Inter-atrial septal balloon dilation to facilitate intracardiac echocardiography guided left atrial appendage occlusion.

INTRODUCTION: Percutaneous left atrial appendage occlusion (LAAO) is traditionally performed under general anesthesia with trans-esophageal echocardiography guidance. Intracardiac echo (ICE)-guided LAAO closure is increasing in clinical use. The ICE catheter is crossed into LA via interatrial septum (IAS) after the septum is dilated with LAAO delivery sheath. This step can be time-consuming and requires significant ICE catheter manipulation, which increases the risk of cardiac perforation. Pre-emptive septal balloon dilation can potentially help with ICE advancement in the LA. We sought to evaluate the effect of pre-dilation of the IAS with an 8 mm balloon on the ease of crossing the ICE catheter, fluoroscopy time for crossing, and overall procedure time. METHODS: The Piedmont LAAO registry was used to identify consecutive patients who underwent LAAO. The initial 25 patients in whom balloon dilation of the IAS was performed served as the experimental cohort, and the 25 consecutive patients before that in whom balloon dilation was not performed served as controls. In the experimental group, after a trans-septal puncture, the sheath was retracted to the right atrium with a guidewire still in the LA. An 8 × 40 mm Evercoss™ over the wire balloon was inflated across the IAS. The ICE catheter was then crossed into the LA using the fluoroscopic landmark of the guide wire and the ICE imaging. The sheath was then advanced along the ICE catheter via the transseptal puncture (TSP) and the procedure continued. Follow-up compputed tomography imaging was obtained at 4-8 weeks. RESULTS: Each group consisted of 25 patients. There were no significant differences in baseline characteristics. All procedures were performed successfully under conscious sedation and ICE guidance. There was a significant reduction in the overall procedure time, fluoroscopy time, and time for transseptal puncture to ICE in LA. There was no difference in the size of the acute residual interatrial shunt, as measured via ICE, or the size and presence of iatrogenic ASD at follow-up. CONCLUSION: Balloon dilation of TSP is safe and is associated with increased efficiency in ICE-guided LAAO procedures.

Impact of intracardiac echocardiography versus transesophageal echocardiography guidance on left atrial appendage occlusion procedures: A meta-analysis.

BACKGROUND: Intracardiac echocardiography (ICE) is increasingly used during left atrial appendage occlusion (LAAO) as an alternative to transesophageal echocardiography (TEE). The objective of this study is to evaluate the impact of ICE versus TEE guidance during LAAO on procedural characteristics and acute outcomes, as well the presence of peri-device leaks and residual septal defects during follow-up. METHODS: All studies comparing ICE-guided versus TEE-guided LAAO were identified. The primary outcomes were procedural efficacy and occurrence of procedure-related complications. Secondary outcomes included lab efficiency (defined as a reduction in in-room time), procedural time, fluoroscopy time, and presence of peri-device leaks and residual interatrial septal defects (IASD) during follow-up. RESULTS: Twelve studies (n = 5637) were included. There were no differences in procedural success (98.3% vs. 97.8%; OR 0.73, 95% CI 0.42-1.27, p = .27; I2 = 0%) or adverse events (4.5% vs. 4.4%; OR 0.81 95% CI 0.56-1.16, p = .25; I2 = 0%) between the ICE-guided and TEE-guided groups. ICE guidance reduced in in-room time (mean-weighted 28.6-min reduction in in-room time) without differences in procedural time or fluoroscopy time. There were no differences in peri-device leak (OR 0.93, 95% CI 0.68-1.27, p = 0.64); however, an increased prevalence of residual IASD was observed with ICE-guided versus TEE-guided LAAO (46.3% vs. 34.2%; OR 2.23, 95% CI 1.05-4.75, p = 0.04). CONCLUSION: ICE guidance is associated with similar procedural efficacy and safety, but could result in improved lab efficiency (as established by a significant reduction in in-room time). No differences in the rate of periprocedural leaks were found. A higher prevalence of residual interatrial septal defects was observed with ICE guidance.

