Intraoperative Pectoral Nerve Blocks During Cardiac Implantable Electronic Device Procedures.

BACKGROUND: Cardiac implantable electronic device (CIED) procedures can cause significant post-operative pain. Opioid use for post-operative pain is associated with risk of persistent use. The benefits of pectoral nerve blocks (PECs) have been established for other chest wall surgeries but adoption in electrophysiology has been limited. OBJECTIVES: To evaluate the efficacy of intraoperative ultrasound guided PECs performed at the time of CIED procedures by the implanting physician from within the device pocket. METHODS: Patients undergoing a pectoral CIED procedure at 7 centers from 2022-2023 were included. Patients underwent intraoperative PECs and subcutaneous local anesthetic vs subcutaneous local anesthetic only at the discretion of the operator. Patients were prospectively evaluated for post-operative pain. RESULTS: 610 patients (67±15 years old, 63% male) were enrolled and half (n=305) underwent PECs. Patients who underwent PECs were more likely to have a history of chronic pain (32 vs 11%, p<0.001). PECs was associated with lower pain scores in the 4 hours after the procedure (1.5±2.1 vs 4.5±2.5, p<0.001). Pain scores were not different after 24-hours (2.8±1.7 vs 3.1±2.2) and 2-weeks (0.9±1.4 vs 0.9±1.2). PECs patients were less likely to receive inpatient opioids (10 vs 48%, p<0.001) and to be discharged with an opioid prescription (15 vs 59%, p<0.001). In multivariable linear regression, PECs (p<0.001), age (p=0.002) and absence of chronic pain (p=0.009) were associated with lower acute post-operative pain. CONCLUSIONS: Intraoperative PECs can reduce post operative pain and opioid use. This procedure can be readily performed by the implanting physician from within the device pocket.

Value of high-output pace-mapping of the right phrenic nerve for enabling safe radiofrequency ablation of atrial fibrillation: insights from three-dimensional computed tomography segmentation.

AIMS: Right phrenic nerve (RPN) injury is a disabling but uncommon complication of atrial fibrillation (AF) radiofrequency ablation. Pace-mapping is widely used to infer RPN's course, for limiting the risk of palsy by avoiding ablation at capture sites. However, information is lacking regarding the distance between the endocardial sites of capture and the actual anatomic RPN location. We aimed at determining the distance between endocardial sites of capture and anatomic CT location of the RPN, depending on the capture threshold. METHODS AND RESULTS: In consecutive patients undergoing AF radiofrequency ablation, we defined the course of the RPN on the electroanatomical map with high-output pacing at up to 50 mA/2 ms, and assessed RPN capture threshold (RPN-t). The true anatomic course of the RPN was delineated and segmented using CT scan, then merged with the electroanatomical map. The distance between pacing sites and the RPN was assessed. In 45 patients, 1033 pacing sites were analysed. Distances from pacing sites to RPN ranged from 7.5 ± 3.0 mm (min 1) when RPN-t was ≤10 mA to 19.2 ± 6.5 mm (min 9.4) in cases of non-capture at 50 mA. A distance to the phrenic nerve > 10 mm was predicted by RPN-t with a ROC curve area of 0.846 [0.821-0.870] (P < 0.001), with Se = 80.8% and Sp = 77.5% if RPN-t > 20 mA, Se = 68.0% and Sp = 91.6% if RPN-t > 30 mA, and Se = 42.4% and Sp = 97.6% if non-capture at 50 mA. CONCLUSION: These data emphasize the utility of high-output pace-mapping of the RPN. Non-capture at 50 mA/2 ms demonstrated very high specificity for predicting a distance to the RPN > 10 mm, ensuring safe radiofrequency delivery.

Incidental ablation of ganglionated plexus during atrial fibrillation ablation.

