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.

Real-world validation of smartphone-based photoplethysmography for rate and rhythm monitoring in atrial fibrillation.

AIMS: Photoplethysmography- (PPG) based smartphone applications facilitate heart rate and rhythm monitoring in patients with paroxysmal and persistent atrial fibrillation (AF). Despite an endorsement from the European Heart Rhythm Association, validation studies in this setting are lacking. Therefore, we evaluated the accuracy of PPG-derived heart rate and rhythm classification in subjects with an established diagnosis of AF in unsupervised real-world conditions. METHODS AND RESULTS: Fifty consecutive patients were enrolled, 4 weeks before undergoing AF ablation. Patients used a handheld single-lead electrocardiography (ECG) device and a fingertip PPG smartphone application to record 3907 heart rhythm measurements twice daily during 8 weeks. The ECG was performed immediately before and after each PPG recording and was given a diagnosis by the majority of three blinded cardiologists. A consistent ECG diagnosis was exhibited along with PPG data of sufficient quality in 3407 measurements. A single measurement exhibited good quality more often with ECG (93.2%) compared to PPG (89.5%; P < 0.001). However, PPG signal quality improved to 96.6% with repeated measurements. Photoplethysmography-based detection of AF demonstrated excellent sensitivity [98.3%; confidence interval (CI): 96.7-99.9%], specificity (99.9%; CI: 99.8-100.0%), positive predictive value (99.6%; CI: 99.1-100.0%), and negative predictive value (99.6%; CI: 99.0-100.0%). Photoplethysmography underestimated the heart rate in AF with 6.6 b.p.m. (95% CI: 5.8 b.p.m. to 7.4 b.p.m.). Bland-Altman analysis revealed increased underestimation in high heart rates. The root mean square error was 11.8 b.p.m. CONCLUSION: Smartphone applications using PPG can be used to monitor patients with AF in unsupervised real-world conditions. The accuracy of AF detection algorithms in this setting is excellent, but PPG-derived heart rate may tend to underestimate higher heart rates.

Predictors of Success for Pulmonary Vein Isolation With Pulsed-field Ablation Using a Variable-loop Catheter With 3D Mapping Integration: Complete 12-month Outcomes From inspIRE.

BACKGROUND: We previously presented the safety and early efficacy of the inspIRE study (Study for Treatment of Paroxysmal Atrial Fibrillation [PAF] by Pulsed-field Ablation [PFA] System With Irreversible Electroporation [IRE]). With the study's conclusion, we report the outcomes of the full pivotal study cohort, with an additional analysis of predictors of success. METHODS: InspIRE was a prospective, multicenter, single-arm clinical trial of drug-refractory paroxysmal atrial fibrillation. Pulmonary vein isolation was performed with a variable-loop circular catheter integrated with a 3-dimensional mapping system. Follow-up with 24-hour Holter was at 3, 6, and 12 months, as well as remote rhythm monitoring: weekly from 3 to 5 months, monthly from 6 to 12 months, and for symptoms. The primary effectiveness end point (PEE) was acute pulmonary vein isolation plus freedom from any atrial arrhythmia at 12 months. Additional subanalyses report predictors of PEE success. RESULTS: The patient cohort included 186 patients: aged 59±10 years, female 30%, and CHA2DS2-VASc 1.3±1.2. The previously reported primary adverse event rate was 0%. One serious procedure-related adverse event, urinary retention, was reported. The PEE was achieved in 75.6% (95% CI, 69.5%-81.8%). The clinical success of freedom from symptomatic recurrence was 81.7% (95% CI, 76.1%-87.2%). Simulating a monitoring method used in standard real-world practice (without protocol-driven remote rhythm monitoring), this translates to a freedom from all and symptomatic recurrence of 85.8% (95% CI, 80.8%-90.9%) or 94.0% (95% CI, 90.6%-97.5%), respectively. Multivariate analyses revealed that left ventricular ejection fraction ≥60% (adjusted odds ratio, 0.30) and patients receiving ≥48 PFA applications (adjusted odds ratio, 0.28) were independent predictors of PEE success. Moreover, PEE success was 79.2% in patients who received ≥12 PFA applications per vein compared with 57.1% in patients receiving fewer PFA applications. CONCLUSIONS: The inspIRE study confirms the safety and effectiveness of pulmonary vein isolation using the novel 3-dimensional mapping integrated circular loop catheter. An optimal number of PFA applications (≥48 total or ≥12 per vein) resulted in an improved 1-year success rate of ≈80%. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04524364.