Intracardiac Echocardiography: An Invaluable Tool in Electrophysiological Interventions for Atrial Fibrillation and Supraventricular Tachycardia.

Researchers have investigated ways to develop optimal imaging techniques to increase the safety and effectiveness of electrophysiological (EP) procedures. Intracardiac echocardiography (ICE) is an advanced imaging tool that can directly visualize cardiac anatomical structures in high resolution, assess tissue heterogeneity and arrhythmogenic substrates, locate intracardiac catheters, monitor catheter-tissue contact and ablation injury in real-time, excluding intracardiac thrombi, and quickly detect procedural complications. Additionally, real-time imaging via ICE can be integrated with a three-dimensional (3D) electroanatomical mapping (EAM) system to reconstruct cardiac anatomy. This technique also promotes the development of zero-radiation EP procedures. Many EP studies and procedures have implemented ICE because it has several advantages over fluoroscopy and transesophageal echocardiography (TEE). ICE-guided EP procedures can be performed under conscious sedation; esophageal intubation and additional anesthesiologists are not required. Atrial fibrillation (AF) and supraventricular tachycardias (SVT) are the most common tachyarrhythmias in clinical settings. A comprehensive understanding of critical anatomical structures, such as the atrial septum, fossa ovalis (FO), and great heart vessels, is needed for the successful catheter ablation of these arrhythmias.

Radiofrequency Catheter Septal Ablation via a Trans-Atrial Septal Approach Guided by Intracardiac Echocardiography in Hypertrophic Obstructive Cardiomyopathy: One-Year Follow-Up.

Background: Percutaneous radiofrequency catheter ablation (RFA) in hypertrophic obstructive cardiomyopathy (HOCM) with intracardiac echocardiography (ICE) guidance is a novel method that has been proven to be safe and effective in a small sample size study. RFA of the interventricular septum through a trans-atrial septal approach in HOCM patients with a longer follow-up has not been reported. Methods: 62 consecutive patients from March 2019 to February 2022 were included in this study. The area between the hypertrophied septum and anterior mitral valve (MV) leaflet was established using the three-dimensional system (CARTO 3 system), and all patients received atrial septal puncture under the guidance of intracardiac echocardiography (ICE). Point-by-point ablation was performed to cover the contact area. After ablation, the patients were followed up for 1, 3, 6, and 12 months. Transthoracic echocardiography was performed at 1, 3, 6, and 12 months, and resting and exercise-provoked left ventricular outflow tract (LVOT) gradients were obtained. Results: During the 1-year follow-up, most patients' symptoms improved. The NYHA grading of the patient decreased from 2 (2, 3) at baseline to 2 (1, 2) (p < 0.001). LVOT peak gradient at rest was decreased from 59 ( ± 27) mmHg to 30 ( ± 24) mmHg (p < 0.001), and the provoked peak gradient was decreased from 99 ( ± 33) mmHg to 59 ( ± 34) mmHg (p < 0.001). The average maximum septal thickness was reduced from 21 ( ± 4) mm to 19 ( ± 4) mm (p < 0.001). Conclusions: After a 1-year follow-up, ice-guided radiofrequency ablation for HOCM might be a safe, accurate, and effective method. The catheter might be reliably attached to the ablation target area via trans-atrial septal access.

Clinical Results and Safety of Intracardiac Echocardiography Guidance for Combined Catheter Ablation and Left Atrial Appendage Occlusion.

