Hybrid ablation for persistent atrial fibrillation: a narrative review.

Background and Objective: Treatment for atrial fibrillation (AF) has evolved significantly, with pulmonary vein isolation (PVI) becoming an established treatment. However, the outcomes following catheter ablation for persistent AF remain unsatisfactory. Hybrid catheter-surgical ablation has emerged as a therapeutic approach for persistent AF, combining the strengths of both interventions. The purpose of this narrative review is to comprehensively examine the current state of knowledge regarding hybrid ablation for AF. Methods: A thorough PubMed search using the terms "hybrid ablation", "atrial fibrillation", "catheter ablation", and "guideline on cardiology" within the timeframe of 1980 to 2024 resulted in 138,969 articles. Consensus on the selected articles was reached through a series of structured meetings and discussions. Key Content and Findings: PVI has demonstrated higher sinus rhythm maintenance rates, especially for paroxysmal AF. However, the efficacy is not as high for persistent AF. Additional ablation strategies, such as linear ablation, complex fractionated atrial electrogram ablation, low voltage zone ablation as well as posterior wall isolation, lack consistent evidence of effectiveness. Hybrid ablation, involving collaboration between cardiac surgeons and electrophysiologists, presents a promising alternative for hard-to-treat AF. Recent studies report favorable outcomes of hybrid ablation, with atrial arrhythmia-free rates ranging from 53.5% to 76%, surpassing those of catheter ablation alone, which might result from better lesion durability or intervention for non-PV foci and left atrial appendage excision or closure during hybrid ablation. The rate of complications associated with hybrid ablation is higher than catheter ablation alone. Conclusions: While favorable outcomes of hybrid ablation for persistent AF have been reported, it is not recommended for all AF patients due to its invasiveness compared to catheter ablation. Additionally, some patients with persistent AF maintain sinus rhythm with catheter ablation alone. More clinical data are needed to determine which patients are suitable candidates for hybrid ablation.

Impact of fracture-prone implantable cardioverter defibrillator leads on long-term patient mortality.

Background: The long-term relationship between fracture-prone implantable cardioverter-defibrillator (ICD) leads and poor prognosis remains unclear in Japanese patients. Methods: We conducted a retrospective review of the records of 445 patients who underwent implantation of advisory/Linox leads (Sprint Fidelis, 118; Riata, nine; Isoline, 10; Linox S/SD, 45) and non-advisory leads (Endotak Reliance, 33; Durata, 199; Sprint non-Fidelis, 31) between January 2005 and June 2012 at our hospital. The primary outcomes were all-cause mortality and ICD lead failure. The secondary outcomes were cardiovascular mortality, heart failure (HF) hospitalization, and the composite outcome of cardiovascular mortality and HF hospitalization. Results: During the follow-up period (median, 8.6 [4.1-12.0] years), there were 152 deaths: 61 (34%) in patients with advisory/Linox leads and 91 (35%) in those with non-advisory leads. There were 32 ICD lead failures: 27 (15%) in patients with advisory/Linox leads and five (2%) in those with non-advisory leads. Multivariate analysis for ICD lead failure demonstrated that the advisory/Linox leads had a 6.65-fold significantly greater risk of ICD lead failure than non-advisory leads. Congenital heart disease (hazard ratio 2.51; 95% confidence interval 1.08-5.83; p = .03) could also independently predict ICD lead failure. Multivariate analysis for all-cause mortality demonstrated no significant association between advisory/Linox leads and all-cause mortality. Conclusions: Patients who have implanted fracture-prone ICD leads should be carefully followed up for ICD lead failure. However, these patients have a long-term survival rate comparable with that of patients with non-advisory ICD leads in Japanese patients.

Prolonged T-peak to T-end Interval Predicts Implantable Cardioverter Defibrillator Therapy in Patients With Cardiac Sarcoidosis.

