Long-term follow-up of patients with a quadripolar active fixation left ventricular lead: An Italian multicenter experience.

INTRODUCTION: Left ventricular (LV) lead optimal positioning is one of the most important determinants of cardiac resynchronization therapy (CRT) success. LV quadripolar active fixation (QAF) leads have been designed to ensure stable LV pacing in the target area and reduce the likelihood of phrenic nerve stimulation (PNS). The aim of this analysis is to compare performances, safety, and clinical outcomes of QAF with those of quadripolar passive fixation leads (QPL) and bipolar active fixation (BAF) leads in a real-world cohort of CRT patients. METHODS AND RESULTS: This retrospective analysis compared the procedure and follow-up data of 117 QAF included in the One Hospital ClinicalService project from nine Italian hospitals with two historical cohorts of 261 BAF and 124 QPL. QAF enabled basal pacing more frequently than QPL (24.1% vs. 6.5%, p < .001) but not differently from BAF (p = .981). At implant, mean QAF LV myocardial threshold (LVMT) was 1.21 ± 0.8 V at 0.4 ms, not different from that of BAF (p = .346) and QPL (p = .333). At a median follow-up of 22 months, LVMT was 1.37 ± 0.90 V (p = .036 vs. implant). Acute LV lead dislodgment occurrence was low in all cohorts: 1 (0.9%) in QAF, 4 in BAF (1.5%), and none (0.0%) in QPL. During follow-up, total LV-related complication rate was lower in QAF (0.5/100 patient-years) than in BAF (4.2/100 patient-years, p = .014) and QPL (3.6/100 patient-years, p = .055). QAF, BAF, and QPL annual rate of heart failure hospitalization were respectively 6.1/100 patient-years, 2.5/100 patient-years (p = .081), and 3.6/100 patient-years (p = .346). CRT responders' rate in QAF was 69.9%, with no difference in comparison to BAF (p = .998) and QPL (p = .509). During follow-up, mean left ventricular ejection fraction (LVEF) of QAF increased from 31.8 ± 10.1% to 40.3 ± 10.7% (p < .001). The average degree of echocardiographic response (ΔLVEF) did not differ between QAF and other cohorts; however, LVEF CRT responder's distribution of QAF differs from those of BAF (p = .003) and QPL (p = .022), due to a higher percentage of super-responders. CONCLUSIONS: QAF with short interelectrode spacing resulted in non-inferior clinical outcomes and CRT responders' rate in comparison to BAF and QPL, while reducing complication rate during follow-up and increasing the possibilities of electronic repositioning to manage PNS or to optimize resynchronization therapy.

Safety and efficacy of pulmonary vein isolation using a surround flow catheter with contact force measurement capabilities: A multicenter registry.

INTRODUCTION: Pulmonary vein (PV) isolation is the cornerstone of catheter ablation in patients with atrial fibrillation (AF). Surround flow and contact force (CF) measurement capabilities might enhance procedure efficacy and safety. We report on the safety and midterm efficacy of a novel ablation catheter for PV isolation in patients with AF. METHODS AND RESULTS: Two hundred thirty-three consecutive patients (57 ± 11 years, 76% males, 51% with structural heart disease), referred for paroxysmal (157) or persistent (76) AF, underwent PV isolation by a surround flow catheter with CF measurement capability in four centers. Ablation was guided by electroanatomic mapping allowing radiofrequency (RF) energy delivery in the antral region aiming at PV isolation. Mean overall procedure time was 100 ± 42 minutes with a mean fluoroscopy time of 6 ± 5 minutes. Mean ablation time was 31±15 minutes; 99% of the targeted veins were isolated. The mean CF value during ablation was 13 ± 4 g. Intraprocedural early (30 minutes) PV reconnection occurred in 12% PVs, and all PVs were effectively reisolated. One pericardial effusion and five groin hematomas were reported. During a mean follow-up of 12 ± 6 months, 30 (12.9%) (10% paroxysmal AF vs. 18% persistent AF, P = 0.07) patients had an atrial arrhythmias recurrence. CONCLUSIONS: In this multicenter registry, RF ablation using a new surround flow catheter, with CF sensor, resulted as feasible, achieving a high rate of isolated PVs. Procedural and fluoroscopy times and success rates were comparable with other techniques with a low complication rate.

Unconventional diagnosis of bradyarrhythmic syncope in Brugada syndrome: a case report.