Background: The goal of this study was to compare the procedural safety and long-term outcome associated with a combined catheter ablation and left atrial appendage occlusion (LAAO) procedure utilizing intracardiac echocardiography (ICE) guidance versus transesophageal echocardiography (TEE) guidance. The study focuses on implementing LAmbre and Watchman devices in patients diagnosed with nonvalvular atrial fibrillation (AF). Methods: A total of 363 patients diagnosed with nonvalvular AF and who underwent a combined procedure were prospectively enrolled between November 2017 and May 2022. Following 1:1 propensity score matching, the TEE group (n = 132) and ICE group (n = 132) were systematically compared in terms of the combined procedure, imaging parameters, events related to the procedure, and subsequent outcomes during follow-up, including mortality, stroke, bleeding, device-related thrombus (DRT), and peri-device leaks (PDLs). Results: The ICE group exhibited a significant reduction in total procedural duration (153.71 ± 31.71 vs. 174.74 ± 18.79 min), fluoroscopy radiation dosage (207.24 ± 108.39 vs. 268.61 ± 122.88 mGy), left atrial appendage occlusion procedure time (34.69 ± 10.91 vs. 51.46 ± 15.84 min), and contrast agent exposure (108.71 ± 37.59 vs. 158.41 ± 45.00 mL) compared to the TEE group. Angiography and ICE demonstrated a substantial correlation between the left atrial appendage (LAA) orifice and landing zone/LAA ostium (Pearson's correlation coefficient r = 0.808 and 0.536/0.697, two-tailed p < 0.001). No occurrences of device-related embolism, thromboembolism, significant bleeding, or unexpected fatalities were observed in either group. Comparable rates of all-cause death (0.76% vs. 0.76%), stroke or transient ischemic attack (2.27% vs. 1.52%), severe bleeding (1.52% vs. 0.76%), PDL (23.81% vs. 24.62%), and DRT (1.52% vs. 1.52%) were noted after an average follow-up of 18.46 ± 7.70 months in both groups, with no discernible differences. Multivariate logistic regression analysis identified a correlation between LAA velocity and the risk of PDL. Conclusions: The effectiveness and safety of ICE-guided combined treatment were demonstrated to be comparable to TEE guidance, accompanied by the additional advantages of decreased procedure time and fluoroscopy radiation exposure. Clinical Trial Registration: NCT04391504, https://register.clinicaltrials.gov.

Intracardiac echocardiography-guided biopsies for right-sided intracardiac tumors: An optimized diagnostic algorithm and case illustrations.

Intracardiac tumors, though uncommon, necessitate a swift and accurate diagnosis for personalized treatment and prognosis estimation. While multi-modality imaging often determines the etiology of these cardiac masses, histological confirmation remains essential for definitive diagnosis and its specific treatment. Since cardiac tumors are often found in high-risk locations (ventricular free wall or atria), precision biopsy is paramount. The least invasive strategy would be to achieve this by means of endomyocardial biopsy (EMB); however real-time additional imaging is essential to reduce the risk of perforation/tamponade and to minimize sampling error. Intracardiac echocardiography (ICE) emerges as an excellent tool to achieve this goal preventing procedural complications and reducing the likelihood of sampling errors obtaining a definitive histopathological diagnosis in all cases. This paper outlines our diagnostic algorithm for optimal patient selection, details three illustrative cases, and elucidates the steps to acquire histopathology via percutaneous transvenous biopsy with ICE guidance in patients with right-sided cardiac tumors. Given the rarity of intracardiac tumors, we advocate these patients be managed by a dedicated multidisciplinary cardio-oncology team including an interventional cardiologist.

Left atrial appendage occlusion and patent foramen ovale closure using a steerable sheath and intracardiac echocardiography.

A patient presenting with acute ischemic stroke associated with patent foramen ovale (PFO) had concurrent deep vein thrombosis, pulmonary embolism, and new-onset atrial fibrillation. Upon initiation of anticoagulation therapy, the patient developed hemorrhagic transformation of the stroke. The patient's multiple potential sources of embolic stroke were treated with concomitant left atrial appendage occlusion and PFO closure through the PFO, made possible by using the Steerable Amulet Sheath under 3D-intracardiac echocardiography guidance.

Midterm follow-up after computed tomography angiography planned left atrial appendage closure.

