Dual energy for pulmonary vein isolation using dual-energy focal ablation technology integrated with a three-dimensional mapping system: SmartfIRE 3-month results.

AIMS: Contact force (CF)-sensing radiofrequency (RF) catheters with an ablation index have shown reproducible outcomes for the treatment of atrial fibrillation (AF) in large multicentre studies. A dual-energy (DE) focal CF catheter to deliver RF and unipolar/biphasic pulsed field ablation (PFA), integrated with a three-dimensional (3D) mapping system, can provide operators with additional flexibility. The SmartfIRE study assessed the safety and efficacy of this novel technology for the treatment of drug-refractory, symptomatic paroxysmal AF. Results at 3 months post-ablation are presented here. METHODS AND RESULTS: Pulmonary vein isolation (PVI) was performed using a DE focal, irrigated CF-sensing catheter with the recommendation of PFA at posterior/inferior and RF ablation at the anterior/ridge/carina segments. Irrespective of energy, a tag size of 3 mm; an inter-tag distance ≤6 mm; a target index of 550 for anterior, roof, ridge, and carina; and a target index of 400 for posterior and inferior were recommended. Cavotricuspid isthmus ablation was permitted in patients with documented typical atrial flutter. The primary effectiveness endpoint was acute procedural success. The primary safety endpoint was the rate of primary adverse events (PAEs) within 7 days of the procedure. A prespecified patient subset underwent oesophageal endoscopy (EE; 72 h post-procedure), neurological assessment (NA; pre-procedure and discharge), and cardiac computed tomography (CT)/magnetic resonance angiogram (MRA) imaging (pre-procedure and 3 months post-procedure) for additional safety evaluation, and a mandatory remapping procedure (Day 75 ± 15) for PVI durability assessment. Of 149 patients enrolled between February and June 2023, 140 had the study catheter inserted (safety analysis set) and 137 had ablation energy delivered (per-protocol analysis set). The median (Q1/Q3) total procedure and fluoroscopy times were 108.0 (91.0/126.0) and 4.2 (2.3/7.7) min (n = 137). The acute procedural success rate was 100%. First-pass isolation was achieved in 89.1% of patients and 96.8% of veins. Cavotricuspid isthmus ablations were successfully performed in 12 patients [pulsed field (PF) only: 6, RF only: 5, and RF/PF: 1]. The PAE rate was 4.4% [6/137 patients; 2 pulmonary vein (PV) stenoses, 2 cardiac tamponades/perforations, 1 stroke, and 1 pericarditis]. No coronary artery spasm was reported. No oesophageal lesion was seen in the EE subset (0/31, 0%). In the NA subset (n = 30), microemboli lesions were identified in 2 patients (2/30, 6.7%), both of which were resolved at follow-up; only 1 was symptomatic (silent cerebral lesion, 3.3%). In the CT/MRA subset (n = 30), severe PV narrowing (of >70%) was detected in 2 patients (2/30, 6.7%; vein level 2/128, 1.6%), of whom 1 underwent dilatation and stenting and 1 was asymptomatic; both were associated with high index values and a small inter-tag distance. In the PV durability subset (n = 30), 100/115 treated PVs (87%) were durably isolated and 18/30 patients (60.0%) had all PVs durably isolated. CONCLUSION: A DE focal CF catheter with 3D mapping integration showed a 100% acute success rate with an acceptable safety profile in the treatment of paroxysmal AF. Prespecified 3-month remapping showed notable PVI durability. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05752487.

Economic analyses in cardiac electrophysiology: from clinical efficacy to cost utility.

Cardiac electrophysiology is an evolving field that relies heavily on costly device- and catheter-based technologies. An increasing number of patients with heart rhythm disorders are becoming eligible for cardiac interventions, not least due to the rising prevalence of atrial fibrillation and increased longevity in the population. Meanwhile, the expansive costs of healthcare face finite societal resources, and a cost-conscious approach to new technologies is critical. Cost-effectiveness analyses support rational decision-making in healthcare by evaluating the ratio of healthcare costs to health benefits for competing therapies. They may, however, be subject to significant uncertainty and bias. This paper aims to introduce the basic concepts, framework, and limitations of cost-effectiveness analyses to clinicians including recent examples from clinical electrophysiology and device therapy.

Targeted left ventricular lead positioning to the site of latest activation in cardiac resynchronization therapy: a systematic review and meta-analysis.

