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The author discusses a study which examined the anatomical and conduction properties of regions of late ventricular myocardial activation during intrinsic rhythm and their correspondence with induced ventricular tachycardia (VT) circuits in 36 patients using the Intellamap Orion high-resolution mapping catheter and Rhythmia Hdx mapping system. Topics include description of the scar patterns and reason that voltage mapping has fallen out of favor in parts of the electrophysiology community.

Abstract: Background: Postablation reentrant ATs depend upon conducting isthmuses bordered by scar. Bipolar voltage maps highlight scar as sites of low voltage, but the voltage amplitude of an electrogram depends upon the myocardial activation sequence. Furthermore, a voltage threshold that defines atrial scar is unknown. We used Ripple Mapping (RM) to test whether these isthmuses were anatomically fixed between different activation vectors and atrial rates. Methods: We studied post‐AF ablation ATs where >1 rhythm was mapped. Multipolar catheters were used with CARTO Confidense for high‐density mapping. RM visualized the pattern of activation, and the voltage threshold below which no activation was seen. Isthmuses were characterized at this threshold between maps for each patient. Results: Ten patients were studied (Map 1 was AT1; Map 2: sinus 1/10, LA paced 2/10, AT2 with reverse CS activation 3/10; AT2 CL difference 50 ± 30 ms). Point density was similar between maps (Map 1: 2,589 ± 1,330; Map 2: 2,214 ± 1,384; P  =  0.31). RM activation threshold was 0.16 ± 0.08 mV. Thirty‐one isthmuses were identified in Map 1 (median 3 per map; width 27 ± 15 mm; 7 anterior; 6 roof; 8 mitral; 9 septal; 1 posterior). Importantly, 7 of 31 (23%) isthmuses were unexpectedly identified within regions without prior ablation. AT1 was treated following ablation of 11/31 (35%) isthmuses. Of the remaining 20 isthmuses, 14 of 16 isthmuses (88%) were consistent between the two maps (four were inadequately mapped). Wavefront collision caused variation in low voltage distribution in 2 of 16 (12%). Conclusions: The distribution of isthmuses and nonconducting tissue within the ablated left atrium, as defined by RM, appear concordant between rhythms. This could guide a substrate ablative approach. [ABSTRACT FROM AUTHOR]

Background Ripple mapping (RM) displays electrograms as moving bars over a three-dimensional surface displaying bipolar voltage, and has shown in a single-center series to be effective for atrial tachycardia (AT) mapping without annotation of local activation time or window-of-interest assignment. We tested the reproducibility of these findings in operators naïve to RM, using it for the first time in postablation AT. Methods Maps were collected with multielectrode catheters and CARTO ConfiDENSE. A diagnosis of the tachycardia mechanism was made using RM and an assessment of operator confidence was made according to a three-grade scale (1 highest-3 lowest). Results The first 20 patients (64 ± 9 years, median two previous ablations) undergoing RM-guided AT ablation across five sites were studied. High-density maps (2,935 ± 1,328 points) in AT (CL = 296 ± 95 milliseconds) were collected. Macroreentrant ATs bordered by scar or anatomical obstacles were identified in n = 12 (60%), small reentrant ATs around scar in n = 3 (15%), and focal ATs from scar in n = 5 (25%). Diagnostic confidence with RM was grade 1 in n = 13 (65%), where operators felt confident to proceed to ablation without entrainment. Ablation offered the correct diagnosis n = 18 (90%). Retrospective review of the accompanying LAT maps demonstrated potential sources for error related to the window of interest selection, interpolation, and differentiating regions of scar during tachycardia on the voltage map. Conclusion RM was easy to adopt by operators using it for the first time, and identified the correct target for ablation with high diagnostic confidence in most cases of complex AT. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 46-year-old man with a history of sudden onset-offset palpitations and referred for electrophysiological study. Also discusses the positioning of quadripolar catheter at the high right atrium (HRA), and diagnosis of atrial fibrillation after electrocardiogram revealing irregular narrow complex tachycardia.