BACKGROUND: While studies have shown the advantages of computed tomography angiography (CTA) over transesophageal echocardiography (TEE) in left atrial appendage closure (LAAC) preprocedural planning for WATCHMAN™ legacy and FLX devices, there has been no reported long-term data for this approach. OBJECTIVES: We sought to evaluate long-term outcomes using CTA-based preprocedural planning for LAAC using the WATCHMAN™ device. METHODS: A prospective analysis of 231 consecutive patients who underwent LAAC in a single, large academic hospital in the United States was conducted over a 5-year period. CTA-guided preprocedural planning was performed in all. Procedural success, adverse events, length of procedure, number of devices used, and length of stay were evaluated. Rates of death, cerebral embolism, systemic embolism, and major and minor bleeding were recorded. Adjusted predicted stroke and major bleeding rates were derived from CHA2DS2-Vasc and HAS-BLED scores, respectively. RESULTS: From January 26, 2017, to November 23, 2021, 231 patients underwent LAAC with CTA preprocedural planning by two operating physicians. The mean age of patients was 76.5 ± 8.4. 59.7% of patients were male. Mean CHA2DS2VASc and HAS-BLED scores were 4.5 ± 1.4 and 3.9 ± 0.9, respectively. All procedures were performed with intracardiac echo (100%). The procedural success rate was 99.1%. The CTA sizing strategy accurately predicted the implant size in 93.5% of patients. Mean number of devices used was 1.10 ± 0.3. Peri-procedural complication rate was 2.2%. 6 patients were lost to follow-up. Mean follow-up was 608.94 days with a total of 377.04 patient years. Median follow-up period of 368 days (interquartile range: 209-1067 days). There were 51 deaths from all causes (13.52 per 100 patient-years), 10 cases of cerebral embolism (2.65 per 100 patient-years), 2 cases of systemic embolism (0.53 per 100 patient-years), 17 cases of major bleeding (4.50 per 100 patient-years), and 31 cases of minor bleeding (8.2 per 100 patient-years). All-cause mortality at 1, 2, and 3 years was 12.7%, 20.9%, and 29.2%, respectively. CV event rates at 1, 2, and 3 years were 2.1%, 6.6%, and 10.5%, respectively. CONCLUSIONS: CTA-based preprocedural planning is accurate in predicting device size for LAAC and associated with excellent clinical outcomes at 5 years.

Intracardiac echocardiography in paediatric and congenital cardiac ablation shortens procedure duration and improves success without complications.

AIMS: Common to adult electrophysiology studies (EPSs), intracardiac echocardiography (ICE) use in paediatric and congenital heart disease (CHD) EPS is limited. The purpose of this study was to assess the efficacy of ICE use and incidence of associated complications in paediatric and CHD EPS. METHODS AND RESULTS: This single-centre retrospective matched cohort study reviewed EPS between 2013 and 2022. Demographics, CHD type, and EPS data were collected. Intracardiac echocardiography cases were matched 1:1 to no ICE controls to assess differences in complications, ablation success, fluoroscopy exposure, procedure duration, and arrhythmia recurrence. Cases and controls with preceding EPS within 5 years were excluded. Intracardiac echocardiography cases without an appropriate match were excluded from comparative analyses but included in the descriptive cohort. We performed univariable and multivariable logistic regression to assess associations between variables and outcomes. A total of 335 EPS were reviewed, with ICE used in 196. The median age of ICE cases was 15 [interquartile range (IQR) 12-17; range 3-47] years, and median weight 57 [IQR 45-71; range 15-134] kg. There were no ICE-related acute or post-procedural complications. There were 139 ICE cases matched to no ICE controls. Baseline demographics and anthropometrics were similar between cases and controls. Fluoroscopy exposure (P = 0.02), procedure duration (P = 0.01), and arrhythmia recurrence (P = 0.01) were significantly lower in ICE cases. CONCLUSION: Intracardiac echocardiography in paediatric and CHD ablations is safe and reduces procedure duration, fluoroscopy exposure, and arrhythmia recurrence. However, not every arrhythmia substrate requires ICE use. Thoughtful selection will ensure the judicious and strategic application of ICE to enhance outcomes.

Long-term outcomes of catheter ablation for ventricular arrhythmias: comparing techniques with and without intracardiac echocardiography - what matters?

