Intramyocardial Hematoma During Catheter Ablation for Scar-Related Ventricular Tachycardia.

BACKGROUND: Intramural hematoma during ablation for scar-related ventricular tachycardia (VT) is a rare but life-threatening complication. OBJECTIVES: The goal of this study was to describe the features and outcomes of intramural hematoma during ablation for scar-related VT. METHODS: From 2010 to 2022, >3,514 ablations for ventricular arrhythmias were performed at 2 institutions. Four cases of intramural hematoma complicating VT ablation for scar-related VT were identified. Intraprocedural details, imaging data, and surgical notes were reviewed to create a recognizable pattern of events highlighting this complication. RESULTS: In 3 of 4 cases, intramural hematoma occurred during catheter ablation with an open irrigated 3.5 mm tipped catheter using normal saline for irrigation. In one case, hematoma was noted after ablation using an investigational needle electrode catheter. The occurrence of a steam pop preceded detection of an expanding intramural hematoma in 3 cases. ST-segment elevation on electrocardiography was evident in 3 cases; intracardiac echocardiographic imaging detected the hematoma in all cases. Epicardial rupture and pericardial effusion requiring drainage occurred in 3 cases, whereas 1 hematoma was self-contained and did not require intervention. Surgical intervention was performed in 2 cases, with successful outcomes. One patient who was deemed not a surgical candidate died of progressive cardiogenic shock. CONCLUSIONS: Intramural hematoma during ablation for scar-related VT is a rare but potentially catastrophic complication that requires prompt recognition. Steam pops during ablation frequently precede the hematoma formation. Surgical intervention may be life-saving, although contained hematomas can occasionally be managed conservatively.

Worldwide Experience With an Irrigated Needle Catheter for Ablation of Refractory Ventricular Arrhythmias: Final Report.

BACKGROUND: We previously reported feasibility of irrigated needle ablation (INA) with a retractable 27-G end-hole needle catheter to treat nonendocardial ventricular arrhythmia substrate, an important cause of ablation failure. OBJECTIVES: The purpose of this study was to report outcomes and complications in our entire INA-treated population. METHODS: Patients with recurrent sustained monomorphic ventricular tachycardia (VT) or high-density premature ventricular contractions (PVCs) despite radiofrequency ablation were prospectively enrolled at 4 centers. Endpoints included a 70% decrease in VT frequency or PVC burden decrease to <5,000/24 h at 6 months. RESULTS: INA was performed in 111 patients (median: 2 failed prior ablations, 71% nonischemic heart disease, and left ventricular ejection fraction 36% ± 14%). INA acutely abolished targeted PVCs in 33 of 37 patients (89%), and PVCs were reduced to <5,000/day in 29 patients (78%). During 6-month follow-up, freedom from hospitalization was observed in 50 of 72 patients with VT (69%), and improvement or abolition of VT occurred in 47%. All patients received multiple INA applications, with more in the VT group than in the PVC group (median: 12 [IQR: 7-19] vs 7 [5-15]; P < 0.01). After INA, additional endocardial standard radiofrequency ablation was required in 23% of patients. Adverse events included 4 pericardial effusions (3.5%), 3 cases of (anticipated) atrioventricular block (2.6%), and 3 heart failure exacerbations (2.6%). During 6-month follow-up, 5 deaths occurred; none were procedure-related. CONCLUSIONS: INA achieves improved arrhythmia control in 78% of patients with PVCs and avoids hospitalization in 69% of patients with VT refractory to standard ablation at 6-month follow-up. Procedural risks are acceptable. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tachycardia, NCT01791543; Intramural Needle Ablation for the Treatment of Refractory Ventricular Arrhythmias, NCT03204981).

Ablation of ectopic atrial foci for successful management of symptomatic bradycardia: A case series (bradycardia and ectopic atrial beats).