AIMS: Several studies have evaluated the use of electrically- or imaging-guided left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT) recipients. We aimed to assess evidence for a guided strategy that targets LV lead position to the site of latest LV activation. METHODS AND RESULTS: A systematic review and meta-analysis was performed for randomized controlled trials (RCTs) until March 2023 that evaluated electrically- or imaging-guided LV lead positioning on clinical and echocardiographic outcomes. The primary endpoint was a composite of all-cause mortality and heart failure hospitalization, and secondary endpoints were quality of life, 6-min walk test (6MWT), QRS duration, LV end-systolic volume, and LV ejection fraction. We included eight RCTs that comprised 1323 patients. Six RCTs compared guided strategy (n = 638) to routine (n = 468), and two RCTs compared different guiding strategies head-to-head: electrically- (n = 111) vs. imaging-guided (n = 106). Compared to routine, a guided strategy did not significantly reduce the risk of the primary endpoint after 12-24 (RR 0.83, 95% CI 0.52-1.33) months. A guided strategy was associated with slight improvement in 6MWT distance after 6 months of follow-up of absolute 18 (95% CI 6-30) m between groups, but not in remaining secondary endpoints. None of the secondary endpoints differed between the guided strategies. CONCLUSION: In this study, a CRT implantation strategy that targets the latest LV activation did not improve survival or reduce heart failure hospitalizations.

Atrial pacing minimization in sinus node dysfunction and risk of incident atrial fibrillation: a randomized trial.

BACKGROUND AND AIMS: High percentages of atrial pacing have been associated with an increased risk of atrial fibrillation. This study is aimed at evaluating whether atrial pacing minimization in patients with sinus node dysfunction reduces the incidence of atrial fibrillation. METHODS: In a nationwide, randomized controlled trial, 540 patients with sinus node dysfunction and an indication for first pacemaker implantation were assigned to pacing programmed to a base rate of 60 bpm and rate-adaptive pacing (DDDR-60) or pacing programmed to a base rate of 40 bpm without rate-adaptive pacing (DDD-40). Patients were followed on remote monitoring for 2 years. The primary endpoint was time to first episode of atrial fibrillation longer than 6 min. Secondary endpoints included longer episodes of atrial fibrillation, and the safety endpoint comprised a composite of syncope or presyncope. RESULTS: The median percentage of atrial pacing was 1% in patients assigned to DDD-40 and 49% in patients assigned to DDDR-60. The primary endpoint occurred in 124 patients (46%) in each treatment group (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.76-1.25, P = .83). There were no between-group differences in atrial fibrillation exceeding 6 or 24 h, persistent atrial fibrillation, or cardioversions for atrial fibrillation. The incidence of syncope or presyncope was higher in patients assigned to DDD-40 (HR 1.71, 95% CI 1.13-2.59, P = .01). CONCLUSIONS: Atrial pacing minimization in patients with sinus node dysfunction does not reduce the incidence of atrial fibrillation. Programming a base rate of 40 bpm without rate-adaptive pacing is associated with an increased risk of syncope or presyncope.

Cost-effectiveness of an antibacterial envelope for infection prevention in patients undergoing cardiac resynchronization therapy reoperations in Denmark.

AIMS: Use of an absorbable antibacterial envelope during implantation prevents cardiac implantable electronic device infections in patients with a moderate-to-high infection risk. Previous studies demonstrated that an envelope is cost-effective in high-risk patients within German, Italian, and English healthcare systems, but these analyses were based on limited data and may not be generalizable to other healthcare settings. METHODS AND RESULTS: A previously published decision-tree-based cost-effectiveness model was used to compare the costs per quality-adjusted life year (QALY) associated with adjunctive use of an antibacterial envelope for infection prevention compared to standard-of-care intravenous antibiotics. The model was adapted using data from a Danish observational two-centre cohort study that investigated infection-risk patients undergoing cardiac resynchronization therapy (CRT) reoperations with and without an antibacterial envelope (n = 1943). We assumed a cost-effectiveness threshold of €34 125/QALY gained, based on the upper threshold used by the National Institute for Health and Care Excellence (£30 000). An antibacterial envelope was associated with an incremental cost-effectiveness ratio (ICER) of €12 022 per QALY in patients undergoing CRT reoperations, thus indicating that the envelope is cost-effective when compared with standard of care. A separate analysis stratified by device type showed ICERS of €6227 (CRT defibrillator) and €29 177 (CRT pacemaker) per QALY gained. CONCLUSIONS: Cost-effectiveness ratios were favourable for patients undergoing CRT reoperations in the Danish healthcare system, and thus are in line with previous studies. Results from this study can contribute to making the technology available to Danish patients and align preventive efforts in the pacemaker and ICD area.