BACKGROUND: Cardioneuroablation targeting the autonomic nerves within ganglionated plexus (GP) has been used to treat atrial fibrillation (AF). Incidental cardioneuroablation may be an important mechanism by which pulmonary vein isolation (PVI) is effective. Automated fractionation mapping software can identify regions of fractionation correlating with GP locations. OBJECTIVE: To examine the overlap between standard PVI ablation lesions and fractionated electrograms suggestive of GP. METHODS: We retrospectively examined AF ablations performed from 2021 to 2023 that included only PVI performed using wide antral circumferential isolation without prospective evaluation of fractionation. Retrospectively, a fractionation map was created (width 10 ms, refractory time 30 ms, roving sensitivity 0.1 mv, and threshold of 2). We evaluated the anatomic overlap between PVI lesions and fractionation in regions associated with GP. RESULTS: Among 52 patients (mean 65 (IQR 46-74) years, 82% male, and 69% paroxysmal AF), sites of fractionation corresponding to GP locations were seen in all cases. PVI ablation incidentally overlapped with fractionation in 50 (96%) patients. On average, 26% of the fractionation corresponding with GP locations were incidentally ablated. The highest proportion of fractionated areas were ablated in the left superior (36%) and right superior (31%) GP regions. More complete incidental ablation of these regions was associated with a greater intraprocedural increase in heart rate (ρ = 0.46, p < 0.001), which was subsequently associated with freedom from AF during 15.9 ± 5.2 months of follow-up. CONCLUSION: Patients undergoing AF ablation universally have fractionated electrograms corresponding to anticipated sites of GP. Partial ablation of these regions frequently occurs incidentally during PVI.

Incremental Benefit of Stepwise Nonpulmonary Vein Trigger Provocation During Catheter Ablation of Atrial Fibrillation.

BACKGROUND: The importance of nonpulmonary vein (PV) triggers for the initiation/recurrence of atrial fibrillation (AF) is well established. OBJECTIVES: This study sought to assess the incremental benefit of provocative maneuvers for identifying non-PV triggers. METHODS: We included consecutive patients undergoing first-time AF ablation between 2020 and 2022. The provocation protocol included step 1, identification of spontaneous non-PV triggers after cardioversion of AF and/or during sinus rhythm; step 2, isoproterenol infusion (3, 6, 12, and 20-30 µg/min); and step 3, atrial burst pacing to induce AF followed by cardioversion during residual or low-dose isoproterenol infusion or induce focal atrial tachycardia. Non-PV triggers were defined as non-PV ectopic beats triggering AF or sustained focal atrial tachycardia. RESULTS: Of 1,372 patients included, 883 (64.4%) underwent the complete stepwise provocation protocol with isoproterenol infusion and burst pacing, 334 (24.3%) isoproterenol infusion only, 77 (5.6%) burst pacing only, and 78 (5.7%) no provocative maneuvers (only step 1). Overall, 161 non-PV triggers were found in 135 (9.8%) patients. Of these, 51 (31.7%) non-PV triggers occurred spontaneously, and the remaining 110 (68.3%) required provocative maneuvers for induction. Among those receiving the complete stepwise provocation protocol, there was a 2.2-fold increase in the number of patients with non-PV triggers after isoproterenol infusion, and the addition of burst pacing after isoproterenol infusion led to a total increase of 3.6-fold with the complete stepwise provocation protocol. CONCLUSIONS: The majority of non-PV triggers require provocative maneuvers for induction. A stepwise provocation protocol consisting of isoproterenol infusion followed by burst pacing identifies a 3.6-fold higher number of patients with non-PV triggers.

Prognostic value of noninvasive programmed stimulation in primary prevention implantable cardioverter-defibrillator recipients.

