Intramural needle ablation or repeated standard ablation in patients referred for repeat ablation of scar-related ventricular tachycardia.

INTRODUCTION: When ventricular tachycardia (VT) recurs after standard RF ablation (sRFA) some patients benefit from repeat sRFA, whereas others warrant advanced methods such as intramural needle ablation (INA). Our objectives are to assess the utility of repeat sRFA and to clarify the benefit of INA when repeat sRFA fails in patients with VT due to structural heart disease. METHODS: In consecutive patients who were prospectively enrolled in a study for INA for recurrent sustained monomorphic VT despite sRFA, repeat sRFA was considered first. INA was performed during the same procedure if repeat sRFA failed or no targets for sRFA were identified. RESULTS: Of 85 patients enrolled, acute success with repeat sRFA was achieved in 30 patients (35%), and during the 6-month follow-up, 87% (20/23) were free of VT hospitalization, 78% were free of any VT, and 7 were lost to follow-up. INA was performed in 55 patients (65%) after sRFA failed, or no endocardial targets were found abolished or modified inducible VT in 35/55 patients (64%). During follow-up, 72% (39/54) were free of VT hospitalization, 41% were free of any VT, and 1 was lost to follow-up. Overall, 59 out of 77 (77%) patients were free of hospitalization and 52% were free of any VT. Septal-origin VTs were more likely to need INA, whereas RV and papillary muscle VTs were less likely to require INA. CONCLUSIONS: Repeat sRFA was beneficial in 23% (18/77) of patients with recurrent sustained VT who were referred for INA. The availability of INA increased favorable outcomes to 52%.

Safety of ventricular arrhythmia radiofrequency ablation with half-normal saline irrigation.

AIMS: Failure of radiofrequency (RF) ablation of ventricular arrhythmias is often due to inadequate lesion size. Irrigated RF ablation with half-normal saline (HNS) has the potential to increase lesion size and reduce sodium delivery to the patient if the same volume of RF irrigant were used for normal saline (NS) and HNS but could increase risks related to steam pops and lesion size. This study aims to assess periprocedural complications and acute ablation outcome of ventricular arrhythmias ablation with HNS. METHODS AND RESULTS: Prospective assessment of outcomes was performed in 1024 endocardial and/or epicardial RF ablation procedures in 935 consecutive patients (median age 64 years, 71.2% men, 73.4% cardiomyopathy, 47.2% sustained ventricular tachycardia). Half-normal saline was selected at the discretion of the treating physician. Radiofrequency ablation power was generally titrated to a ≤15â€…Ω impedance fall with intracardiac echocardiography monitoring. Half-normal saline was used in 900 (87.9%) and NS in 124 (12.1%) procedures. Any adverse event within 30 days occurred in 13.0% of patients treated with HNS RF ablation including 4 (0.4%) strokes/transient ischaemic attacks and 34 (3.8%) pericardial effusions requiring treatment (mostly related to epicardial access). Two steam pops with perforation required surgical repair (0.2%). Patients who received NS irrigation had less severe disease and arrhythmias. In multivariable models, adverse events and acute success of the procedure were not related to the type of irrigation. CONCLUSION: Half-normal saline irrigation RF ablation with power guided by impedance fall and intracardiac echocardiography has an acceptable rate of complications and acute ablation success while administering half of the saline load expected for NS irrigation.

Rationale for and use of the lumenless 3830 pacing lead.

Most currently available pacing and defibrillation leads utilize a stylet-based design that facilitates implantation. This has advantages, but also increases the lead diameter and adds the potential for metal fatigued-based conductor failure. A systematic literature search was conducted, and the authors add their twenty-year experience with this lead design. The global experience with lumenless leads was reviewed both for "standard" positioning and with conduction system pacing. Methods for both placement and system modification are reviewed. Lumenless leads have the potential to improve the durability of endocardial pacing and facilitate conduction system pacing.

Intracardiac thrombi fluttering like hair in the wind at VT ablation.

