Functional study of the soybean stamen-preferentially expressed gene GmFLA22a in regulating male fertility.

China has a high dependence on soybean imports, yield increase at a faster rate is an urgent problem that need to be solved at present. The application of heterosis is one of the effective ways to significantly increase crop yield. In recent years, the development of an intelligent male sterility system based on recessive nuclear sterile genes has provided a potential solution for rapidly harnessing the heterosis in soybean. However, research on male sterility genes in soybean has been lagged behind. Based on transcriptome data of soybean floral organs in our research group, a soybean stamen-preferentially expressed gene GmFLA22a was identified. It encodes a fasciclin-like arabinogalactan protein with the FAS1 domain, and subcellular localization studies revealed that it may play roles in the endoplasmic reticulum. Take advantage of the gene editing technology, the Gmfla22a mutant was generated in this study. However, there was a significant reduction in the seed-setting rate in the mutant plants at the reproductive growth stage. The pollen viability and germination rate of Gmfla22a mutant plants showed no apparent abnormalities. Histological staining demonstrated that the release of pollen grains in the mutant plants was delayed and incomplete, which may due to the locule wall thickening in the anther development. This could be the reason of the reduced seed-setting rate in Gmfla22a mutants. In summary, our study has preliminarily revealed that GmFLA22a may be involved in regulating soybean male fertility. It provides crucial genetic materials for further uncovering its molecular function and gene resources and theoretical basis for the utilization of heterosis in soybean.

Cardiac radioablation of incessant ventricular tachycardia in patients with terminal heart failure under permanent left ventricular assist device therapy-description of two cases.

PURPOSE: Cardiac radioablation (cRA) using a stereotactic single-session radioablative approach has recently been described as a possible treatment option for patients with otherwise untreatable recurrent ventricular tachycardia (VT). There is very limited experience in cRA for patients undergoing left ventricular assist device (LVAD) therapy. We present clinical experiences of two patients treated with cRA for incessant VT under long-term LVAD therapy. METHODS: Two male patients (54 and 61 years old) with terminal heart failure under LVAD therapy (both patients for 8 years) showed incessant VT despite extensive antiarrhythmic drug therapy and repeated catheter ablation. cRA with a single dose of 25 Gy was applied as a last resort strategy under compassionate use in both patients following an electroanatomical mapping procedure. RESULTS: Both patients displayed ongoing VT during and after the cRA procedure. Repeated attempts at post-procedural rhythm conversion failed in both patients; however, one patient was hemodynamically stabilized and could be discharged home for several months before falling prey to a fatal bleeding complication. The second patient initially stabilized for a few days following cRA before renewed acceleration of running VT required bilateral ablation of the stellate ganglion; the patient died 50 days later. No immediate side effects of cRA were detected in either patient. CONCLUSION: cRA might serve as a last resort strategy for patients with terminal heart failure undergoing LVAD therapy and displaying incessant VT. Intermediate- and long-term outcomes of these seriously ill patients often remain poor; therefore, best supportive care strategies should also be evaluated as long as no clear beneficial effects of cRA procedures can be shown. For patients treated with cRA under running ventricular rhythm abnormality, strategies for post-procedural generation of stabilized rhythm have to be established.

Cardiac radiotherapy transiently alters left ventricular electrical properties and induces cardiomyocyte-specific ventricular substrate changes in heart failure.