Paroxysmal Atrial Fibrillation Ablation Using a Novel Variable-Loop Biphasic Pulsed Field Ablation Catheter Integrated With a 3-Dimensional Mapping System: 1-Year Outcomes of the Multicenter inspIRE Study.

BACKGROUND: The inspIRE study (Study for Treatment of Paroxysmal Atrial Fibrillation [PAF] by Pulsed Field Ablation [PFA] System With Irreversible Electroporation [IRE]) evaluated safety and effectiveness of a fully integrated biphasic pulsed field ablation (PFA) system with a variable-loop circular catheter for the treatment of drug-refractory paroxysmal atrial fibrillation. METHODS: Subjects underwent pulmonary vein (PV) isolation with the PFA system, using at least 12 applications per vein; adenosine/isoproterenol was administered to confirm entrance block. Wave I assessed initial safety, including for esophageal lesions, silent cerebral lesions, and PV stenosis. Wave II (pivotal phase) tested (1) primary safety, incidence of early-onset primary adverse events, and (2) primary effectiveness, confirmed PV isolation with freedom from documented atrial arrhythmia at 12 months. The study design specified an interim analysis to determine early success once 30 subjects reached the 12-month follow-up and all subjects reached 3-month follow-up. RESULTS: Across 13 centers in Europe/Canada, 226 subjects were enrolled, met criteria for safety and effectiveness evaluations, and received PFA (Wave I, 40; Wave II, 186). Wave I demonstrated no esophageal thermal lesions or PV stenosis. Among 39 subjects with cerebral magnetic resonance imaging, silent cerebral lesions were detected in 4 of the first 6 subjects, after which workflow enhancements, including a 10-second pause between PFA applications, were implemented; subsequently, only 4 of 33 subjects had silent cerebral lesions. In the Wave II phase, no primary adverse events were reported. Upon declaring early success, 83 subjects reached 12-month follow-up. With 100% entrance block, PV isolation without acute reconnection was achieved in 97.1% of targeted veins. For Wave II, the primary effectiveness end point per Kaplan-Meier at the time of interim analysis was 70.9%; 12-month freedom from symptomatic atrial fibrillation/atrial flutter/atrial tachycardia recurrence and repeat ablation was 78.9% and 92.3%, respectively. Total procedure and transpired PFA times were 70.1±27.7 and 26.7±14.0 minutes, respectively. CONCLUSIONS: The inspIRE trial confirmed the safety and effectiveness of the novel mapping-integrated PFA system. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; unique identifier: NCT04524364.

The MADIT-ICD benefit score helps to select implantable cardioverter-defibrillator candidates in cardiac resynchronization therapy.

AIMS: The aim of this study is to evaluate whether the MADIT-ICD benefit score can predict who benefits most from the addition of implantable cardioverter-defibrillator (ICD) to cardiac resynchronization therapy (CRT) in real-world patients with heart failure with reduced ejection fraction (HFrEF) and to compare this with selection according to a multidisciplinary expert centre approach. METHODS AND RESULTS: Consecutive HFrEF patients who received a CRT for a guideline indication at a tertiary care hospital (Ziekenhuis Oost-Limburg, Genk, Belgium) between October 2008 and September 2016, were retrospectively evaluated. The MADIT-ICD benefit groups (low, intermediate, and high) were compared with the current multidisciplinary expert centre approach. Endpoints were (i) sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and (ii) non-arrhythmic mortality. Of the 475 included patients, 165 (34.7%) were in the lowest, 220 (46.3%) in the intermediate, and 90 (19.0%) in the highest benefit group. After a median follow-up of 34 months, VT/VF occurred in 3 (1.8%) patients in the lowest, 9 (4.1%) in the intermediate, and 13 (14.4%) in the highest benefit group (P < 0.001). Vice versa, non-arrhythmic death occurred in 32 (19.4%) in the lowest, 32 (14.6%) in the intermediate, and 3 (3.3%) in the highest benefit group (P = 0.002). The predictive power for ICD benefit was comparable between expert multidisciplinary judgement and the MADIT-ICD benefit score: Uno's C-statistic 0.69 vs. 0.69 (P = 0.936) for VT/VF and 0.62 vs. 0.60 (P = 0.790) for non-arrhythmic mortality. CONCLUSION: The MADIT-ICD benefit score can identify who benefits most from CRT-D and is comparable with multidisciplinary judgement in a CRT expert centre.

