JACC. Clinical electrophysiology最新文献

Background

Purkinje fibers play an important role in initiation and maintenance of ventricular fibrillation (VF) and polymorphic ventricular tachycardia (PMVT). Fascicular substrate modification (FSM) approaches have been suggested to treat recurrent VF in case reports and small case series.

Objectives

The aim of this study was to investigate outcomes of catheter-based FSM to treat VF and PMVT.

Methods

Of 2,212 consecutive patients with ventricular arrhythmia undergoing catheter ablation, 18 (0.81%) underwent FSM of the Purkinje fibers as identified with high-density mapping during sinus rhythm. Fascicular substrate and VF initiation were mapped using a multipolar catheter. The endpoint of the ablation was noninducibility of VF and PMVT. In select patients, remapping revealed elimination of the targeted Purkinje potentials. Demographic, clinical, and follow-up characteristics were prospectively collected in our institutional database.

Results

A total of 18 patients (mean age 56 ± 3.8 years, 22% women) were included in the study. Of those, 11 (61.1%) had idiopathic VF, 3 (16.7%) had nonischemic cardiomyopathy, and 4 (22.2%) had mixed cardiomyopathy. The average left ventricular ejection fraction was 42.5%. At least 2 antiarrhythmic drugs had failed preablation. At baseline, all patients had inducible VF or PMVT. At the end of the procedure, no patient demonstrated new evidence of fascicular block or bundle branch block. There were no procedure-related complications. After a median follow-up period of 24 months, 16 patients (88.9%) were arrhythmia free on or off drugs: 11 of 11 patients (100%) with idiopathic VF vs 5 of 7 patients (71.4%) with underlying cardiomyopathy (P = 0.06).

Conclusions

Catheter ablation of human VF and PMVT with FSM is feasible and safe and appears highly effective, with high rates of acute VF noninducibility and long-term freedom from recurrent VF.

Background

Current therapies for pulmonary vein stenosis (PVS) or pulmonary vein total occlusion (PVTO) involving angioplasty and stenting are hindered by high rates of restenosis.

Objectives

This study compares a novel approach of drug-coated balloon (DCB) angioplasty and stenting with the current standard of care in PVS or PVTO due to pulmonary vein isolation (PVI).

Methods

A retrospective single-center study analyzed patients with PVS or PVTO due to PVI who underwent either angioplasty and stenting (NoDCB group; December 2012-December 2016) or DCB angioplasty and stenting (DCB group; January 2018-January 2021). Multivariable Andersen-Gill regression analysis assessed the risk of restenosis and target lesion revascularization (TLR).

Results

The NoDCB group comprised 58 patients and 89 veins, with a longer median follow-up of 35 months, whereas the DCB group included 26 patients and 33 veins, with a median follow-up of 11 months. The DCB group exhibited more PVTO (NoDCB: 12.3%; DCB: 42.4%; P = 0.0001), with a smaller reference vessel size (NoDCB: 10.2 mm; DCB: 8.4 mm; P = 0.0004). Follow-up computed tomography was performed in 82% of NoDCB and 85% of DCB, revealing lower unadjusted rates of restenosis (NoDCB: 26%; DCB: 14.3%) and TLR (NoDCB: 34.2%; DCB: 10.7%) in the DCB group. DCB use was associated with a significantly lower risk of restenosis and TLR (HR: 0.003: CI: 0.00009-0.118; P = 0.002).

Conclusions

The novel approach of DCB angioplasty followed by stenting is effective and safe and significantly reduces the risk of restenosis and reintervention compared with the standard of care in PVS or PVTO due to PVI.

Background

Abnormal ventricular activation at rest is reported in Brugada syndrome (BrS).

Objectives

The aim of this study was to evaluate the usefulness of dynamic changes in ventricular activation during exercise to improve disease phenotyping and diagnosis of BrS.

Methods

Digital 12-lead electrocardiograms during stress testing were analyzed retrospectively at baseline, peak exercise, and recovery in 53 patients with BrS and 52 controls. Biventricular activation was assessed from QRS duration (QRSd), whereas right ventricular activation was assessed from S wave duration in the lateral leads (I and V₆) and terminal R wave duration in aVR. Exercise-induced changes in QRS parameters to predict a positive procainamide response were assessed in separate test and validation cohorts with suspected BrS.

Results

Baseline electrocardiogram parameters were similar between BrS and controls. QRSd shortened with exercise in all controls but prolonged in all BrS (−6.1 ± 6.0 ms vs 7.1 ± 6.5 ms [P < 0.001] in V₆). QRSd in recovery was longer in BrS compared with controls (90 ± 12 ms vs 82 ± 11 ms in V₆; P = 0.002). Both groups demonstrated exercise-induced S duration prolongation in V6, with greater prolongation in BrS (8.2 ± 14.3 ms vs 1.2 ± 12.4 ms; P < 0.001). Any exercise-induced QRSd prolongation in V₆ differentiated those with a positive vs negative procainamide response with 100% sensitivity and 95% specificity in the test cohort, and 87% sensitivity and 93% specificity in the validation cohort.