Atrial premature contractions (PACs) that block at the atrio-ventricular (AV) nodal level and occurring in a bigeminal frequency are recognized as a cause of symptomatic bradycardia. Appropriate suppression of the PACs often results in restoration of a regular rhythm with resolution of bradycardia-related symptoms. We report a series of three patients with non-conducted bigeminal PACs arising from the mitral annulus that resulted in symptomatic bradycardia and who were referred for consideration of cardiac pacing. Focal ablation suppressed PACs restoring a normal heart rate and resolution of symptoms without resorting to cardiac pacing.

Tyrosine kinase inhibitor-associated ventricular arrhythmias: a case series and review of literature.

BACKGROUND: Tyrosine kinase inhibitors (TKIs) have been increasingly used as first-line therapy in hematologic and solid-organ malignancies. Multiple TKIs have been linked with the development of cardiovascular complications, especially atrial arrhythmias, but data on ventricular arrhythmias (VAs) is scarce. METHODS: Herein we describe five detailed cases of VAs related to TKI use in patients with varied baseline cardiovascular risk factors between 2019 and 2022 at three centers. Individual chart review was conducted retrospectively. RESULTS: Patient ages ranged from 43 to 83 years. Three patients were on Bruton's TKI (2 ibrutinib and 1 zanubrutinib) at the time of VAs; other TKIs involved were afatinib and dasatinib. Three patients had a high burden of non-sustained ventricular tachycardia (NSVT) requiring interventions, whereas two patients had sustained VAs. While all patients in our case series had significant improvement in VA burden after TKI cessation, two patients required new long-term antiarrhythmic drug therapy, and one had an implantable defibrillator cardioverter (ICD) placed due to persistent VAs after cessation of TKI therapy. One patient reinitiated TKI therapy after control of arrhythmia was achieved with antiarrhythmic drug therapy. CONCLUSIONS: Given the expanding long-term use of TKIs among a growing population of cancer patients, it is critical to acknowledge the association of TKIs with cardiovascular complications such as VAs, to characterize those at risk, and deploy preventive and therapeutic measures to avoid such complications and interference with oncologic therapy. Further efforts are warranted to develop monitoring protocols and optimal treatment strategies for TKI-induced VAs.

Same-day discharge after transvenous lead extraction: feasibility and outcomes.

AIMS: Same-day discharge (SDD) is safe for patients undergoing electrophysiology procedures. There is no existing data regarding SDD for patients undergoing transvenous lead extraction (TLE). We report our experience with SDD for patients undergoing TLE. METHODS AND RESULTS: The study group included patients undergoing TLE between February 2020 and July 2021 without an infectious indication. A modified SDD protocol for device implants/ablations was applied to TLE patients. Patient characteristics, extraction details, outcomes, and complications were reviewed. Of 239 patients undergoing TLE, 210 were excluded (94 infections and 116 did not meet SDD criteria). Of the remaining 29 patients, seven stayed due to patient preference and 22 were discharged home the same day. The SDD group had an average age of 65.9 ± 12 (47-84), 41% female, and LVEF of 52.2 ± 18% (10-80). The indication for TLE was malfunction (20), upgrade (4), advisory lead (2), and magnetic resonance imaging compatibility (1). Extractions included four implantable cardioverter-defibrillators (ICDs), 17 pacemakers (PPM), and one cardiac resynchronization therapy (CRT)-P system. The leads were 9.6 years (1.5-21.7) old, and 1.8 leads were removed per patient (1-3); the lead extraction difficulty (LED) score was 11.6 ± 7. Twenty underwent cardiovascular implantable electronic device (CIED) re-implantation (2 ICD, 3 CRT-D, 13 PPM, and 2 CRT-P). For CIED re-implants, patients sent a remote transmission the next day, and all patients received a next-day call. There were no procedure or device-related issues, morbidities, or mortalities in the 30 days after discharge. CONCLUSION: Same-day discharge after TLE for non-infectious aetiologies is safe and feasible in a select group of patients with early procedure completion who meet strict SDD criteria.

Proarrhythmic effect of radiofrequency catheter ablation on the right ventricular moderator band.

Following ablation on the RV moderator band for suppression of monomorphic PVCs, recurrent VT and VF were triggered by the same PVC at shorter coupling intervals. This is likely a pro arrhythmic effect of ablation on the moderator band.

