Heart rhythm最新文献

Background: For patients with left ventricular systolic dysfunction and prolonged QRS duration, cardiac resynchronization therapy (CRT) can improve cardiac electromechanical synchrony and prevent adverse clinical outcomes.

Objective: This study sought to investigate the role of delta QRS duration (ΔQRSd) in predicting clinical response to CRT.

Methods: The RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure Trial) study randomized 1798 patients to CRT with defibrillator or implantable cardioverter-defibrillator alone. Those who received CRT and had electrocardiograms available at baseline and after CRT implantation were included in this analysis. ΔQRSd was calculated as the absolute difference between QRS duration at baseline and with CRT pacing. The primary outcome was the composite of death and heart failure hospitalization.

Results: There were 813 patients included in this analysis. The median age was 67 years, and 125 patients (15.2%) were female. The median ΔQRSd was -2 ms (-20 to 18 ms), and 447 (55%) patients had a ΔQRSd ≤0 after implantation. ΔQRSd was an independent predictor of the composite outcome for patients with CRT (hazard ratio, 1.012; 95% confidence interval, 1.008-1.017). CRT recipients with ΔQRSd >0 had higher rates of the composite outcome than patients randomized to implantable cardioverter-defibrillator alone.

Conclusion: For patients receiving CRT for heart failure with left ventricular systolic dysfunction and QRS prolongation, ΔQRSd was an independent predictor of long-term mortality and heart failure hospitalization.

Background: Lead-related venous stenosis (LRVS) is common after transvenous lead implantation and generally diagnosed incidentally. Symptomatic LRVS, causing discomfort and swelling, is less common.

Objective: We report on the management and outcomes of patients with symptomatic LRVS after percutaneous balloon venoplasty.

Methods: We included patients with symptomatic LRVS unresponsive to >30 days of anticoagulation who underwent venoplasty at the Hospital of the University of Pennsylvania between 2014 and 2020. Transvenous lead extraction (TLE) was performed first if the lesion could not be crossed with a wire.

Results: Eighteen patients (mean age, 62 ± 10 years; 44% female) underwent 27 venoplasty procedures. Symptoms included arm swelling in 9 (50%), facial/neck swelling in 1 (6%), and both in 8 (44%). Venography revealed LRVS in the axillary/subclavian veins in 10 (56%), the brachiocephalic vein in 6 (33%), and the superior vena cava in 4 (11%). Most patients (83%) required TLE before venoplasty, and only 5 of 18 (28%) remained with leads crossing the stenosed segment. Thirteen patients (72%) had complete symptom resolution, 4 (22%) had partial resolution due to secondary lymphedema, and 1 showed no improvement. Patients with complete resolution had shorter times from symptom onset to intervention (195 vs 690 days; P = .02).

Conclusion: LRVS can affect any part of the venous system and may be manifested with swelling of the arm, face/neck, or both. Balloon venoplasty is safe and effective, often requires TLE, and is particularly durable when leads no longer cross the stenosed region. Venoplasty is less effective for secondary lymphedema, highlighting the need for timely intervention.

Background: To predict worsening heart failure hospitalizations (WHFHs), the HeartInsight multiparametric algorithm calculates a heart failure (HF) Score based on temporal trends of physiologic parameters obtained through automatic daily remote monitoring of implantable cardioverter-defibrillators (ICDs).

Objective: We studied the association of the baseline HF Score, determined at algorithm activation, with long-term patient outcomes.

Methods: Data from 9 clinical trials were pooled, including 1841 ICD patients with a preimplantation ejection fraction ≤35%, New York Heart Association class II/III, and no long-standing atrial fibrillation. The primary end point was a composite of death or WHFH.

Results: After a median follow-up of 631 days (interquartile range, 385-865 days), there were 243 WHFHs in 173 patients (9.4%) and 122 deaths (6.6%), 52 of which (42.6%) were cardiovascular. The primary end point occurred in 265 patients (14.4%). A multivariable time-to-first-event analysis showed that a high baseline HF Score (>23, as determined by a time-dependent receiver operating characteristics curve analysis) was significantly associated with the occurrence of the primary end point (adjusted hazard ratio [HR], 2.05; 95% confidence interval [CI], 1.54-2.71; P < .0001), all-cause death (HR, 2.37; CI, 1.56-3.58; P < .0001), cardiovascular death (HR, 2.19; CI, 1.14-4.22; P = .019), and WHFH (HR, 1.91; CI, 1.35-2.71; P = .0003). In a hierarchical event analysis of all-cause death as the outcome with highest priority and WHFHs as repeated event outcomes, the win ratio was 2.47 (CI, 1.89-3.24; P < .0001).

