-fluoroscopic ablation for supraventricular tachycardias using a novel impedance and magnetic-field-based mapping system.

AIMS: Zero- and near-zero-fluoroscopic ablation techniques reduce the harmful effects of ionizing radiation during invasive electrophysiology procedures. We aimed to test the feasibility and safety of a zero-fluoroscopic strategy using a novel integrated magnetic and impedance-based electroanatomical mapping system for radiofrequency ablation (RFA) of supraventricular tachycardias (SVTs). METHODS: We retrospectively studied 92 consecutive patients undergoing electrophysiology studies with/without RFA for supraventricular tachycardia (SVT) performed by a single operator at a single center. The first 42 (Group 1) underwent a conventional fluoroscopic-guided approach and the second 50 (Group 2) underwent a zero-fluoroscopic approach using the Ensite Precision™ 3-D magnetic and impedance-based mapping system (Abbott Inc). RESULTS: Group 1 comprised 14 AV-nodal re-entrant tachycardia (AVNRT), 12 typical atrial flutter, 4 accessory pathway (AP), 2 atrial tachycardia (AT), and 9 diagnostic EP studies (EPS). Group 2 comprised 16 AVNRT, 17 atrial flutter, 6 AP, 3 AT, 2 AV-nodal ablations, and 7 EPS. A complete zero-fluoroscopic approach was achieved in 94% of Group 2 patients. All procedures were acutely successful, and no complications occurred. There was a significant reduction in fluoroscopy dose, dose area product, and time (p < 0.0001, for all), with no difference in procedure times. Ablation time for typical atrial flutter was shorter in Group 2 (p = 0.006). CONCLUSIONS: A zero-fluoroscopic strategy for diagnosis and treatment of SVTs using this novel 3D-electroanatomical mapping system is feasible in majority of patients, is safe, reduces ionizing radiation exposure, and does not compromise procedural times, success rates, or complication rates.

Evaluation of the Tp-Te Interval, QTc and P-Wave Dispersion in Patients With Coronary Artery Ectasia.

BACKGROUND: Coronary artery ectasia (CAE) is defined as a diffuse dilatation of the diameter of the ectatic segment of the coronary artery, 1.5 times greater than that of the adjacent segment. The Tp-Te interval, P-wave and QTc dispersions are relatively new electrocardiographic markers associated with an increased risk of developing arrhythmias. Despite CAE increasing in prevalence in recent years, there is a sparsity of data available about its arrhythmogenic effect. The aim of the study was to evaluate QTc, P-wave dispersion and Tp-Te and Tp-Te/QT ratio in patients with CAE. METHODS: A retrospective comparative study was designed for consecutive age- and sex-matched patients. Twenty patients with isolated CAE (group 1) and 20 control subjects (group 2), with normal coronary arteries, were included. All patients presented with chest pain and coronary angiogram was indicated. Outcome measures included Tp-Te interval, Tp-Te/QT ratio, QTc dispersion and P-wave dispersion. Measurement of electrocardiogram (ECG) parameters was conducted using standardized digital online software. Descriptive and inferential statistics were performed. RESULTS: Mean Tp-Te (95.5 ± 9.01 ms) and Tp-Te/QT ratio (0.22 ± 0.02) were significantly prolonged in CAE group (Tp-Te: 84 ± 5.62 ms, P = 0.00009; Tp-Te/QT ratio: 0.20 ± 0.01, P = 0.00004). In addition, QTc (31.2 ± 3.71 ms) and P-wave dispersion (31.9 ± 5.46 ms) were significantly increased in comparison to the control group (QTc: 27.6 ± 2.82 ms, P = 0.00532 and 20 ± 3.77 ms, P = 0.00003 respectively). However, there was no difference in ventricular activation time (VAT) between groups. CONCLUSIONS: CAE ECGs were found to be associated with increased Tp-Te, Tp-Te/QT ratio, QTc intervals and P-wave dispersions. This may suggest that CAE existence has a pro-arrhythmogenic nature.

The Brady Bunch? New evidence for nominative determinism in patients' health: retrospective, population based cohort study.