BACKGROUND: The association between the T-peak to T-end interval (Tp-e) and ventricular arrhythmia (VA) events in cardiac sarcoidosis (CS) is unknown. The purpose of this study was to investigate whether Tp-e was associated with VA events in CS patients with implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds).Methods and Results: We retrospectively studied 50 patients (16 men; mean [±SD] age 56.3±10.5 years) with CS and ICD/CRT-D. The maximum Tp-e in the precordial leads recorded by a 12-lead electrocardiogram after ICD/CRT-D implantation was evaluated. The clinical endpoint was defined as appropriate ICD therapy. During a median follow-up period of 85.0 months, 22 patients underwent appropriate therapy and 10 patients died. Kaplan-Meier analysis revealed that the probability of the clinical endpoint was 28.3% at 2 years and 35.3% at 4 years. The optimal cut-off value of the Tp-e for the prediction of the clinical endpoint was 91 ms, with a sensitivity of 72.7% and a specificity of 87.0% (area under the curve=0.81). Multivariate Cox regression analysis showed that Tp-e ≥91 ms (hazard ratio [HR] 5.10; 95% confidence interval [CI] 1.99-13.1; P<0.001) and a histological diagnosis of CS (HR 3.84; 95% CI 1.28-11.5; P=0.016) were significantly associated with the clinical endpoint. CONCLUSIONS: Tp-e ≥91 ms was a significant predictor of VA events in patients with CS and ICD/CRT-D.

Utility of a multipurpose catheter for transvenous extraction of old broken leads: A novel technique for fragile leads.

BACKGROUND: Transvenous lead extraction has been possible since the 1980s. However, complications during lead extraction, such as the distal end fragment of the lead remaining in the myocardium or venous system and injury to the veins or heart, have been reported. OBJECTIVE: The purpose of this study was to examine our method for complete removal of a separated lead, as extraction of long-term implanted devices is difficult using standard methods and may require additional procedures. The removal of leads with inner conductor coil and lead tip separated from outer insulation, conductor coil, and proximal ring electrode using a multipurpose catheter is reported. METHODS: In total, 345 consecutive patients who underwent transvenous lead extraction (TLE) from April 2014 to March 2021 were retrospectively analyzed. Lead characteristics, device type, and indications for extraction were further analyzed in 20 patients who developed separation of the proximal ring electrode and outer conductor coil from the inner conductor and distal tip at the time of extraction. RESULTS: Extractions were performed using an excimer laser sheath laser and a Byrd polypropylene telescoping sheath (n = 15); laser, Byrd polypropylene telescoping sheath, and Evolution RL (n = 2); laser and Evolution RL (n = 3); Byrd polypropylene telescoping sheath and Evolution RL (n = 1); Byrd polypropylene telescoping sheath only (n = 4); and Evolution RL only (n = 2). Twenty-seven leads implanted for more than 10 years had lead separation. A multipurpose catheter was used to protect the fragile leads from further damage. All leads were completely extracted. CONCLUSION: All distal tip-to-proximal ring electrode separated leads were successfully removed using laser and other sheaths with the assistance of a multipurpose catheter, without any part of the leads remaining in the heart.

Lead switching to resolve undersensing of ventricular tachycardia by a cardiac resynchronization therapy defibrillator.

A 63-year-old man was admitted to the hospital due to ventricular tachycardia (VT) undersensing, caused by decreased R-wave amplitude in a cardiac resynchronization therapy defibrillator. The R-wave amplitude of VT sensed by the left ventricular (LV) lead was markedly higher than that by the right ventricular (RV) lead; therefore, we reconnected the IS-1 RV lead to the LV IS-1 port and the IS-1 LV lead to the RV IS-1 port to resolve this issue. After discharge, it was confirmed that VT was successfully terminated by the second sequence of intrinsic ATP (iATP, Medtronic, Minneapolis, MN, USA) from the LV lead.

Impact of the timing of first appropriate shock on outcomes in patients with an implantable cardioverter-defibrillator: Early versus late.

