The latest medical research on Clinical Cardiac Electrophysiology

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about clinical cardiac electrophysiology gathered by our medical AI research bot.

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Automated prediction of isthmus areas in scar-related atrial tachycardias using artificial intelligence.

Journal of Cardiovascular Magnetic Resonance

Ablation of scar-related reentrant atrial tachycardia (SRRAT) involves identification and ablation of a critical isthmus. A graph convolutional network (GCN) is a machine learning structure that is well-suited to analyze the irregularly-structured data obtained in mapping procedures and may be used to identify potential isthmuses.

Electroanatomic maps from 29 SRRATs were collected, and custom electrogram features assessing key tissue and wavefront properties were calculated for each point. Isthmuses were labeled off-line. Training data was used to determine the optimal GCN parameters and train the final model. Putative isthmus points were predicted in the training and test populations and grouped into proposed isthmus areas based on density and distance thresholds. The primary outcome was the distance between the centroids of the true and closest proposed isthmus areas.

A total of 193 821 points were collected. Thirty isthmuses were detected in 29 tachycardias among 25 patients (median age 65.0, 5 women). The median (IQR) distance between true and the closest proposed isthmus area centroids was 8.2 (3.5, 14.4) mm in the training and 7.3 (2.8, 16.1) mm in the test group. The mean overlap in areas, measured by the Dice coefficient, was 11.5 ± 3.2% in the training group and 13.9 ± 4.6% in the test group.

A GCN can be trained to identify isthmus areas in SRRATs and may help identify critical ablation targets.

The world's longest lasting VVI pacemaker device for over 40 years.

Journal of Cardiovascular Magnetic Resonance

Implantable permanent pacemaker function is supported by their energy sources for a mean period of 8.8-12.4 years. We previously published this case of a patient with a normally functioning VVI pacemaker, 31 years after implantation.

In this report, we state that the device is still functioning normally 40 years after implantation. The most recent device interrogation revealed pacing threshold of 0.9 V/0.5 ms. Holter monitoring for 24 hours recorded a total of 98.707 beats with 97.78% paced beats, without any indication of pacemaker malfunction and with stable heart rate at 70-71 bpm.

Most patients with implantable devices have the appropriate follow-up and settings of low energy consumption. Manufacturing companies should focus on prolonging device longevity, to produce future devices with higher energy capacity.

Radiofrequency ablation-Real-time visualization of lesions and their correlation with underlying parameters.

Pacing Clin Electrophysiol

Lesion durability and transmurality are crucial for successful radiofrequency (RF) ablation. This study provides a model of real-time RF lesion visualization and insights into the role of underlying parameters, as local impedance (LI).

A force-sensing, LI-sensing catheter was used for lesion creation in an ex vivo model involving cross-sections of porcine cardiac preparations. During 60 s of RF application, one measurement per second was performed regarding lesion size and available ablation parameters. In total, 1847 measurements from n = 36 lesions were performed. Power (20-50 W) and contact force (1-5 g, 10-15 g, 20-25 g) were systematically alternated.

Lesion formation was most prominent in the first seconds of RF application during which nonlinear lesion growth was observed (max. 1.08 mm/s for lesion depth and 2.71 mm/s for lesion diameter). Power levels determined the extent of lesion formation in the early phase. After 20 s, lesion size growth velocity approaches 0.1 mm/s at all power levels. LI changes were also highest in the first seconds (up to - 12 Ω/s) and decreased to less than - 0.1Ω/s after prolonged application.

Lesion formation in irrigated RF ablation is a nonlinear process. Final lesion size resulting from an RF application is mainly influenced by high rates of lesion growth in the first seconds of ablation. LI seems to be a good surrogate for differentiating changes in lesion formation.

Trends and disparities in cardiac implantable electronic device infection-related mortality in the United States.

Journal of Cardiovascular Magnetic Resonance

We performed a cross-sectional study using the Centers for Disease Control and Prevention's (CDC's) Wide-Ranging Online Data for Epidemiologic Research (WONDER) database to analyze the trends in cardiac implantable electronic device (CIED) infection-related mortality from 1999 to 2020.