Does targeted positioning of the left ventricular pacing lead towards the latest local electrical activation in cardiac resynchronization therapy reduce the incidence of death or hospitalization for heart failure?

BACKGROUND: Cardiac resynchronization therapy (CRT) improves symptoms, health-related quality of life and long-term survival in patients with systolic heart failure (HF) and shortens QRS duration. However, up to one third of patients attain no measurable clinical benefit from CRT. An important determinant of clinical response is optimal choice in left ventricular (LV) pacing site. Observational data have shown that achieving an LV lead position at a site of late electrical activation is associated with better clinical and echocardiographic outcomes compared to standard placement, but mapping-guided LV lead placement towards the site of latest electrical activation has never been investigated in a randomized controlled trial (RCT). The purpose of this study was to evaluate the effect of targeted positioning of the LV lead towards the latest electrically activated area. We hypothesize that this strategy is superior to standard LV lead placement. METHODS: The DANISH-CRT trial is a national, double-blinded RCT (ClinicalTrials.gov NCT03280862). A total of 1,000 patients referred for a de novo CRT implantation or an upgrade to CRT from right ventricular pacing will be randomized 1:1 to receive conventional LV lead positioning preferably in a nonapical posterolateral branch of the coronary sinus (CS) (control group) or targeted positioning of the LV lead to the CS branch with the latest local electrical LV activation (intervention group). In the intervention group, late activation will be determined using electrical mapping of the CS. The primary endpoint is a composite of death and nonplanned HF hospitalization. Patients are followed for a minimum of 2 years and until 264 primary endpoints occurred. Analyses will be conducted according to the intention-to-treat principle. Enrollment for this trial began in March 2018, and per April 2023, a total of 823 patients have been included. Enrollment is expected to be complete by mid-2024. CONCLUSIONS: The DANISH-CRT trial will clarify whether mapping-guided positioning of the LV lead according to the latest local electrical activation in the CS is beneficial for patients in terms of reducing the composite endpoint of death or nonplanned hospitalization for heart failure. Results from this trial are expected to impact future guidelines on CRT. GOV IDENTIFIER: NCT03280862.

Long-term follow-up of selective and non-selective His bundle pacing leads in patients with atrioventricular block.

BACKGROUND: His bundle pacing (HBP) is a novel treatment with limited knowledge on long-term outcome. We aimed to assess long-term safety and effectiveness of HBP in patients with atrioventricular block treated with HBP and a back-up right ventricular pacing (RVP) lead. METHODS: We included 38 patients from a completed single-center, randomized controlled cross-over trial designed to compare left ventricular (LV) function after 12 months of HBP vs. RVP conducted between September 2007 and August 2011. Lead performance beyond the 2-year study period was assessed based on a retrospective review of capture thresholds, sensing, impedance, energy consumption, and rate of HBP interruption. RESULTS: Patients were followed for a mean of 7 ± 4 years. Both at baseline and during follow-up, HBP leads displayed significantly higher capture thresholds than RVP leads (P < 0.001), multifold higher energy consumption (P < 0.001), and lower sensing amplitudes (P < 0.001). During follow-up, 17 (53%) HBP leads were deactivated or abandoned. The principal cause for HBP interruption was high pacing thresholds in patients with preserved LVEF during RVP. Device longevity was shorter than that of contemporary cohorts treated with dual-chamber pacing or CRT, and time to first device exchange was 6.8 ± 1.5 years. No lead dislodgements occurred, but four patients (10%) developed device-related infections requiring device extraction. CONCLUSION: HBP was interrupted in > 50% of patients during long-term follow-up. The principal cause was unacceptably high capture thresholds and no significant difference in LV function with HBP compared with RVP. Device longevity was shorter, and infection rates were higher than anticipated.

Social determinants of health and recurrence of atrial fibrillation after catheter ablation: a Danish nationwide cohort study.