AIMS: Ongoing clinical trials investigate the therapeutic value of stereotactic cardiac radioablation (cRA) in heart failure patients with ventricular tachycardia. Animal data indicate an effect on local cardiac conduction properties. However, the exact mechanism of cRA in patients remains elusive. Aim of the current study was to investigate in vivo and in vitro myocardial properties in heart failure and ventricular tachycardia upon cRA. METHODS AND RESULTS: High-density 3D electroanatomic mapping in sinus rhythm was performed in a patient with a left ventricular assist device and repeated ventricular tachycardia episodes upon several catheter-based endocardial radio-frequency ablation attempts. Subsequent to electroanatomic mapping and cRA of the left ventricular septum, two additional high-density electroanatomic maps were obtained at 2- and 4-month post-cRA. Myocardial tissue samples were collected from the left ventricular septum during 4-month post-cRA from the irradiated and borderzone regions. In addition, we performed molecular biology and mitochondrial density measurements of tissue and isolated cardiomyocytes. Local voltage was altered in the irradiated region of the left ventricular septum during follow-up. No change of local voltage was observed in the control (i.e. borderzone) region upon irradiation. Interestingly, local activation time was significantly shortened upon irradiation (2-month post-cRA), a process that was reversible (4-month post-cRA). Molecular biology unveiled an increased expression of voltage-dependent sodium channels in the irradiated region as compared with the borderzone, while Connexin43 and transforming growth factor beta were unchanged (4-month post-cRA). Moreover, mitochondrial density was decreased in the irradiated region as compared with the borderzone. CONCLUSION: Our study supports the notion of transiently altered cardiac conduction potentially related to structural and functional cellular changes as an underlying mechanism of cRA in patients with ventricular tachycardia.

Left atrial conduction times and regional velocities in persistent atrial fibrillation patients with and without fibrotic atrial cardiomyopathy.

Despite the progress in understanding left atrial substrate and arrhythmogenesis, only little is known about conduction characteristics in atrial fibrillation patients with various stages of fibrotic atrial cardiomyopathy (FACM). This study evaluates left atrial conduction times and conduction velocities based on high-density voltage and activation maps in sinus rhythm (CARTO®3 V7) of 53 patients with persistent atrial fibrillation (LVEF 60% (55-60 IQR), LAVI 39 ml/m2 (31-47 IQR), LApa 24 ± 6 cm2). Measurements were made in low voltage areas (LVA ≤ 0.5 mV) and normal voltage areas (NVA ≥ 1.5 mV) at the left atrial anterior and posterior walls. Maps of 28 FACM and 25 no FACM patients were analyzed (19 FACM I/II, 9 FACM III/IV, LVA 14 ± 11 cm2). Left atrial conduction time averaged to 110 ± 24 ms but was shown to be prolonged in FACM (119 ms, + 17%) when compared to no FACM patients (101 ms, p = 0.005). This finding was pronounced in high-grade FACM (III/IV) (133 ms, + 31.2%, p = 0.001). In addition, the LVA extension correlated significantly with the left atrial conduction time (r = 0.56, p = 0.002). Conduction velocities were overall slower in LVA than in NVA (0.6 ± 0.3 vs. 1.3 ± 0.5 m/s, -51%, p < 0.001). Anterior conduction appeared slower than posterior, which was significant in NVA (1 vs. 1.4 m/s, -29%, p < 0.001) but not in LVA (0.6 vs. 0.8 m/s, p = 0.096). FACM has a significant influence on left atrial conduction characteristics in patients with persistent atrial fibrillation. Left atrial conduction time prolongs with the grade of FACM and the quantitative expanse of LVA up to 31%. LVAs show a 51% conduction velocity reduction compared to NVA. Moreover, regional conduction velocity differences are present in the left atrium when comparing anterior to posterior walls. Our data may influence individualized ablation strategies.

Progress on genic male sterility gene in soybean.

Male sterility refers to the phenomenon that stamens cannot grow normally and produce viable pollen grains in plants. Hybrid seed production by taking advantage of the trait of male sterility is an effective and quick strategy to increase crop yield. Up to date, the yield of rice (Oryza sativa L.), maize (Zea mays L.), wheat (Triticum aestivum L.) and other crops has been greatly increased based on hybrid vigor utilization. Soybean (Glycine max (L.) Merr.) is a self-pollination species, artificial emasculation is not only time-consuming, but also labor-intensive and economically impracticable. So far, large scale hybrid breeding has not been performed in soybean due to the shortage of male sterile lines suitable for hybrid production. Therefore, it is urgent to identify a stable male sterile system for the rapid utilization of heterosis in soybean. In this review, we summarize the progress on the discovery of soybean genic male sterility (GMS) mutants and GMS genes. Combining with the investigation of GMS genes in Arabidopsis, rice and maize, we provide important insights into the identification and potential utilization of GMS genes in soybean in the perspective of reverse genetics.