Quality of life and healthcare utilisation improvements after atrial fibrillation ablation.

OBJECTIVE: Pulmonary vein isolation (PVI) guided by a standardised CLOSE (contiguous optimised lesions) protocol has been shown to increase clinical success after catheter ablation for paroxysmal atrial fibrillation (PAF). This study analysed healthcare utilisation and quality of life (QOL) outcomes from a large multicentre prospective study, measured association between QOL and atrial fibrillation (AF) burden and identified factors associated with lack of QOL improvement. METHODS: CLOSE-guided ablation was performed in 329 consecutive patients (age 61.4 years, 60.8% male) with drug-refractory PAF in 17 European centres. QOL was measured at baseline and 12 months post-ablation via Atrial Fibrillation Effect on QualiTy of Life Survey (AFEQT) and EuroQoL EQ-5D-5L questionnaires. All-cause and cardiovascular hospitalisations and cardioversions over 12 months pre-ablation and post-ablation were recorded. Rhythm monitoring included weekly and symptom-driven trans-telephonic monitoring, plus ECG and Holter monitoring at 3, 6 and 12 months. AF burden was defined as the percentage of postblanking tracings with an atrial tachyarrhythmia ≥30 s. Continuous measures across multiple time points were analysed using paired t-tests, and associations between various continuous measures were analysed using independent sample t-tests. Each statistical test used two-sided p values with a significance level of 0.05. RESULTS: Both QOL instruments showed significant 12-month improvements across all domains: AFEQT score increased 25.1-37.5 points and 33.3%-50.8% fewer patients reporting any problem across EuroQoL EQ-5D-5L domains. Overall, AFEQT improvement was highly associated with AF burden (p=0.009 for <10% vs ≥10% burden, p<0.001 for <20% vs ≥20% burden). Cardiovascular hospitalisations were significantly decreased after ablation (42%, p=0.001). Patients without substantial improvement in AFEQT (55/301, 18.2%) had higher AFEQT and CHA2DS2-VASc scores at baseline, and higher AF burden following PVI. CONCLUSIONS: QOL improved and healthcare utilisation decreased significantly after ablation with a standardised CLOSE protocol. QOL improvement was significantly associated with impairment at baseline and AF burden after ablation. TRIAL REGISTRATION NUMBER: NCT03062046.

Standardized pulmonary vein isolation workflow to enclose veins with contiguous lesions: the multicentre VISTAX trial.

AIMS: To evaluate the safety and effectiveness of pulmonary vein isolation in paroxysmal atrial fibrillation (PAF) using a standardized workflow aiming to enclose the veins with contiguous and optimized radiofrequency lesions. METHODS AND RESULTS: This multicentre, prospective, non-randomized study was conducted at 17 European sites. Pulmonary vein isolation was guided by VISITAG SURPOINT (VS target ≥550 on the anterior wall; ≥400 on the posterior wall) and intertag distance (≤6 mm). Atrial arrhythmia recurrence was stringently monitored with weekly and symptom-driven transtelephonic monitoring on top of standard-of-care monitoring (24-h Holter and 12-lead electrocardiogram at 3, 6, and 12 months follow-up). Three hundred and forty participants with drug refractory PAF were enrolled. Acute effectiveness (first-pass isolation proof to a 30-min wait period and adenosine challenge) was 82.4% [95% confidence interval (CI) 77.4-86.7%]. At 12-month follow-up, the rate of freedom from any documented atrial arrhythmia was 78.3% (95% CI 73.8-82.8%), while freedom from atrial arrhythmia by standard-of-care monitoring was 89.4% (95% CI 78.8-87.0%). Freedom fromrepeat ablations by the Kaplan-Meier analysis was 90.4% during 12 months of follow-up. Of the 34 patients with repeat ablations, 14 (41.2%) demonstrated full isolation of all pulmonary vein circles. Primary adverse event (PAE) rate was 3.6% (95% CI 1.9-6.3%). CONCLUSIONS: The VISTAX trial demonstrated that a standardized PAF ablation workflow aiming for contiguous lesions leads to low rates of PAEs, high acute first-pass isolation rates, and 12-month freedom from arrhythmias approaching 80%. Further research is needed to improve the reproducibility of the outcomes across a wider range of centres.Clinical trial registration: ClinicalTrials.gov, number NCT03062046, https://clinicaltrials.gov/ct2/show/NCT03062046.