Background: Implantable cardioverter-defibrillator (ICD) offers an opportunity to study inducibility of ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict future arrhythmic events or mortality in patients with primary prevention ICD, has not yet been examined. Methods: From the NIPS-ICD study (ClinicalTrials ID: NCT02373306) 41 consecutive patients (34 males, age 64 ± 11 years, 76% ischemic cardiomyopathy [ICM]) had ICD for primary prevention indication. Patients underwent NIPS using a standardized protocol of up to three premature extrastimuli at 600, 500 and 400 ms drive cycle lengths. NIPS was classified as positive if sustained VT or VF was induced. The study endpoint was occurrence of sustained VT/VF during the follow-up. Results: At baseline NIPS, VT/VF was induced in 8 (20%) ICM patients. During the 5-year follow-up, the VT/VF occurred in 7 (17%) patients, all with ICM. The difference between NIPS-inducible versus NIPS-noninducible patients regarding VT/VF occurrence did not meet statistical significance (38% vs. 12%, log rank test p = .11). After a 5-year follow-up, the mortality rate was significantly higher in patients who had VT/VF induced at NIPS versus no VT/VF at NIPS (38% vs. 12%, p = .043). The occurrence of a composite endpoint consisting of VT/VF recurrence or death in patients with ICM was also most frequent in the NIPS-inducible group (75% vs. 35%, p = .037). Conclusions: Inducibility of VT/VF during NIPS in ICM patients with primary prevention ICD is associated with higher mortality and higher incidence of composite endpoint consisting of death or VT/VF during a long-term observation.

Prevalence, timing, and impact of early recurrence of atrial tachyarrhythmias after pulsed field ablation: A secondary analysis of the PULSED AF trial.

BACKGROUND: Early recurrence of atrial tachyarrhythmias (ERAT) within 3 months of thermal ablation for atrial fibrillation (AF) is common and often considered transient. Pulsed field ablation (PFA) is a nonthermal energy source in which ERAT is not well described. OBJECTIVE: The purpose of this study was to analyze ERAT in patients with AF undergoing PFA in the Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF (PULSED AF) trial. METHODS: This analysis included 154 (52.4%) paroxysmal AF and 140 (47.6%) persistent AF who had ≥10 rhythm assessments during the 90-day blanking period. ERAT was defined as any instance of ≥30 seconds of AF, atrial flutter, or atrial tachycardia on transtelephonic monitoring (weekly and symptomatic) or ≥10 seconds on electrocardiography (at 3 months), both within 90 days. Late recurrence of atrial tachyarrhythmias (LRAT) was defined as observed atrial tachyarrhythmias between 90 days and 12 months. RESULTS: The overall prevalence of ERAT was 27.1% in patients with paroxysmal AF and 31.6% in patients with persistent AF. In patients with ERAT, 73% had ERAT onset within the first month of the procedure. The presence of ERAT was associated with LRAT in patients with paroxysmal AF (hazard ratio 6.4; 95% confidence interval 3.6-11.3) and patients with persistent AF (hazard ratio 3.8; 95% confidence interval 2.2-6.6). Yet, in 29.4% of patients with paroxysmal AF and 34.3% of patients with persistent AF with ERAT, LRAT was not observed. LRAT was positively correlated with the number of ERAT observations. CONCLUSION: ERAT after PFA predicted LRAT in patients with paroxysmal and persistent AF. However, the concept of a blanking period after PFA is still valid, as approximately one-third of patients with ERAT did not continue to have LRAT during follow-up and may not need reablation.

The Safety and Efficacy of Epicardial Carbon Dioxide Insufflation Compared With Conventional Epicardial Access.