AIMS: To examine the associations between three social determinants of health (SDOH) and recurrence of AF after ablation. METHODS AND RESULTS: We selected patients who underwent a first ablation after an incident hospital diagnosis of AF between 2005 and 2018 from the entire Danish population. Educational attainment, family income, and whether the patient was living alone were assessed at the time of ablation. We used cause-specific proportional hazard models to estimate hazard ratios (HR) with 95% confidence interval (CI) adjusted for age and sex. In secondary analyses, we adjusted for comorbidities, antiarrhythmic medication, and prior electrical cardioversion.We selected 9728 patients (mean age 61 years, 70% men), and 5881 patients had AF recurrence over an average of 1.37 years after ablation (recurrence rate 325.7 (95% CI 317.6-334.2) per 1000 person-years). Lower education (HR 1.09 [1.02-1.17] and 1.07 [1.01-1.14] for lower and medium vs. higher), lower income [HR 1.14 (1.06-1.22) and 1.09 (1.03-1.17) for lower and medium vs. higher], and living alone [HR 1.07 (1.00-1.13)] were associated with increased rates of recurrence of AF. We found no evidence of interaction between sex or prior HF with SDOH. The association between family income and AF recurrence was stronger among patients < 65 years compared with those aged ≥ 65 years. The associations between SDOH and AF recurrence did not persist in the multivariable model. CONCLUSION: AF was more likely to recur among patients with lower educational attainment, lower family income, or those living alone. Multidisciplinary efforts are needed to reduce socioeconomic inequity in the effect of ablation.

Social determinants of health and catheter ablation after an incident diagnosis of atrial fibrillation: a Danish nationwide cohort study.

AIMS: To examine (i) the sex-specific associations between three social determinants of health (SDOH) and use of ablation after incident atrial fibrillation (AF), and (ii) the temporal trends in these associations. METHODS AND RESULTS: We conducted a nationwide cohort study of patients with an incident hospital diagnosis of AF between 2005 and 2018. SDOH at the time of AF diagnosis included three levels of educational attainment, tertile groups of family income, and whether the patient was living alone. Outcome was catheter ablation for AF. We used cause-specific proportional hazard models to estimate hazard ratios (HR) with 95% CI and adjusted for age. To examine temporal trends, we included an interaction term between the exposure and calendar years. Among 122 276 men, those with lower education [HR 0.49 (95%CI 0.45-0.53)] and 0.72 (0.68-0.77) for lower and medium vs. higher], lower income [HR 0.31 (0.27-0.34) and 0.56 (0.52-0.60) for lower and medium vs. higher], and who lived alone [HR 0.60 (0.55-0.64)] were less likely to receive AF ablation. Among 98 476 women, those with lower education [HR 0.45 (0.40-0.50) and 0.83 (0.75-0.91) for lower and medium vs. higher], lower income [HR 0.34 (0.28-0.40) and 0.51 (0.46-0.58) for lower and medium vs. higher], and who lived alone [HR 0.67 (0.61-0.74)] were less likely to receive AF ablation. We found no evidence of temporal trends in the associations. CONCLUSION: In the Danish universal healthcare system, patients with AF who had lower educational attainment, lower family income, or were living alone were less likely to undergo AF ablation.

Cardiac surgery in patients with cardiac implantable electronic devices and risk of device infections: a nationwide nested case-control study.

PURPOSE: Cardiac surgery in patients with cardiac implantable electronic devices (CIEDs) has been associated with a higher risk of infective endocarditis, but how it influences risk of CIED-specific infections is not known. Our aim was to examine risk of systemic CIED infections after cardiac surgery in patients with CIEDs. METHODS: Based on data obtained from Danish administrative registries and the Danish Pacemaker and ICD Register, we conducted a case-control study nested within a nationwide cohort of patients who underwent a de novo CIED implantation in Denmark between 1998 and 2017. We defined cases as incident systemic CIED infections resulting in device system extraction. Controls were sampled 1:100 on time, age, sex and device type using risk set sampling. Exposure was defined as coronary artery bypass graft, or cardiac heart valve replacement or repair surgery. RESULTS: From a study cohort comprising 67,621 patients, we identified 170 cases and 16,788 controls. In the minimally adjusted model, the incidence rate ratio (IRR) for systemic CIED infection was 6.4 (95% confidence interval (CI) 3.8-10.7) with cardiac surgery, and after additional confounder adjustment, 5.4 (95% CI 3.2-9.2). IRRs were higher with restriction to heart valve replacement surgery (adjusted IRR 7.5, 95% CI 4.0-16.6), and when limiting our exposure time window to one year (adjusted IRR 10.1, 95% CI 4.5-22.3). CONCLUSION: Cardiac surgery in patients with de novo CIEDs was associated with a high risk of systemic CIED infections. Highest risk was observed after heart valve replacement surgery and within the first year of surgery.