Atrial fibrillation screening with photo-plethysmography through a smartphone camera.

AIMS: This cross-sectional study was set up to assess the feasibility of mass screening for atrial fibrillation (AF) with only the use of a smartphone. METHODS AND RESULTS: A local newspaper published an article, allowing to subscribe for a 7-day screening period to detect AF. Screening was performed through an application that uses photo-plethysmography (PPG) technology by exploiting a smartphone camera. Participants received instructions on how to perform correct measurements twice daily, with notifications pushed through the application's software. In case of heart rhythm irregularities, raw PPG signals underwent secondary offline analysis to confirm a final diagnosis. From 12 328 readers who voluntarily signed up for screening (49 ± 14 years; 58% men), 120 446 unique PPG traces were obtained. Photo-plethysmography signal quality was adequate for analysis in 92% of cases. Possible AF was detected in 136 individuals (1.1%). They were older (P < 0.001), more frequently men (P < 0.001), and had higher body mass index (P = 0.004). In addition, participants who strictly adhered to the recommended screening frequency (i.e. twice daily) were more often diagnosed with possible AF (1.9% vs. 1.0% in individuals who did not adhere; P = 0.008). Symptoms of palpitations, confusion, and shortness of breath were more frequent in case of AF (P < 0.001). The cumulative diagnostic yield for possible AF increased from 0.4% with a single heart rhythm assessment to 1.4% with screening during the entire 7-day screening period. CONCLUSION: Mass screening for AF using only a smartphone with dedicated application based on PPG technology is feasible and attractive because of its low cost and logistic requirements.

Sacubitril/valsartan reduces ventricular arrhythmias in parallel with left ventricular reverse remodeling in heart failure with reduced ejection fraction.

BACKGROUND: Sacubitril/valsartan reduced the occurrence of sudden cardiac death in the PARADIGM-HF trial. However, limited information is available about the mechanism. METHODS: Heart failure (HF)-patients receiving sacubitril/valsartan for a class-I indication equipped with an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT) with remote tele-monitoring were retrospectively analyzed. Device-registered arrhythmic-events were determined [ventricular tachycardia/fibrillation (VT/VF), appropriate therapy, non-sustained VT (NsVT; > 4beats and < 30 s), hourly premature ventricular contraction (PVC)-burden], following sacubitril/valsartan initiation (incident-analysis) and over an equal time period before initiation (antecedent-analysis). Reverse remodeling to sacubitril/valsartan was defined as an improvement of left ventricular ejection fraction of ≥ 5% between baseline and follow-up. RESULTS: A-total of 151 HF-patients with reduced LVEF (29 ± 9%) were included. Patients were switched from ACE-I or ARB to equal doses of sacubitril/valsartan (expressed as %-target-dose; before = 58 ± 30% vs. after = 56 ± 27%). The mean follow-up of both the incident and antecedent analysis was 364 days. Following the initiation, VT/VF-burden dropped (individual patients with VT/VF pre_n = 19 vs. post_n = 10, total-episodes of VT/VF pre_n = 51 vs. post_n = 14, both p < 0.001), resulting in reduced occurrence of appropriate therapy (pre_n = 16 vs. post_n = 6; p < 0.001). NsVT-burden per patient also dropped (mean episodes pre_n = 7.7 ± 11.8 vs. post_n = 3.7 ± 5.4; p < 0.001). There was no impact on atrial-fibrillation burden. PVC-burden dropped significantly which was associated with an improvement in BiV-pacing in patients with < 90% BiV-pacing at baseline. A higher degree of reverse remodeling was associated with a lower burden of NsVT and PVCs (both p < 0.05). CONCLUSION: Initiation of sacubitril/valsartan is associated with a lower degree of VT/VF, resulting in less ICD-interventions. This beneficial effect on ventricular arrhythmias might be related to cardiac reverse remodeling.

