Mechanism of recurrence after radiofrequency catheter ablation of atrial fibrillation guided by complex fractionated atrial electrograms

Background A better understanding of the mechanisms of recurrent atrial fibrillation (AF) after radiofrequency ablation of complex, fractionated atrial electrograms (CFAEs) may be helpful for refining AF ablation strategies. Methods and results Electrogram-guided ablation (EGA) was repeated in 30 consecutive patients (mean age = 59 ± 8 years) for recurrent paroxysmal AF, 10 ± 4 months after the first ablation. During the first procedure, CFAEs were targeted without isolating all pulmonary veins (PVs). During repeat ablation, all PVs and the superior vena cava (SVC) were mapped with a circular catheter and the left atrium was mapped for CFAEs. EGA was performed until AF was rendered noninducible or all identified CFAEs were eliminated. During repeat ablation, ≥1 PV tachycardia was found in 83 PVs in 29 of the 30 patients (97%). Among these 83 PVs, 63 (76%) had not been completely isolated previously. During repeat ablation, drivers originating in a PV or PV antrum were identified only after infusion of isoproterenol (20 μg/min) in 12 patients (40%). At 9 ± 4 months of follow-up after the repeat ablation procedure, 21 of the 30 patients (70%) were free from recurrent AF and flutter without antiarrhythmic drugs. Conclusions Recurrence of AF after EGA is usually due to PV tachycardias. Therefore, it may be preferable to systematically map and isolate all PVs during the first procedure. High-dose isoproterenol may be helpful to identify AF drivers.     

Cardiac CT: Technological Advances in Hardware,Software, and Machine Learning Applications

Purpose of Review

Multidetector row computed tomography (CT) allows noninvasive imaging of the heart and coronary arteries. The purpose of this review is to briefly summarize recent advances in CT hardware and software technology, and machine learning applications for cardiovascular imaging.

Recent Findings

In the last decades, there have been significant improvements in CT hardware focusing on faster gantry rotation resulting in improved temporal resolution. Concurrent hardware improvements include improved spatial resolution and higher coverage of the patient, enabling faster acquisition. Advances in cardiac CT software include methods for measurement of noninvasive FFR, coronary plaque characterization, and adipose tissue characteristics around the heart. Machine learning approaches using cardiac CT have been shown to improve both risk of prognosis and lesion-specific ischemia.

Summary

Recent advances in CT hardware and software have expanded the clinical utility of CT for cardiovascular imaging. In the next decades, continued advances can be anticipated in these areas, and in machine learning applications in cardiac CT, as they are incorporated into clinical routine for image acquisition, image analysis, and prediction of patient outcomes.

     

Quantification of Antioxidant Contents in Sweet Pepper as Influenced by Planting Time and Fruit Picking Stage

The present study reports the quantification of changes in the contents of plant pigments and ascorbic acid as influenced by the planting time and fruit picking stages in sweet pepper. The crop was planted on five different dates at 10 days interval in randomized block design under open field conditions in temperate area to quantify the changes which took place in the contents of plant pigments and ascorbic acid in green and red fruits. The results showed that the planting time and fruit picking stage had significant (p ≤ 0.05) influence on plant pigments and ascorbic acid contents in sweet pepper. The last week of May was observed as the optimal planting time when fruits exhibited higher contents of lycopene, β-carotene and ascorbic acid. The red fruit picking stage had significantly higher concentration of these phytonutrients than the green picking stage. In order to pick-up fruits at right stage and time with high plant pigments and ascorbic acid contents, these results would help meet out the increasing demand of sweet pepper quality fruits.     

Capacity building for the provision of rheumatological services in sub-Saharan Africa

Clinical Rheumatology - A project aimed to develop and deliver a clinical training course in Accra, Ghana, to increase patient access to physicians trained in the diagnosis, treatment and...     

Lesion-Specific and Vessel-Related Determinants of Fractional Flow Reserve Beyond Coronary Artery Stenosis

Objectives

The aims of the present study were: 1) to investigate the contribution of the extent of luminal stenosis and other lesion composition-related factors in predicting invasive fractional flow reserve (FFR); and 2) to explore the distribution of various combinations of morphological characteristics and the severity of stenosis among lesions demonstrating normal and abnormal FFR.