We analyzed the death certificate data from the CDC WONDER database from 1999 to 2020 for CIED infections in the US population aged ≥25 years using International Classification of Diseases, Tenth Revision (ICD-10) codes, listed as the underlying or contributing cause of death. Age-adjusted mortality rates (AAMR) and 95% confidence intervals (CIs) were computed per 1 million population by standardizing crude mortality rates to the 2000 US census population. To assess annual mortality trends, we employed the Joinpoint regression model, calculating the annual percent change (APC) in AAMR and corresponding 95% CIs.

Overall, there was an observed declining trend in AAMRs related to CIED infection-related mortality. Males accounted for 55% of the total deaths, with persistently higher AAMRs compared to females over the study duration. Both males and females had an overall decreasing trend in AAMRs throughout the study duration. On race/ethnicity stratified analysis, non-Hispanic (NH) Blacks exhibited the highest overall AAMR, followed by NH American Indians or Alaska Natives, NH Whites, Hispanic or Latinos, and NH Asian or Pacific Islanders. On a stratified analysis based on region, the South region had the highest overall AAMR, followed by the Midwest, West, and Northeast regions.

Our study demonstrates a significant decline in CIED infection-related mortality in patients over the last two decades. Notable gender, racial/ethnic, and regional differences exist in the rates of mortality related to CIED infections.

Utilizing median and maximum QTc values improves prediction of breakthrough cardiac events in pediatric long QT syndrome.

Journal of Cardiovascular Magnetic Resonance

Although prior studies indicate that a QTc > 500 ms on a single baseline 12-lead electrocardiogram (ECG) is associated with significantly increased risk of arrhythmic events in long QT syndrome (LQTS), less is known about the risk of persistent QT prolongation. We sought to determine QTc persistence and its prognostic effect on breakthrough cardiac events (BCEs) among pediatric patients treated for LQTS.

We performed a retrospective analysis of 433 patients with LQTS evaluated, risk-stratified, and undergoing active guideline-based LQTS treatment between 1999 and 2019. BCEs were defined as arrhythmogenic syncope/seizure, sudden cardiac arrest (SCA), appropriate VF-terminating ICD shock, and sudden cardiac death (SCD).

During the median follow-up of 5.5 years (interquartile range [IQR] = 3-9), 32 (7%) patients experienced a total of 129 BCEs. A maximum QTc threshold of 520 ms and median QTc threshold of 490 ms were determined to be strong predictors for BCEs. A landmark analysis controlling for age, sex, genotype, and symptomatic status demonstrated models utilizing both the median QTc and maximum QTc demonstrated the highest discriminatory value (c-statistic = 0.93-0.95). Patients in the high-risk group (median QTc > 490 ms and maximum QTc > 520 ms) had a significantly lower BCE free survival (70%-81%) when compared to patients in both medium-risk (93%-97%) and low-risk (98%-99%) groups.

The risk of BCE among patients treated for LQTS increases not only based upon their maximum QTc, but also their median QTc (persistence of QTc prolongation). Patients with a maximum QTc > 520 ms and median QTc > 490 ms over serial 12-lead ECGs are at the highest risk of BCE while on guideline-directed medical therapy.

Comparison of outcomes and required tools between transvenous extraction of pacemaker and implantable cardioverter defibrillator leads: Insight from single high-volume center experience.

Journal of Cardiovascular Magnetic Resonance

Reports of comparison with procedural outcomes for implantable cardioverter defibrillator (ICD) and pacemaker (PM) transvenous lead extraction (TLE) are old and limited. We sought to compare the safety, efficacy, and procedural properties of ICD and PM TLE and assess the impact of lead age.

The study cohort included all consecutive patients with ICD and PM TLE in the Cleveland Clinic Prospective TLE Registry between 2013 and 2022. Extraction success, complications, and failure employed the definitions described in the HRS 2017 TLE guidelines.