Iron-Catalyzed Regiodivergent Alkyne Hydrosilylation.

Although tremendous effort has been devoted to the development of methods for iron catalysis, few of the catalysts reported to date exhibit clear superiority to other metal catalysts, and the mechanisms of most iron catalysis remain unclear. Herein, we report that iron complexes bearing 2,9-diaryl-1,10-phenanthroline ligands exhibit not only unprecedented catalytic activity but also unusual ligand-controlled divergent regioselectivity in hydrosilylation reactions of various alkynes. The hydrosilylation protocol described herein provides a highly efficient method for preparing useful di- and trisubstituted olefins on a relatively large scale under mild conditions, and its use markedly improved the synthetic efficiency of a number of bioactive compounds. Mechanistic studies based on control experiments and density functional theory calculations were performed to understand the catalytic pathway and the observed regioselectivity.

Versatile hybrid plasmonic microfiber knot resonator.

A planar, all-optical fiber polarizer-based device based on a hybrid plasmonic microfiber knot resonator (HPMKR) is demonstrated in this Letter. A microfiber knot resonator (MKR) can be flexibly attached to the gold film, which forms the hybrid plasmonic mode with high propagation loss. Therefore, the device can be used not only as a broadband polarizer, but also as a high-quality resonator by tuning the geometry of the MKR. The polarizer has an extinction ratio of more than 15 dB ranging from 1200 to 1600 nm, and the Q-factor is more than 52,000 for one polarization state. For a chosen polarization, the resonator has an extinction ratio of nearly 15 dB, even though the diameter of the microfiber is more than 5 µm, which is unattainable for a normal MKR. By further optimizing and packaging, the device can be utilized as a weight sensor, with a sensitivity of 18.28 pm/g (51.2 pm/kPa) for the cavity resonant wavelength. Further, a vibration sensor on a HPMKR structure for detecting vibration from tens of hertz to several kilohertz is demonstrated.

[Animal models of Peyronie's disease: An update].

Peyronie's disease is characterized by local fibrosis of the tunica albuginea and relatively rare clinically. Few relevant basic researches could be retrieved, which might be attributed to the absence of a robust animal model of the disease as well as to its rareness. At present, some animal models available for Peyronie's disease have their own merits and demerits. TGF-ß1-induced and Fibrin-induced models are lack of penile curvature and calcification/ossification. A surgical model might be established for the acute phase of the disease. The characteristic of a widespread fibrotic process involving many organs in the spontaneous model is quite different from that of human Peyronie's disease. Therefore, choosing the right model is essential for researches. This paper presents an overview of the animal models of Peyronie's disease, meant to provide some reference for the basic research of the disease.

Second generation of cryoballoons can improve efficiency of cryoablation for atrial fibrillation.