Objectives: Since 2005, newly qualified doctors in the UK have had their time to prepare for career subspecialization application cut short to 16 months. To have enough time to become a competitive applicant, the choice of specialization may now have to be made as early as in medical school. This study aimed to assess how prepared medical students are towards committing to a specialty while in medical school, and their opinion about having to make such a decision. Design: A cross-sectional questionnaire. A list of all career specialties available to doctors at the point of specialization was provided and asked students to rank their top choice. An assessment of the certainty of their choice was then determined. Setting: Questionnaires were distributed at the end of an optional final year medical student academic meeting held at a leading London medical school university. Participants: One hundred and thirty final year students attended the meeting. Questionnaires were distributed to all attenders; 115 responses were collected. Main outcome measures: The certainty of career specialization choice was assessed in qualitative form, with responses ranging from 'not likely', 'maybe', 'probably', 'almost certainly' and 'definitely'. Their feelings in having to decide upon career specialty while in medical school was assessed through either a 'yes' or 'no' response. Results: A total of 115 responses were collected. The second most common selection was the 'undecided' option at 15%. The highest certainty factor occurred at 'maybe' with 41% and progressively fewer responses occurred as the certainty factor increased, with only 10% at 'definitely'; 95% voted 'no' to having to decide what they want to specialize in by the end of medical school. Conclusions: The majority of students have yet to commit to a specialty and almost all agree that they should not have to decide what they want to specialize in by the end of medical school. There is thus greater responsibility from medical schools to incorporate more career discussions into their syllabus. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Access site complications remain common following atrial fibrillation (AF) catheter ablation. Femoral vascular closure devices (VCDs) reduce time to hemostasis compared with manual compression, although large‐scale data comparing clinical outcomes between the two approaches are lacking.Two cohorts of patients undergoing AF ablation were identified from 36 healthcare organizations using a global federated research network (TriNetX): those receiving a VCD for femoral hemostasis, and those not receiving a VCD. A 1:1 propensity score matching (PSM) model based on baseline characteristics was used to create two comparable cohorts. The primary outcome was a composite of all‐cause mortality, vascular complications, bleeding events, and need for blood transfusion. Outcomes were assessed during early (within 7 days of ablation) and extended follow‐up (within 8–30 days of ablation).After PSM, 28 872 patients were included (14 436 in each cohort). The primary composite outcome occurred less frequently in the VCD cohort during early (1.97% vs. 2.60%, odds ratio (OR) 0.76, 95% confidence interval (CI) 0.65–0.88; p < .001) and extended follow‐up (1.15% vs. 1.43%, OR 0.80, 95% CI 0.65–0.98; p = .032). This was driven by a lower rate of vascular complications during early follow‐up in the VCD cohort (0.83% vs. 1.26%, OR 0.66, 95% CI 0.52–0.83; p < .001), and fewer bleeding events during early (0.90% vs. 1.23%, OR 0.73, 95% CI 0.58–0.92; p = .007) and extended follow‐up (0.36% vs. 0.59%, OR 0.61, 95% CI 0.43–0.86; p = .005).Following AF ablation, femoral venous hemostasis with a VCD was associated with reduced complications compared with hemostasis without a VCD. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centers, and deep sedation is prohibited in some countries without anaesthetic support. Very high‐power short duration (vHPSD—90W/4 s) PVI using the Q‐Dot catheter is generally well tolerated under mild conscious sedation (MCS) though an understanding of catheter stability and long‐term effectiveness is lacking. We analyzed lesion metrics and 12‐month freedom from atrial arrythmia with this approach. Methods: Our approach to radiofrequency (RF) PVI under MCS is standardized and includes a single catheter approach with a steerable sheath. We identified patients undergoing Q‐Dot RF PVI between March 2021 and December 2022 in our center, comparing those undergoing vHPSD ablation under MCS (90W/MCS) against those undergoing 50 W ablation under GA (50 W/GA) up to 12 months of follow‐up. Data were extracted from clinical records and the CARTO system. Results: Eighty‐three patients met our inclusion criteria (51 90W/MCS; 32 50 W/GA). Despite shorter ablation times (353 vs. 886 s; p <.001), the 90 W/MCS group received more lesions (median 87 vs. 58, p <.001), resulting in similar procedure times (149.3 vs. 149.1 min; p =.981). PVI was achieved in all cases, and first pass isolation rates were similar (left wide antral circumferential ablation [WACA] 82.4% vs. 87.5%, p =.758; right WACA 74.5% vs. 78.1%, p =.796; 90 W/MCS vs. 50 W/GA respectively). Analysis of 6647 ablation lesions found similar mean impedance drops (10.0 ± 1.9 Ω vs. 10.0 ± 2.2 Ω; p =.989) and mean contact force (14.6 ± 2.0 g vs. 15.1 ± 1.6 g; p =.248). Only median 2.5% of lesions in the 90 W/MCS cohort failed to achieve ≥ 5 Ω drop. In the 90 W/MCS group, there were no procedural related complications, and 12‐month freedom from atrial arrhythmia was observed in 78.4%. Conclusion: vHPSD PVI is feasible under MCS, with encouraging acute and long‐term procedural outcomes. This provides a compelling option for centers with limited anaesthetic support. [ABSTRACT FROM AUTHOR]

