Daily Cardiology Research Analysis
Analyzed 117 papers and selected 3 impactful papers.
Summary
Three impactful cardiology studies stood out today: a prespecified analysis from the SELECT trial shows semaglutide reduces major adverse cardiovascular events in patients at high risk for liver fibrosis; a nanotechnology advance enables long-duration, high-fidelity intracellular action potential recording in cardiomyocytes; and human mapping data reveal pervasive epicardial–endocardial asynchrony and conduction block in the left atrial posterior wall during persistent atrial fibrillation.
Research Themes
- Cardiometabolic therapeutics and MACE reduction
- Mechanistic electrophysiology and bioengineering tools
- Atrial fibrillation substrate characterization and ablation strategy
Selected Articles
1. Semaglutide on liver fibrosis and heart outcomes in patients at high risk of liver fibrosis: a prespecified analysis of the SELECT randomized trial.
In a prespecified subgroup of SELECT, semaglutide reduced MACE by 26% in patients with FIB-4 ≥1.3 and by 21% using age-specific FIB-4 thresholds; an even larger but non-significant 34% reduction was observed at FIB-4 >2.67. Semaglutide also produced a 28% greater decrease in fatty liver index over 104 weeks compared with placebo.
Impact: This analysis strengthens the cardiometabolic rationale for semaglutide by demonstrating cardiovascular benefit in patients at high risk for liver fibrosis, a common comorbidity in ASCVD with obesity.
Clinical Implications: Semaglutide may be prioritized for ASCVD patients with obesity who also have elevated FIB-4, given concurrent MACE reduction and improvements in steatosis indices; integrating FIB-4 could help risk stratify for cardiometabolic therapy.
Key Findings
- Semaglutide reduced MACE by 26% for FIB-4 ≥1.3 (HR 0.74, 95% CI 0.63-0.88) and by 21% using age-specific FIB-4 thresholds (HR 0.79, 95% CI 0.63-0.98).
- A non-significant 34% MACE reduction was observed for FIB-4 >2.67 (HR 0.66, 95% CI 0.39-1.10).
- Semaglutide achieved a 28% greater reduction in fatty liver index versus placebo over 104 weeks (P<0.0001).
Methodological Strengths
- Prespecified subgroup analysis within a large, randomized, placebo-controlled outcomes trial (SELECT).
- Objective fibrosis risk stratification using FIB-4 and steatosis assessment via fatty liver index over 104 weeks.
Limitations
- Secondary analysis; subgroup sizes and event counts by FIB-4 strata are not detailed in the abstract.
- FIB-4 and fatty liver index are indirect biomarkers and do not replace histology or elastography.
Future Directions: Prospective studies using imaging or histologic fibrosis endpoints can validate whether fibrosis risk enrichment modifies semaglutide’s cardiovascular benefit; explore integration with NAFLD/NASH care pathways.
In the SELECT trial, once-weekly subcutaneous semaglutide reduced major adverse cardiovascular events (MACE) by 20% versus placebo in patients with atherosclerotic cardiovascular disease and obesity but without diabetes. We examined semaglutide in SELECT patients at high risk for substantial liver fibrosis in a prespecified secondary analysis. Liver biochemical tests and steatosis risk according to fatty liver index were assessed over 104 weeks. Subgroup analyses of the primary MACE (a composite endpoint including cardiovascular death, nonfatal myocardial infarction or nonfatal stroke) outcome used baseline Fibrosis-4 scores ≥ 1.3, age-specific (≥1.3 (<65 years) or ≥2.0 (≥65 years)) and any age with Fibrosis-4 > 2.67. MACE was reduced by 26% (hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.63-0.88; P = 0.0004), 21% (HR 0.79; 95% CI 0.63-0.98; P = 0.035) and 34% (HR 0.66; 95% CI 0.39-1.10; P = 0.11), respectively. Semaglutide led to a 28% greater decrease in fatty liver index versus placebo (HR 0.72; 95% CI 0.71-0.73; P < 0.0001). In conclusion, semaglutide reduced MACE versus placebo in patients at risk for substantial liver fibrosis, as seen in the overall SELECT population. ClinicalTrials.gov registration no. NCT03574597.