BACKGROUND: Appropriate implantable cardioverter-defibrillator (ICD) shocks are associated with an increased risk of mortality and heart failure (HF) events. The first appropriate shock may occur late after implantation. However, whether the timing of the first appropriate shock influences prognosis is unknown. This study aimed to evaluate the clinical significance of the timing of the first appropriate shock in patients with ICD. METHODS: This retrospective and observational study enrolled 565 consecutive ICD patients. Patients who received an appropriate shock were divided into the early group (first appropriate shock <1 year after ICD implantation) and late group (first appropriate shock ≥1 year after ICD implantation). All-cause mortality was compared between the two groups. RESULTS: Over a median follow-up of 5.6 years, 112 (19.8%) patients received an appropriate shock, including 32 patients (28.6%) in the early group and 80 patients (71.4%) in the late group. Comparisons of baseline characteristics at ICD implantation revealed that the late group was more likely to receive cardiac resynchronization therapy (66.3% vs. 31.3%, p < 0.001), ICD for primary prevention (60.0% vs. 31.3%, p = 0.001), and angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker treatment (88.8% vs. 71.9%, p = 0.028). Survival after shock was significantly worse in the late group than in the early group (p = 0.027). In multivariable Cox proportional hazards analysis, the late group had an increased risk of all-cause mortality compared with the early group (HR: 2.22; 95% CI 1.01-4.53; p = 0.029). In both groups, the most common cause of death was HF. CONCLUSIONS: Late occurrence of the first appropriate ICD shock was associated with a worse prognosis compared with early occurrence of the first appropriate shock. Cardiac death was the most common cause of death in patients who experienced late occurrence of the first appropriate ICD shock, resulting from HF in most cases.

Prognostic significance of cardiorenal dysfunction within 1 year after atrial fibrillation ablation in patients with systolic dysfunction.

Atrial fibrillation (AF) ablation can improve left ventricular ejection fraction (LVEF) and renal function and can even reduce mortality in patients with impaired LVEF. However, the effect of post-ablation cardiorenal dysfunction on the prognosis of patients with impaired LVEF who underwent AF ablation remains unclear. Of the 1243 consecutive patients undergoing AF ablation, the prognosis of 163 non-dialysis patients who underwent AF ablation with < 50% LVEF was evaluated. The primary outcome was a composite of all-cause mortality, heart failure hospitalization, and a need for modification of the treatment for heart failure. During the median follow-up of 4.2 years after the first AF ablation procedure, the primary outcome occurred in 30 of 163 patients (18%). The receiver operating characteristic curve analysis demonstrated that the post-LVEF (LVEF within 1 year after the procedure, and before the occurrence of primary outcome) had larger areas under the curve (0.70) than the pre-LVEF (LVEF before the procedure), and the most optimal cutoff value was LVEF ≤ 42%. Multivariate analysis demonstrated that patients with post-LVEF ≤ 42% and worsening renal function (WRF; an absolute increase in serum creatinine [SCr] ≥ 0.3 mg/dL compared with the SCr at baseline within 1 year after the procedure and before the occurrence of primary outcome) had a 3.4- to 4.3-fold and 3.4- to 3.7-fold higher risk of the primary outcome compared with those without these predictors, respectively. Patients were categorized using post-LVEF ≤ 42% and WRF as follows: group 1 (post-LVEF > 42% without WRF), group 2 (post-LVEF ≤ 42% without WRF), group 3 (post-LVEF > 42% with WRF), and group 4 (post-LVEF ≤ 42% with WRF). Group 4 had a 15.8-fold (P = 0.0001) higher risk of the primary outcome compared with group 1 after adjusting for pre-procedural factors. In patients with impaired LVEF undergoing AF ablation, post-LVEF ≤ 42% and WRF were independent predictors of poor prognosis. The combination of post-LVEF ≤ 42% and WRF is strongly associated with a poor prognosis in patients with AF undergoing ablation, who with these post-ablation cardiorenal dysfunction may have to be treated more intensively after AF ablation.