Comparisons of prostaglandin vasoactive effects and interactions in the in vivo microcirculation of the rat urinary bladder

A combination of techniques for in vivo transillumination, topical application of vasoactive agents, and direct microscopic observation of microcirculatory responses was utilized to evaluate the vasomotor actions of prostaglandins (PGs) E₁, E₂, F_1α, F_2α, A₁, and A₂ on rat urinary bladder arterioles and venules. The effects of PGE₁ and histamine (HIS) on arteriolar responsiveness to norepinephrine (NE), serotonin (5-HT), and PGF_2α were measured. Histochemical studies were completed to determine the primary site of prostaglandin (PG) metabolic deactivation in the urinary bladder. Arteriolar dilatation occurred with HIS, PGE₁, PGE₂, PGA₁, PGA₂, and PGF_1α, all of which (with the exception of HIS) demonstrated significant dose-related responses. Overall, PGE₁ and PGE₂ were of greatest potency. Significant dose-related arteriolar constriction occurred with NE > PGF_2α > 5-HT (in order of decreasing potency). HIS, PGE₁, PGE₂, and PGA₁ produced significant venular dilatation; PGE₁ and HIS were dose related. Only NE resulted in significant venoconstriction. Arteriolar responsiveness to NE and PGF_2α decreased after pretreatment with PGE₁ but was unchanged by HIS pretreatment, whereas application of 5-HT following pretreatment with PGE₁ or HIS produced equivalent levels of arteriolar constriction. The primary site of deactivation of PGE₁ was histochemically localized to bundles of smooth muscle fibers in the muscular coat of the rat urinary bladder wall.     

Isolation of Micro-organisms from Phyllosphere of Plagiomnium rostratum (Schrad.) T.J. Kop. from Darjeeling Hills

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Microbial association is considered as a significant innovation for land colonization of mosses. Plagiomnium...     

Reproducibility of quantitative plaque measurement in advanced coronary artery disease

BackgroundThe ability to characterize and to quantify the extent of coronary artery disease has the potential to improve the prognostic capability of coronary computed tomography angiography. Although reproducible techniques have been described in those with mild coronary disease, this has yet to be assessed in patients with advanced disease.MethodsTwenty patients with known multivessel disease underwent repeated computed tomography coronary angiography, 2 weeks apart. Coronary artery segments were analysed using semi-automated software by two trained observers to determine intraobserver, interobserver and interscan reproducibility.ResultsOverall, 149 coronary arterial segments were analysed. There was excellent intraobserver and interobserver agreement for all plaque volume measurements (Lin’s coefficient 0.95 to 1.0). There were no substantial interscan differences (P ?> ?0.05 for all) for total (2063 ?± ?1246 ?mm³, mean of differences ?35.6 ?mm³), non-calcified (1795 ?± ?910 ?mm³, mean of differences ?4.3 ?mm³), calcified (298 ?± ?425 ?mm³, mean of differences ?31.3 ?mm³) and low-attenuation (13 ?± ?13 ?mm³, mean of differences ?2.6 ?mm³) plaque volumes. Interscan agreement was highest for total and noncalcified plaque volumes. Calcified and low-attenuation plaque (?236.6 to 174 ?mm³ and -15.8 to 10.5 ?mm³ respectively) had relatively wider 95% limits of agreement reflecting the lower absolute plaque volumes.ConclusionIn the presence of advanced coronary disease, semi-automated plaque quantification provides excellent reproducibility, particularly for total and non-calcified plaque volumes. This approach has major potential to assess change in disease over time and optimize risk stratification in patients with established coronary artery disease.     

Correction: Thermodynamically stable vesicle formation of biodegradable double mPEG-tailed amphiphiles with sulfonate head group

Correction for ‘Thermodynamically stable vesicle formation of biodegradable double mPEG-tailed amphiphiles with sulfonate head group’ by Rita Ghosh et al., RSC Adv., 2020, 10, 32522–32531, DOI: 10.1039/D0RA05613H

The authors regret that an incorrect version of Fig. 5 was included in the original article. The correct version of Fig. 5 is presented below.Open in a separate windowFig. 1Upper panel: Size distribution histograms of aggregates in 2.0 mM solutions (pH 7) of (a) (mPEG₄)₂SO₃Na, and (b) (mPEG₂₃)₂SO₃Na at 25 °C; lower panel: unstained HRTEM images of 2 mM (c) (mPEG₄)₂SO₃Na and (d) (mPEG₂₃)₂SO₃Na solutions in phosphate buffer (pH 7.0).The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.