BACKGROUND: The increasing use of intracardiac echocardiography (ICE) in the ablation of premature ventricular complexes (PVCs) has raised questions about its true efficacy and safety. METHODS: This retrospective study collected the periprocedural complications and PVC burden post ablation. The risk factors of PVC recurrence was further explored. RESULTS: The study included patients treated without ICE (control group, n = 451) and with ICE (ICE group, n = 155) from May 2019 to July 2022. The ICE group demonstrated significantly lower fluoroscopy times and X-ray doses. There were no major complications in the ICE group, and the difference in the occurrence of periprocedural complications between the groups was not statistically significant (p = 0.072). The long-term success rates were similar for the control and ICE groups (89.6% and 87.1%, respectively). The origin of PVCs was identified as the independent factor for ablation success. CONCLUSIONS: The use of ICE did not confer an advantage with regard to long-term success in PVCs ablation. To thoroughly evaluate the safety and effectiveness of ICE in PVCs ablation, a prospective, multicenter, randomized study is warranted.

Second Micra leadless pacemaker implantation by using intracardiac echocardiography.

The strategy after battery depletion was not established in Micra leadless pacemaker system (Micra). There are still some concerns in the 2nd Micra implantation, such as the mechanical interaction between both devices. The position of the 2nd Micra should be placed apart from the 1st Micra. We present a case of 1st Micra battery depletion who successfully underwent the 2nd Micra implantation under the intracardiac echo guidance. In our case, intracardiac echo was a very effective tool for confirming the location of Micra implantation.

Randomized Controlled Trial Comparing Training of Transseptal Puncture With or Without Intracardiac Echocardiography.

BACKGROUND: Intracardiac echocardiography (ICE) has been widely used in the catheter ablation of atrial fibrillation (AF). However, the value of ICE in the training of transseptal puncture (TSP) is unclear. METHODS: ICE-Training Study was a single-center, parallel-group, unmasked, randomized controlled trial registered in ChineseClinicalTrials.gov. Participants were randomly assigned (1:1) to different groups (1) the ICE simulator training group (ICE-ST), in which TSP was trained and performed under the guidance of both ICE and x-ray; and (2) the conventional simulator training group (Con-ST), in which TSP was trained and performed only under the guidance of x-ray. The trainees need to undergo the training stage and the evaluation stage. RESULTS: From October 2022 to December 2022, 18 consecutive fellows (age 32.4 ± 4.4 years, 12 males) without experience of TSP were included. The training period (16.9 ± 6.6 vs. 29.6 ± 8.7 times, p = 0.003) and the fluoroscopy time (120.3 ± 25.3 vs. 189.3 ± 40.2 s, p < 0.001) of the ICE-ST group was significantly shorter than that of the Con-ST group. No significant difference was found in the comprehensive performance of TSP in the ICE-ST group (composite score 96.7 ± 5.7) and the Con-ST group (composite score 95.9 ± 6.3, p = 0.62), but the selection of TSP sites in the ICE-ST group was commonly better than that in the Con-ST group. CONCLUSIONS: ICE could improve the efficiency of TSP training and optimize the site of TSP to facilitate catheter manipulation in the ablation. TRIAL REGISTRATION: ChineseClinicalTrials.gov identifier: ChiCTR2200058377.

Zero-fluoroscopy ablation with multielectrode pulse field ablation system: Case series.

Pulse field ablation (PFA) is a novel nonthermal ablation modality for treatment of atrial fibrillation. While mostly lacking 3D electroanatomical mapping integration, reported radiation doses in procedures using multielectrode PFA catheters are relatively high. We report a first case series of three patients where a zero-fluoroscopy approach by intracardiac echocardiography was utilized and present a possible workflow for zero-fluoroscopy ablation with the Farapulse PFA system.

Intracardiac echocardiography-guided catheter ablation of highly symptomatic accelerated idioventricular rhythm originating from the right ventricular apical diverticulum.

Ventricular diverticula are saccule-like structures formed by the protrusion of the ventricular myocardium from the endocardial surface towards the free wall. Most diverticula are muscular structures, and patients usually have no obvious clinical symptoms. However, diverticula may contribute to arrhythmogenesis due to localized myocardial structural disturbances. Right ventricular apical diverticulum (RVAD) is very rare, and we report a case of highly symptomatic accelerated idioventricular rhythm (AIVR) originating from the RVAD that underwent intracardiac echocardiography (ICE)-guided catheter ablation with no recurrence during follow-up.