Conclusion: Based on a retrospective analysis of clinical trial data with adjudicated events, baseline HF Score derived from device-monitored variables was able to stratify patients at higher long-term risk of death or WHFH.

Background: Torsades de pointes (TdP) represent a complex polymorphic ventricular tachycardia. While the triggering mechanisms of early afterdepolarization and increased dispersion of repolarization are well investigated, the sudden self-limiting termination remains poorly understood.

Objective: The purpose of this study was to perform analysis of TdP to investigate factors causing spontaneous termination.

Methods: We used a large data set from Langendorff experiments in isolated rabbit hearts in which drug-induced QT prolongation, bradycardia, and hypokalemia provoke TdP. We included 427 episodes with typical TdP characteristics of polymorphic self-terminating beats and twisting QRS complexes occurring in the presence of abnormal QT prolongation due to various different QT-prolonging drugs. The use of 8 monophasic action potential catheters allowed the characterization of action potential duration, configuration, and dispersion of repolarization beyond the capabilities of the surface electrocardiogram. To identify possible mechanisms of arrhythmia termination, the initial, midpoint, and terminal 3 ventricular complexes were analyzed for each episode.

Results: An abrupt decrease in spatial dispersion over the course of a TdP episode was identified as a precursor for termination of TdP. Within the last 3 beats, a sudden significant decrease in the dispersion of repolarization was observed as a predictor of termination. In parallel, there was a decrease in action potential duration (action potential duration at 90% repolarization) before termination. Also, a change in action potential configuration (action potential duration at 90% repolarization/action potential duration at 50% repolarization ratio) in terms of the loss of action potential dome with a restitution of action potential triangulation was observed.

Conclusion: In >400 TdP episodes, homogenization of myocardial repolarization with the recovery of an action potential configuration determines the termination of TdP episodes.

Background: Arrhythmias can lead to cardiac arrest and heart failure. When intractable, heart transplantation (HTX) can become the only viable treatment. This rare high-risk cohort has not been reported as a distinct group.

Objective: The purpose of this study was to characterize the outcomes of pediatric patients listed for HTX with the primary indication being malignant arrhythmia (MA).

Methods: Using the Pediatric Heart Transplant Society prospective registry, we identified all patients younger than 18 years listed between 2014 and 2022. MA as the listing indication was categorized into primary tachyarrhythmia (PT), inherited arrhythmia (IA), congenital heart disease, and cardiomyopathy (CM) with secondary arrhythmia. Demographic, listing, and transplant data were analyzed.

Results: Among 4630 patients listed and 3317 transplanted, MA was the indication in 63 (1.4%) and 49 (1.5%), respectively. Patients with MA were categorized as PT in 11 (17%), IA in 4 (6%), congenital heart disease in 6 (10%), and CM in 42 (67%). Compared with the non-MA cohort, patients listed for MA were older (mean age 10.6 ± 6.2 years vs 6.1 ± 6.2 years; P < .01), more likely to present with cardiac arrest (43% vs 11%; P < .01), and less likely to be in the intensive care unit (40% vs 58%; P < .01) or on inotropes (30% vs 60%; P < .01) at the time of listing. Outcomes including waitlist mortality, transplantation, posttransplant survival, and freedom from rejection were comparable to those of the non-MA cohort.

Conclusion: Patients with MA constitute a small proportion of those listed for HTX in childhood. CM was the most common category, while IA and PT were rare. Their waitlist mortality and posttransplant outcomes were comparable to those of the non-MA cohort.

Background: Sinoatrial node (SAN) activation and sinoatrial conduction pathways (SACPs) have been assessed in animals but not in humans.

Objectives: We used ultrahigh-density mapping and simulated models to characterize the SAN and to investigate whether slowed SAN conduction may contribute to the atrial flutter (AFL) substrate.

Methods: Twenty-seven patients undergoing electrophysiologic procedures had right atrial mapping. SAN activation patterns and conduction block were analyzed. The interaction between the SAN and the intercaval line of block (LOB) was analyzed, and right atrial simulations with different degrees of block were created to investigate arrhythmia mechanisms.