Background: The Brugada syndrome (BrS) is an inherited disorder associated with the risk of ventricular fibrillation and sudden cardiac death (SCD). The current main therapy is an implantable cardioverter-defibrillator (ICD). However, the risk stratification and management of patients remain challenging. Here, we present a case of BrS representative of the pitfalls that clinicians may encounter in the management of Brugada patients in routine clinical practice. Case summary: A 39-year-old man with BrS and recurring syncope was implanted with a subcutaneous ICD (S-ICD) (EMBLEM MRI S-ICD, Boston Scientific). Syncope recurred some months later. Subcutaneous ICD interrogation showed no arrhythmic events, but SMART Pass (high-pass filter) deactivation was noted. A query was sent to Boston Scientific clinical service, unveiling an extremely long asystolic pause as syncope determinant. Subcutaneous ICD was explanted and replaced by conventional single chamber ICD in the pre-pectoral region. Discussion: Brugada syndrome patients with high-risk features are candidates for ICD implantation to prevent SCD. Recent evidence highlighted that symptomatic patients carry a substantially higher risk compared with asymptomatic ones. Syncope may represent a pivotal symptom in BrS patients, but young patients with Type 1 Brugada pattern may experience syncope other than from tachyarrhythmias. Subcutaneous ICD is an advisable option in young ICD recipients to avoid lifetime complication related to standard transvenous systems. However, S-ICD lacks pacing capabilities and, therefore, is not indicated when an anti-bradycardia system is needed. The diagnostic workup of syncope in Brugada patients may be ineffective in elucidating the underlying aetiology whose understanding is essential to offer a personalized therapeutic approach.

Daily and automatic remote monitoring of implantable cardiac monitors: A descriptive analysis of transmitted episodes.

BACKGROUND: Remote Monitoring (RM) is recognized for its ability to enhance the clinical management of patients with implantable cardiac monitor (ICM). This study aims to provide a comprehensive description of the arrhythmic episodes transmitted by a daily and automatic RM system from a cohort of ICM patients. METHODS: The study retrospectively analyzed daily transmissions from consecutive patients who had been implanted with a long-sensing vector ICM (BIOMONITOR III/IIIm) at four sites. All transmitted arrhythmic recordings were evaluated to determine whether they were true positive episodes or false positives (FP). RESULTS: A total of 14,136 episodes were transmitted from 119 patients (74.8% male, median age 62 years old) during a median follow-up of 371 days. The rate of arrhythmic episodes was 14.2 per patient-year (interquartile range: 1.8-126), with 97 patients (81.5%) experiencing at least one ICM activation. Fifty-five percent of episodes were identified as FP, and 67 patients (56.3%) had at least one inappropriate activation. The FP rate was 1.4 per patient-year (0-40). The best per-episode predictive positive values were observed for bradycardia and atrial fibrillation (0.595 and 0.553, respectively). Notably, the implementation of an algorithm designed to minimize false detections significantly reduced the prevalence of atrial fibrillation FP episodes (17.6% vs. 43.5%, p = 0.008). CONCLUSION: Daily and automatic RM appears to be a reliable tool for the comprehensive remote management of ICM patients. However, the number of arrhythmic episodes requiring review is high, and further improvements are needed to reduce FP and facilitate accurate interpretation of transmissions.

Design and rationale of the Impact of MultiPoint pacing in CRT patients with reduced RV-to-LV delay (IMAGE-CRT) study.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment in patients with heart failure and prolonged QRS duration. A biventricular device is implanted to achieve faster activation and more synchronous contraction of the ventricles. Despite the convincing effect of CRT, 30-40% of patients do not respond. We decided to investigate the role of multipoint pacing (MPP) in a selected group of patients with right ventricle (RV)-to-left ventricle (LV) intervals less than 80 ms that do not respond to traditional CRT. METHODS: We will enrol 248 patients in this patient-blinded, observational, clinical study aiming to investigate if MPP could decrease LV end-systolic volume (ESV) in patients with RV-to-LV interval less than 80 ms. MPP will be activated ON at implant in patients with RV-to-LV delay less than 80 ms and OFF in RV-to-LV at least 80 ms. At follow-up the activation of MPP will be related to CRT response. The primary study endpoint will be the responder rate at 6 months, defined as a decrease in LV ejection fraction, LV end-diastolic volume, LV end-systolic volume (LVESV) at least 15% from baseline. Secondary outcomes include 12 months relative percentage reduction in LVESV and a combined clinical outcome measure of response to CRT defined as the patient being alive, no hospitalization due to heart failure, and experiencing an improvement in New York Heart Association functional class (Composite-Score). CONCLUSION: Reducing the nonresponder rate continues to be an important goal for CRT.If an increase in reverse remodelling can be achieved by MPP, this study supports the conduct of larger trials investigating the role of MPP on clinical outcomes in selected patients treated, right now, only with traditional CRT. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02713308. Registered on 18 March 2016.

