Comparison of physiological and transcriptome responses of corals to strong light and high temperature.

Coral reefs are essential for marine ecology and biodiversity. Global climate change has resulted in severe coral reef degradation, partly via coral bleaching, which is caused by rising sea temperatures and solar light intensity. In this study, we examined the impact of strong light (300 µmol.m-2.s-1) and high temperature (33°C) on the growth, immunity, and gene expression of Galaxea fascicularis. Strong light caused coral bleaching in the absence of high sea temperatures, while no obvious bleaching was observed under high temperature alone. The effect of strong light on calcification rate of G. fascicularis is significantly weaker than that of high temperature. Both strong light and high temperatures significantly affected the immune enzyme activity of G. fascicularis symbionts, with the former having a strong effect on their photosystem. Temperature affected the digestive system, replication and repair, and cell growth and death of coral hosts, as indicated by transcriptomics analysis. These results provide a valuable for strategies to mitigate coral bleaching. TEASER: We explored the effects of strong light exposure and high temperature on coral reefs and their symbiont algae.

Fecal calprotectin: A novel predictor of ulcerated esophageal injury after atrial fibrillation catheter ablation.

BACKGROUND: Atrial esophageal fistula (AEF) is a lethal complication that can occur post atrial fibrillation (AF) ablation. Esophageal injury (EI) is likely to be the initial lesion leading to AEF. Endoscopic examination is the gold standard for a diagnosis of EI but extensive endoscopic screening is invasive and costly. This study was conducted to determine whether fecal calprotectin (Fcal), a marker of inflammation throughout the intestinal tract, may be associated with the existence of esophageal injury. METHODS: This diagnostic study was conducted in a cohort of 166 patients with symptomatic AF undergoing radiofrequency catheter ablation from May 2020 to June 2021. Fcal tests were performed 1-7 days after ablation. All patients underwent endoscopic ultrasonography 1 or 2 days after ablation. RESULTS: The levels of Fcal were significantly different between the EI and non-EI groups (404.9 µg/g (IQR 129.6-723.6) vs. 40.4 µg/g (IQR 15.0-246.2), p < .001). Analysis of ROC curves revealed that a Fcal level of 125 µg/g might be the optimal cut-off value for a diagnosis of EI, giving a 78.8% sensitivity and a 65.4% specificity. The negative predictive value of Fcal was 100% for ulcerated EI. CONCLUSIONS: The level of Fcal is associated with EI post AF catheter ablation. 125 µg/g might be the optimal cut-off value for a diagnosis of EI. Negative Fcal could predict the absence of ulcerated EI, which could be considered a precursor to AEF.

Use of intracardiac echocardiography in vein of Marshall ethanol infusion for ablation of persistent atrial fibrillation.

BACKGROUND: Few methods have been reported to demonstrate real-time effects during vein of Marshall (VOM) ethanol infusion in persistent atrial fibrillation (PeAF). OBJECTIVE: This study was to evaluate the impact of left atrial (LA) monitoring using intracardiac echocardiography (ICE) during VOM ethanol infusion. METHODS: Seventy-four consecutive patients with PeAF who underwent VOM ethanol infusion followed by radiofrequency (RF) ablation were included. Patients with findings on ICE consistent with echogenic streaming in the LA and with increased myocardial local echogenicity along the VOM area were placed into one group (group A) and those without into the other group (group B). Outcomes between the 2 groups were compared. RESULTS: Forty-six patients (62%) were placed into group A. A new ethanol-induced low-voltage area in group A was larger than that in group B (8.5 cm2 [5.5-10.2 cm2] and 4.0 cm2 (2.4-6.3 cm2]; P < .001). The RF ablation time required to achieve MI block was reduced in group A patients (263.0 seconds [196.0-351.0 seconds] vs 417.0 seconds [315.0-709.5 seconds] in group B patients; P < .001). MI block was achieved in 46 patients (100%) via an endocardial approach in group A and 27 patients (96.4%) in group B (extra coronary sinus ablation in 4 patients). One patient developed clinically significant pericardial effusions and required pericardiocentesis in group B. CONCLUSION: Presence of increased myocardial local echogenicity at the ridge and consistent echogenic streaming in the LA detected by ICE-based imaging during VOM ethanol infusion suggests increased ablated tissue in that region and lower RF ablation time during ablation for PeAF.