BACKGROUND: We investigated whether the new second generation of cryoballoons can improve the efficiency and safety of cryoablation for atrial fibrillation (AF) during ablation and in terms of outcome. METHODS: Data of AF patients consecutively treated with a single 28-mm cryoballoon were analyzed. Patients were divided into two groups: the G1 group was treated with the first-generation cryoballoons (ArcticFront) and G2 with the second generation (ArcticFront Advance). Failure of cryoablation treatment was defined as detection of an episode of AF, atrial flutter, or atrial tachycardia lasting ≥ 30 seconds during 3-month follow-up. Left atrial diameter (LAD) was measured by transthoracic echocardiography before cryoablation. RESULTS: One hundred twenty-five patients (group G1/G2: 57/68) were enrolled. Mean total time of the whole procedure, cryomapping, and cryoablation was shorter with G2 than with G1 (P < 0.05). No complication occurred with G1 whereas with G2 the complication rate was 8.8%. During mean 12 ± 4 months follow-up, the overall success rate of cryoablation was 76.0% (95/125); it was higher with G2 (89.7% [61/68] vs 59.7% [34/57], P < 0.001). Patients in whom treatment failed had larger LAD (48 ± 8 mm vs 44 ± 6 mm, P = 0.002) than those in whom it succeeded. Type of cryoballoon (relative risk [RR] = 5.75 [2.16, 15.27], P < 0.0001) and LAD (RR = 0.90 [0.83, 0.97], P = 0.0043) were shown in multivariable analysis to be individually related to the difference in success rate. CONCLUSION: Ablation for AF with the new generation of cryoballoons is associated with higher success rate of pulmonary vein isolation and better outcome. However, more complications occurred during the early stage of application of the G2 cryoballoon.

[Bladder reconstruction using autologous bone marrow mesenchyaml stem cells-seeded bladder acellelar matrix graft in a canine model].

OBJECTIVE: To investigate the feasibility of autologous bone marrow mesenchymal stem cells(BMSCs) seeded on bladder acellular matrix graft (BAMG) for bladder reconstruction in a canine model. METHODS: This study included 25 mongrel dogs. Five dogs were sacrificed for the preparation of BAMG. Twenty dogs were randomly divided into two groups and received partial cystectomy. In group A, the bladder defect was repaired with unseeded BAMG. In group B, the bladder defect was repaired with autologous BMSCs-seeded BAMG. The bladders were retrieved and studied histologically and immunohistochemically at the time point of 1, 2, 4, 8, 12 weeks after surgery to evaluate tissue regeneration. RESULTS: All dogs survived the procedure. Histopathological examination in group B showed there was urothelium developed at the end of the 2 weeks. By 8 and 12 weeks all bladder wall components were regenerated in the repaired area, which were similar to normal bladder tissue. In group A, urothelium regeneration was observed at the end of the 4 weeks, whereas smooth muscle was still not well-formed by 12 weeks. CONCLUSION: Autologous BMSCs-seeded BAMG could promote the repair of bladder defect, which is superior to unseeded BAMG in regenerative properties.

Prolonged ablation on critical segments of pulmonary vein ostia in paroxysmal atrial fibrillation: a prospective randomized controlled study.

INTRODUCTION: Electrical reconnection of the pulmonary veins (PVs) plays a key role in the recurrence of atrial fibrillation (AF) after ablative treatment. This randomized controlled study tested the hypothesis that prolonged ablations, on areas that may be critical for left atrial (LA)-PV conduction, can significantly reduce the rate of acute PV reconnection and AF recurrence. METHODS: Patients with paroxysmal AF were randomly assigned to either a control or an add-on group.Ostial PV isolation (PVI) was performed by point-to-point RF ablation (irrigated tip, 30 Watts, 30 seconds).An ostial segment was assumed to be critical for LA-PV connection if any of the following reactions occurred during RF application: (1) sudden delay of LA-PV conduction, (2) change of activation sequence,and (3) PVI. In this case, RF application was prolonged from 30 seconds to 90 seconds in the add-on group only. RESULTS: A total of 131 patients (58 ± 11 years, 47 female) were assigned to a control (n = 64) and an add-on (n = 67) group. Ablation time was longer in the add-on (48 ± 16 minutes vs 37 ± 15 minutes, P = 0.03). Acute PV reconnection was observed in 20 of 64 controls and in eight of 66 add-on patients (31% vs 12%, P < 0.001). During a follow-up of 26 months, AF recurred in 33 of 64 controls and in 16 of 66 add-on patients (52% vs 24%, P = 0.001) after a single ablation procedure. CONCLUSIONS: Prolonged radiofrequency application on critical segments of LA-PV connection is a safe and effective ablative strategy that significantly reduces acute PV reconnection and AF recurrence rates after a single ablation procedure for paroxysmal AF.