Durable pulmonary vein isolation with diffuse posterior left atrial ablation using low-flow, median power, short-duration strategy.

INTRODUCTION: To target posterior wall isolation (PWI) in atrial fibrillation (AF) ablation, diffuse ablation theoretically confers a lower risk of conduction recovery compared to box set. We sought to assess the safety and efficacy of diffuse PWI with low-flow, medium-power, and short-duration (LF-MPSD) ablation, and evaluate the durability of pulmonary vein isolation (PVI) and PWI among patients undergoing repeat ablations. METHODS: We retrospectively studied patients undergoing LF-MPSD ablation for AF (PVI + diffuse PWI) between August 2017 and December 2019. Clinical characteristics were collected. Kaplan-Meier survival analysis was performed to study AF/atrial flutter (AFL) recurrence. Ablation data were analyzed in patients who underwent a repeat AF/AFL ablation. RESULTS: Of the 463 patients undergoing LF-MPSD AF ablation (PVI alone, or PVI + diffuse PWI), 137 patients had PVI + diffuse PWI. Acute PWI with complete electrocardiogram elimination was achieved in 134 (97.8%) patients. Among the 126 patients with consistent follow-up, 38 (30.2%) patients had AF/AFL recurrence during a median duration of 14 months. Eighteen patients underwent a repeat AF/AFL ablation after PVI + diffuse PWI, and 16 (88.9%) patients had durable PVI, in contrast to 10 of 45 (23.9%) patients who had redo ablation after LF-MPSD PVI alone. Seven patients (38.9%) had durable PWI, while 11 patients had partial electrical recovery at the posterior wall. The median percentage of area without electrical activity at the posterior wall was 70.7%. Conduction block across the posterior wall was maintained in 16 (88.9%) patients. CONCLUSION: There was a high rate of PVI durability in patients undergoing diffuse PWI and PVI. Partial posterior wall electrical recovery was common but conduction block across the posterior wall was maintained in most patients.

HeartMate 3: new challenges in ventricular tachycardia ablation.

AIM: To describe clinical characteristics, procedural details, specific challenges, and outcomes in patients with HeartMate3™ (HM3), a left ventricular assist device system with a magnetically levitated pump, undergoing ventricular tachycardia ablation (VTA). METHODS AND RESULTS: Data were collected from patients with an HM3 system who underwent VTA in seven tertiary centres. Data included baseline patient characteristics, procedural data, mortality, and arrhythmia-free survival. The study cohort included 19 patients with cardiomyopathy presenting with ventricular tachycardia (VT) (53% with VT storm). Ventricular tachycardias were induced in 89% of patients and a total of 41 VTs were observed. Severe electromagnetic interference was present on the surface electrocardiogram. Hence, VT localization required analysis of intra-cardiac signals or the use of filter in the 40-20 Hz range. The large house pump HM3 design obscured the cannula inflow and therefore multi imaging modalities were necessary to avoid catheter entrapment in the cannula. A total of 32 VTs were mapped and were successfully ablated (31% to the anterior wall, 38% to the septum and only 9% to the inflow cannula region). Non-inducibility of any VT was reached in 11 patients (58%). Over a follow-up of 429 (interquartile range 101-692) days, 5 (26%) patients underwent a redo VT ablation due to recurrent VTA and 2 (11%) patients died. CONCLUSIONS: Ventricular tachycardia ablation in patients with HM3 is feasible and safe when done in the appropriate setup. Long-term arrhythmia-free survival is acceptable but not well predicted by non-inducibility at the end of the procedure.

Candidemia in patients with cardiovascular implantable electronic devices.