BACKGROUND: Epicardial (Epi) access is commonly required during ventricular tachycardia ablation. Conventional Epi (ConvEpi) access targets a "dry" pericardial space presenting technical challenges and risk of complications. Recently, intentional puncture of coronary venous branches with Epi carbon dioxide insufflation (EpiCO2) has been described as a technique to improve Epi access. The safety of this technique relative to conventional methods remains unproven. OBJECTIVES: The authors sought to compare the feasibility and safety of EpiCO2 to ConvEpi access. METHODS: All patients at a high-volume center undergoing Epi access between January 2021 and December 2023 were included and grouped according to ConvEpi or EpiCO2 approach. Access technique was according to the discretion of the operator. RESULTS: Epi access was attempted in 153 cases by 17 different operators (80 ConvEpi vs 73 EpiCO2). There was no difference in success rate whether the ConvEpi or EpiCO2 approach was used (76 [95%] cases vs 67 [91.8%] cases; P = 0.4). Total Epi access time was shorter in the ConvEpi group compared with the EpiCO2 group (16.3 ± 11.6 minutes vs 26.9 ± 12.7 minutes; P < 0.001), though the total procedure duration was similar. Major Epi access-related complications occurred in only the ConvEpi group (6 [7.5%] ConvEpi vs 0 [0%] EpiCo2; P = 0.02). Bleeding ≥80 mL was more frequently observed following ConvEpi access (14 [17.5%] cases vs 4 [5.5%] cases; P = 0.02). After adjusting for age, repeat Epi access, and antithrombotic therapy, EpiCO2 was associated with a reduction in bleeding ≥80 mL (OR: 0.27; 95% CI: 0.08-0.89; P = 0.03). CONCLUSIONS: EpiCO2 access is associated with lower rates of major complication and bleeding when compared with ConvEpi access.

Long-Term Freedom From Ventricular Arrhythmias in ARVC With Endocardial Only Ablation: Predictors of Success.

BACKGROUND: Although the epicardial predominance of substrate abnormalities has been well demonstrated in early stages of arrhythmogenic right ventricular cardiomyopathy (ARVC), endocardial (ENDO) ablation may suffice to eliminate ventricular tachycardia (VT) in some patients. OBJECTIVES: This study aimed to report the long-term outcomes of ENDO-only ablation in ARVC patients and factors that predict VT-free survival. METHODS: We included consecutive patients with Task Force Criteria diagnosis of ARVC undergoing a first ENDO-only VT ablation between 1998 and 2020. Ablation was predominantly guided by activation/entrainment mapping for mappable VTs and pace mapping/targeting abnormal electrograms for unmappable VTs. The primary endpoint was freedom from any recurrent sustained VT after the last ENDO-only ablation. RESULTS: Seventy-four ARVC patients underwent ENDO-only VT ablation. VT noninducibility was achieved in 49 (66%) patients. During median follow-up of 6.6 years (Q1-Q3: 3.4-11.2 years), 40 (54.1%) patients remained free from any VT recurrence with rare VT ≤2 episodes in additional 12.2%. Among patients with noninducibility, VT-free survival was 75.5% during long-term follow-up. In multivariable analysis, >45 y of age at diagnosis (HR: 0.41; 95% CI: 0.17-0.98) and VT noninducibility (HR: 0.36; 95% CI: 0.16-0.80) were predictors of VT-free survival. CONCLUSIONS: Long-term VT-free survival can be achieved in over half of ARVC patients following ENDO-only VT ablation, increasing to over 75% if VT noninducibility is achieved. Our results support consideration of a stepwise ENDO-only approach before proceeding to epicardial ablation if VT noninducibility can be achieved particularly in older patients.

Utility of noninvasive electrocardiographic imaging in the localization of nonpulmonary vein triggers of atrial fibrillation determined by pacing common trigger sites.