Precordial electrode placement for optimal ECG monitoring: implications for ambulatory monitor devices and event recorders.

INTRODUCTION: Detection of QRS complexes, P-waves and atrial fibrillation f-waves in electrocardiographic (ECG) signals is critical for the correct diagnosis of arrhythmias. We aimed to find the best bipolar lead (BL) with the highest signal amplitude and shortest inter-electrode spacing. METHODS: ECG signals (120 seconds) were recorded in 36 patients with 16 precordial electrodes placed in a standardized pattern. An average signal was analysed for each of 120 possible BLs obtained by calculating the difference between pairs of unipolar leads. Peak-to-peak amplitudes of QRS waves (50ms around R-peak) and P waves (270-70ms before R-peak) were calculated. For patients with atrial fibrillation, power of the fibrillatory (f) wave was used instead. Maximum values at each distance were considered and differentiation analysis was performed based on incremental changes (amplitude to distance). RESULTS: There was a significant correlation between distance and QRS-amplitude (r=0.78, p<0.001), P-wave amplitude (r=0.60, p<0.01) and f-wave power (r=0.79, p<0.001). The range of values was: QRS-amplitude 0.7-2.33mV, P-wave amplitude 0.07-0.18mV, and f-wave power 0.55-2.12mV(2)/s. The maximum value for the shortest distance was on a heart-aligned axis over the left ventricle for the QRS complex (1.9mV at 8.7cm) and over the atria for the P-wave (0.98mV) and f-waves (1.45mV(2)/s at 8cm, respectively). CONCLUSION: There is a strong positive correlation between electrode distance and ECG signal-amplitude. Distance of 8cm on a heart-aligned axis and over the relevant heart-chamber provides the highest signal amplitude for the shortest distance. These findings are essential for the design and use of ambulatory monitoring devices.

[Characteristics of renal occupying lesions in contrast-enhanced ultrasonography].

OBJECTIVE: To determine the value of contrast-enhanced ultrasonography (CEUS) in the diagnosis of renal occupying lesions. METHODS: Seventy-eight patients with a preliminary diagnosis of renal masses in West China Hospital, Sichuan University were examined by CEUS. The characteristics of enhancement, phase of enhancement/decline, pseudocapsule sign, and time-intensity curve (TIC) were compared between the malignant and benign lesions. RESULTS: Of the 78 renal occupying lesions, 50 were malignant and 28 were benign. Malignant lesions showed enhanced signs to various degrees. The renal clear cell carcinoma mainly presented as "fast wash-in and fast wash-out", while the other malignant lesions presented as " slow wash-in and fast wash-out" Pseudocapsule signs were found mostly in renal clear cell carcinoma. No enhancement was found in renal cyst. Renal angiomyolipoma presented as diffuse hypo-enhancement characterized with "slow wash-in and slow wash-out". The time-to-peak (TTP) in malignant lesions appeared earlier than benign lesions. Higher levels of peak intensity (PI) and area under the curve (AUC) were found in malignant lesions compared with the benign lesions (P<0. 05). CONCLUSION: CEUS plus time-intensity curve can provide evidence for identifying different kinds of renal occupying lesions.

Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation.

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively, and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.

Mechanistic assessment and ablation of left ventricular assist device related ventricular tachycardia in patients with severe heart failure.