Impact of atrial fibrillation ablation on long-term outcomes in patients with tachycardia-bradycardia syndrome.

Background: Reports of long-term outcomes after atrial fibrillation (AF) ablation for tachycardia-bradycardia syndrome (TBS) are limited. This study aimed to investigate the impact of radiofrequency catheter ablation (RFCA) on clinical outcomes in patients with TBS. Methods: Among 1669 patients who underwent AF ablation between January 2010 and April 2020, we retrospectively enrolled 53 patients (62.3% males; age, 67.1 ± 7.0 years) who had been diagnosed with TBS before RFCA for paroxysmal AF (TBS group). After 1:2 propensity score-matching based on age, gender, AF type, and left atrial dimension, 106 patients were assigned to the control group (non-TBS group). The atrial tachyarrhythmia (ATA) recurrence rate and rate of avoidance of permanent pacemaker implantation (PMI) were examined. Results: During a median follow-up period of 37.7 months, the ATA recurrence rate after a single ablation procedure was significantly higher in the TBS group than in the non-TBS group (51.0% vs. 38.5%; log-rank p = .008); however, the ATA recurrence rate after the final ablation procedure did not significantly differ between groups. In the TBS group, the rate of PMI avoidance after AF ablation was 92.5%. A Cox-regression multivariate analysis revealed that the presence of non-pulmonary vein/superior vena cava premature atrial contractions (odds ratio, 3.38; 95% confidence interval, 1.49-7.66; p = .004) was an independent predictor of ATA recurrence in the TBS group. Conclusions: Patients with TBS had higher ATA recurrence rates after the first ablation procedure compared to those without TBS. However, ATA recurrence after AF ablation did not necessarily result in PMI for TBS patients.

Prognostic significance of diastolic dysfunction in patients with systolic dysfunction undergoing atrial fibrillation ablation.

Background: The relationship between pre-ablation left ventricular diastolic dysfunction (LVDD) and prognosis in patients with left ventricular systolic dysfunction (LVSD) undergoing atrial fibrillation (AF) ablation remains unclear. Methods: The prognosis of 173 patients with impaired left ventricular ejection fraction (<50%) who underwent AF ablation was examined. The primary outcome was a composite of all-cause mortality, heart failure (HF) hospitalization, and worsening HF symptoms requiring unplanned outpatient intensification of decongestive therapy. Results: During the follow-up period (median, 3.5 years), the primary outcome after AF ablation occurred in 28 patients (16%). The receiver operating characteristic curve analysis showed that early septal diastolic mitral annular velocity (e') had a larger area under the curve (0.70) than other LVDD parameters, and optimal cut-off values of LVDD, represented by e', septal E (early diastolic left ventricular filling velocity)/e', and peak tricuspid valve regurgitation velocity (TRV), were 5.0 cm/s, 13.2, and 2.5 m/s, respectively. Multivariate analysis revealed that e' ≤5.0 cm/s (standard hazard ratio [HR], 3.87; 95% confidence interval [CI], 1.73-8.69; p = 0.001), septal E/e' ≥13.2 (HR, 3.62; 95% CI, 1.60-8.21; p = 0.002), and peak TRV ≥ 2.5 m/s (HR, 2.42; 95% CI, 1.13-5.16; p = 0.02) independently predicted the outcome. Patients with New York Heart Association functional status ≥ III had a 3.3-4.5-fold higher risk of the outcome. Conclusions: LVDD or severe HF symptoms predict poor outcomes in patients with LVSD undergoing AF ablation. Therefore, patients with LVDD or severe HF symptoms should receive more intensive treatment even after AF ablation.

Regional differences in the predictors of acute electrical reconnection following high-power pulmonary vein isolation for paroxysmal atrial fibrillation.