PURPOSE: Current guidelines recommend complete extraction of cardiovascular implantable electronic devices (CIEDs) in the case of persistent or recurrent fungemia without other identifiable sources, though supporting evidence is lacking. We sought to evaluate the prognosis of patients with candidemia and CIEDs. METHODS: Twelve consecutive patients (54 ± 12 years, 8 male) with CIED and concurrent candidemia were reviewed. RESULTS: At the time of diagnosis with candidemia, seven patients were immunocompromised, six were on long-term antibacterial therapy, two were intravenous drug users, four were on chronic hemodialysis, and six had a central venous catheter. Four patients were confirmed as definite CIED infection as vegetation was visible on lead by echocardiogram. The other 8 patients were considered possible CIED infection with candidemia of unknown focus. All patients with visible vegetation underwent CIED removal without complications, and other patients were initially managed non-operatively. After 1 year of follow-up, 7 patients had died and at extended follow-up, all patients without lead removal died while 3 of 4 patients with lead extraction survived. Of note, 50% of deaths in the patients without lead removal were associated with fungal sepsis. CONCLUSIONS: Candida fungemia is associated with a high mortality. CIED removal should be an early consideration in these patients even if lead vegetations are not seen.

Percutaneous management of superior vena cava syndrome in patients with cardiovascular implantable electronic devices.

BACKGROUND: There is no consensus regarding the optimal management of cardiovascular implantable electronic device (CIED)-related superior vena cava (SVC) syndrome. OBJECTIVE: We report our experience with transvenous lead extractions (TLEs) in the setting of symptomatic CIED-related SVC syndrome. METHODS: We reviewed all TLEs performed at a high-volume center over a 14-year period and identified patients in which TLE was performed for symptomatic SVC syndrome. Patient characteristics, extraction details, percutaneous management of SVC occlusions, and clinical follow up data were analyzed. RESULTS: Over a 14-year period, more than 1600 TLEs were performed. Of these, 16 patients underwent TLE for symptomatic SVC syndrome. The mean age was 53.1 ± 12.8 years, and 9 (56.3%) were men. Thirty-seven leads, with a mean dwell time of 5.8 years (range 2-12 years), were extracted. After extraction, 6 patients (37.5%) received an SVC stent. Balloon angioplasty was performed before stenting in 5 cases (31.3%). There was 1 major complication (6.3%) due to an SVC tear that was managed surgically with a favorable outcome. Eleven patients underwent reimplantation of a CIED. Over a median follow-up of 5.5 years (interquartile range 2.0-8.5 years), 12 patients (75%) remained free of symptoms. CONCLUSION: Combining TLE with the percutaneous treatment of symptomatic SVC syndrome is a safe and viable treatment strategy.

Electrocardiographic localization of ventricular arrhythmias successfully ablated from the distal great cardiac vein.

BACKGROUND: Idiopathic ventricular arrhythmias (IVAs) from the left ventricular (LV) summit may be successfully ablated from the distal great cardiac vein (dGCV). Using a 12-lead electrocardiogram (ECG) to localize IVAs that can be ablated from the dGCV is valuable for ablation planning. OBJECTIVE: To determine if a "w" wave, a notch in the Q wave in lead I, and other ECG features can identify IVAs that can be successfully ablated from the dGCV. METHODS: We reviewed outflow tract premature ventricular contraction (PVC) ablations performed at two centers between September 2010 and June 2018. Successful PVC ablations, in which the PVCs were mapped from the right ventricular outflow tract, coronary cusps, commissures, endocardial LV, and the coronary venous system including the dGCV were included. ECG characteristics were compared between patients with successful ablations in the dGCV and non-dGCV sites. RESULTS: Of the 120 patients (age 56.8 ± 13.8 years, 45% female) that met the inclusion criteria, the dGCV was the successful ablation site in 18 patients (15%). Multivariate analysis with binary logistic regression showed that a "w" in lead I in combination with an early precordial pattern break and a maximum deflection index (MDI) ≥ 0.5 had sensitivity and specificity for a successful ablation in the dGCV of 94.4% and 96.1%, respectively. CONCLUSION: Combining a "w" wave in lead I with an early precordial pattern break and an MDI ≥ 0.5 is highly sensitive and specific for identifying the dGCV as a successful ablation site for PVCs.

Frequency Content of Unipolar Electrograms May Predict Deep Intramural Excitable Substrate: Insights From Intramural Needle Catheter Ablation of Ventricular Tachycardia.