Intracardiac echocardiography guided electrified J-wire trans-septal puncture: A prospective randomized controlled trial.

BACKGROUND: Application of electrocautery to a J-wire is used to perform transseptal puncture (TSP), but with limited evidence supporting safety and efficacy. We conducted a prospective randomized controlled trial to evaluate the safety and efficacy of this technique. METHODS: Two hundred consecutive patients were randomized in a 1:1 fashion to either the ICE-guided electrified J-wire TSP group or a conventional Brockenbrough (BRK) needle TSP group. The TSP was performed with a 0.032″ guidewire under 20 W, "coag" mode and was compared to TSP using the BRK needle. The primary safety endpoints were complications related to TSP. The primary efficacy endpoints included the TSP success rate, the total TSP time, and the total procedure time. RESULTS: All patients complete the procedure safely. The electrified J-wire TSP group had a significantly shorter TSP time than BRK needle TSP group. The total procedure time, number of TSP attempts required to achieve successful LA access, width of the intra-atrial shunt at the end of ablation were similar between the two groups. The incidence of new cerebral infarction detected by MRI were similar between the two groups (3/32 patients in the J-wire TSP group and 2/26 patients in conventional BRK TSP group, p = .82). And no difference in the incidence of residual intra-atrial shunt (4.3% vs. 6%, p = .654) during the 3-month's follow up. CONCLUSION: Using an electrified J-wire for TSP under the guidance of ICE appears to be as safe as and more efficient than conventional BRK needle TSP, which may be especially useful in the era of non-fluoroscopy AF ablation.

A comparison of intracardiac echocardiography and transesophageal echocardiography for guiding device closure of ostium secundum atrial septal defect: A 15-year experience.

BACKGROUND AND AIM: Our aim was to evaluate the fluoroscopy time (FT), procedure time (PT) safety and efficacy when using intracardiac echocardiography (ICE) in comparison to transesophageal echocardiography (TEE) guidance for transcatheter closure of Ostium Secundum Atrial Septal Defect (OS-ASD). METHOD: Ninety patients (n = 90) diagnosed with OS-ASD underwent transcatheter closure between March 2006 and October 2021. Fifty-seven patients were treated under ICE guidance, while 33 patients were treated under TEE guidance. RESULTS: Mean age was 43 ± 15 years and 42 ± 10 years in the ICE and TEE groups, respectively. The majority of patients had a centrally placed defect. Median FT was 8.40 min versus 11.70 min (p < .001) in the ICE group compared to the TEE group, respectively. Median PT was 43 min versus 94 min (p < .001) in the ICE group compared to the TEE group, respectively. Both ICE and TEE provided high quality images. All interventions were completed successfully, except for one patient in the ICE group who experienced a device migration, the development of atrial tachycardia in one patient and atrial fibrillation in two patients in the ICE group which spontaneously cardioverted. There were no other complications. CONCLUSION: This study on a consistent cohort of patients with OS-ASD undergoing percutaneous closure suggests that use of ICE is safe and efficacious. Compared to TEE, ICE demonstrated significantly shorter FT and PT, decreasing the entire duration of the procedure and x-ray exposure. No relevant differences were observed in terms of success rate and complications.

The use of Intracardiac Echocardiography in Catheter Ablation of Atrial Fibrillation.

PURPOSE OF THE REVIEW: Intracardiac echocardiography (ICE) provides real-time, fluoroless imaging of cardiac structures, allowing optimal catheter positioning and energy delivery during ablation procedures. This review summarizes the use of ICE in catheter ablation of atrial fibrillation (AF). RECENT FINDINGS: Growing evidence suggests that the use of ICE improves procedural safety and facilitates radiofrequency and cryoballoon AF ablation. ICE-guided catheter ablation is associated with reduced procedural duration and fluoroscopy use. Recent studies have examined the role of ICE in guiding novel ablation techniques, such as pulsed field ablation. Finally, the use of ICE allows for early detection and timely management of potentially serious procedural complications. Intracardiac echocardiography offers significant advantages during AF ablation procedures and its use should be encouraged to improve procedural safety and efficacy.