2. Vertical Graphene-Based Microelectrode Array Coupled with Microelectroporation for Real-Time Monitoring of Intracellular Action Potential.
A rapidly fabricated vertical graphene MEA integrated with microelectroporation achieved robust, multichannel intracellular AP recordings in cardiomyocytes with ∼6-minute durations per session, ∼45 dB SNR, and superior fidelity versus planar MEAs. The platform tolerated repeated electroporation, supported continuous intracellular recording up to 9 days, and was reusable across multiple cycles.
Impact: This methodological advance enables scalable, high-fidelity intracellular electrophysiology in cardiomyocytes beyond the limits of patch clamps and planar MEAs, accelerating cardiac arrhythmia mechanism studies and drug screening.
Clinical Implications: While preclinical, the platform could streamline cardiotoxicity testing, proarrhythmic risk assessment, and phenotyping of engineered tissues or iPSC-derived cardiomyocytes to inform safer cardiac therapeutics.
Key Findings
- VG-MEA achieved intracellular AP recordings with ∼6-minute duration per electroporation cycle, ∼45 dB SNR, and superior waveform fidelity versus planar gold/carbon and fuzzy graphene MEAs.
- Fabrication via PECVD and laser etching avoided nanoscale photolithography and yielded low-impedance, high-surface-area electrodes with improved cell–electrode sealing.
- Supported repeated microelectroporation within 1 hour without altering cellular behavior and enabled continuous intracellular recording for up to 9 days; devices were reusable for 9 cycles over a year.
Methodological Strengths
- Direct performance comparison against multiple MEA baselines (planar gold, planar carbon, fuzzy graphene).
- Demonstrated long-term stability (up to 9 days continuous recording) and device reusability across cycles.
Limitations
- In vitro cardiomyocyte systems; in vivo translation and tissue-level integration remain to be shown.
- Potential long-term biocompatibility and effects on excitable tissue under chronic use were not fully characterized.
Future Directions: Integrate VG-MEAs with iPSC-derived human cardiomyocyte networks and engineered heart tissues, and evaluate in organoid or ex vivo preparations; explore high-throughput drug safety and proarrhythmia screening workflows.
Multisite intracellular action potential (AP) recording is essential for studying the electrophysiology in excitatory cell networks. Recent approaches combining 3D structure micro/nanoelectrode arrays with perforation technology are promising solutions to achieve multichannel intracellular recording, which remains challenging for conventional microelectrode arrays and patch clamps. However, most of the existing 3D micro/nanoelectrode arrays involved nanoscale photolithographic processes and were less compatible with fabricating 3D-nanostructured carbon electrodes. Here, we present a vertical graphene-based microelectrode array (VG-MEA) integrated with microelectroporation for robust, high-quality multichannel intracellular AP recordings in cardiomyocytes. The VG-MEAs were rapidly fabricated via plasma-enhanced chemical vapor deposition and laser etching, avoiding nanoscale photolithography. The VG microelectrode offers low interfacial impedance and a high surface area, and its 3D structure enhances cell-electrode sealing. The VG-MEA enabled higher quality intracellular AP recordings with longer recording duration (∼6 min), higher SNR (∼45 dB), and higher waveform fidelity compared to planar gold MEAs, planar carbon MEAs, and fuzzy graphene MEAs. The VG-MEA supported repeated microelectroporation cycles within 1 h without impacting cellular behavior. VG-MEA also allowed continuous intracellular recording for up to 9 days and could be robustly reused for 9 cycles within a year. This VG-MEA platform provides promising tools for intracellular electrophysiology research.
3. Epicardial-to-Endocardial Activation Gradients and Conduction Block During Atrial Fibrillation in the Human Left Atrial Posterior Wall.