Safety and long-term effectiveness of paroxysmal atrial fibrillation ablation with a contact force-sensing catheter: real-world experience from a prospective, multicentre observational cohort registry.

Aims: Real-time contact force (CF)-sensing radiofrequency ablation catheter for treatment of paroxysmal atrial fibrillation (PAF) allows optimization of electrode-tissue contact, which correlates with long-term success. This prospective, multicentre observational registry assessed the real-world clinical effectiveness of a CF-sensing catheter for ablation of drug-refractory PAF. Methods and results: Patients were followed-up at 3, 6, and 12 months after ablation. Outcome measures included isolation of targeted pulmonary veins (PVs) confirmed by entrance block (acute success), patient-reported freedom from symptomatic atrial fibrillation (AF) at 12 months (long-term effectiveness), Atrial Fibrillation Effect on Quality-of-life scores at 6 and 12 months, and incidence of predefined procedural complications. The registry enrolled 261 PAF patients (mean age 58.8 ± 11.3 years; 70.7% men; 91.7% Caucasian). Acute PV isolation was reported in 98.8% of patients [95% confidence interval (CI): 96.4-99.7%], and 12-month success for freedom from symptomatic AF was 75.7% (95% CI: 69.7-80.7%). Average CF for the evaluable cohort was 16.4 ± 3.9 g. There was a significant correlation between long-term effectiveness and stability of CF use [percentage of time CF was within investigator-selected working range; odds ratio (95% Wald CI), 1.0 (1.00-1.1); P = 0.030]. Average CF did not correlate with 12-month success. Clinically meaningful quality of life (QoL) improvements were observed at 6 and 12 months. Primary adverse events occurred in 2.7% patients. Conclusion: This observational registry showed that PAF ablation with a CF-sensing catheter had high acute success rates, favourable 12-month outcomes, and a good safety profile. Patients' QoL improved significantly. Long-term effectiveness significantly correlated with stable CF with adequate catheter-tissue contact (NCT01677052).

Long-Term Performance of the Riata/ST Implantable Cardioverter-Defibrillator Lead.

Riata and Riata ST implantable cardioverter-defibrillator leads are prone to structural and electrical failure (EF). Our objective was to evaluate Riata/ST lead performance over a long-term follow-up. Of 184 patients having undergone Riata/ST and Riata ST Optim lead implantation from September 2003 to June 2008, 154 patients were evaluated for EF and radiographic conductor externalization (CE). Survival analysis for EF was performed for Riata/ST leads, both for failure-free lead survival and cumulative hazard. Subanalysis on 7Fr leads was performed to evaluate EF and CE rates both for different Riata ST lead management (monitoring vs proactive) and between Riata ST and Riata ST Optim leads. During a mean follow-up of 7 years, Riata/ST lead EF rate was 13% overall. Similar failure-free survival rate was noted for 7Fr as for 8Fr leads (log-rank, p = 0.63). Of all failed leads, 64% failed only after 5 years of follow-up. Compared with the absolute failure rate of 1.84% per device year, cumulative hazard analysis for leads surviving past 5 years revealed an estimated failure rate of 7% per year. No clinical or procedural predictors for EF were found. The subanalysis on 7Fr leads showed an excellent outcome both for a proactive lead management approach as for Optim leads. In conclusion, long-term survival of the Riata/ST lead is impaired with an accelerating EF risk over time. An initial exponential trend was followed by a linear lead failure pattern for leads surviving past 5 years, corresponding to an estimated 7% annual EF rate. These findings may have repercussions on the lead management strategy in patients currently surviving with a Riata/ST lead to prevent significant clinical events like inappropriate shocks or failed device interventions.

Asymptomatic episodes of device-registered atrial tachyarrhythmia are not associated with worse cardiac resynchronization therapy response.