Aims: Left-ventricular-assist-devices (lvad) are an established treatment for patients with severe heart failure with reduced ejection fraction (HF) and reduce mortality. However, HF patients have significant substrate for ventricular tachycardia (VT) and the lvad itself might be pro-arrhythmogenic. We investigated the mechanism of VT in lvad-patients in relation to the underlying etiology and provide in silico and ex-vivo data for ablation in these HF patients. Methods and Results: We retrospectively analyzed invasive electrophysiological (EP) studies of 17 patients with VT and lvad. The mechanism of VT was determined using electroanatomical, entrainment and activation time mapping. Ischemic cardiomyopathy was present in 70% of patients. VT originated from the lvad region in >30%. 1/6 patients with VT originating from the lvad region had episodes before lvad implantation, while 7/11 patients with VT originating from other regions had episodes before implantation. Number and time of radiofrequency (RF)-ablation lesions were not different between VTs originating from the lvad or other regions. Long-term freedom from VT was 50% upon ablation in patients with VT originating from the lvad region and 64% if ablation was conducted in other regions. To potentially preemptively mitigate lvad related VT in patients undergoing lvad implantation, we obtained in silico derived data and performed ex-vivo experiments targeting ventricular myocardium. Of the tested settings, application of 25 W for 30 s was safe and associated with optimal lesion characteristics. Conclusion: A significant percentage of patients with lvad undergoing VT ablation exhibit arrhythmia originating in close vicinity to the device and recurrence rates are high. Based on in silico and ex-vivo data, we propose individualized RF-ablation in selected patients at risk for/with lvad related VT.

Correlations of podocyte injury with glucose regulated protein 78 expression and proteinuria in patients with diabetic nephropathy.

OBJECTIVE: To explore the podocyte injury in patients with diabetic nephropathy (DN) and analyze its relationship with glucose regulated protein 78 (GRP78) and proteinuria. METHODS: The clinical data of 48 patients diagnosed as DN by renal biopsy were reviewed. All patients were divided into two groups according to proteinuria (>3.5 g/d, n=31 and 3.5 g/d, n=17). The density of podocytes was illustrated by immunohistochemistry staining of Wilms tumor-1 (WT-1), and the immunofluorescence double-staining results of synaptopodin and GRP78 in podocytes were detected. RESULTS: The podocyte dentistry of urine protein > 3.5 g/d group was significantly lower than that of urine protein>3.5 g/d group urine protein<3.5 g/d group(P=0.003), and it was negatively correlated with proteinuria (P=0.005). The expressions of synaptopodin and GRP78 in podocytes were also negatively correlated with proteinuria (P=0.004 and P=0.001). CONCLUSION: The podocyte injury is aggravated with increased proteinuria in DN patients, along with the decrease of the adaptive ability of endoplasmic reticulum to stress.

Hierarchical MXene/Polypyrrole-Decorated Carbon Nanofibers for Asymmetrical Capacitive Deionization.

Membrane capacitive deionization (MCDI) has emerged as a promising electric-field-driven technology for brackish water desalination and specific salt or charged ion separation. The use of carbon-based or pseudocapacitive materials alone for MCDI usually suffers from the drawbacks of low desalination capacity and poor cycling stability due to their limited accessible adsorption sites and obstructed charge-carrier diffusion pathways. Therefore, developing a hybrid electrode material with multiple charge storage mechanisms and continuous electron/ion transport pathways that can synergistically improve its specific capacitance and cycling durability has currently become one of the most critical technical demands. Herein, we developed a novel hierarchically architectured hybrid electrode by first spinning MXene into polyacrylonitrile (PAN)-based carbon nanofibers (MCNFs) to obtain a highly conductive carbon nanocomposite framework. The excellent spatial support structure can effectively prevent the dense packing of Cl-- and DBS--doped polypyrrole (PPy) molecular chains during the following electrodeposition process, which not only ensures the efficient transport of electrons in the continuous hybrid carbon nanofibrous skeleton but also provides abundant accessible sites for ion adsorption and insertion. The obtained self-supporting membrane electrodes (MCNF@PPy+Cl- and MCNF@PPy+DBS-) have the advantages of outstanding specific capacitance (318.4 and 153.9 F/g, respectively), low charge transfer resistance (10.0 and 5.3 Ω, respectively), and excellent cycling performance (78% and 90% capacitance retention ratios, respectively, after 250 electrochemical cycles). Furthermore, the asymmetrical membrane electrodes showed a superior desalination capacity of 91.2 mg g-1 in 500 mg/L NaCl aqueous solution and obvious divalent ion (Ca2+, Mg2+) selective adsorption properties in high-salt water from the cooling towers of thermal power plants.

