Heart rhythm最新文献

Background: Traumatic brain injury (TBI) is associated with a variety of adverse long-term outcomes and increases sympathetic nervous system activation which could increase the risk of arrhythmias including atrial fibrillation or atrial flutter (AF/AFL).

Objective: To examine episodes of TBI and subsequent AF/AFL in a large cohort of post-9/11 Servicemembers and Veterans.

Methods: The variable of interest was TBI, stratified by severity (mild, moderate/severe, and penetrating). The outcome was a subsequent diagnosis of AF/AFL. We used Fine-Gray competing risks models to evaluate the potential risk imparted by TBI on subsequent AF/AL.

Results: Among the 1,924,900 subjects included in the analysis, 369,891 (19.2%) experienced an episode of documented TBI. Most were young (63% less than 35 years), male (81.7%) and non-Hispanic White (62.7%). AF/AFL was diagnosed in 22,087 subjects. On univariate analysis, only penetrating TBI (hazard ratio [HR] 2.02, 95% confidence interval [CI] 1.84-2.23; p<0.001) was associated with AF/AFL compared to Veterans without TBI. After adjustment in the full multivariable model (adjusted for age, sex, race and ethnicity, service branch, rank, component, and comorbidities), mild (HR 1.27, 95% CI 1.22-1.32; p<0.001), moderate/severe (HR 1.34, 95% CI 1.24-1.44; p<0.001), and penetrating TBI (HR 1.82, 95% CI 1.65-2.02; p<0.001) were significantly associated with AF/AFL compared to no TBI. Post-hoc analyses demonstrated that the risk of AF/AFL was concentrated in female and younger patients.

Conclusion: We found that an episode of TBI, particularly penetrating TBI, significantly increased the risk for AF/AFL. Further work is needed to delineate the long-term risk of arrhythmias after TBI.

Background: Enhanced characterization of the atrial electrical substrate may lead to better comprehension of atrial fibrillation (AF) pathophysiology.

Objective: With the use of high-density substrate mapping, we sought to investigate the occurrence of functional electrophysiological phenomena in the left atrium and to assess potential association with arrhythmia recurrences following catheter ablation.

Methods: Sixty-three consecutive patients with AF referred for ablation were enrolled. Conduction abnormalities analysis relied on two acquired left atrial electro-anatomical maps (sinus and atrial paced rhythm). We classified conduction abnormalities as fixed (if these were present in both rhythms), or functional rhythm-dependent (if unmasked in one of the two rhythms). Esophagus and aorta locations were recorded to check the correspondence with abnormal conduction sites.

Results: 234 conduction abnormalities were detected, of which 125 (53.4%) were functional rhythm-dependent. In sinus rhythm the most frequent anatomical site of functional phenomena was the anterior wall followed by the posterior wall and in paced rhythm, the pulmonary venous antra. Sites of functional phenomena in 82.6% of cases corresponded with extra-cardiac structures such as sinus of Valsalva of ascending aorta anteriorly and the esophagus posteriorly. The vast majority (88%) of areas with functional phenomena had normal bipolar voltage. After pulmonary vein ablation, the number of residual functional phenomena is an indipendent predictor of AF recurrence (HR 2.539 [1.458 - 4.420], p-value = 0.001) with a risk of recurrences at multivariable Cox analysis.

Conclusions: Dual high-density mapping (during sinus and paced rhythms) is able to unmask functional, rhythm-dependent, phenomena which are predictive of AF recurrences during the follow-up.

Background: Paced QRS morphology may vary during left bundle branch area pacing (LBBAP) as per the pacing location. It remains unclear whether electrocardiographic changes observed during LBBAP can predict clinical outcomes.

Objective: To assess correlation between characteristics of paced QRS on electrocardiogram and clinical outcomes in heart failure (HF) patients with non-ischemic cardiomyopathy.