AIMS: To assess the influence of device-registered episodes of atrial tachyarrhythmia (AT) on the response to cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Consecutive CRT patients without history of atrial fibrillation (AF; n = 118) were followed prospectively. AT was defined as a device-registered episode of atrial rate >190 b.p.m. for ≥30 s. Episodes of electrocardiographically documented AF, accompanied by symptoms, or need for cardioversion, were classified as clinical AF. During mean follow-up of 26 ± 9 months, 39 patients (33%) had ≥1 episode of asymptomatic device-registered AT. Twenty-one patients (18%) developed clinical AF of whom seven had previously experienced episodes of asymptomatic device-registered AT. Patients with asymptomatic AT or AF had a higher body mass index, but otherwise similar baseline characteristics, compared with the subjects without AT. Reverse remodelling after CRT was similar among the groups. While clinical AF was significantly associated with the composite endpoint of all-cause mortality or unplanned hospital admission (hazard ratio = 2.43, 95% confidence interval: 1.40-4.24), this correlation was not observed in patients with asymptomatic device-registered AT (P value = 0.540). CONCLUSION: Episodes of asymptomatic device-registered AT are frequent in CRT patients, but are not associated with impaired reverse remodelling. In contrast to clinical AF, such episodes are not associated with worse clinical outcome.

Catheter ablation of ventricular fibrillation: importance of left ventricular outflow tract and papillary muscle triggers.

BACKGROUND: Monomorphic ventricular premature depolarizations (VPDs) have been found to initiate ventricular fibrillation (VF) or polymorphic ventricular tachycardia (PMVT) in patients with and without structural heart disease. OBJECTIVE: The purpose of this study was to describe and characterize sites of origin of VPDs triggering VF and PMVT. METHODS: The distribution of mapping-confirmed VPDs, electrophysiology laboratory findings, and results of radiofrequency catheter ablation were analyzed. RESULTS: Among 1132 consecutive patients who underwent ablation for ventricular arrhythmias, 30 patients (2.7%) with documented VF/PMVT initiation were identified. In 21 patients, VF/PMVT occurred in the setting of cardiomyopathy; in 9 patients, VF/PMVT was idiopathic. The origin of VPD trigger was from the Purkinje network in 9, papillary muscles in 8, left ventricular outflow tract in 9, and other low-voltage areas unrelated to Purkinje activity in 4. Each distinct anatomic area of origin was associated with VF/PMVT triggers in patients with and without heart disease. Acute VPD elimination was achieved in 26 patients (87%), with a decrease in VPDs in another 3 patients (97%). During median follow-up of 418 days (interquartile range [IQR] 144-866), 5 patients developed a VF/PMVT recurrence after a median of 34 days (IQR 1-259). Rare recurrence was noted in patients with and without structural disease and from each distinct anatomic origin. The total burden of VF/PMVT episodes/shocks was reduced from a median of 9 (IQR 2.5-22.5) in the 3 months before ablation to 0 (IQR 0-0, total range 0-2) during follow-up (P <.0001). CONCLUSION: Catheter ablation of VPD-triggered VF/PMVT is highly successful. Left ventricular outflow tract and papillary muscles are common and are previously unrecognized sites of origin of these triggers in patients with and without structural heart disease.

Revisiting diastolic filling time as mechanistic insight for response to cardiac resynchronization therapy.

AIMS: Intraventricular dyssynchrony and commonly associated prolonged atrioventricular conduction both reduce diastolic filling time (DFT), which can be improved by cardiac resynchronization therapy (CRT). Our aim was to investigate whether change in DFT corrected for RR interval (DFTC) after CRT might serve to assess the mechanistic response to CRT. METHODS AND RESULTS: Echocardiography data of consecutive patients in sinus rhythm (n = 91) were studied before and 6 months after implantation. Mortality and heart failure hospitalization data were collected. Patients with vs. without DFTC increase after 6 months were compared. The programmed atrioventricular delay, percentage of biventricular pacing, and change in PR interval were similar in both groups. DFTC increase after 6 months reflected favourable reverse left ventricular remodelling and was significantly associated with freedom from death or heart failure admission (P = 0.008). In multivariate analysis including guideline criteria for CRT (i.e. QRS width, presence of left bundle branch block, and ejection fraction), interventricular mechanical delay, and Tei index, baseline DFTC was the strongest predictor of adverse outcome. Notably, while patients with impaired relaxation had a large and highly significant reduction in all-cause mortality and heart failure admissions when DFTC increased [hazard ratio (HR), 95% confidence interval (CI) = 0.24, 0.08-0.73; P = 0.012], this benefit was less pronounced and did not reach statistical significance in patients with pseudonormal or restrictive filling (HR, 95% CI = 0.64, 0.23-1.77; P = 0.388). CONCLUSION: DFTC increase after CRT reflects favourable reverse remodelling and is associated with better clinical outcome.

