Cardioembolic stroke accounts for over 20% of ischemic strokes and is associated with worse outcomes than other types of strokes. Atrial fibrillation (AF) is the most common risk factor for ...cardioembolic stroke. In this narrative review, we present an update about cardioembolic stroke mainly related to AF and atrial cardiopathy. Direct oral anticoagulants (DOACs) have revolutionized stroke prevention in patients with AF; however, their efficacy in preventing recurrent embolic stroke of unknown source remains uncertain. Various cardiac monitoring methods are used to detect AF, which is crucial for preventing stroke recurrence. DOACs are preferred over warfarin for AF-related stroke prevention; however, the timing of initiation after acute ischemic stroke is debated. Resuming anticoagulation after intracerebral hemorrhage in AF patients requires careful assessment of the risks. While catheter ablation may reduce the incidence of cardiovascular events, its effect on stroke prevention is unclear, especially in heart failure patients. Atrial cardiopathy is the emerging cause of embolic stroke of unknown source, which indicates atrial structural and functional disorders that can precede AF. Future research should focus on refining stroke risk prediction models, optimizing AF detection, understanding the roles of ablation and anticoagulation in stroke prevention, and establishing atrial cardiopathy as a therapeutic target, which could significantly reduce the burden of stroke.
Actinoporins are pore-forming proteins found in sea anemones. Although we now have a large collection of data on actinoporins, our knowledge is based heavily on those identified in shallow-water ...anemones. Because the deep sea differs considerably from shallow waters in hydrostatic pressures, temperatures, and the prey composition, the deep-sea actinoporin may have evolved in unique ways. This study, therefore, aimed to obtain new actinoporins in the deep-sea anemone Cribrinopis japonica (Actiniaria, Actiniidae). An actinoporin-like sequence was identified from the previously established C. japonica RNA-Seq database, and the complete length (663 bp) of the deep-sea actinoporin gene, Cjtox I, was obtained. In addition, a similar gene, Cjtox II (666 bp), was also identified from RNA of actinopharynx. CJTOX I and CJTOX II were similar in their primary structures, but CJTOX I lacked one residue in the middle of the protein. There was also a difference in the gene expression in live animals, where only Cjtox I was expressed in tentacles of C. japonica. In the heterologous expression where BL21 (DE3) strain was retransformed with the plasmid containing either Cjtox I or Cjtox II gene, the supernatants of both cell lysates showed hemolytic activity on the equine erythrocytes. Preincubation of the supernatants with sphingomyelin caused reduced activity, implying that the CJTOX I and II would target sphingomyelin as with other actinoporins. Because of the structures similarity to the known actinoporins and the sphingomyelin-inhibitable hemolytic activity, both CJTOX I and II were concluded to be new actinoporins, which were identified for the first time from a deep-sea anemone.
•Two actinoporins, CJTOX I and CJTOX II, were identified from the deep-sea anemone Cribrinopsis japonica.•The complete nucleotide sequences of the two actinoporins were determined by RNA-Seq and RACE analyses.•In live C. japonica, only the Cjtox I gene was expressed in the tentacles of the anemone.•In the heterologous expression of the two toxins using E. coli, the supernatants of the cell lysates were hemolytic.•The hemolytic activity of the supernatants was inhibited by preincubation with sphingomyelin.
The Senning operation used to be widely performed for an intracardiac repair in a complete transposition of the great arteries. During the long-term follow-up, supraventricular tachycardia (SVT) is ...often observed because of the complex suture lines. The typical mechanism of a Senning-related SVT is cavo-tricuspid isthmus-dependent atrial flutter. On rare occasions, complex SVTs (e.g., biatrial tachycardia (BiAT)) whose diagnosis and treatment are challenging, may occur. We report a rare case of a BiAT following a Senning operation that was successfully ablated from the superior vena cava, and the local activation time histogram module (CARTO3 V7 module Biosense Webster, Irvine, CA, USA) was crucial for analyzing the complex circuit.
Sub-optimal atrioventricular delay (AVD) is one of the main causes of non-responder for cardiac resynchronization therapy (CRT). Recently, device-based algorithms (DBAs) that provide optimal AVD ...based on intracardiac electrograms, have been developed. However, their long-term effectiveness is still unknown. This study aims to investigate the effect of optimizing AVD using DBAs over a long period, on the prognosis of patients undergoing CRT. A total of 118 patients who underwent CRT at our hospital between April 2008 and March 2018, were retrospectively reviewed; 61 of them with optimizing AVD using DBAs were classified into the treated group (group 1), and the remaining 57 were classified into the control group (group 2). The median follow-up period was 46.0 months. The responder and survival rate in group 1 were significantly better than those in group 2 (group 1 vs. group 2: responder rate = 64% vs. 46%,
p
= 0.046; survival rate: 85.2% vs. 64.9%,
p
= 0.02). Moreover, investigating only the non-responder population showed that group 1 had an improved survival rate compared to group 2 (group 1 vs. group 2 = 72.7% vs. 45.1%,
p
= 0.02). Optimizing AVD using DBAs was a significant contributor to the improved survival rate in CRT non-responders in multivariate analysis (HR 3.6,
p
= 0.01). In conclusion, the long-term optimizing AVD using DBAs improved the survival rate in CRT and the prognosis of CRT non-responders, as well.