A total of 885 ICD leads, a median implant duration of 8 (5-11) years in 810 patients, and 1352 PM leads of 7 (3-13) years in 807 patients were included. Procedural success rates in ICD patients were superior to those of PM in >20 years leads but similar in ≤20 years leads. In the PM group, the complete success rate of TLE decreased significantly according to the increase of lead age, but not in the ICD group. ICD TLE required more extraction tools compared with PM TLE but cases with older leads required non-laser sheath extraction tools in both groups. The most common injury site in major complication cases differed between ICD and PM TLE, although major complication rates showed no difference in both groups (2.7% vs. 1.6%, p = .12).

The procedural success rate by TLE is greater for ICD patients than PM patients with leads >20 years old but requires more extraction tools. Common vascular complication sites and the impact of lead age on procedural outcomes and required tools differed between ICD and PM TLE.

P-wave alternans rebound following pulmonary vein isolation predicts atrial arrhythmia recurrence.

Journal of Cardiovascular Magnetic Resonance

Numerous P-wave indices have been explored as biomarkers to assess atrial fibrillation (AF) risk and the impact of therapy with variable success.

We investigated the utility of P-wave alternans (PWA) to track the effects of pulmonary vein isolation (PVI) and to predict atrial arrhythmia recurrence.

This medical records study included patients who underwent PVI for AF ablation at our institution, along with 20 control subjects without AF or overt cardiovascular disease. PWA was assessed using novel artificial intelligence-enabled modified moving average (AI-MMA) algorithms. PWA was monitored from the 12-lead ECG at ~1 h before and ~16 h after PVI (n = 45) and at the 4- to 17-week clinically indicated follow-up visit (n = 30). The arrhythmia follow-up period was 955 ± 112 days.

PVI acutely reduced PWA by 48%-63% (p < .05) to control ranges in leads II, III, aVF, the leads with the greatest sensitivity in monitoring PWA. Pre-ablation PWA was ~6 µV and decreased to ~3 µV following ablation. Patients who exhibited a rebound in PWA to pre-ablation levels at 4- to 17-week follow-up (p < .01) experienced recurrent atrial arrhythmias, whereas patients whose PWA remained reduced (p = .85) did not, resulting in a significant difference (p < .001) at follow-up. The AUC for PWA's prediction of first recurrence of atrial arrhythmia was 0.81 (p < .01) with 88% sensitivity and 82% specificity. Kaplan-Meier analysis estimated atrial arrhythmia-free survival (p < .01) with an adjusted hazard ratio of 3.4 (95% CI: 1.47-5.24, p < .02).

A rebound in PWA to pre-ablation levels detected by AI-MMA in the 12-lead ECG at standard clinical follow-up predicts atrial arrhythmia recurrence.

Application of artificial intelligence in the diagnosis and treatment of cardiac arrhythmia.

Pacing Clin Electrophysiol

The rapid growth in computational power, sensor technology, and wearable devices has provided a solid foundation for all aspects of cardiac arrhyth...

Gradual development of left bundle branch current of injury during left bundle branch pacing lead implantation.

Pacing Clin Electrophysiol

A larger left bundle branch (LBB) potential or LBB current of injury (COI) indicates a low LBB capture threshold in LBB pacing. During LBB pacing i...

The Role of Soluble Urokinase Plasminogen Activator Receptor (suPAR) as an Early Indicator of Mortality in Pediatric Septic Shock.

Clinical Laboratory

Despite advancements in antibiotic therapy and resuscitation protocols, sepsis and septic shock remain major contributors to morbidity and mortality in children. We aimed to investigate the utility of soluble urokinase plasminogen activator receptor (suPAR) for the early detection of septic shock and to evaluate its accuracy in predicting mortality.

A prospective study was conducted in a tertiary pediatric emergency department (ED), enrolling patients diagnosed with the sepsis, severe sepsis, or septic shock. In addition to assessing infection biomarkers such as C-reactive protein and procalcitonin, suPAR levels were quantified upon admission using enzyme-linked immunosorbent assay. The primary outcome measure was 30-day mortality.