Chinese expert consensus on the construction of the fluoroless cardiac electrophysiology laboratory and related techniques.

Transcatheter radiofrequency ablation has been widely introduced for the treatment of tachyarrhythmias. The demand for catheter ablation continues to grow rapidly as the level of recommendation for catheter ablation. Traditional catheter ablation is performed under the guidance of X-rays. X-rays can help display the heart contour and catheter position, but the radiobiological effects caused by ionizing radiation and the occupational injuries worn caused by medical staff wearing heavy protective equipment cannot be ignored. Three-dimensional mapping system and intracardiac echocardiography can provide detailed anatomical and electrical information during cardiac electrophysiological study and ablation procedure, and can also greatly reduce or avoid the use of X-rays. In recent years, fluoroless catheter ablation technique has been well demonstrated for most arrhythmic diseases. Several centers have reported performing procedures in a purposefully designed fluoroless electrophysiology catheterization laboratory (EP Lab) without fixed digital subtraction angiography equipment. In view of the lack of relevant standardized configurations and operating procedures, this expert task force has written this consensus statement in combination with relevant research and experience from China and abroad, with the aim of providing guidance for hospitals (institutions) and physicians intending to build a fluoroless cardiac EP Lab, implement relevant technologies, promote the standardized construction of the fluoroless cardiac EP Lab.

False Tendons in the Left Ventricle: Implications for Successful Ablation of Left Posterior Fascicular Tachycardias.

BACKGROUND: The anatomical substrate for left posterior fascicular ventricular tachycardia (LPF-VT) is still unclear. OBJECTIVES: The purpose of this study is to describe the endocavitary substrate of the re-entrant loop of LPF-VT. METHODS: A total of 26 consecutive patients with LPF-VT underwent an electrophysiology study and radiofrequency ablation. RESULTS: Intracardiac echocardiography imaging observed a 100% prevalence of false tendons (FTs) at the left posterior septal region in all patients, and 3 different types of FTs could be classified according to their location. In 22 patients, a P1 potential could be recorded via the multielectrode catheter from a FT. In 4 patients without a recorded P1 during LPF-VT, the earliest P2 potentials were recorded from a FT in 3 patients, and from a muscular connection between 2 posteromedial papillary muscles in 1 patient. Catheter ablation focused on the FTs with P1 or earliest P2 (in patients without P1) was successful in all 26 patients. After 19 ± 8.5 months of follow-up, no patients had recurrence of LPF-VT. CONCLUSIONS: FTs provide an electroanatomical substrate for LPF-VT and a "culprit FT" may be identified as the critical structure bridging the macro-re-entrant loop. Targeting the "culprit FT" is a novel anatomical ablation strategy that results in long-term arrhythmia-free survival.

Selective anatomical catheter ablation of left atrial ganglionated plexus for vasovagal syncope: Left superior and right anterior ganglionated plexus ablation.

BACKGROUND: Vasovagal syncope (VVS) is one of the most common causes of syncope. Traditional treatment has not achieved satisfactory results. The purpose of this study was to assess the feasibility and efficacy of selective anatomical catheter ablation of left atrial ganglionated plexus (GP) as a therapeutic strategy for the patients of symptomatic VVS. METHODS: A total of 70 patients with at least once recurrent syncopal episode of VVS with a positive head-up tilt test were enrolled. They were divided into GP ablation group and control group. Patients in GP ablation group received anatomical catheter ablation of left superior ganglionated plexus (LSGP) and right anterior ganglionated plexus (RAGP). Patients in the control group were guideline-directed conventional therapy. The primary endpoint was VVS recurrences. The secondary endpoint was the recurrence of syncope and prodrome events. RESULTS: There were no statistical differences in clinical characteristics between the ablation group (n = 35) and the control group (n = 35). Over a follow-up of 12 months, the ablation group had significantly lower syncope recurrence compared with the control group (5.7% vs. 25.7%, p = .02), and the ablation group had significantly lower syncope and prodrome recurrence compared with the control group (11.4% vs. 51.4%, p < .001). In GP ablation, 88.6% of the patients showed significant vagal response during LSGP ablation, and 88.6% of the patients showed significantly increased heart rate during RAGP ablation. CONCLUSIONS: For patients with recurrent VVS, selective anatomical catheter ablation of LSGP and RAGP is superior to conventional therapy in reducing syncope recurrence.

