Risk of Cardiac Implantable Electronic Device Infection after Early versus Delayed Lead Repositioning.

(1) Background: Early reintervention increases the risk of infection of cardiac implantable electronic devices (CIEDs). Some operators therefore delay lead repositioning in the case of dislocation by weeks; however, there is no evidence to support this practice. The aim of our study was to evaluate the impact of the timing of reoperation on infection risk. (2) Methods: The data from consecutive patients undergoing lead repositioning in two European referral centers were retrospectively analyzed. The odds ratio (OR) of CIED infection in the first year was compared among patients undergoing early (≤1 week) vs. delayed (>1 week to 1 year) reoperation. (3) Results: Out of 249 patients requiring CIED reintervention, 85 patients (34%) underwent an early (median 2 days) and 164 (66%) underwent a delayed lead revision (median 53 days). A total of nine (3.6%) wound/device infections were identified. The risk of infection was numerically lower in the early (1.2%) vs. delayed (4.9%) intervention group yielding no statistically significant difference, even after adjustment for typical risk factors for CIED infection (adjusted OR = 0.264, 95% CI 0.032-2.179, p = 0.216). System explantation/extraction was necessary in seven cases, all being revised in the delayed group. (4) Conclusions: In this bicentric, international study, delayed lead repositioning did not reduce the risk of CIED infection.

The effect of kidney function on guideline-directed medical therapy implementation and prognosis in heart failure with reduced ejection fraction.

BACKGROUND: Kidney dysfunction (KD) is a main limiting factor of applying guideline-directed medical therapy (GDMT) and reaching the recommended target doses (TD) in heart failure (HF) with reduced ejection fraction (HFrEF). HYPOTHESIS: We aimed to assess the success of optimization, long-term applicability, and adherence of neurohormonal antagonist triple therapy (TT:RASi [ACEi/ARB/ARNI] + ßB + MRA) according to the KD after a HF hospitalization and to investigate its impact on prognosis. METHODS: The data of 247 real-world, consecutive patients were analyzed who were hospitalized in 2019-2021 for HFrEF and then were followed-up for 1 year. The application and the ratio of reached TD of TT at hospital discharge and at 1 year were assessed comparing KD categories (eGFR: ≥90, 60-89, 45-59, 30-44, <30 mL/min/1.73 m2 ). Moreover, 1-year all-cause mortality and rehospitalization rates in KD subgroups were investigated. RESULTS: Majority of the patients received TT at hospital discharge (77%) and at 1 year (73%). More severe KD led to a lower application ratio (p < .05) of TT (92%, 88%, 80%, 73%, 31%) at discharge and at 1 year (81%, 76%, 76%, 68%, 40%). Patients with more severe KD were less likely (p < .05) to receive TD of MRA (81%, 68%, 78%, 61%, 52%) at discharge and a RASi (53%, 49%, 45%, 21%, 27%) at 1 year. One-year all-cause mortality (14%, 15%, 16%, 33%, 48%, p < .001), the ratio of all-cause rehospitalizations (30%, 35%, 40%, 43%, 52%, p = .028), and rehospitalizations for HF (8%, 13%, 18%, 20%, 38%, p = .001) were significantly higher in more severe KD categories. CONCLUSIONS: KD unfavorably affects the application of TT in HFrEF, however poorer mortality and rehospitalization rates among them highlight the role of the conscious implementation and up-titration of GDMT.

The Impact of Specialised Heart Failure Outpatient Care on the Long-Term Application of Guideline-Directed Medical Therapy and on Prognosis in Heart Failure with Reduced Ejection Fraction.

(1) Background: Besides the use of guideline-directed medical therapy (GDMT), multidisciplinary heart failure (HF) outpatient care (HFOC) is of strategic importance in HFrEF. (2) Methods: Data from 257 hospitalised HFrEF patients between 2019 and 2021 were retrospectively analysed. Application and target doses of GDMT were compared between HFOC and non-HFOC patients at discharge and at 1 year. 1-year all-cause mortality (ACM) and rehospitalisation (ACH) rates were compared using the Cox proportional hazard model. The effect of HFOC on GDMT and on prognosis after propensity score matching (PSM) of 168 patients and the independent predictors of 1-year ACM and ACH were also evaluated. (3) Results: At 1 year, the application of RASi, MRA and triple therapy (TT: RASi + ßB + MRA) was higher (p < 0.05) in the HFOC group, as was the proportion of target doses of ARNI, ßB, MRA and TT. After PSM, the composite of 1-year ACM or ACH was more favourable with HFOC (propensity-adjusted HR = 0.625, 95% CI = 0.401-0.974, p = 0.038). Independent predictors of 1-year ACM were age, systolic blood pressure, application of TT and HFOC, while 1-year ACH was influenced by the application of TT. (4) Conclusions: HFOC may positively impact GDMT use and prognosis in HFrEF even within the first year of its initiation.