INTRODUCTION: Intracardiac echocardiography (ICE) reveals mobile thrombus on implantable electronic device leads in some patients undergoing electrophysiologic procedures. METHODS: ICE was performed in a patient undergoing ventricular tachycardia (VT) ablation. RESULTS: ICE showed extensive mobile thrombi on the implantable cardioverter defibrillator lead. Radiofrequency catheter ablation of VT from perimitral scar was safely performed via a retrograde aortic approach. After the procedure, chronic anticoagulation was initiated. CT-angiography of the chest 2 months later showed no pulmonary emboli. CONCLUSIONS: The significance of these thrombi, as related to chronic pulmonary embolization, warrants further study.

Percutaneous aspiration and removal of infected leadless pacemaker vegetation.

INTRODUCTION: Leadless pacemakers represent an increasingly utilized alternative to traditional pacing methods in those with prior bacteremia or at high risk for infection. The acknowledged resistance to infection is illustrated by the exceedingly rare documentation of it. METHODS: We present a case of methicillin-sensitive Staphylococcus aureus endocarditis with associated leadless pacemaker infection necessitating percutaneous aspiration of the device-associated vegetation followed by extraction of the leadless pacemaker. RESULTS: Large vegetation associated with a leadless pacemaker was percutaneously aspirated with a vacuum-assisted aspiration device, followed by successful extraction of the leadless pacemaker. CONCLUSION: While leadless pacemakers are seldom involved in infective endocarditis, ultrasound evaluation in high-risk patients with an undetermined source is reasonable. Before extraction, it is practical to consider aspiration of large associated vegetations with a vacuum-assisted device.

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.

Use of a clot aspiration system during transvenous lead extraction.

INTRODUCTION: The optimal approach to the extraction of leads with large vegetations remains uncertain. METHODS: High-risk patients with lead associated vegetations undergoing device extraction at Vanderbilt Hospital with concomitant use of the Penumbra Aspiration System (Penumbra Inc, Alameda, CA) are described. An 8.5 Fr Agilis NXT (Abbott Inc, St. Paul, MN) was advanced to the right atrium, through which a Penumbra Indigo Cat-8 catheter was advanced. Using intracardiac echocardiography, the Penumbra was positioned directly on the vegetation, suction was applied until adherent, and the Indigo catheter and Agilis sheath were then removed en-bloc and aspirated debris flushed out. This was repeated until debulking was considered successful. RESULTS: Eight cases were performed. The median vegetation size was 2 cm. Pathogens were Enterococcus, Staphylococcus, Candida, Cutibacterium, and Enterobacter. In seven of eight cases, aspiration successfully reduced vegetations to less than 1 cm before successful percutaneous cardiac implantable electronic device removal. One patient underwent surgical removal via thoracotomy. There were no acute complications related to the Penumbra catheter. Three patients had CT evidence of small pulmonary emboli postprocedure. The length of stay was 3 to 27 days. One patient died on POD 1 of refractory ventricular tachycardia unrelated to the procedure. One patient died of ongoing sepsis 2 weeks postextraction. CONCLUSIONS: The Penumbra Indigo Aspiration system can be useful for vegetation debulking before transvenous lead extraction.

Staged versus Simultaneous Thoracoscopic Hybrid Ablation for Persistent Atrial Fibrillation Does Not Affect Time to Recurrence of Atrial Arrhythmia.

INTRODUCTION: Totally thoracoscopic (TT) epicardial ablation combined with endocardial catheter ablation is an emerging treatment for persistent AF. The effects of timing of the TT and endocardial portion on AT/AF recurrence are not known. METHODS: We retrospectively analyzed patients undergoing TT staged versus simultaneous hybrid AF ablation at our institution. Arrhythmia-free outcome was compared using time to recurrence (AF or AT greater than 30 seconds after a 3-month blanking period from endocardial ablation) at 12 months. All subjects had continuous ILR or PM monitoring. RESULTS: Eighty-three patients (52 same-day, 31 staged) underwent TT hybrid AF ablation. Recurrence was observed in 23 (29%) patients at a median time of 147 days (IQR 91,238). In univariate analysis, a staged approach significantly increased the likelihood of detecting incomplete PVI (OR 6 [95% CI 2-17] P = 0.001). However, only longstanding persistent AF (LSP-AF) status predicted recurrence (HR 4 [95% CI 1.4-12] P = 0.01). Neither a staged approach (HR 1.0 [95% CI 0.4-2.4] P = 0.9), nor detection of incomplete PVI (HR 0.9 [95% CI 0.4-2.3] P = 0.8) predicted time to first AF/AT recurrence. CONCLUSIONS: Staged hybrid ablation of AF significantly increases the likelihood of discovering incomplete PVI at the time of endocardial mapping versus a same-day procedure. However, the staged approach did not improve time to first AT/AF recurrence.