A review of metal contamination in seagrasses with an emphasis on metal kinetics and detoxification.

Seagrasses are important foundation species in coastal ecosystems, and they provide food and habitat that supports high biodiversity. However, seagrasses are increasingly subjected to anthropogenic disturbances such as metal pollution, which has been implicated as a significant factor driving seagrass losses. There have been several reviews synthesizing the metal concentrations in seagrasses and evaluating their utility as biomonitors for metal pollution in the coastal environment at the local scale. However, the interpretation of metal data in seagrass biomonitors requires a more mechanistic understanding of the processes governing metal bioaccumulation and detoxification. In this review, the progress and trends in metal studies in seagrasses between 1973 and 2022 were analyzed to identify frontier topics in this field. In addition, we tried to (1) analyze and assess the current status of metal contamination in seagrasses on a global scale by incorporating more metal data from tropical and Indo-Pacific seagrasses, (2) summarize the geochemical and biological factors governing metal uptake and loss in seagrasses, and (3) provide an up-to-date understanding of metals' effects on seagrasses and their physiological responses to metal challenges. This review improves our understanding of the highly variable metal concentrations observed in the field.

His bundle pacing versus left bundle branch pacing on ventricular function in atrial fibrillation patients referred for pacing: a prospective crossover comparison.

BACKGROUND: His bundle pacing (HBP) and left bundle branch pacing (LBBP) both provide physiologic pacing which maintain left ventricular synchrony. They both improve heart failure (HF) symptoms in atrial fibrillation (AF) patients. We aimed to assess the intra-patient comparison of ventricular function and remodeling as well as leads parameters corresponding to two pacing modalities in AF patients referred for pacing in intermediate term. METHODS: Uncontrolled tachycardia AF patients with both leads implantation successfully were randomized to either modality. Echocardiographic measurements, New York Heart Association (NYHA) classification, quality-of-life assessments and leads parameters were obtained at baseline and at each 6-month follow up. Left ventricular function including the left ventricular endo-systolic volume (LVESV), left ventricular ejection fraction (LVEF) and right ventricular (RV) function quantified by tricuspid annular plane systolic excursion (TAPSE) were all assessed. RESULTS: Consecutively twenty-eight patients implanted with both HBP and LBBP leads successfully were enrolled (69.1 ± 8.1 years, 53.6% male, LVEF 59.2% ± 13.7%). The LVESV was improved by both pacing modalities in all patients (n = 23) and the LVEF was improved in patients with baseline LVEF at less than 50% (n = 6). The TAPSE was improved by HBP but not LBBP (n = 23). CONCLUSION: In this crossover comparison between HBP and LBBP, LBBP was found to have an equivalent effect on LV function and remodeling but better and more stable parameters in AF patients with uncontrolled ventricular rates referred for atrioventricular node (AVN) ablation. HBP could be preferred in patients with reduced TAPSE at baseline rather than LBBP.

Mapping seagrasses on the basis of Sentinel-2 images under tidal change.

Tidal variations make the water bodies in satellite remote sensing images on different shooting dates have different inundation ranges and depths. Although the underwater substrates do not change, the spectral properties differ due to attenuation effects. These differences have an impact on the results when multi-temporal remote sensing images are used to analyze seagrasses. This paper proposes a remote sensing mapping method for seagrasses taking the tidal influence, using the seagrasses growth area in Xincun Bay, Hainan Province, China as a case study. a) The seagrasses growth area was determined from remote sensing images. The seagrasses were divided into two types: the seagrasses exposed to water surface or tidal flats (non-submerged seagrasses) and the seagrasses submerged in water (submerged seagrasses). b) The spectral features of seagrasses in Sentienl-2 image were analyzed. We found that the spectral characteristics of non-submerged seagrasses were similar to terrestrial vegetation and these seagrasses could be extracted by using NDVI. The submerged seagrasses spectral was different, forming a reflection peak at the first vegetation red edge band (i.e.705 nm) in Sentinel-2 images. This reflection peak was used to design the Submerged Seagrasses Identification Index (SSII) for extracting underwater seagrass. c) The extraction results of non-submerged seagrasses and submerged seagrasses were merged to map the seagrasses in the study area. The experimental results show that the mapping method proposed in this study can fully consider the influence of tidal changes in remote sensing images on seagrasses identification. The SSII constructed based on Sentinel-2 images extracted submerged seagrasses effectively. This study will provide references to remote sensing mapping of seagrasses and integrated ecological management in coastal zones.