A case study of 78-year-old male underwent radiofrequency ablation for symptomatic outflow tract ventricular tachycardia is presented. Topics discussed include nonclinical rhythm requiring immediate electrical cardioversion, centrifugal activation away from the septum, and nonclinical rhythm requiring immediate electrical cardioversion.

An answer to a question related to cause of recurrent blackouts is presented.

Introduction We hypothesized that very high-density mapping of typical atrial flutter (AFL) would facilitate a more complete understanding of its circuit. Such very high-density mapping was performed with the RhythmiaTM (Boston Scientific) mapping system using its 64 electrode basket catheter. Methods and results Data were acquired from 13 patients in AFL. Functional anatomy of the right atrium (RA) was readily identified during mapping including the Crista Terminalis and Eustachian ridge. The leading edge of the activation wavefront was identified without interruption and its conduction velocity (CV) was calculated. CV was not different at the cavotricuspid isthmus (CTI) compared to the remainder of the RA (1.02 vs. 1.03 m/s, P = 0.93). The sawtooth pattern of the surface electrocardiogram (EKG) flutter waves was compared to the position of the dominant wavefront. The downslope of the surface EKG flutter waves represented on average 73% ± 9% of the total flutter cycle length. During the downslope, the activation wavefront traveled significantly further than during the upslope (182 ± 21 milliseconds vs. 68 ± 29 milliseconds, P < 0.0001) with no change in CV between the two phases (0.88 vs. 0.91 m/s, P = 0.79). Conclusion CV at the CTI is not slower than other RA regions during typical AFL. The gradual downslope of the sawtooth EKG is not due to slow conduction at the CTI suggesting that success of ablation at this site relates to anatomical properties rather than the presence of a 'slow isthmus.' [ABSTRACT FROM AUTHOR]

Background: Ventricular scar is traditionally highlighted on a bipolar voltage (BiVolt) map in areas of myocardium <0.50 mV. We describe an alternative approach using Ripple Mapping (RM) superimposed onto a BiVolt map to differentiate postinfarct scar from conducting borderzone (BZ) during ventricular tachycardia (VT) ablation. Methods: Fifteen consecutive patients (left ventricular ejection fraction 30 ± 7%) underwent endocardial left ventricle pentaray mapping (median 5148 points) and ablation targeting areas of late Ripple activation. BiVolt maps were studied offline at initial voltage of 0.50–0.50 mV to binarize the color display (red and purple). RMs were superimposed, and the BiVolt limits were sequentially reduced until only areas devoid of Ripple bars appeared red, defined as RM‐scar. The surrounding area supporting conducting Ripple wavefronts in tissue <0.50 mV defined the RM‐BZ. Results: RM‐scar was significantly smaller than the traditional 0.50 mV cutoff (median 4% vs. 12% shell area, p <.001). 65 ± 16% of tissue <0.50 mV supported Ripple activation within the RM‐BZ. The mean BiVolt threshold that differentiated RM‐scar from BZ tissue was 0.22 ± 0.07 mV, though this ranged widely (from 0.12 to 0.35 mV). In this study, septal infarcts (7/15) were associated with more rapid VTs (282 vs. 347 ms, p =.001), and had a greater proportion of RM‐BZ to RM‐scar (median ratio 3.2 vs. 1.2, p =.013) with faster RM‐BZ conduction speed (0.72 vs. 0.34 m/s, p =.001). Conversely, scars that supported hemodynamically stable sustained VT (6/15) were slower (367 ± 38 ms), had a smaller proportion of RM‐BZ to RM‐scar (median ratio 1.2 vs. 3.2, p =.059), and slower RM‐BZ conduction speed (0.36 vs. 0.63 m/s, p =.036). RM guided ablation collocated within 66 ± 20% of RM‐BZ, most concentrated around the RM‐scar perimeter, with significant VT reduction (median 4.0 episodes preablation vs. 0 post, p <.001) at 11 ± 6 months follow‐up. Conclusion: Postinfarct scars appear significantly smaller than traditional 0.50 mV cut‐offs suggest, with voltage thresholds unique to each patient. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 50 year old woman who complained of anginal sounding chest discomfort at rest and upon further examining her coronary angiography revealed two-vessel spontaneous coronary artery dissection (SCAD).