OBJECTIVES: This study sought to identify midmyocardial arrhythmogenic substrates by examining the frequency content of unipolar endocardial surface electrograms, comparing sites with transmural scar versus sites with intramural excitable substrate (IES) as identified during needle catheter ablation for ventricular tachycardia (VT). BACKGROUND: Midmyocardial arrhythmogenic substrates are a common reason catheter ablation for VT may fail. METHODS: A total of 659 intramural needle sites were studied in 26 patients (age 61 ± 9 years, 85% male, 69% nonischemic cardiomyopathy) who underwent intramural needle catheter ablation for VT. Among 136 sites where endocardial pacing did not capture (threshold >10 mA), needle pacing captured at 29 indicating IES, and did not capture at 107 indicating transmural scar. Intramural needle ablation was performed at 21 of 29 IES sites. Analysis of voltage amplitude, duration, and power spectra of endocardial and intramural needle electrograms was performed. RESULTS: IES sites compared with transmural scar had higher endocardial unipolar electrogram voltage, 0.99 (interquartile range [IQR]: 0.69 to 1.62) mV versus 0.78 (IQR: 0.61 to 1.09) mV; p = 0.038; higher unipolar intramural needle electrogram voltage, 1.16 (0.80 to 1.69) mV versus 0.76 (0.6 to 1.12) mV; p = 0.003; higher endocardial unipolar frequency power particularly in the 5- to 20-Hz band, 1.97 (IQR: 0.93 to 3.89) mV2/s versus 1.03 (IQR: 0.63 to 2.22) mV2/s; p = 0.002; and higher unipolar intramural electrogram frequency particularly in the 0 to 10 Hz range, 3.02 (IQR: 0.98 to 6.95) mV2/s versus 1.33 (IQR: 0.70 to 3.13) mV2/s; p = 0.018. Endocardial unipolar frequency in the 5- to 20-Hz band identified sites with IES, area under the curve of 0.676; p = 0.002; power frequency integral of >0.77 mV2/s provided a 90% sensitivity and 41% specificity. CONCLUSIONS: The frequency content of unipolar electrograms may complement voltage in the detection of deep intramural substrates to facilitate VT catheter ablation. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tachycardia; NCT01791543).

Outcomes in patients with cardiac amyloidosis and implantable cardioverter-defibrillator.

AIMS: Cardiac amyloidosis (CA) is associated with increased mortality due to arrhythmias, heart failure, and electromechanical dissociation. However, the role of an implantable cardioverter-defibrillator (ICD) remains unclear. We conducted case-control study to assess survival in CA patients with and without a primary prevention ICD and compared outcomes to an age, sex, and device implant year-matched non-CA group with primary prevention ICD. METHODS AND RESULTS: There were 91 subjects with CA [mean age= 71.2 ± 10.2, female 22.0%, 49 AL with Mayo Stage 2.9 ± 1.0, 41 transthyretin amyloidosis (ATTR), 1 other] followed by Vanderbilt Amyloidosis centre. Patients with ICD (n = 23) were compared with those without (n = 68) and a non-amyloid group with ICD (n = 46). All subjects with ICD had implantation for primary prevention. Mean left ventricular ejection fraction was 36.2% ± 14.4% in CA with ICD, 41.0% ± 10.6% in CA without ICD, and 33.5% ± 14.4% in non-CA patients. Over 3.5 ± 3.1 years, 6 (26.1%) CA, and 12 (26.1%) non-CA subjects received ICD therapies (P = 0.71). Patients with CA had a significantly higher mortality (43.9% vs. 17.4%, P = 0.002) compared with the non-CA group. Mean time from device implantation to death was 21.8 months in AL and 22.8 months in ATTR patients. There was no significant difference in mortality between CA patients who did and did not receive an ICD (39.0% vs. 46.0%, P = 0.59). CONCLUSIONS: Despite comparable event rates patients with CA had a significantly higher mortality and ICDs were not associated with longer survival. With the emergence of effective therapy for AL amyloidosis, further study of ICD is needed in this group.