Initial experience with AcQMap catheter for treatment of persistent atrial fibrillation and atypical atrial flutter.

INTRODUCTION: The AcQMap High Resolution Imaging and Mapping System was recently introduced. This system provides 3D maps of electrical activation across an ultrasound-acquired atrial surface. METHODS: We evaluated the feasibility and the acute and short-term efficacy and safety of this novel system for ablation of persistent atrial fibrillation (AF) and atypical atrial flutter. RESULTS: A total of 21 consecutive patients (age (mean ± standard deviation) 62 ± 8 years, 23% female) underwent catheter ablation with the use of the AcQMap System. Fourteen patients (67%) were treated for persistent AF and 7 patients (33%) for atypical atrial flutter. Eighteen patients (86%) had undergone at least one prior ablation procedure. Acute success, defined as sinus rhythm without the ability to provoke the clinical arrhythmia, was achieved in 17 patients (81%). At 12 months, 4 patients treated for persistent AF (29%) and 4 patients treated for atypical flutter (57%) remained in sinus rhythm. Complications included hemiparesis, for which intra-arterial thrombolysis was given with subsequent good clinical outcome (n = 1), and complete atrioventricular block, for which a permanent pacemaker was implanted (n = 2). No major complications attributable to the mapping system occurred. CONCLUSION: The AcQMap System is able to provide fast, high-resolution activation maps of persistent AF and atypical atrial flutter. Despite a high acute success rate, the recurrence rate of persistent AF was relatively high. This may be due to the selection of the patients with therapy-resistant arrhythmias and limited experience in the optimal use of this mapping system that is still under development.

Chloroquine-induced QTc prolongation in COVID-19 patients.

BACKGROUND: In the battle against the SARS-CoV­2 pandemic, chloroquine has emerged as a new potential therapeutic option for the treatment of infected patients. A safety consideration for the application of chloroquine is its QTc-prolonging potential. Thus far, no data are available on the QTc-prolonging potential of chloroquine in COVID-19 patients. OBJECTIVE: To assess the degree of chloroquine-induced QTc prolongation in hospitalised COVID-19 patients. METHODS: A baseline electrocardiogram (ECG) and ECGs recorded during chloroquine treatment were retrospectively collected in patients suspected of having COVID-19. The QTc interval was calculated by computerised and manual interpretation. Baseline and follow-up QTc intervals were compared using the paired samples t-test. RESULTS: A total of 95 patients had a baseline ECG recording and at least one ECG recording during chloroquine therapy. Chloroquine treatment resulted in a mean QTc prolongation of 35 ms (95% CI 28-43 ms) using computerised interpretation and 34 ms (95% CI 25-43 ms) using manual interpretation. No torsade de pointes was observed during chloroquine treatment. After manual review, 22 patients (23%) had a QTc interval exceeding 500 ms during chloroquine treatment. None of these patients had a prolonged QTc interval prior to the initiation of chloroquine treatment. CONCLUSIONS: Chloroquine significantly prolongs the QTc interval in a clinically relevant matter. This highlights the need for ECG monitoring when prescribing chloroquine to COVID-19 patients.

Severe conduction defects requiring permanent pacemaker implantation in patients with a new-onset left bundle branch block after transcatheter aortic valve implantation.

AIMS: Transcatheter aortic valve implantation (TAVI) is frequently associated with cardiac conduction defects (CCD) requiring permanent pacemaker implantation (PPI). Although new-onset left bundle branch block (LBBB) is often seen, the rate of progression to severe CCD is unclear. We aimed to find clinical and electrocardiographic (ECG) parameters associated with severe CCD requiring PPI in patients with a new-onset LBBB after TAVI and assess its effect on clinical outcome. METHODS AND RESULTS: All consecutive patients undergoing TAVI who developed a new-onset LBBB were retrospectively analysed. We excluded patients with pre-existing bundle branch block or pacemaker. Patients were divided into two groups: with or without PPI after TAVI. We included 155 patients (50% female, 80 ± 7 years), of which 37 (24%) developed CCD requiring PPI, mainly due to a total atrioventricular block (n = 17; 46%). Cardiac conduction defects requiring PPI were associated with the following pre-existing parameters: atrial fibrillation (AF), the use of digoxin, CoreValve implantation, and left heart axis. Furthermore, it was associated with the following post-procedural parameters: left heart axis, lower mean heart rate, and prolonged PQ and QRS times. During follow-up, patients with PPI showed a lower mortality rate (11 vs. 29%, P = 0.03). In patients without PPI, mortality was lower in those with narrower QRS complex and transient LBBB. CONCLUSION: The severity and persistence of a new-onset LBBB after TAVI is associated with mortality. Cardiac conduction defects requiring PPI are associated with prior AF, the use of digoxin, CoreValve implantation, and a left heart axis. In these patients, PPI portends a better prognosis than no PPI.

Outpatient treatment with the wearable cardioverter defibrillator: clinical experience in two Dutch centres.