Intracardiac echocardiography is a safe and effective alternative to transesophageal echocardiography for left atrial appendage thrombus evaluation at the time of atrial fibrillation ablation: The ICE-TEE study.

BACKGROUND: Intracardiac echocardiography (ICE) technology has been increasingly accepted as an integral part of atrial fibrillation (AF) ablation procedures. It is still unknown whether ICE can routinely replace transesophageal echocardiography (TEE) for routine thrombus screening in non-selective AF patients. OBJECTIVE: To assess whether ICE can routinely replace TEE in screening for left atrial (LA)/left atrial appendage (LAA) thrombus in general patients undergoing catheter ablation for AF. METHODS: A total of 2003 consecutive patients undergoing AF ablation were included. 1155 patients (ICE group) received intra-procedural ICE examination for LA/LAA thrombus screening, while 848 patients (TEE group) received pre-procedure TEE examination. The incidence of thrombus, peri-procedure complications, and hospital efficiency were assessed. RESULTS: The LA and LAA were adequately visualized in all patients. Five patients in the ICE group and 15 patients in the TEE group were found to have LAA thrombus. The incidence of major periprocedural thrombo-embolic events was comparable between two groups (0.2% vs. 0.1%, p = .76), none were due to undetected LA/LAA thrombus. Other major periprocedural complications occurred at similar rates in both groups, while post-procedure fever was less common in the ICE group (12.7% vs. 17.4%, p < .001). Procedure times and hospital length of stay were both shorter in the ICE group (142 min [87-197 min] vs. 150 min [95-205 min], and 3[2-4] day vs. 4[3-5] day, respectively, both p < .001). CONCLUSIONS: ICE can replace TEE for atrial thrombus screening in AF patients undergoing ablation without increased complications. An "ICE replacing TEE" workflow can also reduce the incidence of postoperative fever and improve hospital efficiency.

Respiratory control minimizes diaphragmatic contraction and dry cough during pulsed-field ablation of atrial fibrillation.

AIMS: Pulsed-field ablation (PFA) is a promising new ablation modality to treat atrial fibrillation. However, PFA can cause varying degrees of diaphragmatic contraction and dry cough, especially under conscious sedation. This prospective study presents a method to minimize the impact of PFA on diaphragmatic contraction and dry cough during the procedure. METHODS AND RESULTS: Twenty-eight patients underwent PFA for pulmonary vein (PV) and superior vena cava isolation under conscious sedation. Each patient received two groups of ablations in each vein: the control group allowed PFA application during any phase of respiratory cycle, while the test group used respiratory control, delivering PFA energy only at the end of expiration. A rating score system was developed to assess diaphragmatic contraction and dry cough. A total of 1401 control ablations and 4317 test ablations were performed. The test group had significantly lower scores for diaphragmatic contraction (P < 0.01) and dry cough (P < 0.001) in all PVs compared to the control group. The average relative reductions in scores for all PVs were 33-47% for diaphragmatic contraction and 67-83% for dry cough. The percentage of ablations with scores ≧2 for diaphragmatic contraction decreased significantly from 18.5-28.0% in the control group to 0.4-2.6% in the test group (P < 0.001). For dry cough, the percentage decreased from 11.9-43.7% in the control group to 0.7-2.1% in the test group. CONCLUSION: Pulsed-field ablation application at the end of expiration can reduce the severity of diaphragmatic contraction and eliminate moderate and severe dry cough during PV isolation performed under conscious sedation.

Physiological basis and differentially expressed genes in the salt tolerance mechanism of Thalassia hemprichii.