Mexiletine as an adjunctive therapy to amiodarone reduces the frequency of ventricular tachyarrhythmia events in patients with an implantable defibrillator.

The most effective pharmacological management of frequent ventricular tachyarrhythmia events in patients with an implantable defibrillator who failed or did not tolerate amiodarone is unknown. The aim of this retrospective cohort study was to assess the efficacy and tolerability of mexiletine in such patients. The patients served as self-controls. The number of treated ventricular tachyarrhythmia episodes (primary outcome); mortality, shocks from the defibrillator, and electrical storm events (secondary outcomes) during mexiletine therapy was compared with a matched duration of observation just before initiating mexiletine in 29 patients who were treated with a median dose of 300 mg/d of mexiletine and were followed for a median of 12 months. None of the patients had to stop mexiletine due to side effect. There was a significant reduction in the incidence of ventricular tachycardia/fibrillation episodes (median 2 vs. 12 events, P = 0.001) and shocks (median 0 vs. 2 events, P = 0.003) in the first 3 months of treatment, but long-term efficacy was only observed among patients who continued amiodarone therapy. In conclusion, mexiletine, when added to amiodarone in case of amiodarone inefficacy, reduces ventricular tachycardia/fibrillation events and appropriate therapies in patients with an implantable cardioverter defibrillator. A randomized trial should validate the efficacy and safety of mexiletine as an adjunctive therapy to amiodarone.

Cardiac resynchronization therapy with or without defibrillator: experience from a high-volume Belgian implantation centre.

OBJECTIVE: Cardiac resynchronization therapy (CRT) is an important treatment modality for heart failure with reduced ejection fraction and ventricular conduction delay. Considering limited health care budgets in an aging population, adding a defibrillator function to CRT remains a matter of debate. Our aim was to describe the experience of a high-volume Belgian implantation centre with CRT with/without defibrillator (CRT-D/P). METHODS AND RESULTS: Consecutive CRT patients (n = 221), implanted between October 2008 and April 2011 in Ziekenhuis Oost-Limburg (Genk), were reviewed. From 209 primo-implantations, 74 CRT-D and 98 CRT-P patients with complete follow-up inside the centre, were analysed. Despite differences in baseline characteristics, both groups demonstrated similar reverse left ventricular remodelling, improvement in New York Heart Association functional class and maximal aerobic capacity. During mean follow-up of 18 +/- 9 months, 21 patients died and 83 spent a total of 1200 days in hospital. Annual mortality was 8% and equal among the groups. The mode of death differed between CRT-D (predominantly pump failure) and CRT-P patients (pump failure, comorbidity and sudden death). The yearly population attributable risk of malignant ventricular arrhythmia was 8.16% in CRT-D and 1.38% in CRT-P patients. CONCLUSIONS: With current guidelines applied to the Belgian reimbursement criteria and at physicians'discretion, patient selection for CRT-D/ CRT-P was appropriate, with similar reverse remodelling, functional capacity improvement and good clinical outcome in both groups. High-risk patients for malignant ventricular arrhythmia were more likely to receive CRT-D, although the yearly attributable risk remained 1.38% in CRT-P patients.

Response to cardiac resynchronization therapy in elderly patients (≥70 years) and octogenarians.

AIMS: Cardiac resynchronization therapy (CRT) leads to reverse ventricular remodelling, improved functional capacity, and better clinical outcome in patients with advanced chronic heart failure, reduced ejection fraction, and evidence of ventricular conduction delay, who are under optimal medical therapy. This study investigated whether these benefits can be extrapolated to older patients, typically not included in randomized clinical trials. METHODS AND RESULTS: Consecutive patients who received a CRT device between October 2008 and June 2011, including optimization afterwards in a dedicated clinic, were stratified into 3 pre-specified groups, according to age: <70 years (n = 76); 70-79 years (n = 95); and ≥80 years (n = 49). Left ventricular remodelling, functional capacity, heart failure hospitalization, and mortality data were assessed during follow-up. Reverse left ventricular remodelling and improvement in New York Heart Association functional class were similar in all groups at 6 months after implantation. During mean follow-up of 20 months, 32 patients died and 66 were admitted for heart failure. Annualized mortality rates were significantly higher in elderly patients (6% vs. 8% vs. 15% in all groups, respectively; P < 0.001), but time to death or first heart failure admission was similar among age groups (P = 0.531). Progressive pump failure was the major cause of death (50%), with co-morbidity-related deaths also being frequent (41%). CONCLUSION: Reverse left ventricular remodelling and functional capacity improvement after CRT are sustained at advanced age. Moreover, time to all-cause mortality or heart failure admission was similar, irrespective of age, in a context of maximized optimization including optimal medical therapy.