Use of mexiletine in therapy-refractory recurrent ventricular tachycardia storm.

Electrical storm due to recurrent ventricular tachycardias (VTs) is a life-threatening arrhythmic emergency. The authors present a case report of a 69-year-old male patient with VT storm of non-ischemic etiology. Despite optimal medical treatment escalated by amiodarone antiarrhythmic drug therapy, the patient experienced multiple implantable cardioverter defibrillator (ICD) shocks. An electrophysiological study revealed an epicardial substrate; however, considering the patient's extreme obesity and active anticoagulant effect, catheter ablation was deemed to be unfeasible. Subsequently, mexiletine was added to the patient's drug regimen, resulting in successful control of arrhythmias during the following 6 months. Although the most recent European guidelines for the management of patients with ventricular arrhythmias mention mexiletine only for the treatment of LQT3 patients, its use for treatment-refractory VT storm seems to also be an important indication area.

Phenogrouping and risk stratification of patients undergoing cardiac resynchronization therapy upgrade using topological data analysis.

Choosing the optimal device during cardiac resynchronization therapy (CRT) upgrade can be challenging. Therefore, we sought to provide a solution for identifying patients in whom upgrading to a CRT-defibrillator (CRT-D) is associated with better long-term survival than upgrading to a CRT-pacemaker (CRT-P). To this end, we first applied topological data analysis to create a patient similarity network using 16 clinical features of 326 patients without prior ventricular arrhythmias who underwent CRT upgrade. Then, in the generated circular network, we delineated three phenogroups exhibiting significant differences in clinical characteristics and risk of all-cause mortality. Importantly, only in the high-risk phenogroup was upgrading to a CRT-D associated with better survival than upgrading to a CRT-P (hazard ratio: 0.454 (0.228-0.907), p = 0.025). Finally, we assigned each patient to one of the three phenogroups based on their location in the network and used this labeled data to train multi-class classifiers to enable the risk stratification of new patients. During internal validation, an ensemble of 5 multi-layer perceptrons exhibited the best performance with a balanced accuracy of 0.898 (0.854-0.942) and a micro-averaged area under the receiver operating characteristic curve of 0.983 (0.980-0.986). To allow further validation, we made the proposed model publicly available ( https://github.com/tokmarton/crt-upgrade-risk-stratification ).

Useful Electrocardiographic Signs to Support the Prediction of Favorable Response to Cardiac Resynchronization Therapy.

Cardiac resynchronization therapy (CRT) is a cornerstone therapeutic opportunity for selected patients with heart failure. For optimal patient selection, no other method has been proven to be more effective than the 12-lead ECG, and hence ECG characteristics are extensively researched. The evaluation of particular ECG signs before the implantation may improve selection and, consequently, clinical outcomes. The definition of a true left bundle branch block (LBBB) seems to be the best starting point with which to select patients for CRT. Although there are no universally accepted definitions of LBBB, using the classical LBBB criteria, some ECG parameters are associated with CRT response. In patients with non-true LBBB or non-LBBB, further ECG predictors of response and non-response could be analyzed, such as QRS fractionation, signs of residual left bundle branch conduction, S-waves in V6, intrinsicoid deflection, or non-invasive estimates of Q-LV which are described in newer publications. The most important and recent study results of the topic are summarized and discussed in this current review.

[The effect of kidney function on the optimization of medical therapy and on mortality in heart failure with reduced ejection fraction]. / A vesefunkció hatása a gyógyszeres terápia optimalizálására és a mortalitásra csökkent ejekciós frakciójú szívelégtelenségben.