BACKGROUND: Acute pulmonary vein reconnection (PVR) is associated with long procedure times and large radiofrequency (RF) energy delivery during pulmonary vein isolation (PVI). Although the efficacy of high-power PVI (HP-PVI) has been recently established, the determinants of acute PVR following HP-PVI remain unclear. METHODS: We evaluated data on 62 patients with paroxysmal atrial fibrillation undergoing unipolar signal modification (USM)-guided HP-PVI. A 50-W RF wave was applied for 3-5 seconds after USM. In the segments adjacent to the esophagus (SAEs), the RF time was limited to 5 seconds. Each circle was subdivided into six regions (segments), and the possible predictors of acute PVR, including minimum contact force (CFmin), minimum force-time integral (FTImin), minimum ablation index (AImin), minimum impedance drop (Imp-min), and maximum inter-lesion distance (ILDmax), were assessed in each segment. RESULTS: We investigated 1162 ablations in 744 segments (including 124 SAEs). Acute PVR was observed in 21 (17%) SAEs and 43 (7%) other segments (P = .001). The acute PVR segments were characterized by significantly lower CFmin, FTImin, AImin, and Imp-min values in the segments other than the SAEs and larger ILDmax values in the SAEs. Furthermore, lower Imp-min and larger ILDmax values independently predicted acute PVR in the segments other than the SAEs and SAEs (odds ratios 0.90 and 1.39 respectively). Acute PVR was not significantly associated with late atrial fibrillation recurrence. CONCLUSIONS: Avoiding PVR remains a challenge in HP-PVI cases, but it might be resolved by setting the optimal target impedance drop and lesion distance values.

Leadless cardiac pacemaker implantations after infected pacemaker system removals in octogenarians.

BACKGROUND: Management of pacemaker (PM) infections among advanced aged patients possesses particular clinical challenges due to higher rates of concurrent cardiovascular disease and medical comorbidities. Novel leadless cardiac pacemakers (LCPs) may provide new opportunities for better management options in this population, however, there is limited data especially in Asian populations to guide the decision making. METHODS: We reviewed 11 octogenarians (median age: 86 [minimum 82-maximum 90] years; male: 73%; median body mass index (BMI): 20.1 kg/m2) who received Micra Transcatheter Pacing System (Medtronic Inc, Minneapolis, MN) implantations following transvenous lead extractions (TLEs) for PM infections. RESULTS: All patients had more than two medical comorbidities (average 3.7 comorbidities). The indications for LCP implantations were atrioventricular block in four patients, atrial fibrillation bradycardia in five, and sinus node dysfunction in two. Eight patients (73%) were bridged with temporary pacing using active fixation leads (median interval of 14.0 days), while one with severe dementia underwent a concomitant LCP implantation and TLE during the same procedure. Successful TLEs and LCP implantations were successfully accomplished in all without any complications. The median time from the TLE procedure to discharge was 22 days (minimum 7-maximum 136). All patients remained free of infections during a mean follow-up period of 17.2 ± 6.5 months. CONCLUSIONS: LCP implantations were safe and effective after removing the entire infectious PM system in all octogenarians. The novel LCP technology may offer an alternative option for considering a re-implantation strategy after transvenous PM infections in elderly patients, particularly those with severe frailty and PM dependency.

Left Ventricular Stimulation With Electrical Latency Predicts Mortality in Patients Undergoing Cardiac Resynchronization Therapy.