This study sought to identify subcellular Ca2+ signals within and among cells comprising the sinoatrial node (SAN) tissue.
The current paradigm of SAN impulse generation: 1) is that full-scale action ...potentials (APs) of a common frequency are initiated at 1 site and are conducted within the SAN along smooth isochrones; and 2) does not feature fine details of Ca2+ signaling present in isolated SAN cells, in which small subcellular, subthreshold local Ca2+ releases (LCRs) self-organize to generate cell-wide APs.
Immunolabeling was combined with a novel technique to detect the occurrence of LCRs and AP-induced Ca2+ transients (APCTs) in individual pixels (chronopix) across the entire mouse SAN images.
At high magnification, Ca2+ signals appeared markedly heterogeneous in space, amplitude, frequency, and phase among cells comprising an HCN4+/CX43− cell meshwork. The signaling exhibited several distinguishable patterns of LCR/APCT interactions within and among cells. Rhythmic APCTs that were apparently conducted within the meshwork were transferred to a truly conducting HCN4−/CX43+ network of striated cells via narrow functional interfaces where different cell types intertwine, that is, the SAN anatomic/functional unit. At low magnification, the earliest APCT of each cycle occurred within a small area of the HCN4 meshwork, and subsequent APCT appearance throughout SAN pixels was discontinuous and asynchronous.
The study has discovered a novel, microscopic Ca2+ signaling paradigm of SAN operation that has escaped detection using low-resolution, macroscopic tissue isochrones employed in prior studies: synchronized APs emerge from heterogeneous subcellular subthreshold Ca2+ signals, resembling multiscale complex processes of impulse generation within clusters of neurons in neuronal networks.
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Background
The local impedance (LI) reflects the electrical catheter‐tissue coupling and correlates with the local tissue temperature. However, there have been few clinical studies showing the ...recommended method for LI monitoring catheters. This study aimed to investigate the optimal ablation setting for this catheter in an in vitro experimental model.
Methods
LI monitoring catheters were used in an excised swine heart experimental model. The tissue contact force (CF) was directly monitored from an external weight scale. Radiofrequency ablation was performed with a combination of various energy power settings (30, 40, and 50 W), and various CFs (10, 30, and 50 g) for 60 s. The correlation between the LI‐related indexes, power, and CF with the lesion formation was statistically analyzed.
Results
A positive correlation between the LI or lesion formation and CF was observed under all powers. Although the LI drop always correlated with the maximum lesion depth, lesion diameter, and lesion volume, the coefficient of the correlation value was lower under a high CF (lesion depth, diameter, and volume; 10 g, r = 0.8064, r = 0.8389, r = 0.8477; 30 g, r = 0.7590, r = 0.8063, r = 0.8060; 50 g r = 0.5555, r = 0.5701, and r = 0.5678, respectively). Steam pops occurred only under a 50 W ablation and the LI drop cutoff value for steam pops was 46 Ω.
Conclusion
The same LI drop did not always lead to the same lesion size when the CF differed. Monitoring the LI and not exceeding 46 Ω would be useful for a safe ablation.
We constructed a detailed welding phenomenon analysis model and a simplified analysis model using the thermal shrinkage technique capable of predicting welding deformation for thin plate box-shaped ...lap-welded joints assuming automotive components. In the thermal shrinkage technique, a new method for setting the thermal shrinkage parameter was proposed to improve the accuracy of predicting welding deformation for thin plate structure. The accuracy of each model was confirmed by comparison with the experimental results, and the calculation cost of each model was compared and evaluated.
Several reports have noted that coronary vasospasms may occur during CA. Because it is commonly caused by direct thermal effects or an autonomic neuronal imbalance, coronary vasospasms before ...ablation are rare. ...our patient never experienced any CSA or any chest pain before the ablation. ...a detailed investigation is needed to assess the necessity of long-term treatment for CSA. The present case indicated that coronary vasospasms during procedures do not necessarily correlate with clinical CSA, suggesting the potential usefulness of a CSA provocation test. ...a CSA provocation test may be useful for those who develop coronary vasospasms during procedures regardless of the cause.
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