Seagrass plays a vital role in the stability of marine ecology. The human development of marine resources has greatly affected the survival of seagrass. Seawater salinity is one of the important factors affecting its survival. Seagrass can survive in high saline environments for a long time and has evolved a variety of effective tolerance mechanisms. However, little is known about the molecular mechanisms underlying salinity tolerance by seagrass. Thalassia hemprichii is a seagrass species with a global distribution. It is also an ecologically important plant species in coastal waters. Nevertheless, the continuous environmental deterioration has gradually reduced the ecological niche of seagrasses. In this study, experiments were conducted to examine the effects of salinity changes on T. hemprichii. The result showed that the optimal salinity for T. hemprichii is 25 to 35 PSU. Although it can survive under high and low salinity, high mortality rates are common in such environments. Further analyses revealed that high salinity induces growth and developmental retardation in T. hemprichii and further causes yellowing. The parenchyma cells in T. hemprichii also collapse, the structure changes, soluble sugar accumulates rapidly, soluble proteins accumulate rapidly, the malondialdehyde (MDA) content reduces, and lipid peroxidation reduces in plant membranes. The molecular mechanisms of salt tolerance differ significantly between marine and terrestrial plants. We found 319 differentially expressed genes (DEGs). These genes regulate transport and metabolism, promoting environmental adaptation. The expression of these genes changed rapidly upon exposure of T. hemprichii to salinity stress for three hours. This is the first report on the physiological and biochemical changes and gene expression regulation of T. hemprichii under different salinity conditions. The findings of this study well deepen our understanding of T. hemprichii adaptations to changes in the shoal living environment.

Nitrogen budgets for freshwater aquaculture and mariculture in a large tropical island - A case study for Hainan Island 1998-2018.

Nitrogen is an essential nutrient in aquaculture. It is also an important factor in coastal and river eutrophication. We present an island-scale model to study the nitrogen flows in different aquaculture systems in Hainan Island during 1998-2018. The result indicated that nitrogen losses associated with pond sludge, wastewater discharge and gaseous emission increased by a factor of 1.4, 4.6 and 3.2, respectively. Sludge and wastewater account for 84% of the total losses to the environment. During the past 20 years, aquacultural yields and the nitrogen use efficiency (NUE) improved considerably in Hainan Island. Nevertheless, nitrogen losses to the environment increased significantly as well, with negative effects for local ecosystems. In the future, sustainable aquacultural practices are needed to improve NUE and to reduce nitrogen losses to the environment.

Influence of algal organic matter on metal accumulation in adjacent sediments of aquaculture from a tropical coast region.

The rapid development of coastal aquaculture in recent decades has led to excessive discharge of organic matter and nutrients into surrounding waters, which could result in eutrophication and potentially affect metal cycling. In our study, the influence of algal organic matter on metal accumulation was examined in three coastal sediment cores taken from a tropical region, Hainan Island, China. Overall, metal pollution adjacent to aquaculture ponds remained at low levels on the coast, except Zn, Cd, and Sn were moderately to highly enriched in the Dongjiao sediments. The δ13C values and the atomic C/N ratios indicated a major contribution of phytoplankton to sedimentary organic matter at the Dongjiao site. Moreover, both the algae-derived organic matter and effluent nitrogen were significantly associated with the enriched Zn, Cd, and Sn, suggesting that nutrient-induced phytoplankton growth and its organic matter may act as a "biological pump" to enhance the accumulation of metals. Wastewater treatment for aquaculture ponds should include the control of algal organic matter.

Catheter ablation for persistent atrial fibrillation with left ventricular systolic dysfunction: Who is the best candidate?