INTRODUCTION: The latest European Society of Cardiology Guidelines recommend consideration of a wearable cardioverter-defibrillator (WCD) for patients with a poor left ventricular ejection fraction (LVEF) who are at risk of sudden arrhythmic death but are not eligible for an implantable defibrillator. For these patients a WCD can be an alternative to long-term hospitalisation. PURPOSE: To evaluate the use of WCD therapy in these patient groups in two Dutch centres. METHODS: All consecutive patients treated with the WCD between 2009 and 2016 were included from two centres in the Netherlands. Data on events and compliance were collected retrospectively through home monitoring systems and adjudicated by the investigators. RESULTS: A total of 79 patients were treated with a WCD. Common indications were newly diagnosed cardiomyopathy without optimal medical treatment in 46 patients (58.2%) and bridge to implantable cardioverter-defibrillator (ICD) implant in 33 patients (41.8%). Bridge to implant indications consisted of contraindications for immediate implantation such as infections (e. g. previous device-related infections) and radiotherapy. Compliance was over 97% per day (median 23.3 h, 22.6-23.7), during a median of 79 days (50.0-109.8.0). Two patients (2.6%) received an appropriate shock (annual rate 13.6%), there was 1 (1.3%) inappropriate shock (annual rate 6.7%). In 24 patients (52.2%) without optimal medical treatment, the LVEF was sufficiently improved and ICD implant was avoided. Eight (10.1%) patients did not receive an ICD. In 45 patients an ICD was implanted (57.0%). CONCLUSION: WCD therapy provides a safe and effective treatment in outpatient setting for patients at high risk for sudden cardiac death and reduces the number of ICDs implanted.

Percutaneous left atrial appendage occlusion in patients with a cardiac implantable electronic device.

BACKGROUND: Left atrial appendage occlusion (LAAO) may be a viable option for stroke prevention in patients with non-valvular atrial fibrillation and a contraindication for oral anticoagulation. No evidence evaluating the safety of this procedure in patients with a cardiac implantable electronic device (CIED) exists. The aim of this study was to evaluate whether CIED function is affected by LAAO and to explore LAAO procedural characteristics and complications in patients with a CIED. METHODS: This single-center cohort study included consecutive patients scheduled for percutaneous LAAO. Patients with a CIED prior to LAAO were selected and compared to the patients without CIED, concerning procedural characteristics and peri-procedural complications. In the group of patients with CIEDs, essential pacemaker integrity parameters were compared before and after the procedure to detect possible micro and macro lead displacements. RESULTS: Thirty-one patients with CIED were scheduled for LAAO (age 73.7 ± 5.4 years, 65% males, CHA2DS2-VASc 4.3 ± 1.5, and HAS-BLED 3.3 ± 1.0). The 245 patients without CIED were younger, and HAS-BLED-score was slightly lower (69.4 ± 8.2 years, p < 0.001; 2.8 ± 1.0, p = 0.022). Patients without CIED more frequently underwent LAAO combined with catheter ablation (p = 0.002). All other procedural characteristics were comparable between both groups. No visible lead displacement was observed on chest X-ray after LAAO. Additionally, no differences in impedance, threshold, or intracardiac sensing in various CIED lead locations were found prior versus post LAAO. CONCLUSION: This study supports the feasibility and safety of LAAO in patients with a CIED.

2-year outcomes of phased radiofrequency ablation for atrial fibrillation with the second-generation PVAC Gold ablation catheter.

PURPOSE: The second-generation multi-electrode catheter, PVAC Gold, was designed to improve the safe delivery of phased radiofrequency energy using a "single shot" approach for pulmonary vein isolation (PVI), while retaining efficacy. This large registry presents long-term performance in a daily practice setting. METHODS: A total of 1011 patients undergoing first time ablation for atrial fibrillation (AF) using PVAC Gold were included, 639 patients with PVI for paroxysmal AF (PAF PVI) and 372 patients with persistent or long-standing persistent AF, divided into 175 patients receiving PVI only (PersAF PVI) and 197 patients receiving PVI with additional substrate ablation (PersAF PVI +). RESULTS: At 24-month follow-up, single procedure freedom from atrial tachyarrhythmia (ATA) was 58% (368/639) in the PAF PVI group, 44% (77/175) in the PersAF PVI group, and 29% (57/197) in the PersAF PVI + group. Allowing one repeat procedure in 33% of patients, 76%, 65%, and 54% were free from ATA at 24 months, respectively. Pulmonary vein reconnection was observed in 98% of patients with recurrent arrhythmia after PVI. CONCLUSIONS: Although phased RF ablation with PVAC Gold is quick and safe, the efficacy outcomes are modest compared to current mainstream ablation strategies.

High-density versus low-density mapping in ablation of atypical atrial flutter.