Comorbidity significantly affects clinical outcome after cardiac resynchronization therapy regardless of ventricular remodeling.

BACKGROUND: The influence of comorbid conditions on ventricular remodeling, functional status, and clinical outcome after cardiac resynchronization therapy (CRT) is insufficiently elucidated. METHODS AND RESULTS: The influence of different comorbid conditions on left ventricular remodeling, improvement in New York Heart Association (NYHA) functional class, hospitalizations for heart failure, and all-cause mortality after CRT implantation was analyzed in 172 consecutive patients (mean age 71 ± 9 y), implanted from October 2008 to April 2011 in a single tertiary care hospital. During mean follow-up of 18 ± 9 months, 21 patients died and 57 were admitted for heart failure. Left ventricular remodeling and improvement in NYHA functional class were independent from comorbidity burden. However, diabetes mellitus (hazard ratio [HR] 3.45, 95% confidence interval [CI] 1.24-9.65) and chronic kidney disease (HR 3.11, 95% CI 1.10-8.81) were predictors of all-cause mortality, and the presence of chronic obstructive pulmonary disease (HR 1.89, 95% CI 1.02-3.53) was independently associated with heart failure admissions. Importantly, those 3 comorbid conditions had an additive negative impact on survival and heart failure admissions, even in patients with reverse left ventricular remodeling. CONCLUSIONS: Reverse ventricular remodeling and improvement in functional status after CRT implantation are independent from comorbidity burden. However, comorbid conditions remain important predictors of all-cause mortality and heart failure admissions.

Idiopathic right ventricular arrhythmias not arising from the outflow tract: prevalence, electrocardiographic characteristics, and outcome of catheter ablation.

BACKGROUND: Most idiopathic right ventricular (RV) ventricular tachycardias (VTs) originate from the outflow tract. Data on VT from the lower body of the RV are limited. OBJECTIVE: The purpose of this study was to describe a large experience with idiopathic VT detailing the prevalence and characteristics of VT arising from the body of the RV. METHODS: The distribution of mapping confirmed VTs within the RV body, ECG characteristics, and results of radiofrequency (RF) ablation were analyzed. RESULTS: Among 278 patients who underwent ablation for idiopathic VT or ventricular premature depolarizations (VPDs) arising from the RV, 29 (10%) had VT/VPDs from the lower RV body. Fourteen (48%) patients had VT/VPDs within 2 cm of the tricuspid valve annulus (TVA), 8 (28%) from the basal and 7 (24%) from the apical RV segments. Among the VT/VPDs from the TVA, 8 (57%) originated from the free wall and 6 (43%) from the septum. All but one RV basal or apical VT/VPDs originated from the free wall. All VT/VPDs had a left bundle branch block pattern. VT/VPDs from the free wall had longer QRS duration (P = .0032) and deeper S wave in lead V(2) (P = .042) and V(3) (P = .046) than those from the septum. Apical VT/VPDs more often had precordial R wave transition ≥V(6) (P = .0001) and smaller R wave in lead II (P = .024) and S wave in lead aVR (P = .001) compared to VT/VPDs from basal RV or TVA. RF catheter ablation eliminated VT/VPDs in 96% of patients. No complications were observed. During median follow-up of 27 months (range 4-131 months), 81% of patients had elimination of all symptomatic VT/VPDs. Nineteen percent had rare symptoms (8% without medications, 11% on beta-blocker). CONCLUSION: Idiopathic VT/VPDs from the body of RV comprise an important subgroup of idiopathic RV VTs. Although most VTs originate from the RV free wall and nearly 50% from the TVA region, septal and more apical VTs are common. ECG characteristics distinguish free-wall versus septal and more apical origin of VTs, and RF catheter ablation provides good long-term arrhythmia control.