Safety and efficacy of atrial fibrillation ablation guided by Ablation Index module.

PURPOSE: Reconnection of pulmonary veins (PVs) remains common following radiofrequency catheter ablation for atrial fibrillation (AF). Ablation Index (AI) is a novel ablation quality marker that incorporates stability, contact force (CF), time, and power in a weighted formula. Its use seems to improve lesion durability. This is a prospective, single-arm registry to investigate on the safety and mid-term efficacy of AF ablation guided by the AI. METHODS: One hundred fifty-six consecutive patients (mean age 58 ± 10 years, 49% males, 44% with structural heart disease) referred for paroxysmal (124) or persistent (32) AF underwent antral PV isolation using a surround flow CF-sensing catheter guided by the AI. Radiofrequency was delivered targeting interlesion distance ≤ 6 mm and Ablation Index of 330-350 at posterior wall and 400-450 at anterior wall. RESULTS: Mean overall procedure time was 95 ± 30 min with a mean fluoroscopy time of 5 ± 6 min. Mean ablation time was 26 ± 10 min, 627/628 targeted PV were isolated. One pericardial effusion and two groin hematomas were reported; none required intervention. During a mean follow-up of 14 ± 6 months, 17 (10.8%) (9% paroxysmal AF vs 22% persistent AF, p = 0.09) patients had an atrial arrhythmia recurrence. CONCLUSIONS: PV ablation guided by AI resulted feasible, achieving a high rate of isolated PVs, with a low complication rate, and allowed a high single-procedure arrhythmia-free survival at 14 months.

Maximization of interventricular conduction time by means of quadripolar leads for cardiac resynchronization therapy.

PURPOSE: Identifying the left ventricular (LV) site associated with the maximum spontaneous interventricular conduction time (right ventricle (RV)-to-LV interval) has proved to be an effective strategy for optimal LV pacing site selection in cardiac resynchronization therapy (CRT). The aim of our study was to determine whether quadripolar LV lead technology allows RV-to-LV interval maximization. METHODS: We enrolled 108 patients undergoing implantation of a CRT system using an LV quadripolar lead and 114 patients who received a bipolar lead. On implantation, the RV-to-LV interval was measured for the dipole of the bipolar leads and for each electrode of the LV lead (tip, ring 2, ring 3, ring 4). RESULTS: In the quadripolar group, the mean RV-to-LV interval ranged from 90 ± 33 ms (tip) to 94 ± 32 ms (R4) (p > 0.05 for all comparisons). In 55 (51%) patients, the RV-to-LV interval was > 80 ms at all electrodes, while in 27 (25%) patients, no electrodes were associated with an RV-to-LV interval > 80 ms. At least one LV pacing electrode was associated with an RV-to-LV interval > 80 ms in 62 (70%) patients with a short (36 mm) inter-electrode distance, and in 19 (95%, p = 0.022) of those with a long distance (50.5 mm). In the bipolar group, the mean RV-to-LV interval was 72 ± 37 ms (p < 0.001 versus quadripolar). The RV-to-LV interval was > 80 ms in 44 (39%) patients (p < 0.001 versus quadripolar leads with both short and long inter-electrode distance). CONCLUSIONS: Quadripolar leads allow RV-to-LV interval maximization. An optimal RV-to-LV interval seems achievable in the majority of patients, especially if the leads present a long inter-electrode distance.

Radiation Dose is Significantly Reduced by Use of Contact Force Sensing Catheter During Circumferential Pulmonary Vein Isolation.

The creation of a durable radiofrequency (RF) lesion depends on several parameters, including catheter tip electrode size and composition, tip orientation, temperature, RF pulse duration, power, blood flow, and catheter to tissue contact. The development of new contact force (CF) sensor catheters has allowed the measurement of the tip to tissue CF during the RF ablation procedure. Here, we describe the clinical experience obtained using CF catheters for atrial fibrillation ablation, with a specific focus on the impact of CF technology on acute procedural data (procedure and fluoroscopy time).