BACKGROUND: Tachycardia-induced cardiomyopathy is poorly recognized pre-ablation. It remains unclear of better patient selection and timing for catheter ablation in persistent atrial fibrillation (PerAF) with heart failure (HF). METHODS: Consecutive patients with PerAF and left ventricular ejection fraction (LVEF) <50% referred for AF ablation were retrospectively included. The impact of LV size, heart rate (HR), and LVEF pre-ablation were analyzed for assessing LV systolic function recovery, defined as LVEF increase of ≥20% or to a value ≥55% after ablation. RESULTS: A total of 120 patients (2017-2020) were included. After 19 ±14 months post ablation, LVEF improvement was similar in patients with normal or dilated LV (18.3 ± 9.4% vs. 16.1 ± 10.8%, P = .25), rapid or controlled HR (19.5 ± 10% vs. 16.1 ± 10%, P = .09), but higher in HFrEF (HF with reduced EF) than HFmrEF (HF with midrange EF) (21.6 ± 10.3% vs. 14.9 ± 9.3%, P < .01). There was more LV systolic function recovery in those with normal to moderate LV dilation (80%, odds ratio [OR] 15.22, P < .01), HR ≥80 bpm (79%, OR 5.38, P < .01) and HFmrEF (80%, OR 4.03, P < .01). The overall AF freedom was similar between normal and dilated LV (59% vs. 62%, P = .95), rapid and controlled HR (67% vs. 56%, P = .18), and HFmrEF and HFrEF (65% vs. 50%, P = .19). CONCLUSION: Catheter ablation is effective independent of LV dilation, rate control or HFrEF. Patients with normal to moderate LV dilation, resting HR ≥80 bpm and HFmrEF may be candidates for early PerAF ablation to achieve LVEF normalization.

Ingested microplastics impair the metabolic relationship between the giant clam Tridacna crocea and its symbionts.

Microplastics are emerging as widespread pollutants in coral reef ecosystems worldwide; however, there is limited knowledge regarding their impact on giant clams, which are important reef builders. In the present study, the cytological, physiological, and molecular response of the giant clam Tridacna crocea to a 5 d exposure of microplastics was investigated. The concentration of microplastics in the intestine and outer mantle increased significantly and gradually after the exposure to microplastics. There were no significant changes in the density of symbiotic Symbiodiniaceae throughout the exposure period, but symbiont chlorophyll content increased significantly after 1 d of exposure. There was a significant increase in symbiont superoxide dismutase (SOD) activity, but a decrease in giant clam SOD activity and symbiont glutathione S-transferase (GST) activity. No significant changes in catalase (CAT) activity and caspase3 activation level were observed in the two symbiotic partners. Transcriptomic analysis of the giant clam revealed 138 significantly upregulated and 1390 significantly downregulated genes after 5 d of microplastic exposure. The top 20 GO terms overrepresented by these significantly downregulated genes were related to primary metabolic processes and cellular metabolic processes. No significantly upregulated genes were observed in symbionts, but 28 genes were significantly downregulated, including chloroplast oxygen-evolving enhancer, photosystem I reaction center subunit II, peptide/nitrate transporter, sodium-coupled neutral amino acid transporter, beta-glucosidase, and TPA: lipase. These results suggest that T. crocea ingests microplastics through the outer mantle and intestine, and these microplastics can suppress the photosynthesis, organic nutrient transportation, and detoxification ability of the symbionts, as well as the primary metabolism of the giant clam. This eventually could threaten their metabolic relationship and long-term survival.

Selective Interventricular Septal Radiofrequency Ablation in Patients With Hypertrophic Obstructive Cardiomyopathy: Who Can Benefit?

Introduction: Septal mass reduction is beneficial for hypertrophic obstructive cardiomyopathy (HOCM) patients with severe left ventricular outflow (LVOT) gradient and symptoms, with surgical myectomy or alcohol septal ablation (ASA) currently recommended in selected patients. Radiofrequency (RF) ablation of hypertrophied septum has been published as a novel method to alleviate LVOT obstruction in small populations. This study aims to investigate factors influencing clinical outcomes of radiofrequency septum ablation. Methods and Results: In this study, 20 patients with HOCM who underwent endocardial ablation were included. Echocardiography and cardiac MRI (CMR) data was collected and analyzed pre- and (or) post- procedure. Nineteen patients underwent ablation successfully, while ablation was aborted in one patient with prior RBBB due to transient complete atrioventricular block (AVB). After 6 months of follow-up, NYHA heart functional class improved from III (2 - 3) to II (1 - 2) (p < 0.001), and resting LVOT gradient was significantly reduced (87.6 ± 29.5 mmHg vs. 48.1 ± 29.7, p < 0.001). LVOT gradient reduction was significantly higher in patients with limited basal septal hypertrophy (60.9 ± 8.3 vs. 27.9 ± 7.1, p = 0.01), shorter anterior mitral leaflet (56.1 ± 6.4 vs. 20.4 ± 5.0, p < 0.01), and normally positioned papillary muscle (36.9 ± 7.1 vs. 75.0 ± 6.3, p < 0.05). Conclusions: Endocardial septal ablation appears to be a safe and effective procedure for alleviating LVOT gradient in patients with HOCM, especially in those with limited basal septal hypertrophy, shorter anterior mitral leaflet, and normal positioned papillary muscle.