Background Ripple Mapping (RM) is designed to overcome the limitations of existing isochronal 3D mapping systems by representing the intracardiac electrogram as a dynamic bar on a surface bipolar voltage map that changes in height according to the electrogram voltage–time relationship, relative to a fiduciary point. Objective We tested the hypothesis that standard approaches to atrial tachycardia CARTO™ activation maps were inadequate for RM creation and interpretation. From the results, we aimed to develop an algorithm to optimize RMs for future prospective testing on a clinical RM platform. Methods CARTO-XP™ activation maps from atrial tachycardia ablations were reviewed by two blinded assessors on an off-line RM workstation. Ripple Maps were graded according to a diagnostic confidence scale (Grade I — high confidence with clear pattern of activation through to Grade IV — non-diagnostic). The RM-based diagnoses were corroborated against the clinical diagnoses. Results 43 RMs from 14 patients were classified as Grade I (5 [11.5%]); Grade II (17 [39.5%]); Grade III (9 [21%]) and Grade IV (12 [28%]). Causes of low gradings/errors included the following: insufficient chamber point density; window-of-interest < 100% of cycle length (CL); < 95% tachycardia CL mapped; variability of CL and/or unstable fiducial reference marker; and suboptimal bar height and scar settings. Conclusions A data collection and map interpretation algorithm has been developed to optimize Ripple Maps in atrial tachycardias. This algorithm requires prospective testing on a real-time clinical platform. [ABSTRACT FROM AUTHOR]

Epicardial ganglionated plexuses (GP) have an important role in the pathogenesis of atrial fibrillation (AF). The relationship between anatomical, histological and functional effects of GP is not well known. We previously described atrioventricular (AV) dissociating GP (AVD-GP) locations. In this study, we hypothesised that ectopy triggering GP (ET-GP) are upstream triggers of atrial ectopy/AF and have different anatomical distribution to AVD-GP. We mapped and characterised ET-GP to understand their neural mechanism in AF and anatomical distribution in the left atrium (LA). 26 patients with paroxysmal AF were recruited. All were paced in the LA with an ablation catheter. High frequency stimulation (HFS) was synchronised to each paced stimulus for delivery within the local atrial refractory period. HFS responses were tagged onto CARTO™ 3D LA geometry. All geometries were transformed onto one reference LA shell. A probability distribution atlas of ET-GP was created. This identified high/low ET-GP probability regions. 2302 sites were tested with HFS, identifying 579 (25%) ET-GP. 464 ET-GP were characterised, where 74 (16%) triggered ≥30s AF/AT. Median 97 (IQR 55) sites were tested, identifying 19 (20%) ET-GP per patient. >30% of ET-GP were in the roof, mid-anterior wall, around all PV ostia except in the right inferior PV (RIPV) in the posterior wall. ET-GP can be identified by endocardial stimulation and their anatomical distribution, in contrast to AVD-GP, would be more likely to be affected by wide antral circumferential ablation. This may contribute to AF ablation outcomes. • ET-GP can be stimulated endocardially using high frequency stimulation within the local atrial refractory period. • ET-GP stimulation displays a wide range of responses from single ectopy to sustained AF and occasionally AV block. • ET-GP have distinct anatomical regions in patients with AF, and their distribution contrasts that of AV dissociating GP. • Most ET-GP are in the roof/PV ostia and inadvertently ablated during PVI. This may contribute to AF ablation success. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article related two-vessel spontaneous coronary artery dissection and acute coronary syndrome published in July 25, 2013 issue of the periodical.