Results: Fifteen AFL patients and 12 reference patients were enrolled. SACPs were identified in all patients with sinus rhythm maps. An SAN-adjacent LOB was observed in AFL patients. SAN conduction velocity was slower in AFL vs reference (0.60 m/s [0.56-0.78 m/s] vs 1.13 m/s [1.00-1.21 m/s]; P = .0021). Coronary sinus paced maps displayed an intercaval LOB in AFL patients but not in reference patients, which was completed superiorly by the SAN-adjacent LOB. Corrected sinus node recovery time was longer in AFL patients (552.3 ± 182.9 ms vs 325.4 ± 138.3 ms; P < .006) and correlated with degree of intercaval block (r = 0.7236; P = .0003). Computer modeling supported an important role of SAN-associated block in the flutter substrate.

Conclusion: Ultrahigh-density mapping accurately identifies SAN activation and SACPs. The LOB important for typical AFL was longer in AFL patients, and when partial, it was always present inferiorly and completed superiorly because of slowed conduction across the SAN. Corrected sinus node recovery time correlated with intercaval block, suggesting a role for SAN disease in the genesis of the typical AFL substrate.

Background: Atrial fibrillation (AF) leads to impaired left atrial appendage contractility, increasing the risk of thromboembolic stroke. The left atrial appendage emptying velocity (LAAev) measured on transesophageal echocardiogram (TEE) is a marker of increased thromboembolic risk.

Objectives: The purpose of this study was to evaluate predictors of reduced LAAev for identifying individuals at increased risk for cardioembolic stroke.

Methods: This was a single-center retrospective review of TEEs and clinical charts. Predictors of LAAev <30 cm/s were identified using logistic regression. A risk prediction model was created using stepwise selection in a derivation set (n = 695) and separately tested in a validated set (n = 300).

Results: We included TEEs on 995 patients (age 71.3±12.7 years; female 38.1%; history of AF 82.1%; in AF at evaluation 27.7%; CHA₂DS₂-VASc score 4.1 ± 1.9; LAAev 41.6 ± 21.0 cm/s). Significant multivariable predictors of LAAev <30 cm/s in derivation set were used to create the CHIRP³M_-1 score containing 8 variables: Coronary artery disease (1), congestive Heart failure (1), Increased left atrial volume index ≥42 mL/m² (1), current Rhythm AF (1), Paroxysmal AF (2), Persistent AF (3), longstanding Persistent/permanent AF (4), and greater than moderate Mitral regurgitation (-1). In the validation set, as compared to intermediate scores (3-4), those with low scores (≤2) and high scores (≥5) had odds ratios for LAAev <30 cm/s of 0.41 (0.21, 0.78, P = .007) and 2.58 (95% confidence interval 1.45-4.61, P = .001), respectively.

Conclusion: We developed and validated a novel risk stratification system to predict reduced LAAev using clinical and echocardiographic variables. This may help refine the stratification of cardioembolic stroke risk.

Background: In patients with implantable cardioverter-defibrillators (ICDs), inappropriate therapies (ITs) are often caused by supraventricular tachyarrhythmias (SVTs).

Objective: We aimed to estimate the incidence of IT in modern single-lead ICDs.

Methods: The THINGS study enrolled patients with single-lead ICDs with 2 SVT discrimination modalities: dual chamber (DC) with an atrial floating dipole or single chamber (SC) with morphology criterion. All devices were programmed with 2-zone therapy: ventricular tachycardia (VT) zone from 170 beats/min with ≥15 seconds (≥36 beats) detection time and SVT discriminators; and ventricular fibrillation (VF) zone from 214 beats/min with ≥7 seconds (≥24 beats) detection time. The primary end point was the first occurrence of IT, adjudicated by an independent board.

Results: A total of 526 patients (median age, 66 years; 83% male), 183 (34.8%) with DC and 343 (65.2%) with SC discrimination, were observed for a median of 2.2 years. The incidence rate of IT was 4.2% (95% confidence interval [CI], 2.7%-6.4%) at 1 year and 7.1% (95% CI, 5.0%-9.9%) at 2 years. Younger age (adjusted hazard ratio, 0.97; 95% CI, 0.95-0.99; P = .013) and history of atrial fibrillation (adjusted hazard ratio, 2.67; 95% CI, 1.30-5.46; P = .007) were significantly associated with increased IT risk. In a propensity score-matched comparison, DC discrimination showed a trend toward reduced IT rates compared with SC discrimination in the VT zone (1-year incidence, 1.8% vs 3.5%; P = .105).

Conclusion: High-rate VF cutoff and prolonged detection time programming resulted in a low IT rate in single-lead ICD patients with modern SVT discriminators. A trend favoring the DC system was observed in the VT zone.