INTRODUCTION: Renal dysfunction is a main limiting factor of applying and up-titrating guideline-directed medical therapy (GDMT) among patients with heart failure with reduced ejection fraction (HFrEF). OBJECTIVE: Our retrospective monocentric observational study aimed to analyse the application ratio of combined neurohormonal antagonist therapy (RASi: ACEI/ARB/ARNI + ßB + MRA) and 12-month all-cause mortality differences in terms of renal dysfunction among HFrEF patients hospitalized for heart failure. METHOD: We retrospectively analysed the cohort of consecutive HFrEF patients, hospitalized at the Heart Failure Unit of our tertiary cardiological centre in 2019-2021. The application ratio of discharge triple therapy (TT) in five groups established on admission eGFR parameters, representing severity of renal dysfunction (eGFR≥90, eGFR = 60-89, eGFR = 45-59, eGFR = 30-44, eGFR<30 ml/min/1.73 m2) was investigated with chi-square test, while 12-month mortality differences were analysed with Kaplan-Meier method and log-rank test. RESULTS: 257 patients were included. Median eGFR was 57 (39-75) ml/min/1.73 m2, 54% of patients had eGFR<60 ml/min/1.73 m2. The proportion of patients in eGFR≥90, 60-89, 45-59, 30-44, <30 ml/min/1.73 m2 subgroups was 12%, 34%, 18%, 21%, 15%, respectively. 2% of patients were on dialysis. Even though the application rate of TT was notably high (77%) in the total cohort, more severe renal dysfunction led to a significantly lower implementation rate of TT (94%, 86%, 91%, 70%, 34%; p<0.0001): the application rate of RASi (100%, 98%, 96%, 89%, 50%, p<0.0001), ßB (94%, 88%, 96%, 79%, 68%; p = 0.003) and MRA therapy (97%, 99%, 98%, 94%, 82%; p = 0.001) differed significantly. 12-month all-cause mortality was 23% in the whole cohort. Mortality rates were higher in more severe renal dysfunction (3%, 15%, 22%, 31%, 46%; p<0.0001). CONCLUSION: Even though the proportion of patients on TT in the whole cohort was remarkably high, renal dysfunction led to a significantly lower application ratio of TT, associating with worse survival. Our results highlight that despite renal dysfunction the application of HFrEF cornerstone pharmacotherapy is essential. Orv Hetil. 2023; 164(35): 1387-1396.

Zero fluoroscopy catheter ablation for atrial fibrillation: a systematic review and meta-analysis.

Introduction: Catheter ablation for atrial fibrillation (AF) is the most frequently performed cardiac ablation procedure worldwide. The majority of ablations can now be performed safely with minimal radiation exposure or even without the use of fluoroscopy, thanks to advances in 3-dimensional electroanatomical mapping systems and/or intracardiac echocardiography. The aim of this study was to conduct a meta-analysis to compare the effectiveness of zero fluoroscopy (ZF) versus non-zero fluoroscopy (NZF) strategies for AF ablation procedures. Methods: Electronic databases were searched and systematically reviewed for studies comparing procedural parameters and outcomes of ZF vs. NZF approaches in patients undergoing catheter ablation for AF. We used a random-effects model to derive the mean difference (MD) and risk ratios (RR) with a 95% confidence interval (CI). Results: Our meta-analysis included seven studies comprising 1,593 patients. The ZF approach was found to be feasible in 95.1% of patients. Compared to the NZF approach, the ZF approach significantly reduced procedure time [mean difference (MD): -9.11 min (95% CI: -12.93 to -5.30 min; p < 0.01)], fluoroscopy time [MD: -5.21 min (95% CI: -5.51 to -4.91 min; p < 0.01)], and fluoroscopy dose [MD: -3.96 mGy (95% CI: -4.27 to -3.64; p < 0.01)]. However, there was no significant difference between the two groups in terms of total ablation time [MD: -104.26 s (95% CI: -183.37 to -25.14; p = 0.12)]. Furthermore, there was no significant difference in the acute [risk ratio (RR): 1.01, 95% CI: 1.00-1.02; p = 0.72] and long-term success rates (RR: 0.96, 95% CI: 0.90-1.03; p = 0.56) between the ZF and NZF methods. The complication rate was 2.76% in the entire study population and did not differ between the groups (RR: 0.94, 95% CI: 0.41-2.15; p = 0.89). Conclusion: The ZF approach is a feasible method for AF ablation procedures. It significantly reduces procedure time and radiation exposure without compromising the acute and long-term success rates or complication rates.