PURPOSE: Ablation of atypical atrial flutter (AAFL) can be challenging. High-density (HD) mapping of ablation targets may potentially increase procedural success and freedom from recurrent AAFL. The objective of the present study was to explore whether employing HD mapping leads to a more favorable outcome in ablation of AAFL. METHODS: We compared baseline and procedural characteristics, procedural success, safety and outcome of mapping and ablation of atypical flutter in three groups. (1) HD Grid catheter + the high-density electroanatomical mapping (EAM) system EnSite Precision; (2) standard 10-pole circular mapping catheter (CMC) + EnSite Precision; (3) CMC + the low-density EnSite Velocity EAM. Voltage and propagation maps were constructed. RESULTS: Mapping of 142 AAFL in 82 patients was performed. Acute ablation success was 78%, 68%, and 51% in groups 1, 2, and 3 (p = 0.037 between group 1 and 3, non-significant between groups otherwise). Moreover, 8%, 27%, and 36% of flutters were unmappable in groups 1, 2, and 3, respectively (p < 0.05 between group 1 and both groups 2 and 3). AAFL recurrence at 1-year FU was 26%, 36%, and 62% in groups 1, 2, and 3 (p = 0.007 between groups 1 and 3, p = 0.05 between groups 2 and 3). AAFL-free survival was significantly higher in patients mapped with Precision than with Velocity (p = 0.011). No strokes or mortality occurred within 30 days. CONCLUSIONS: Acute procedural success of ablation of atypical atrial flutter is higher and the number of unmappable flutters is lower using the HD Grid mapping catheter in combination with the high-density EnSite Precision system, as compared to a decapolar circular mapping catheter and the low-density EnSite Velocity EAM system. This may lead to increased freedom from recurrent AAFL at 1 year. HD mapping is safe.

Acute success and safety of the second-generation PVAC GOLD phased RF ablation catheter for atrial fibrillation.

PURPOSE: The second-generation multi-electrode catheter, pulmonary vein ablation catheter (PVAC) GOLD, was designed to improve the delivery of phased radiofrequency energy and reduce procedure times using a 'single-shot' approach for pulmonary vein isolation (PVI), while retaining efficacy and safety. This large registry presents acute success rates and safety outcomes in a daily practice setting. METHODS: A total of 1017 patients undergoing first-time ablation for atrial fibrillation (AF) using PVAC GOLD were included, 644 patients with paroxysmal AF and 373 patients with non-paroxysmal AF, divided into 175 patients receiving PVI only and 198 patients receiving PVI with additional substrate modification. RESULTS: High and comparable percentages of successful PVI could be achieved in all groups (98%, 95% and 99%; p = 0.108). The median total procedure time for all groups was 90 min [70-100]. As expected, the total procedure, ablation and fluoroscopy time were significantly longer in the PVI + substrate modification group compared with the PVI-only cases (all p < 0.001), but not between the PVI-only groups (p = 0.306, p = 0.088, p = 0.233, respectively). A total of 44 complications were observed in 43 patients (4.2%). Major complications were seen in 19 patients (1.87%) and non-major procedure-related complications were seen in 25 patients (2.46%). Complications leaving permanent sequelae were rare and occurred in only four patients (0.39%). Complications did not differ between groups (p = 0.199, p = 0.438, p = 0.240 and p = 0.465 respectively). CONCLUSION: PVAC GOLD performs successful PVI, while reducing procedure times and retaining safety for paroxysmal, persistent and long-standing persistent AF. Safety was unaffected by additional substrate modification.

Real-time transthoracic three-dimensional echocardiography provides additional information of left-sided AV valve morphology after AVSD repair.

AIMS: The purpose of this study was to assess the feasibility of real-time 3D echocardiography (RT-3DE) data acquisition in adult patients after atrioventricular septal defect (AVSD) repair and to evaluate whether RT-3DE has additional value over 2D echocardiography, regarding morphology and function of the left-sided AV valve (LAVV). METHODS: Twenty consecutive patients with surgically corrected partial or complete AVSD were enrolled in this study. The 3DE data sets were acquired with the Hewlett-Packard Sonos 7500 echo system (Philips Medical Systems, Andover, MA, USA). Images were reviewed off-line with assistance of TomTec Echoview 5.2 software (TomTec Inc., Munich, Germany) by experienced observers. En face reconstructions, from, respectively, the ventricular and atrial view, were made to evaluate the LAVV morphology and motion. RESULTS: 3DE reconstruction of the LAVV was feasible in 17 of 20 patients (85%). Mean time of 3DE acquisition was 9+/-6 min. The quality of the 3DE images was optimal in 35%, good in 30%, sufficient in 20% and insufficient in 15%. Identification of the LAVV structures was importantly better facilitated from a ventricular view. Accurate identification of LAVV morphology was possible in all 17 patients (85%). Relationship of the LAVV and the abnormal position of the LVOT was easier to evaluate from the 3DE reconstructions than from 2D echo. CONCLUSION: This study demonstrate that RT-3DE is feasible in daily practice and provides new insight into the dynamic morphology of the left-sided AV valve and LVOT anatomy after AVSD repair.