Overall 72 patients and 80 healthy children included. Plasma suPAR levels demonstrated a statistically significant elevation in the sepsis, severe sepsis, and septic shock groups compared with the control group (p < 0.001 for all). The septic shock group exhibited the highest suPAR levels upon admission, surpassing both the sepsis and severe sepsis groups (p = 0.009 and 0.042). ROC analysis underscored the promising potential of suPAR with an AUC of 0.832 for septic shock. Analysis of mortality prediction revealed significantly higher suPAR levels in nonsurvivors than survivors (9.7 ng/mL vs. 4.2 ng/mL; p < 0.001). Employing plasma suPAR levels to discriminate between mortality and survival, a threshold of ≥7.0 ng/mL demonstrated a sensitivity of 90.9% and specificity of 71.0%.

Plasma suPAR levels have the potential as a biomarker for predicting mortality in children with septic shock. In pediatric septic shock, the presence of plasma suPAR ≥7 ng/mL along with an underlying disease significantly increases the risk of mortality.

Contemporary trends of leadless pacemaker implantation in the United States.

Journal of Cardiovascular Magnetic Resonance

Leadless pacemakers (LPM) have established themselves as the important therapeutic modality in management of selected patients with symptomatic bradycardia. To determine real-world utilization and in-hospital outcomes of LPM implantation since its approval by the Food and Drug Administration in 2016.

For this retrospective cohort study, data were extracted from the National Inpatient Sample database from the years 2016-2020. The outcomes analyzed in our study included implantation trends of LPM over study years, mortality, major complications (defined as pericardial effusion requiring intervention, any vascular complication, or acute kidney injury), length of stay, and cost of hospitalization. Implantation trends of LPM were assessed using linear regression. Using years 2016-2017 as a reference, adjusted outcomes of mortality, major complications, prolonged length of stay (defined as >6 days), and increased hospitalization cost (defined as median cost >34 098$) were analyzed for subsequent years using a multivariable logistic regression model.

There was a gradual increased trend of LPM implantation over our study years (3230 devices in years 2016-2017 to 11 815 devices in year 2020, p for trend <.01). The adjusted mortality improved significantly after LPM implantation in subsequent years compared to the reference years 2016-2017 (aOR for the year 2018: 0.61, 95% CI: 0.51-0.73; aOR for the year 2019: 0.49, 95% CI: 0.41-0.59; and aOR for the year 2020: 0.52, 95% CI: 0.44-0.62). No differences in adjusted rates of major complications were demonstrated over the subsequent years. The adjusted cost of hospitalization was higher for the years 2019 (aOR: 1.33, 95% CI: 1.22-1.46) and 2020 (aOR: 1.69, 95% CI: 1.55-1.84).

The contemporary US practice has shown significantly increased implantation rates of LPM since its approval with reduced rates of inpatient mortality.

AV-optimized conduction system pacing for treatment of AV dromotropathy: A randomized, cross-over study.

Journal of Cardiovascular Magnetic Resonance

Severe first-degree atrioventricular (AV) block may produce symptoms similar to heart failure due to AV dyssynchrony, a syndrome termed AV dromotropathy. According to guidelines, it should be considered for permanent pacemaker implantation, yet evidence supporting this treatment is scarce.

This study aimed to determine the impact of AV-optimized conduction system pacing (CSP) in patients with symptomatic severe first-degree AV block and echocardiographic signs of AV dyssynchrony.

Patients with symptomatic first-degree AV block (PR > 250 ms), preserved left ventricular ejection fraction, narrow QRS, and AV dyssynchrony were included in the study. In a single-blind cross-over design, patients were randomized to AV sequential CSP or backup VVI pacing with a base rate of 40 bpm. We compared exercise capacity, echocardiographic parameters, and symptom occurrence at the end of 3 months of each period.

Fourteen patients completed the study. During the AV-optimized CSP compared to the backup pacing period, patients achieved a higher workload on exercise test (147.2 ± 50.9 vs. 140.7 ± 55.8 W; p = .032), with a trend towards higher peak VO2 (23.3 ± 7.1 vs. 22.8 ± 7.1 mL/min/kg; p = .224), and higher left ventricular stroke volume (LVSV 74.5 ± 13.8 vs. 66.4 ± 12.5 mL; p < .001). Symptomatic improvement was recorded, with fewer patients reporting general tiredness and 71% of patients preferring the AV-optimized CSP (p = .008).

AV-optimized CSP could improve symptoms, exercise capacity and LVSV in patients with severe first-degree AV block.