OBJECTIVE: To ascertain whether a name can influence a person's health, by assessing whether people with the surname "Brady" have an increased prevalence of bradycardia. DESIGN: Retrospective, population based cohort study. SETTING: One university teaching hospital in Dublin, Ireland. PARTICIPANTS: People with the surname "Brady" in Dublin, determined through use of an online telephone directory. MAIN OUTCOME MEASURE: Prevalence of participants who had pacemakers inserted for bradycardia between 1 January 2007 and 28 February 2013. RESULTS: 579 (0.36%) of 161,967 people who were listed on the Dublin telephone listings had the surname "Brady." The proportion of pacemaker recipients was significantly higher among Bradys (n=8, 1.38%) than among non-Bradys (n=991, 0.61%; P=0.03). The unadjusted odds ratio (95% confidence interval) for pacemaker implantation among individuals with the surname Brady compared with individuals with other surnames was 2.27 (1.13 to 4.57). CONCLUSIONS: Patients named Brady are at increased risk of needing pacemaker implantation compared with the general population. This finding shows a potential role for nominative determinism in health.

Family-based cardiac screening in relatives of victims of sudden arrhythmic death syndrome.

AIMS: Sudden arrhythmic death syndrome (SADS) occurs when a person suffers a sudden, unexpected death, with no cause found at postmortem examination. We aimed to describe the cardiac screening outcomes in a population of relatives of SADS victims METHODS AND RESULTS: Prospective and retrospective cohort study of consecutive families attending the Family Heart Screening clinic at the Mater Misericordiae Hospital in Dublin, Ireland, from January 2007 to September 2011. Family members of SADS victims underwent a standard screening protocol. Adjunct clinical and postmortem information was sought on the proband. Families who had an existing diagnosis, or where the proband had epilepsy, were excluded. Of 115 families identified, 73 were found to fit inclusion criteria and were retained for analysis, with data available on 262 relatives. Over half of the screened family members were female, and the mean age was 38.6 years (standard deviation 15.6). In 22 of 73 families (30%), and 36 of 262 family members (13.7%), a potentially inheritable cause of SADS was detected. Of the population screened, 32 patients (12.2%) were treated with medication, and 5 (1.9%) have received implantable cardiac defibrillators. Of the five families with long QT syndrome (LQTS) who had a pathogenic gene mutation identified, three carried two such mutations. CONCLUSION: In keeping with international estimates, 30% of families of SADS victims were found to have a potentially inherited cardiac disease. The most common positive finding was LQTS. Advances in postmortem standards and genetic studies may assist in achieving more diagnoses in these families.

Cardiac MRI in arrhythmogenic right ventricular cardiomyopathy.

OBJECTIVE: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a cause of sudden cardiac death in otherwise healthy young adults. This article outlines the spectrum of MRI findings in ARVC using a combination of static and cine images. CONCLUSION: The detection of right ventricular enlargement, fatty infiltration, fibrosis, and wall motion abnormalities at MRI is useful in the diagnosis of ARVC.

Contemporary management of and outcomes from cardiac device related infections.

AIMS: To describe the incidence and management of cardiac device infection. Infection is a serious, potentially fatal complication of device implantation. The numbers of device implants and infections are rising. Optimal care of device infection is not well defined. METHODS AND RESULTS: We retrospectively identified cases of device infection at our institution between 2000 and 2007 by multiple source record review, and active surveillance. Device infection was related to demographics, clinical, and procedural characteristics. Descriptive analysis was performed. From 2000 to 2007, a total of 2029 permanent pacemakers and 1076 biventricular/implantable cardioverter-defibrillators (ICDs) or ICDs were implanted. Thirty-nine cases of confirmed device infections were identified--27 pacemaker and 12 bivent/ICD or ICD infections, giving an infection rate of 1.25%. Median time from implant or revision to presentation was 150 days (range 2915 days, IQR25% 35-IQR75% 731). Ninety percent of patients presented with generator-site infections. The most common organism was methicillin-sensitive Staphylococcus aureus (30.8%), followed by coagulase negative Staphylococcus (20.5%). Complete device extraction occurred in 82%. Of these, none had relapse, and mortality was 7.4% (n = 2/27). With partial removal or conservative therapy (n = 13), relapse occurred in 67% (n = 8/12), with mortality of 8.4% (n = 1/12). Median duration of antibiotics was 42 days (range 47 days, IQR25% 28-IQR75% 42 days). Re-implantation of a new device occurred in 54%, at a median of 28 days (range 73 days, IQR25% 8.5-IQR75% 35 days). Methicillin-Resistant Staphylococcus Aureus infection predicted mortality (P < 0.004, RR 37, 95% CI 5.3-250). Median follow-up was 36 months. CONCLUSION: Cardiac device infection is a rare complication, with significant morbidity and mortality. Complete hardware removal with appropriate duration of antimicrobial therapy results in the best outcomes for patients.