Magnetic resonance imaging in patients with temporary external pacemakers.

AIMS: To describe safety and feasibility of magnetic resonance imaging (MRI) in patients with transvenous temporary external pacemakers and whether artefacts affect the diagnostic image quality during cardiac MRI. METHODS AND RESULTS: We reviewed records of all patients treated with temporary external pacing between 2016 and 2020 at a tertiary centre. Temporary pacing was established using a transvenous standard active fixation pacing lead inserted percutaneously and connected to a MRI-conditional pacemaker taped to the skin. All patients undergoing cardiac or non-cardiac MRI during temporary transvenous pacing were identified. Before MRI, devices were programmed according to guidelines for permanent pacemakers, and patients were monitored with continuous electrocardiogram during MRI. Of 827 consecutive patients receiving a temporary external pacemaker, a total of 44 (5%) patients underwent MRI (mean age 71 years, 13 [30%] females). Cardiac MRI was performed in 22 (50%) patients, while MRI of cerebrum, spine, and other regions was performed in the remaining patients. Median time from implantation of the temporary device to MRI was 6 (3-11) days. During MRI, we observed no device-related malfunction or arrhythmia. Nor did we detect any change in lead sensing, impedance, or pacing threshold. We observed no artefacts from the lead or pacemaker compromising the diagnostic image quality of cardiac MRI. MRI provided information to guide the clinical management in all cases. CONCLUSION: MRI is feasible and safe in patients with temporary external pacing established with a regular MRI-conditional pacemaker and a standard active fixation lead. No artefacts compromised the diagnostic image quality.

Prediction of Cardiac Resynchronization Therapy Response Using a Lead Placement Score Derived From 4-Dimensional Computed Tomography.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an effective treatment for patients with heart failure; however, 30% of patients do not respond to the treatment. We sought to derive patient-specific left ventricle maps of lead placement scores (LPS) that highlight target pacing lead sites for achieving a higher probability of CRT response. METHODS: Eighty-two subjects recruited for the ImagingCRT trial (Empiric Versus Imaging Guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy) were retrospectively analyzed. All 82 subjects had 2 contrast-enhanced full cardiac cycle 4-dimensional computed tomography scans: a baseline and a 6-month follow-up scan. CRT response was defined as a reduction in computed tomography-derived end-systolic volume ≥15%. Eight left ventricle features derived from the baseline scans were used to train a support vector machine via a bagging approach. An LPS map over the left ventricle was created for each subject as a linear combination of the support vector machine feature weights and the subject's own feature vector. Performance for distinguishing responders was performed on the original 82 subjects. RESULTS: Fifty-two (63%) subjects were responders. Subjects with an LPS≤Q1 (lower-quartile) had a posttest probability of responding of 14% (3/21), while subjects with an LPS≥ Q3 (upper-quartile) had a posttest probability of responding of 90% (19/21). Subjects with Q1

Lead complications after cardiac surgery in patients with cardiac implantable electronic devices.

OBJECTIVES: Manipulation of the heart during cardiac surgery in patients with cardiac implantable electronic devices (CIEDs) may result in lead damage or displacement, but whether cardiac surgery truly infers an excess risk of lead failure is not known. The objective of this study was to examine the risk of lead complications after cardiac surgery in patients with CIEDs. METHODS: We conducted a nationwide nested case-control study. The source population comprised all Danish patients ≥18 of age who underwent a de novo CIED implantation during 1998-2017. For inclusion, patients had to be alive and event free 6 months after implantation. Cases were matched 1:30 to controls on time, age, sex, and device type using risk set sampling. We used conditional logistic regression to estimate incidence rate ratios (IRRs) for the association between cardiac surgery and lead-related reoperation. RESULTS: Our final population consisted of 67 621 patients. We identified 1437 (2.1%) incident cases of lead-related reoperations and 42 698 controls. Risk of lead complications was highest within 6 months of cardiac surgery [IRR 9.7, 95% confidence interval (CI) 6.3-14.8, adjusted IRR 9.6, 95% CI 6.2-14.7], and at 1 year, the relative risk of lead-related reoperation was close to unity (adjusted IRR 1.2, 95% CI 0.8-1.7). CONCLUSIONS: Cardiac surgery was associated with a considerable risk of lead complications in patients with de novo CIEDs.