Fontan Fenestration Reduction with an Occlutech Atrial Flow Regulator: Unique Views from Three-Dimensional Intracardiac Echocardiography.

Three-dimensional intracardiac echocardiography (3D ICE) has gained popularity in interventional cardiology given its improved spatial and temporal imaging in assessing intracardiac anatomy pre- and post-intervention. We describe the use of 3D ICE in the reduction of a Fontan fenestration with an Occlutech atrial flow regulator (AFR) device.

Two distinct stages and mechanisms of ST-elevation during cryothermal cavotricuspid isthmus ablation guided by intracardiac echocardiography: A case report.

Radiofrequency (RF) catheter ablation is the primary treatment for cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), with cryothermal energy as an alternative. While cryoablation offers comparable effectiveness and safety to RF ablation, it poses a risk of coronary artery spasm leading to ST-elevation. This case report presents a 65-year-old man with drug-refractory atrial fibrillation (AF) and AFL undergoing cryothermal CTI ablation guided by intracardiac echocardiography (ICE). During the procedure, two distinct ST-elevation episodes were observed. The first episode coincided with the pull-down of the cryoablation catheter, potentially resulting in coronary compression, as indicated by ICE, and was rapidly resolved by discontinuing the freezing process. The second episode, occurring without active freezing, was attributed to coronary artery spasm and resolved with intracoronary nitroglycerin administration. During the second episode, emergent right coronary angiography confirmed total occlusion in the segment 4 AV adjacent to the region where cryoablation was performed, which fully resolved post-nitroglycerin. This report underscores the dual mechanisms of ST-elevation-coronary artery compression and spasm-during cryothermal CTI ablation, highlighting the critical role of ICE in enhancing procedural safety.

Correlation of spatial patterns of endocardial pace mapping to underlying scar topography in patients with scar-related ventricular tachycardia.

INTRODUCTION: Endocardial pace mapping (PM) can identify conducting channels for ventricular tachycardia (VT) circuits in patients with structural heart disease (SHD). Recent findings show the temporal and spatial pattern of PM may aid identification of the surface harboring VT isthmii. The specific correlation of PM patterns to scar topography has not been examined. OBJECTIVE: To correlate the pattern of endocardial PMs to underlying scar topography in SHD patients with VT. METHODS: Data from patients undergoing VT ablation from August 2018 to February 2022 were reviewed. RESULTS: Sixty-three patients with SHD-related VT (mean age 65 ± 14 years) with 83 endocardial PM correlation maps were analysed. Two main correlation patterns were identified, an "abrupt-change correlation pattern (AC-pattern)" and "centrifugal-attenuation correlation pattern (CA-pattern)." AC-pattern had lower scar ratio (unipolar/bipolar % scar area; 1.1 vs. 1.5, p < .001), had longer maximal stimulus-QRS intervals (97.5 vs. 68 ms, p = .002), and higher likelihood of endocardial dominant scar (11/21 [52%] vs. 3/38 [8%], p < .001) than CA-pattern seen on intracardiac echocardiography (ICE). In contrast, CA-pattern was more likely to have epicardial dominant scar or mid-intramural scar on ICE (epicardial dominant scar; CA-pattern: 12/38 [32%] vs. AC-pattern: 1/21 [5%], p = .02, mid-intramural scar; CA-pattern: 15/38 [39%] vs. AC-pattern: 1/21 [5%], p = .005). CONCLUSIONS: The spatial pattern of endocardial PM in SHD-related VT directly correlates with scar topography. AC-pattern is associated with endocardial dominant scar on ICE with lower scar ratio and longer stimulus-QRS intervals, whereas CA-pattern is strongly associated with epicardial dominant or mid-intramural scar with higher scar ratio and shorter stimulus-QRS intervals.