Indications for mexiletine in the new ESC guidelines and beyond.

INTRODUCTION: Mexiletine is a class IB sodium-channel blocker. Unlike class IA or IC antiarrhythmic drugs, mexiletine rather shortens than prolongs action potential duration; therefore, it is less associated with proarrhythmic effects. AREAS COVERED: Recently, new European Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death were published, including a reappraisal of some established older antiarrhythmic drugs. EXPERT OPINION: Mexiletine offers a first-line, genotype-specific treatment strategy for LQT3 patients as emphasized by the most recent guidelines. Besides this recommendation, current study reports suggest that in therapy-refractory ventricular tachyarrhythmias and electrical storms adjunctive mexiletine treatment may offer the possibility of stabilizing patients with or without concomitant interventional therapy such as catheter ablation.

Editorial: Developments in cardiac implantable electronic device therapy: how can we improve clinical implementation?

CIED, cardiac implantable electronic devices; CRT, cardiac resynchronization therapy; CRT-D, cardiac resynchronization therapy defibrillator; EA, electroanatomical; ICD, implantable cardioverter defibrillator; LBB, left bundle branch; LBBAP, left bundle branch area pacing; LV, left ventricular; LVEF, left ventricular ejection fraction; NT-proBNP, N-terminal pro-B-type natriuretic peptide; MRI, cardiac magnetic resonance imaging; S-ICD, subcutaneous defibrillator.

Ultrasound guidance for femoral venous access in patients undergoing pulmonary vein isolation: A quasi-randomized study.

INTRODUCTION: Routine ultrasound (US) guidance for femoral venous access to decrease vascular complications of atrial fibrillation (AF) ablation procedures has been advocated. However, the benefit has not been unequivocally demonstrated by randomized-trial data. METHODS: Consecutive patients undergoing pulmonary vein isolation (PVI) on uninterrupted anticoagulant treatment were included. A quasi-random allocation to either US-guided or conventional puncture group was based on which of the two procedure rooms the patient was scheduled in, with only one of the rooms equipped with a US machine including a vascular transducer. The same four novice operators in rotation, with no relevant previous experience in US-guided vascular access performed venous punctures in both rooms. Major and minor vascular complications and the rate of prolonged hospitalization were compared. Major vascular complication was defined as groin hematoma, arteriovenous fistula, or pseudoaneurysm. Hematoma was considered as a major vascular complication if it met type 2 or higher Bleeding Academic Research Consortium criteria (requiring nonsurgical, medical intervention by a health care professional; leading to hospitalization or increased level of care, or prompting evacuation). RESULTS: Of the 457 patients 199 were allocated to the US-guided puncture group, while the conventional, palpation-based approach was performed in 258 cases. Compared with the conventional technique, US guidance reduced the rate of any vascular complication (11.63% vs. 2.01%, p < .0001), including both major (4.26% vs. 1.01%, p = .038) and minor (7.36% vs. 1.01%, p = .001) vascular complications. In addition, the rate of prolonged hospitalization was lower in the US-guided puncture group (5.04% vs. 1.01%, p = .032). CONCLUSION: The use of US for femoral vein puncture in patients undergoing PVI decreased the rate of both major and minor vascular complications. This quasi-randomized comparison strongly supports adapting routine use of US for AF ablation procedures.

A head-to-head comparison of laser vs. powered mechanical sheaths as first choice and second line extraction tools.