Comparative outcomes of transvenous extraction of sprint fidelis and riata defibrillator leads: a single center experience.

INTRODUCTION: The FDA has issued class I advisories for Medtronic Sprint Fidelis(®) and St. Jude Medical Riata(TM) ICD lead families. Transvenous Riata(TM) ICD lead extraction is typically considered higher risk than Fidelis(®) extraction, based on longer duration from implant, presence of externalized conductors and lack of silicone backfill in the SVC and RV coils. However, published data comparing procedural outcomes between these leads are limited. METHODS: Records were reviewed for all patients undergoing transvenous extraction of Sprint Fidelis(®) or Riata(TM) ICD leads at the Vanderbilt Heart and Vascular Institute from July 2006 to April 2013 to ascertain indication for extraction, procedural details, complications, and 30-day mortality. RESULTS: There were significant differences between those undergoing extraction of a Sprint Fidelis(®) (n = 145) or Riata(TM) lead (n = 47). In the Riata(TM) group, device-related endocarditis was a more common indication for extraction, the mean duration of implant was longer, and larger excimer laser sheaths were required. Lead malfunction was a more common indication in the Fidelis(®) group. There were no statistically significant differences in median procedure duration, procedural success (97.9% vs 95.7%, P = 0.41), median length of hospital stay (1 day vs 1 day, P = 0.23), procedural complication rate (5.5% vs 10.6%, P = 0.23) or 30-day mortality (2.1% vs 2.1%, P = 0.98). Analyses excluding patients with device infection revealed similar results. CONCLUSION: Despite differences in baseline characteristics, this study indicates that Medtronic Sprint Fidelis(®) and St. Jude Riata(TM) ICD leads have similar procedural outcomes with transvenous lead extraction.

Termination Without Global Propagation in Re-Entrant Ventricular Tachycardia: Electrophysiologic Characteristics and 3D-Electroanatomical Mapping Analysis.

BACKGROUND: Termination of ventricular tachycardia (VT) by a pacing stimulus that does not generate a QRS complex (termination without global propagation [TWGP]) can be a marker for a critical re-entry circuit isthmus. However, the electrophysiologic and anatomic features of these sites and their relation to VT substrate defined by 3-dimensional electroanatomical maps (3D-EAM) remain unknown. OBJECTIVES: This retrospective study aimed to characterize TWGP sites and their relation to VT substrate identified by 3D-EAM. METHODS: A total of 632 consecutive cases of catheter ablation for scar-related VT at 2 University medical centers were reviewed to identify TWGP. RESULTS: TWGP was observed 12 times at 11 different sites in 10 patients (5 ischemic cardiomyopathy). The TWGP stimulus fell immediately before or synchronous with the QRS in all cases, and evidence of local capture despite absence of a QRS complex was observed 6 times. In 5 sites, pacing after VT termination produced a QRS different than the VT. Four sites were in dense scar areas (<0.1 mV), and 6 in abnormal low voltage zone (0.1-1.5 mV). Additional mapping or ablation that abolished VT were consistent with the TWGP site being in a VT isthmus. A substrate marker for VT of late potentials, evoked delayed potentials, or slow conduction was present at 6 of 11 TWGP sites. CONCLUSIONS: TWGP may be a marker for detecting a re-entry circuit isthmus that has escaped detection based on electrogram or pace mapping-based substrate mapping.

