98%
921
2 minutes
20
Background: Atrioventricular (AV) conduction time is rate-dependent. As the atrial coupling interval (A1A2) shortens, AV conduction time (A2H2) prolongs. Thus, the AV conduction curve, plotted using A1A2 vs A2H2, is usually "smooth" and "monotonic". A "jump" in the curve is the current clinical criterion of dual-pathway electrophysiology, whereas a "gap" in the curve has also been described.
Objective: This study described a new phenomenon, a "drop" in the AV conduction curve. The potential relationship between a drop in the AV conduction curve and the dual-pathway electrophysiology was also examined.
Methods: Overall, 81 experimental records from rabbit AV nodal preparations containing the following data were analyzed: (1) had at least 1 AV conduction curve and (2) had a recording of His electrogram alternans (a validated new index of dual-pathway conduction). Most cases had intracellular action potential recordings from the AV nodal fibers.
Results: Of the 81 preparations, 3 (3.7%) showed a drop in the AV conduction curve. The drops (at A1A2 = 115 ± 35 ms) always occurred after fast pathway to slow pathway (SP) transition (at 148 ± 7 ms). The drops showed an SP-fast pathway pattern in 2 of the 3 preparations and an SP-SP pattern in the remaining 1 preparation. The drops were associated with and most likely caused by the formation of intranodal/nodal-atrial reentry and its subsequent conduction.
Conclusion: A new phenomenon, a drop in the AV conduction curve, has been demonstrated in this study. A drop is likely caused by the formation of intranodal/nodal-atrial reentry and its subsequent conduction.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC12411965 | PMC |
http://dx.doi.org/10.1016/j.hroo.2025.05.022 | DOI Listing |
JMIR AI
September 2025
Faculty of Medicine, Universidade Federal de Alagoas, Av. Lourival Melo Mota, S/n - Tabuleiro do Martins, Maceió, 57072-900, Brazil, 558232141461.
Background: Artificial intelligence (AI) has the potential to transform global health care, with extensive application in Brazil, particularly for diagnosis and screening.
Objective: This study aimed to conduct a systematic review to understand AI applications in Brazilian health care, especially focusing on the resource-constrained environments.
Methods: A systematic review was performed.
JAMA Psychiatry
September 2025
Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville.
Importance: Behavioral variant frontotemporal dementia (bvFTD), the most common subtype of FTD, is a leading form of early-onset dementia worldwide. Accurate and timely diagnosis of bvFTD is frequently delayed due to symptoms overlapping with common psychiatric disorders, and interest has increased in identifying biomarkers that may aid in differentiating bvFTD from psychiatric disorders.
Objective: To summarize and critically review studies examining whether neurofilament light chain (NfL) in cerebrospinal fluid (CSF) or blood is a viable aid in the differential diagnosis of bvFTD vs psychiatric disorders.
JAMA Cardiol
September 2025
Department of Cardiology, Inselspital University Hospital of Bern, University of Bern, Bern, Switzerland.
Importance: Right anomalous aortic origin of a coronary artery (R-AAOCA) is a rare congenital condition increasingly diagnosed with the growing use of cardiac imaging. Due to dynamic compression of the anomalous vessel, invasive fractional flow reserve (FFR) during a dobutamine-atropine volume challenge (FFR-dobutamine) is considered the reference standard. A reliable alternative method is needed to reduce extensive invasive testing, but it remains uncertain whether noninvasive imaging can accurately assess the hemodynamic relevance of R-AAOCA.
View Article and Find Full Text PDFGenes Genomics
September 2025
Department of Clinical Laboratory, The First Affiliated Hospital of Guilin Medical University, Le Qun Road 15, Guilin, 541001, Guangxi, China.
Background: Lung cancer (LC) is the leading cause of cancer-related deaths globally. Genetic variants in mismatch repair (MMR) genes, such as MutS homolog 2 (MSH2), MutS homolog 6 (MSH6) and MutL homolog 1 (MLH1), may influence individual susceptibility and clinical outcomes in LC.
Objective: This study investigated the associations of genetic polymorphisms in MSH2, MSH6, and MLH1 with susceptibility and survival outcomes in lung cancer patients in the Guangxi Zhuang population.
Curr Med Sci
September 2025
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
Objective: To develop a novel prognostic scoring system for severe cytokine release syndrome (CRS) in patients with B-cell acute lymphoblastic leukemia (B-ALL) treated with anti-CD19 chimeric antigen receptor (CAR)-T-cell therapy, aiming to optimize risk mitigation strategies and improve clinical management.
Methods: This single-center retrospective cohort study included 125 B-ALL patients who received anti-CD19 CAR-T-cell therapy from January 2017 to October 2023. These cases were selected from a cohort of over 500 treated patients on the basis of the availability of comprehensive baseline data, documented CRS grading, and at least 3 months of follow-up.