AIMS: During transvenous lead extraction (TLE) longer dwelling time often requires the use of powered sheaths. This study aimed to compare outcomes with the laser and powered mechanical tools. METHODS AND RESULTS: Single-centre data from consecutive patients undergoing TLE between 2012 and 2021 were retrospectively analysed. Efficacy and safety of the primary extraction tool were compared. Procedures requiring crossover between powered sheaths were also analysed. Moreover, we examined the efficacy of each level of the stepwise approach. Out of 166 patients, 142 (age 65.4 ± 13.7 years) underwent TLE requiring advanced techniques with 245 leads (dwelling time 9.4 ± 6.3 years). Laser sheaths were used in 64.9%, powered mechanical sheaths in 35.1% of the procedures as primary extraction tools. Procedural success rate was 85.5% with laser and 82.5% with mechanical sheaths (P = 0.552). Minor and major complications were observed in similar rate. Procedural mortality occurred only in the laser group in the case of three patients. Crossover was needed in 19.5% after laser and in 12.8% after mechanical extractions (P = 0.187). Among crossover procedures, only clinical success favoured the secondary mechanical arm (87.1 vs. 54.5%, aOR: 0.09, 95% CI: 0.01-0.79, P = 0.030). After step-by-step efficacy analysis, procedural success was 64.9% with the first-line extraction tool, 75.1% after crossover, 84.5% with bailout femoral snare, and 91.8% by non-emergency surgery. CONCLUSION: The efficacy and safety of laser and mechanical sheaths were similar, however in the subgroup of crossover procedures mechanical tools had better performance regarding clinical success. Device diversity seems to help improving outcomes, especially in the most complicated cases.

Reimplantation and long-term mortality after transvenous lead extraction in a high-risk, single-center cohort.

PURPOSE: The use of cardiac implantable electronic devices (CIEDs) has increased significantly over the last decades. With the development of transvenous lead extraction (TLE), procedural success rates also improved; however, data regarding long-term outcomes are still limited. The aim of our study was to analyze the outcomes after TLE, including reimplantation data, all-cause and cause-specific mortality. METHODS: Data from consecutive patients undergoing TLE in our institution between 2012 and 2020 were retrospectively analyzed. Periprocedural, 30-day, long-term, and cause-specific mortalities were calculated. We examined the original and the revised CIED indications and survival rate of patients with or without reimplantation. RESULTS: A total of 150 patients (age 66 ± 14 years) with 308 leads (dwelling time 7.8 ± 6.3 years) underwent TLE due to pocket infection (n = 105, 70%), endocarditis (n = 35, 23%), or non-infectious indications (n = 10, 7%). All-cause mortality data were available for all patients, detailed reimplantation data in 98 cases. Procedural death rate was 2% (n = 3), 30-day mortality rate 2.6% (n = 4). During the 3.5 ± 2.4 years of follow-up, 44 patients died. Arrhythmia, as the direct cause of death, was absent. Cardiovascular cause was responsible for mortality in 25%. There was no significant survival difference between groups with or without reimplantation (p = 0.136). CONCLUSIONS: Despite the high number of pocket and systemic infection and long dwelling times in our cohort, the short- and long-term mortality after TLE proved to be favorable. Moreover, survival without a new device was not worse compared to patients who underwent a reimplantation procedure. Our study underlines the importance of individual reassessment of the original CIED indication, to avoid unnecessary reimplantation.

Geno- and phenotypic characteristics and clinical outcomes of CACNA1C gene mutation associated Timothy syndrome, "cardiac only" Timothy syndrome and isolated long QT syndrome 8: A systematic review.

Background: Mutations in the CACNA1C gene-encoding for the major Ca2+ channel of the heart-may exhibit a variety of clinical manifestations. These include typical or atypical Timothy syndromes (TS) which are associated with multiple organ manifestations, and cardiac involvement in form of malignant arrhythmias, QTc prolongation, or AV block. "Cardiac only" Timothy syndrome (COTS) shows no extracardiac manifestation, whereas some CACNA1C gene mutations are associated with QTc prolongation alone (isolated long QT syndrome 8, LQT8). Methods: A systematic search of the literature reporting cases of CACNA1C gene mutation associated syndromes, including TS, COTS and isolated LQT8 via major databases published from 2004 through 2019 was performed. Detailed patient-level phenotypic and genotypic characteristics, as well as long-term outcome measures were collected and compared between pre-specified patient groups, defined both on phenotype and genotype. Results: A total of 59 TS, 6 COTS, and 20 isolated LQT8 index cases were identified. Apart of syndactyly or baldness, there were no major differences regarding clinical manifestations or outcome measures between TS subtypes, either defining TS subtypes on the genotype or based on the phenotype. Both subtypes were characterized by an extreme degree of QTc prolongation (median ≥600 ms) which were reflected in high major adverse cardiac event rate. On the other hand, there were marked differences between TS, COTS, and isolated LQT8. Timothy syndrome was characterized by a much earlier disease onset, much more pronounced QTc prolongation and much higher mortality rate than COTS or isolated LQT8. Similar differences were observed comparing CACNA1C exon 8/8A vs. non-exon 8/8A mutation carriers. TS showed a high degree of genetic homogeneity, as the p.Gly406Arg mutation either in exon 8 or exon 8A alone was responsible for 70% of the cases. Conclusions: Clinical phenotypes associated with mutations in the CACNA1C gene show important clinical differences. Timothy syndrome is associated with the most severe clinical phenotype and with the highest risk of morbidity and mortality. However, distinguishing TS subtypes, in any form, are not supported by our data. Systematic review registration: [https://www.crd.york.ac.uk/prospero/], identifier [CRD42020184737].