Conclusions

Exercise-induced QRSd prolongation is ubiquitous in BrS primarily owing to delayed right ventricular activation. This electrocardiogram phenotype predicts a positive procainamide response and may provide a noninvasive screening tool to aid in the diagnosis of BrS before drug challenge.

Within the broad spectrum of atrial fibrillation (AF) symptomatology, there is a striking subset of patients with predominant or even solitary nocturnal onset of the arrhythmia. This review covers AF with nocturnal onset, with the aim of defining this distinctive subgroup among patients with AF. A periodicity analysis is provided showing a clear increased onset between 10:00 pm and 7:00 am. Multiple interacting mechanisms are discussed, such as circadian modulation of electrophysiological properties, vagal tone, and sleep disorders, as well as the potential interaction and synergism between these factors, to provide a better understanding of this clinical entity. Lastly, potential therapeutic targets for AF with nocturnal onset are addressed such as upstream therapy for underlying comorbidities, type of drug and timing of drug administration and pulmonary vein isolation, ablation of the ganglionated plexus, and autonomic nervous system modulation. Understanding the underlying AF mechanisms in the individual patient with nocturnal onset will contribute to patient-specific therapy.

Background

Biventricular pacing is a well-established therapy for patients with heart failure (HF), left bundle branch block (LBBB) and left ventricular (LV) dysfunction. Left bundle branch pacing (LBBP) has emerged as an alternative to biventricular pacing.

Objectives

The aim of this study was to assess the retrograde conduction properties of the left bundle branch in patients with nonischemic cardiomyopathy and LBBB during LBBP and its clinical implications.

Methods

Patients undergoing successful LBBP for nonischemic cardiomyopathy with LV ejection fraction (LVEF) ≤35% and LBBB were included. Continuous recording of His potential was performed using a quadripolar catheter. Unidirectional block was defined as retrograde His bundle activation during LBBP with stimulus to His potential (SH) duration less than or equal to antegrade HV interval and bidirectional block as VH dissociation or SH duration greater than HV interval. HF hospitalization, ventricular arrhythmias, and mortality were documented.

Results

A total of 165 patients were included. The mean follow-up duration was 21.8 ± 13.1 months. Bidirectional block (group I) was observed in 82% (n = 136), and these patients were noted to have advanced HF stage and prolonged baseline QRS duration. Unidirectional block (group II) with intact retrograde conduction was observed in 18% (n = 29) and was associated with narrow paced QRS duration and higher LVEF during follow-up. Super-response (LVEF ≥50%) was observed in 54.4% (n = 74) in group I compared with 73.3% (n = 22) in group II (P = 0.03). The OR for LVEF normalization was 4.1 (95% CI: 1.26-13.97; P = 0.02), with unidirectional block compared with bidirectional block in patients with LBBB and LV dysfunction. Adverse clinical outcomes as measured by a composite of HF hospitalization, ventricular arrhythmias, and mortality were significantly higher in group I compared with group II (12.5% vs 0%; P = 0.04).

Conclusions

Bidirectional block in LBBB was characterized by advanced HF symptoms, while unidirectional block was associated with better clinical outcomes after cardiac resynchronization therapy by LBBP.

Background

The extravascular (EV) implantable cardioverter-defibrillator (ICD) includes features to address sensing and arrhythmia detection challenges presented by its substernal lead location.

Objectives

In this study, the authors sought to evaluate sensing and detection performance in 299 patients discharged with an EV-ICD in the global pivotal study.

Methods

We reviewed and adjudicated all induced ventricular fibrillation (VF) episodes and spontaneous device-stored episodes that satisfied rate and duration criteria in a programmed ventricular tachycardia (VT)/VF therapy zone.

Results

At implantation, all EV-ICDs detected induced VF at the programmed sensitivity; 95.9% detected VF with a 3× safety margin. In follow-up, EV-ICDs detected all 59 VT/VF episodes that sustained until therapy. Of 1,034 non-VT/VF episodes, oversensing caused 87.9% and supraventricular tachycardia caused 12.1%. Therapy was withheld in 80.9%, aborted in 10.6%, and delivered in 8.5%. The most common causes of oversensing were myopotentials (61.2%) and P-wave oversensing (PWOS) (19.9%). Inappropriate shocks occurred in only 3.2% of myopotential episodes, but in 21.8% of PWOS episodes. Myopotential oversensing was more common with Ring-Can sensing (P < 0.0001) and correlated with low R-wave amplitude (P < 0.0001). PWOS occurred almost exclusively with Ring1-Ring2 sensing (P = 0.0001) and began with transient decrease in R-wave or increase in P-wave amplitude (P < 0.0001). In software emulation, a new PWOS discriminator significantly reduced total inappropriate detections.

Conclusions

In a global population, EV-ICD detected induced and spontaneous VT/VF accurately. Although discriminators withheld detection from most non-VT/VF episodes, inappropriate shocks were common. The most common cause was PWOS, which may be reduced by optimizing sensing at implantation and incorporation of the PWOS discriminator, which is now in the current device. (Extravascular ICD Pivotal Study [EV ICD]; NCT04060680)