INTRODUCTION: Identifying the origin of nonpulmonary vein atrial fibrillation (AF) triggers (NPVTs) after pulmonary vein isolation (PVI) can be challenging. We aimed to determine if noninvasive electrocardiographic imaging (ECGi) could localize pacing from common NPVT sites. ECGi combines measured body surface potentials with heart-torso geometry acquired from computed tomography (CT) to generate an activation map. METHODS: In 12 patients with AF undergoing first time ablation, the ECGi vest was fitted for preprocedural CT scan and worn during the procedure. After PVI, we performed steady-state pacing from 15 typical anatomic NPVT sites at a cycle length of 700-800 ms. We co-registered the invasive anatomic map with the CT-based ECGi epicardial activation map to compare ECGi predicted to true pacing origin. RESULTS: In the study cohort (67% male, 58% persistent AF, and 67% with left atrial dilation), 148 (82%) pacing sites had both capture and adequate anatomy acquired from the three-dimensional mapping system to co-register with ECGi activation map. Median distance between true pacing sites and point of earliest epicardial activation derived from the ECGi maps for all sites was 17 mm (interquartile range, 10-22 mm). Assuming paced sites treated as regions with a radius of 2.5 cm, the earliest activation site on ECGi map falls within the region with 94% accuracy. CONCLUSION: ECGi can approximate the origin of paced beats from common NPVT sites to within a median distance of 17 mm. A rapidly identified region may then be the focus of more detailed catheter-based mapping techniques to facilitate successful localization and ablation of NPVTs.

Feasibility, Efficacy, and Safety of Fluoroless Ablation of VT in Patients With Structural Heart Disease.

BACKGROUND: Catheter ablation of ventricular tachycardia (VT) typically requires radiation exposure with its potential adverse health effects. A completely fluoroless ablation approach is achievable using a combination of electroanatomical mapping and intracardiac echocardiography. Nonetheless, data in patients undergoing VT ablation are limited. OBJECTIVES: This study aimed to determine the feasibility, efficacy, and safety of VT ablation in patients with structural heart disease using a zero-fluoroscopy approach. METHODS: This multicenter study included consecutive patients with ischemic and nonischemic cardiomyopathy undergoing fluoroless VT ablation. Patients requiring epicardial access or coronary angiography were excluded. RESULTS: Between 2017 and 2023 a total of 198 patients (aged 66.4 ± 13.4 years, 76% male, 48% ischemic) were included. Most patients (95.4%) underwent left ventricular (LV) mapping and/or ablation, which was conducted via transseptal route in 54.5% (n = 103), via retrograde aortic route in 43.4% (n = 82), and using a combined approach in 2.1% (n = 4). Two-thirds of patients had a cardiac device, including a biventricular device in 15%; 2 patients had a LV assist device, and 1 patient had a mechanical aortic valve prosthesis. The mean total procedural time was 211 ± 70 minutes, and the total radiofrequency time was 30 ± 22 minutes. During a follow-up period of 22 ± 18 months, the freedom from VT recurrence was 80%, and 7.6% of patients underwent a repeated ablation. Procedural-related complications occurred in 6 patients (3.0%). CONCLUSIONS: Fluoroless ablation of VT in structural heart disease is feasible, effective, and safe when epicardial mapping/ablation is not required.

Lipomatous Metaplasia Is Associated With Ventricular Tachycardia Recurrence Following Ablation in Patients With Nonischemic Cardiomyopathy.

BACKGROUND: Ventricular tachycardia (VT) recurrence rates remain high following ablation among patients with nonischemic cardiomyopathy (NICM). OBJECTIVES: This study sought to define the prevalence of lipomatous metaplasia (LM) in patients with NICM and VT and its association with postablation VT recurrence. METHODS: From patients who had ablation of left ventricular VT, we retrospectively identified 113 consecutive NICM patients with preprocedural contrast-enhanced cardiac computed tomography (CECT), from which LM was segmented. Nested within this cohort were 62 patients that prospectively underwent CECT and cardiac magnetic resonance from which myocardial border zone and dense late gadolinium enhancement (LGE) were segmented. A control arm of 30 NICM patients without VT with CECT was identified. RESULTS: LM was identified among 57% of control patients without VT vs 83% of patients without VT recurrence and 100% of patients with VT recurrence following ablation. In multivariable analyses, LM extent was the only independent predictor of VT recurrence, with an adjusted HR per 1-g LM increase of 1.1 (P < 0.001). Patients with LM extent ≥2.5 g had 4.9-fold higher hazard of VT recurrence than those with LM <2.5 g (P < 0.001). In the nested cohort with 32 VT recurrences, LM extent was independently associated with VT recurrence after adjustment for border zone and LGE extent (HR per 1 g increase: 1.1; P = 0.036). CONCLUSIONS: Myocardial LM is prevalent in patients with NICM of a variety of etiologies, and its extent is associated with postablation VT recurrence independent of the degree of fibrosis.