Clinical outcomes of subcutaneous vs. transvenous implantable defibrillator therapy in a polymorbid patient cohort.

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) has been designed to overcome lead-related complications and device endocarditis. Lacking the ability for pacing or resynchronization therapy its usage is limited to selected patients at risk for sudden cardiac death (SCD). Objective: The aim of this single-center study was to assess clinical outcomes of S-ICD and single-chamber transvenous (TV)-ICD in an all-comers population. Methods: The study cohort comprised a total of 119 ICD patients who underwent either S-ICD (n = 35) or TV-ICD (n = 84) implantation at the University Hospital Frankfurt from 2009 to 2017. By applying an inverse probability-weighting (IPW) analysis based on the propensity score including the Charlson Comorbidity Index (CCI) to adjust for potential extracardiac comorbidities, we aimed for head-to-head comparison on the study composite endpoint: overall survival, hospitalization, and device-associated events (including appropriate and inappropriate shocks or system-related complications). Results: The median age of the study population was 66.0 years, 22.7% of the patients were female. The underlying heart disease was ischemic cardiomyopathy (61.4%) with a median LVEF of 30%. Only 52.9% had received an ICD for primary prevention, most of the patients (67.3%) had advanced heart failure (NYHA class II-III) and 16.8% were in atrial fibrillation. CCI was 5 points in TV-ICD patients vs. 4 points for patients with S-ICD (p = 0.209) indicating increased morbidity. The composite endpoint occurred in 38 patients (31.9 %), revealing no significant difference between patients implanted with an S-ICD or TV-ICD (unweighted HR 1.50, 95 % confidence interval (CI) 0.78-2.90; p = 0.229, weighted HR 0.94, 95% CI, 0.61-1.50, p = 0.777). Furthermore, we observed no difference in any single clinical endpoint or device-associated outcome, neither in the unweighted cohort nor following inverse probability-weighting. Conclusion: Clinical outcomes of the S-ICD and TV-ICD revealed no differences in the composite endpoint including survival, freedom of hospitalization and device-associated events, even after careful adjustment for potential confounders. Moreover, the CCI was evaluated in a S-ICD cohort demonstrating higher survival rates than predicted by the CCI in young, polymorbid (S-)ICD patients.

Inability to perform 'en bloc' pulmonary vein isolation requiring ablation of the intervenous carina increases recurrence of atrial fibrillation: A meta-analysis.

INTRODUCTION: Failure to isolate ipsilateral pulmonary veins (PV) "en bloc" by wide-area circumferential ablation (WACA) may necessitate ablation at the intervenous carina. It is unknown how this scenario impacts rates of atrial fibrillation (AF) recurrence. METHODS: A standard random-effect meta-analysis of randomized or observational studies were performed, where the outcome of first-time AF ablation was reported in patients with "en bloc" isolation of PVs by WACA as compared with those in whom ablation at the intervenous carina was needed after WACA to achieve complete isolation. RESULTS: A total of five single-center, observational studies (N = 1185) and one, multi-center randomized trial (N = 234) were enrolled. PV isolation could be achieved by WACA "en bloc" in 902/1419 (63.6%) cases. The rest required additional ablation at one or both of the left and right intervenous carinas to achieve isolation. The follow-up time after ablation ranged from 1 to 2 years in the included trials. The incidence of AF recurrence proved to be significantly lower in patients with successful "en bloc" isolation compared to those requiring carina ablation(s) to achieve complete bilateral PV isolation (MH-OR 1.89, 95% CI 1.42-2.53, p < .01) CONCLUSION: This present meta-analysis demonstrates a lower arrhythmia recurrence rate in patients with bilateral "en bloc" isolation, as compared to those who needed additional carina ablation for complete PVI. Therefore, it is imperative that every effort be made to isolate ipsilateral PVs "en bloc" during PVI.