OBJECTIVES: This study sought to evaluate the prognostic value of the time interval from left ventricular (LV) pacing to the earliest onset of QRS complex (S-QRS) for long-term clinical outcomes in patients who underwent cardiac resynchronization therapy (CRT). BACKGROUND: The electrical latency during LV pacing evaluated by S-QRS is associated with local tissue property, and the S-QRS ≥37 ms has been previously proposed as an independent predictor of mechanical response to CRT. METHODS: This study included 82 consecutive patients with heart failure with reduced LV ejection fraction (≤35%) and a wide QRS complex (≥120 ms) who underwent CRT. Patients were divided into a short S-QRS group (SS-QRS; <37 ms) and a long S-QRS group (LS-QRS; ≥37 ms). The primary endpoint was total mortality, including LV assist device implantation or heart transplantation, whereas the secondary endpoint was total mortality or HF hospitalization. RESULTS: S-QRS was 25.9 ± 5.3 ms in SS-QRS and 51.5 ± 13.7 ms in LS-QRS (p < 0.01), and baseline QRS duration and electrical activation at the LV pacing site (i.e., Q-LV) were similar. During mean follow-up of 44.5 ± 21.1 months, 24 patients (29%) reached the primary endpoint, whereas the secondary endpoints were observed in 47 patients (57%). LS-QRS had significantly worse event-free survival for both endpoints. LS-QRS was an independent predictor of total mortality (hazard ratio: 2.6; 95% confidence interval: 1.11 to 6.12; p = 0.03) and the secondary composite events (hazard ratio: 2.4; 95% confidence interval: 1.31 to 4.33; p < 0.01). CONCLUSIONS: The S-QRS ≥37 ms at the LV pacing site was a significant predictor of total mortality and HF hospitalization. S-QRS-guided optimal LV lead placement is critical in patients who receive CRT.

Technical Features and Clinical Outcomes of Coronary Venous Left Ventricular Lead Removal and Reimplantation.

BACKGROUND: The number of patients undergoing cardiac resynchronization therapy has increased. Consequently, there is increased frequency in the removal and reimplantation of coronary venous (CV) leads due to infection or malfunction.Methods and Results:A total of 345 consecutive patients referred for lead(s) extraction were reviewed. Of these, 34 patients who underwent a CV lead removal were investigated. The indications for CV leads removal were device-related infections in 29 patients and lead malfunctions in 5 patients. The average duration of the CV leads was 4.1±3.8 years. All CV leads were successfully removed without any major complications, except for 1 in-hospital death. Successful CV lead removal by simple traction (ST) was achieved in 21 patients (62%), whereas extraction tools were required in 13 patients (38%). Local infection and CV lead dwell time were significantly associated with successful ST (P=0.04 and P=0.014, respectively). CV lead re-implantation was successfully performed in 25 patients; however, a right-side approach was required in 92%, and occlusion/stenosis of the previous CV was observed in 80% of the patients. CONCLUSIONS: CV lead removal is relatively successful and safe. The presence of local infection and a shorter lead duration may enable successful ST of a CV lead. However, the re-implantation procedure should be well prepared for the complexity related to the right-side approach and occlusion/stenosis of the previous CV.

Transvenous lead extraction in a patient with polysplenia and inferior vena cava defect.

A 28-year-old woman with polysplenia was referred to our hospital for atrial lead failure. She had undergone an intracardiac repair (ICR) for incomplete atrioventricular septal defect and the implantation of epicardial pacing leads due to complete atrioventricular block at the age of 1 year. When she was 13 years old, an endocardial dual-chamber pacemaker was implanted via the right subclavian vein because of epicardial lead failure. The contrast-enhanced computed tomography scan revealed an inferior vena cava defect with an azygos vein connection to the superior vena cava, occlusion of the right brachiocephalic vein, a defect of the left brachiocephalic vein, and a persistent left superior vena cava ligated at the ICR. Therefore, lead exchange was indicated. During the operation, the temporary pacing lead and the guidewire for emergent deployment of the Bridge Occlusion Balloon® were advanced through the azygos vein and placed at the right ventricle and the hepatic vein, respectively. Both 11-Fr and 13-Fr mechanical rotational dilator sheaths were needed for the lead extraction owing to dense calcification and tight adhesions. The atrial lead was successfully extracted without any complications despite extremely restricted venous access. A new atrial lead was inserted through the space created by the 13-Fr sheath. .