Stroke and Bleeding Risks of Endocardial Ablation for Ventricular Arrhythmias.

BACKGROUND: Risks of radiofrequency catheter ablation for ventricular arrhythmias include emboli and bleeding complications but data on antithrombotic regimens are limited and guidelines do not specify a systematic approach. OBJECTIVES: This study sought to assess embolic and bleeding complications in relation to pre-periprocedure and post-periprocedure antithrombotic regimens. METHODS: Prospective assessment for complications was performed for 663 endocardial radiofrequency catheter ablation procedures in 616 consecutive patients (median age 64 years [Q1-Q3: 54-73 years], 70.3% men, 71.6% with cardiomyopathy, 44.5% with sustained ventricular tachycardia). RESULTS: There were 2 strokes (0.3%; 95% CI: 0.0%-0.8%), 1 transient ischemic attack (0.15%), and 2 pulmonary emboli (0.3%). There were 39 bleeding complications (5.9%) including 11 pericardial effusions (1.7%), and 28 related to vascular access (4.2%). Consistent with the prevalence of coronary artery disease (47.5%), atrial fibrillation (30.0%), and prior stroke (10.6%), preprocedure, 464 patients (70.0%) were taking antithrombotic agents including 220 (33.2%) taking aspirin alone (ASA), and 163 (24.6%) taking warfarin or a direct acting oral anticoagulant (DOAC). Preprocedure non-ASA antiplatelet use (OR: 2.846; P = 0.011) and DOAC use (OR: 2.585; P = 0.032) were associated with risk of bleeding complications. Following ablation, 49.8% of patients were treated with ASA 325 mg/d and 30.3% received DOACs or warfarin. New DOAC or warfarin administration was initiated in only 6.6% of patients. Overall, 39.7% of patients continued the same preprocedure antithrombotic regimen. CONCLUSIONS: Stroke is a rare complication of radiofrequency catheter ablation for ventricular arrhythmia using ASA 325 mg/d as a minimal postprocedure regimen with more potent regimens for selected patients.

Can Intracardiac Echocardiography Reduce Steam Pops During Half-Normal Saline Irrigated Radiofrequency Ablation?

BACKGROUND: Irrigated radiofrequency ablation with half-normal saline can potentially increase lesion size but may increase the risk of steam pops with the risk of emboli or perforation. We hypothesized that pops would be preceded by intracardiac echocardiography (ICE) findings as well as a large impedance fall. METHODS: In 100 consecutive patients undergoing endocardial ventricular arrhythmia radiofrequency ablation with half-normal saline, we attempted to observe the ablation site with ICE. Radiofrequency ablation power was titrated to a 15 to 20 Ohm impedance fall and could be adjusted for tissue whitening and increasing bubble formation on ICE. Steam pops were defined as audible or a sudden explosion of microbubbles on ICE. RESULTS: Of 2190 ablation applications in 100 patients (82% cardiomyopathy, 50% sustained ventricular tachycardia), pops occurred during 43 (2.0%) applications. Sites with pops had greater impedance decreases of 18 [14, 21]% versus 13 [10, 17]% (P<0.001). ICE visualized 1308 (59.7%) radiofrequency sites, and fewer pops occurred when ICE visualized the radiofrequency ablation site (1.4%) compared with without ICE visualization (2.8%; P=0.016). Of the 18 ICE-visible pops, 7 (39%) were silent but recognized as an explosion of bubbles on ICE. With ICE, 89% of pops were preceded by either tissue whitening or a sudden increase in bubbles. In a multivariable model, tissue whitening and a sudden increase in bubbles were associated with steam pops (odds ratio, 7.186; P=0.004, and odds ratio, 29.93; P<0.001, respectively), independent of impedance fall and power. There were no pericardial effusions or embolic events with steam pops. CONCLUSIONS: Steam pops occurred in 2% of half-normal saline radiofrequency applications titrated to an impedance fall and are likely under-recognized without ICE. On ICE, steam pops are usually preceded by tissue whitening or a sudden increase in bubble formation, which can potentially be used to adjust radiofrequency application to help reduce pops.