Association between electrical and mechanical remodeling after cardiac resynchronization therapy: systematic review and meta-analysis of observational studies.

Cardiac resynchronization therapy (CRT) may improve not only impaired left ventricular contractility but can also induce reverse remodeling of native conduction system. Measurement of intrinsic QRS complex width during follow-up is the simplest method to assess reverse electrical remodeling (RER). We aimed to provide a literature review and meta-analysis on incidence and impact of RER and its association with mechanical remodeling. A systematic review and random-effect meta-analysis of studies reporting data on RER was performed. A total of 16 studies were included in this meta-analysis with 930 patients undergoing CRT (mean age 64.0 years, 64.1% males). The weighted mean incidence of RER was 42%. Reverse mechanical remodeling assessed by echocardiography was more frequently observed in patients with RER compared to patients without RER (75.7% vs. 46.6%; odds ratio [OR] 3.7, 95% confidence interval [CI] 2.24-6.09, p < 0.01). Mechanical responders had a mean iQRS shortening of 7.7 ms, while mechanical non-responders experienced a mean widening of iQRS by 5.2 ms (p < 0.01). Clinical improvement was more frequent in patients with RER vs. patients without RER (82.9% vs. 49.0%; OR 5.26; 95% CI 2.92-9.48; p < 0.01). No significant difference in all-cause mortality between patients with and without RER was found. Mean difference between baseline intrinsic QRS and post-implantation paced QRS was significant in patients with later RER (21.2 ms, 95% CI 9.4-32.9, p < 0.01), but not in patients without RER (6.6 ms, 95% CI -2.2-15.4, p = 0.14). Gender, initial left bundle block morphology and heart failure etiology were found not to be predictive for RER. Our meta-analysis demonstrates that shortening of iQRS duration is a common finding during follow-up of patients undergoing CRT and is associated with mechanical reverse remodeling and clinical improvement. Clinical Trial Registration: Prospero Database-CRD42021253336.

Zero and Minimal Fluoroscopic Approaches During Ablation of Supraventricular Tachycardias: A Systematic Review and Meta-Analysis.

Introduction: Catheter ablations for cardiac arrhythmias are conventionally performed under fluoroscopic guidance. To guide these procedures, zero/minimal fluoroscopy (Z/MF) approaches have become available, using three-dimensional electroanatomical mapping systems. Our aim was to conduct a meta-analysis comparing these two different methods for the treatment of paroxysmal supraventricular tachycardia (SVT). Methods: Electronic databases were searched and systematically reviewed for studies comparing procedural parameters and outcomes of conventional, fluoroscopy-guided vs. Z/MF approaches in patients undergoing electrophysiology (EP) procedures for SVTs. The random-effects model was used to derive mean difference (MD) and risk ratios (RRs) with 95% confidence interval (CI). Results: Twenty-four studies involving 9,074 patients met our inclusion criteria. There was no difference between the groups in terms of acute success rate (RR = 1.00, 95% CI, 0.99-1.01; p = 0.97) and long-term success rate (RR: 1.01, 95% CI, 1.00-1.03; p = 0.13). Compared to the conventional method, zero-and-minimal fluoroscopy (Z/MF) ablation significantly reduced fluoroscopic time [MD: -1.58 min (95% CI, -2.21 to -0.96 min; p < 0.01)] and ablation time [MD: -25.23 s (95% CI: -42.04 to -8.43 s; p < 0.01)]. No difference could be detected between the two groups in terms of the procedure time [MD: 3.06 min (95% CI: -0.97 to 7.08; p = 0.14)] and the number of ablation applications [MD: 0.13 (95% CI: -0.86 to 1.11; p = 0.80)]. The complication rate was 1.59% in the entire study population and did not differ among the groups (RR: 0.68, 95% CI: 0.45-1.05; p = 0.08). Conclusions: The Z/MF approach for the catheter ablation of SVTs is a feasible method that reduces radiation exposure and ablation time without compromising the acute and long-term success or complication rates.