Minimally invasive approach to the treatment of atrial fibrillation: Concomitant Convergent and LARIAT procedure.

The Convergent procedure comprises epi- and endocardial ablation of the left atrium and represents an effective alternative to conventional endocardial ablation in patients with therapy-resistant atrial fibrillation. The LARIAT approach allows the epi- and endocardial closure of the left atrial appendage and effectively reduces the risk of stroke in patients with atrial fibrillation. In this video tutorial, we provide step-by-step guidance through the concomitant Convergent and LARIAT procedures.

Clinical outcomes of cryoballoon ablation for pulmonary vein isolation: Impact of intraprocedural heart rhythm.

BACKGROUND: The current study sought to assess the impact of the intraprocedural heart rhythm (sinus rhythm [SR] vs. atrial fibrillation [AF]) on acute procedural characteristics, durability of pulmonary vein isolation (PVI) and long-term clinical outcomes of cryoballoon (CB) ablation. METHODS: A total of 195 patients with symptomatic paroxysmal (n = 136) or persistent AF (n = 59) underwent CB-based PVI. Ablation procedures were either performed in SR (SR group; n = 147) or during AF (AF group; n = 48). Persistent AF was more frequent in the AF group than in the SR group (62% vs. 20%). All other patient baseline characteristics did not differ between the two groups. RESULTS: The nadir temperature during the CB applications was significantly lower in the AF group than in patients in the SR group (-49 [interquartile range, -44; -54]°C vs. -47 [-42; -52]°C, p = 0.002). Median procedure and fluoroscopy times as well as the rate of real-time recordings were not different between the two groups. Repeat ablation for the treatment of atrial arrhythmia recurrence was performed in 60 patients (SR: 44 [30%] patients; AF: 16 [33%] patients), with a trend towards a lower rate of pulmonary vein reconnections in the AF group (p = 0.07). There was no difference in 3-year arrhythmia-free survival (p = 0.8). CONCLUSIONS: Cryoballoon-based PVI during AF results in lower nadir balloon temperatures and a trend towards a higher durability of PVI as compared to procedures performed in SR. The rate of real-time PVI recordings was not affected by the intraprocedural heart rhythm.

Cardiovascular magnetic resonance imaging for accurate sizing of the left atrium: predictability of pulmonary vein isolation success in patients with atrial fibrillation.

PURPOSE: To prospectively determine the most reproducible approach for left-atrial size assessment using cardiovascular magnetic resonance (CMR) imaging in patients with atrial fibrillation and its value for prediction of pulmonary vein isolation (PVI) treatment success. MATERIALS AND METHODS: Eighty patients underwent CMR imaging prior to PVI; the CMR examination included standard cine sequences, a multislice cine sequence in 4-chamber orientation with full left-atrial coverage, and a contrast-enhanced MR angiography of the left atrium. Left-atrial size was determined as: diameter, area, volume segmented from angiography, and diastolic/systolic volumes from cine imaging (Simpson's rule). All measurements were carried out by two independent observers and repeated by one observer to assess inter- and intrareader variability. Treatment success was defined as persisting sinus rhythm after PVI (follow-up period 12.6 ± 6.6 months). RESULTS: All left-atrial measurements showed substantial intrareader agreement. Interreader agreement was substantial for diastolic/systolic left-atrial volumes only. Calculated bias was found to be minimal (0.1%-4.9%). Predictability of PVI treatment success was best using cine volumetric measurements (cutoff value for diastolic volume, 112 mL) yielding a sensitivity and specificity of 80% and 70%, respectively. CONCLUSION: Left-atrial volumetry based on cine imaging represented the most reproducible approach to determine left-atrial size. PVI success was predicted best using cine volumetry.