Programmed Ventricular Stimulation: Risk Stratification and Guiding Antiarrhythmic Therapies.

Electrophysiologic testing with programmed ventricular stimulation (PVS) has been utilized to induce ventricular tachycardia (VT), thereby improving risk stratification for patients with ischemic and nonischemic cardiomyopathies and determining the effectiveness of antiarrhythmic therapies, especially catheter ablation. A variety of procedural aspects can be modified during PVS in order to alter the sensitivity and specificity of the test including the addition of multiple baseline pacing cycle lengths, extrastimuli, and pacing locations. The definition of a positive result is also critically important, which has varied from exclusively sustained monomorphic VT (>30 seconds) to any ventricular arrhythmia regardless of morphology. In this review, we discuss the history of PVS and evaluate its role in sudden cardiac death risk stratification in a variety of patient populations. We propose an approach to future investigations that will capitalize on the unique ability to vary the sensitivity and specificity of this test. We then discuss the application of PVS during and following catheter ablation. The strategies that have been utilized to improve the efficacy of intraprocedural PVS are highlighted during a discussion of the limitations of this probabilistic strategy. The role of noninvasive programmed stimulation is also reviewed in predicting recurrent VT and informing management decisions including repeat ablations, modifications in antiarrhythmic drugs, and implantable cardioverter-defibrillator programming. Based on the available evidence and guidelines, we propose an approach to future investigations that will allow clinicians to optimize the use of PVS for risk stratification and assessment of therapeutic efficacy.

Correlation of extent of left ventricular endocardial unipolar low-voltage zones with ventricular tachycardia in nonischemic cardiomyopathy.

BACKGROUND: Endocardial electrogram (EGM) characteristics in nonischemic cardiomyopathy (NICM) have not been explored adequately for prognostication. OBJECTIVE: We aimed to study correlation of bipolar and unipolar EGM characteristics with left ventricular ejection fraction (LVEF) and ventricular tachycardia (VT) in NICM. METHODS: Electroanatomic mapping of the left ventricle was performed. EGM characteristics were correlated with LVEF. Differences between groups with and without VT and predictors of VT were studied. RESULTS: In 43 patients, unipolar EGM variables had better correlation with baseline LVEF than bipolar EGM variables: unipolar voltage (r = +0.36), peak negative unipolar voltage (r = -0.42), peak positive unipolar voltage (r = +0.38), and percentage area of unipolar low-voltage zone (LVZ; r = -0.41). Global mean unipolar voltage (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2-0.8), extent of unipolar LVZ (HR, 1.6; 95% CI, 1.1-2.3), and percentage area of unipolar LVZ (HR, 1.6; 95% CI, 1.1-2.3) were significant predictors of VT. For classification of patients with VT, extent of unipolar LVZ had an area under the curve of 0.82 (95% CI, 0.69-0.95; P < .001), and percentage area of unipolar LVZ had an area under the curve of 0.83 (95% CI, 0.71-0.96; P = .01). Cutoff of >3 segments for extent of unipolar LVZ had the best diagnostic accuracy (sensitivity, 90%; specificity, 67%) and cutoff of 33% for percentage area of unipolar LVZ had the best diagnostic accuracy (sensitivity, 95%; specificity, 60%) for VT. CONCLUSION: In NICM, extent and percentage area of unipolar LVZs are significant predictors of VT. Cutoffs of >3 segments of unipolar LVZ and >33% area of unipolar LVZ have good diagnostic accuracies for association with VT.