Methods: Of 79 consecutive HF patients receiving LBBAP, 59 patients were included in this prospective study after exclusions. LBBAP was performed using Medtronic 3830 lead. Patients were categorized into various groups based on paced QRS morphology in lead V1 (qR and Qr), QRS axis (normal, left or right) and V6 R wave peak time (RWPT, ≤80 or >80 ms) to compare echocardiographic outcomes.

Results: RWPT was significantly shorter (75.7±17.5 vs 85.3±11.3 ms, P=0.014), transition during threshold test more commonly observed (81.5% vs 53%, P=0.02) and improvement in left ventricular ejection fraction (LVEF) was significantly greater in qR group (21.4±6.4 vs 16.4±8.3%, P=0.013) compared to Qr group. RWPT or LVEF did not differ in patients with different paced QRS axis (P>0.05). While qR morphology and presence of transition during threshold test independently predicted LVEF improvement, RWPT lacked predictive value. Non-responders had greater incidence of loss of 'R' prime (P=0.009) and prolonged RWPT (P=0.003) on follow up compared to average and super-responders.

Conclusions: Paced qR morphology and transition during threshold test predicted greater improvement in LVEF while RWPT lacked predictive value. Loss of terminal 'R' in lead V1 and prolongation of RWPT on follow up prognosticated non-response to LBBAP.

Background: End-stage kidney disease (ESKD) patients are prone to bloodstream infections which may result in a higher risk of cardiac implantable electronic device (CIED) infections.

Objective: To assess the incidence, risk predictors, management strategies and long-term outcomes of CIED infections in ESKD patients undergoing de-novo CIED implantation.

Methods: This is a retrospective study utilizing the United States Renal Data System. ESKD patients with de-novo CIED implant between 1/1/2006-9/30/2014 were included. Patients were followed until death, kidney transplantation, end of Medicare coverage or 9/30/2015 to assess incidence of CIED infection. Management approach was determined from procedure codes for lead extraction within 60 days of CIED infection diagnosis. Patients with CIED infection were followed until 12/31/2019 to assess long-term outcomes.

Results: Among 15,515 ESKD patients undergoing de-novo CIED implant, incidence of CIED infection was 4.8% over a median follow-up of 1.3 years. The presence of a defibrillator (aHR 1.48), higher BMI (aHR 1.01), younger age (aHR 0.96) were independent risk factors for CIED infection. Lead extraction occurred in only 50.71% patients by 60 days. After propensity score matching, the 3-year mortality was higher in those who did not undergo lead extraction compared to those who did (80.3% vs 72.3%) and time to mortality was shorter (0.3 vs 0.6 years). Only 13.8% patients underwent reimplantation with a new CIED after lead extraction.

Conclusion: CIED infections occur frequently in ESKD patients and are associated with a very high mortality. Early lead extraction is not performed routinely but is associated with improved survival.

Background: Isolation line placed at the pulmonary vein antrum (PVA) area is superior to ostium level in atrial fibrillation (AF) control. However, less is known about the electrophysiological characteristics of PVA.

Objective: To describe the electrophysiological properties of PVA.

Methods: High-density mapping of the left atrium was performed in 18 paroxysmal AF (PAF) patients and 9 age- and sex-matched paroxysmal supraventricular tachycardia (PSVT) patients. Each PVA was divided into 8, pulmonary vein (PV) into 4 segments. The electrophysiological properties included slow conduction, complex fractionated electrograms, and effective refractory period (ERP).

Results: The slow conduction was more prevalent at PVA (43.2±19.5 vs. 14.7±13.0 %, P=0.001) and PV (61.9±16.4 vs. 9.1±9.0 %, P<0.001) in PAF patients than in PSVT patients during sinus rhythm (SR). Similarly, the area with complex fractionated electrograms was significantly larger at PVA (133.8 [61.6, 233.2] vs. 0.0 [0.0, 41.4] mm², P=0.011) in PAF patients during SR. The ERP of PVA was longer in PAF patients than in control at the drive length of 600 ms (260 [230, 280] vs. 220 [190, 250] ms, P=0.001) and 400 ms (230 [205, 250] vs. 200 [190, 220] ms, P=0.007). The ERP net difference between the PV and PVA is larger in PAF patients than in control both at 600 ms (40 [20, 70] vs. 10 [10, 30] ms, P<0.001) and (40 [20, 60] vs. 20 [10, 30] ms, P<0.001) at 400 ms pacing, respectively.