In 27 patients with nonparoxysmal AF undergoing hybrid ablation, simultaneous high-density mapping of the left atrial posterior wall showed universally asynchronous epicardial–endocardial activation, higher epicardial bipolar voltages, and frequent inter-surface conduction block during AF. These findings highlight dynamic 3D arrhythmogenicity of the LAPW with implications for epicardial-targeted ablation strategies.
Impact: This human mechanistic study refines AF substrate understanding by directly demonstrating epicardial–endocardial asynchrony and conduction block in a key ablation target region, informing more comprehensive mapping and lesion strategies.
Clinical Implications: Comprehensive AF ablation may need to account for epicardial drivers and inter-surface block on the LAPW; combined endocardial–epicardial mapping or surrogate markers could improve lesion set efficacy.
Key Findings
- Epicardial LAPW bipolar voltages were significantly greater than endocardial voltages during AF.
- Simultaneous mapping showed universal epicardial–endocardial activation asynchrony and more rapid epicardial activity.
- Conduction block between epicardial and endocardial LAPW surfaces was common during AF; 12-month arrhythmia-free survival was 68% after hybrid ablation.
Methodological Strengths
- Simultaneous endocardial–epicardial high-density mapping with grid catheters in humans.
- Systematic characterization of voltage, activation gradients, and conduction block patterns.
Limitations
- Single-arm descriptive study with a modest sample size; selection limited to hybrid ablation candidates.
- Causal links to ablation outcomes are not established; mapping surrogates for routine practice need validation.
Future Directions: Prospective studies should test whether targeting epicardial drivers or inter-surface block signatures improves AF ablation outcomes; develop noninvasive or endocardial surrogates for epicardial activity.
BACKGROUND: Although emerging evidence supports 3-dimensional myocardial activation during atrial fibrillation (AF), human studies remain limited. We thus characterized the endocardial and epicardial left atrial posterior wall (LAPW) in humans to assess the prevalence of asynchronous endocardial-epicardial LAPW conduction during AF. METHODS: Patients with symptomatic nonparoxysmal AF who had unsuccessful antiarrhythmic or catheter ablation therapy referred for hybrid epicardial-endocardial AF ablation and left atrial appendage ligation underwent high-density mapping of LAPW with Grid catheters, including simultaneous endocardial-epicardial mapping. RESULTS: Twenty-seven patients (19 men, median 69 years, 55% long-standing persistent AF) were included. There was significantly greater epicardial compared with endocardial LAPW bipolar voltages during AF. In areas of low endocardial bipolar voltage, normal endocardial unipolar voltage corresponded to normal epicardial bipolar voltage. Asynchronous endocardial-epicardial LAPW AF activation during simultaneous endocardial-epicardial mapping was universal. Furthermore, more rapid epicardial compared with endocardial LAPW AF activity was observed during simultaneous endocardial-epicardial mapping in AF. Conduction block between the endocardial and epicardial LAPW surfaces was also common during organized AF, with instances of isolated or multiple blocked beats, Wenckebach conduction, and sustained endocardial LAPW entrance block with ongoing epicardial AF observed. Epicardial-to-endocardial entrance block was also infrequently observed during sinus rhythm. At 12-month follow-up, freedom from atrial arrhythmias was 68%. CONCLUSIONS: Endocardial-epicardial LAPW asynchrony may be observed during human persistent AF and is characterized by: (1) greater epicardial compared with endocardial bipolar voltages, (2) more frequent epicardial-to-endocardial activation gradients during AF, and (3) conduction block commonly seen between the epicardial and endocardial surfaces during AF. Although the study was predominantly descriptive in nature, the observations suggest a dynamic 3-dimensional arrhythmogenicity of the LAPW and the potential importance of the epicardial layer, with implications for ablation therapies. Future prospective studies are required to determine the significance of these findings to clinical ablation outcomes.