ICE-Derived Left Atrial and Left Ventricular Endocardial and Myocardial Speckle Tracking Strain Patterns in Atrial Fibrillation at the Time of Radiofrequency Ablation.

Objectives: Intracardiac echocardiography(ICE) has excellent imaging resolution and border recognition which increase strain measurement accuracy. We hypothesized that left atrial(LA) substrate and functional impairment can be detected by measuring LA strain deformation in patients with persistent and paroxysmal atrial fibrillation(AF), as compared to those with no AF. Strain deformation changes in LA and left ventricle(LV) can also be assessed post-ablation to determine its effect. Methods: ICE-derived speckle tracking strain(STS) was prospectively performed in 96 patients, including 62 patients with AF(31 persistent and 31 paroxysmal AF) pre-/post-ablation, and 34 patients with no AF. We measured major strain parameters including longitudinal segmental(endo/myocardial) "average peak overall strain of all segments"(PkAll), peak strain rate(SR),and different time-to-peak strain in LA and LV images. Results: At baseline, persistent AF patients had significantly lower(p<0.01) LA endocardial(4.3±2.5 vs. 20.3±8.9 and 25.5±12.9 %) and myocardial PkAll(4.4±2.6 vs. 15.7±7.2 and 20.9±9.2 %), endocardial(0.9±0.4 vs. 1.8±0.7 and 2.2±0.6 1/s) and myocardial peak SR(0.7±0.4 vs. 1.5±0.6 and 1.9±0.5 1/s), as compared to paroxysmal AF and no AF patients. After successful ablation, endo-/myocardial LA PkAll and peak SR were significantly improved, most dramatically in patients with persistent AF. LV endocardial/myocardial strain and SR also improved in AF patients post-ablation. Conclusion: LA longitudinal strain(%)/SR(1/s) parameters in AF patients are more abnormal than those with no AF, suggesting LA substrate/functional damage. AF ablation improved LA strains/SR but with values in paroxysmal > persistent AF suggesting background LA damage in persistent AF.

Implantable loop recorder for augmenting detection of new-onset atrial fibrillation after typical atrial flutter ablation.

BACKGROUND: Patients with typical atrial flutter (AFL) undergoing successful cavotricuspid isthmus ablation remain at risk for future development of new-onset atrial fibrillation (AF). Conventional monitoring (CM) techniques have shown AF incidence rates of 18%-50% in these patients. OBJECTIVES: To evaluate whether continuous monitoring using implantable loop recorders (ILRs) would enhance AF detection in this patient population. METHODS: Veteran patients undergoing AFL ablation between 2002 and 2019 who completed at least 6 months of follow-up after the ablation procedure were included. We compared new-onset AF detection between those who underwent CM and those who received ILRs immediately following AFL ablation. RESULTS: A total of 217 patients (age: 66 ± 9 years; all male) participated. CM was used in 172 (79%) and ILR in 45 (21%) patients. Median follow-up duration after ablation was 4.1 years. Seventy-nine patients (36%) developed new-onset AF, which was detected by CM in 51 and ILR in 28 (30% vs 62%, respectively, P < .001). AF detection occurred at 7.7 months (IQR: 4.7-17.5) after AFL ablation in the ILR group vs 41 months (IQR: 23-72) in the CM group (P < .001). Eleven patients (5%) experienced cerebrovascular events (all in the CM group) and only 4 of these patients (36%) were on long-term anticoagulation. CONCLUSION: Patients undergoing AFL ablation remain at an increased risk of developing new-onset AF, which is detected sooner and more frequently by ILR than by CM. Improving AF detection may allow optimization of rhythm management strategies and anticoagulation in this patient population.