Conclusion: PAF patients have the PVA electrical substrate including slow conduction, complex fractionated electrograms and ERP dispersion.

Background: Targeting the maximal ventricular resynchronization, with the shortest QRS duration (QRSd), is commonly implemented after cardiac resynchronization therapy (CRT).

Objective: We compared optimization of ventricular resynchronization with optimization of left ventricular (LV) filling during CRT by measuring their acute hemodynamic effects.

Methods: Patients with standard CRT indications, recruited from two centers, underwent biventricular pacing (BVP) and left bundle branch pacing (LBBP). We performed a within-patient comparison of acute hemodynamic response of systolic blood pressure (SBP) at the atrioventricular delay (AVD) with the shortest QRSd against the AVD with the most efficient LV filling. In a validation sub-study, we also performed electrical assessment using QRS area (QRSa) and hemodynamic assessment with the maximum rate of LV pressure rise (dP/dt_max).

Results: Thirty patients (age 65 ± 10, 53% male) were recruited. The AVD producing maximal ventricular resynchronization was associated with a significantly shorter QRSd (difference 15 ± 12 ms for BVP and 18 ± 13 ms for LBBP, both P < 0.01) and a significantly smaller improvement in SBP (difference 3 ± 4 mmHg for BVP, and 2 ± 2 mmHg for LBBP, both P < 0.01) compared with the AVD that optimized filling. Similar findings were observed in the sub-study, with a significantly smaller improvement in dP/dt_max assessed with QRSd and QRSa (difference 9 ± 7% and 6 ± 4% during BVP, and 5 ± 6% and 3 ± 3% during LBBP, all P < 0.01).

Conclusion: Targeting the maximal ventricular resynchronization results in suboptimal acute hemodynamic performance with both BVP and LBBP as CRT. These findings support prioritizing LV filling when programming AVD for CRT.

Background: Atrial fibrillation (AF) poses a major risk for heart failure, myocardial infarction, and stroke. Several studies have linked SCN5A variants to AF, but their precise mechanistic contribution remains unclear. Human induced pluripotent stem cells (hiPSCs) provide a promising platform for modeling SCN5A-linked AF variants and their functional alterations.

Objective: The purpose of this study was to assess the electrophysiological impact of three AF-linked SCN5A variants, K1493R, M1875T and N1986K identified in three unrelated individuals.

Methods: CRISPR-Cas9 was used to generate a new hiPSC line in which Na_V1.5 was knocked-out. Following differentiation into specific atrial cardiomyocyte by using retinoic acid, the adult WT and SCN5A variants were introduced into the Na_V1.5 KO line through transfection. Subsequent analysis including molecular biology, optical mapping, and electrophysiology were performed.

Results: The absence of Na_V1.5 channels altered the expression of key cardiac genes. Na_V1.5 KO hiPSC-aCMs displayed slower conduction velocities, altered action potential (AP) parameters, and impaired calcium transient propagation. The transfection of the WT channel restored sodium current density and AP characteristics. Among the AF variants, one induced a loss-of-function (N1986K) while the other two induced a gain-of-function in Na_V1.5 channel activity. Cellular excitability alterations, and early afterdepolarizations were observed in AF variants.

Conclusion: Our findings suggest that distinct alterations in Na_V1.5 channel properties may trigger atrial hyperexcitability and arrhythmogenic activity in AF. Our KO model offers an innovative approach for investigating SCN5A variants in a human cardiac environment.