Safety, efficacy, and clinical applicability of pulmonary vein isolation with circular multi-electrode ablation systems: PVAC® vs. nMARQ™ for atrial fibrillation ablation

AIMS

We compare our experience with available circular multi-electrode catheters for atrial fibrillation (AF) ablation: PVAC(®), a phased radiofrequency system, and nMARQ™, an irrigated tip-CARTO-based technology.

METHODS AND RESULTS

Prospective observational study of 175 consecutive patients with follow-up duration of at least 5 months who underwent pulmonary vein isolation (PVI) for symptomatic AF using PVAC(®) (n = 93, age 61.4 ± 9.8 years; 60% male, 13% persistent AF) vs. nMARQ™ (n = 82, age 63.2 ± 10.6 years; 67% male, 24% persistent AF). Procedure and radiation times were 94 ± 27 and 33 ± 13 min for PVAC(®) and 81 ± 18 and 30 ± 8.5 for nMARQ™ (P = 0.0008 and P = 0.18), respectively. The number of applications and the total burning time (min) were 20 ± 7 and 19 ± 6.7 for PVAC(®) and 16 ± 5.6 and 11 ± 4 for nMARQ™ (P < 0.0001 for both), respectively. In two nMARQ™ patients with small atria and pulmonary veins (PVs) and in two PVAC(®) patients with large PVs, the procedure failed; switching to the alternative technology was successful. Acute success rate was 97% for PVAC(®) and 95% for nMARQ™. There was one tamponade in nMARQ™ group and non-significant different minor complications for both techniques. One-year freedom from AF was 79 and 80.7% with PVAC(®) vs. nMARQ™, after one PVI, and 88 vs. 87.7% after two PVIs.

CONCLUSION

Both technologies have short procedure and fluoroscopy times, comparable complication rates, and comparable acute and 1-year success rates. The number of applications and total procedure and burning times were shorter with nMARQ™. nMARQ™ was more suitable for larger atria and PVs. Thus, a patient-based pre-ablation anatomy definition is probably warranted for appropriate selection of technology type.

Site localization of painful lesions during radiofrequency ablation of pulmonary veins using circular multi-electrode catheters

PURPOSE

Previous data showed that pain sensation was common during pulmonary vein isolation (PVI) using an 8-mm radiofrequency (RF) ablation catheter. Pain was more common in the left pulmonary veins (PVs). We characterized the location of pain during PVI using circular multi-electrode ablation catheters.

METHODS

Included are all consecutive patients with atrial fibrillation (AF) who underwent PVI using the phased RF PVAC® catheter (Medtronic) or the irrigated nMARQ™ catheter (Biosense Webster) under conscious sedation between July 2011 and March 2015. Site of pain reaction was marked for each patient.

RESULTS

A total of 251 patients (141 PVAC®, 110 nMARQ™) were studied; 214 (85 %) had at least one lesion associated with pain. Gender (r = 0.084, p = 0.186), type of AF (r = 0.048, p = 0.452), age (r = 0.078, p = 0.216), and repeat procedure (r = 0.018, p = 0.78) were not correlated with pain. There was no association between site of pain and catheter type; only 33% of the painful PVs were also the largest ones (p = 0.5, kappa = 0.03, R = -0.083). One-year freedom from AF was similar for patients with and without painful PVs (p = 0.6). The distribution of pain was as follows: 126 (59%) left superior PV (LSPV), 28 (13%) left inferior, 28 (13%) all PVs, 12 (5.6%) right superior, 12 (5.6%) right inferior, 18 (8.4%) left common, and 2 (0.9%) right common PV.

CONCLUSIONS

PVI using multi-electrode catheters more commonly caused pain sensation in LSPV. There was no influence of catheter type or PV size on pain localization. Our findings, which are similar to those using an 8-mm ablation catheter, imply that location of pain is not catheter dependent but rather a reflection of autonomic physiology.

Busulfan fludarabine vs busulfan cyclophosphamide as a preparative regimen before allogeneic hematopoietic cell transplantation: systematic review and meta-analysis

We aimed to evaluate the efficacy and toxicity profile of busulfan-fludarabine (Bu-Flu) compared with busulfan-cyclophosphamide (Bu-Cy) as a preparative regimen for patients undergoing allogeneic hematopoietic cell transplantation. We performed a systematic review and meta-analysis of all comparative trials, both randomized controlled trials (RCTs) and non-randomized. Our search yielded 15 trials recruiting 1830 patients. Four trials were RCTs and 11 were either one-arm intervention trials compared with historical controls or retrospective studies. There was a lower risk for non-relapse mortality (NRM) at 100 days in patients given Bu-Flu regimen compared with those given Bu-Cy regimen (relative risk (RR) 0.56; 95% confidence interval (CI) 0.34-0.92, 8 trials); however, there were no differences in all-cause mortality at 100 days (RR 0.85; 95% CI 0.56-1.30, 9 trials) and at the end of study (RR 0.81; 95% CI 0.64-1.02, 13 trials). The risks of sinusoidal obstruction syndrome (SOS) and microbiologically documented infections were lower in patients given Bu-Flu regimen (RR 0.34; 95% CI 0.19-0.62, 8 trials and RR 0.79; 95% CI 0.64-0.97, 2 trials, respectively); however, risk for SOS was no longer lower when performing sensitivity analysis according to RCTs. Engraftment kinetics, risk of grade 3-4 mucositis, GvHD, relapse and NRM at the end of the study were all similar between the two groups. We conclude that both regimens have similar efficacy profiles, whereas toxicity is lower with the Bu-Flu regimen.

Androgen Receptor CAG Repeat Length in Relation to Phenotype Among Females with Nonclassical 21-Hydroxylase Deficiency

Nonclassical 21-hydroxylase deficiency (NC21OHD) manifests with various degrees of post natal virilization. The length of CAG repeats of the androgen receptor gene (AR) is inversely correlated to activity of the human androgen receptor (AR) and affects phenotype of several androgen-dependent disorders. The aim of the study was to investigate the associations between CAG repeat length and the phenotype of females with NC21OHD. CAG repeat length and AR inactivation were assessed in females with NC21OHD, and related to their clinical presentation. CAG repeat length and AR inactivation were assessed in 119 females with NC21OHD. Biallelic mean (BAM) of the CAG repeat length and the weighted BAM (WBAM) were related to various clinical parameters. Age at diagnosis and age of menarche positively correlated with BAM (r=0.22, p=0.02, and r=0.23, p=0.01, respectively). A shorter (<25) BAM was associated with younger age at diagnosis (14.8 vs. 21.4 years, p<0.01), at adrenarche (8.1 vs. 10.2 years, p<0.01) and gonadarche (9.9 vs. 11.2 years, p<0.01), and higher corrected height standard deviation score at diagnosis (0.77 vs. 0.15, p=0.01). Precocious pubarche and precocious puberty were more frequent in these with the shorter BAM. Results of WBAM were similar. The CAG repeat length of the AR gene contributes to the clinical diversity of the phenotype in females with NC21OHD.

Nonequilibrium ensemble inequivalence and large deviations of the density in the ABC model

We consider the one-dimensional driven ABC model under particle-conserving and particle-nonconserving processes. Two limiting cases are studied: (a) The rates of the nonconserving processes are vanishingly slow compared with the conserving processes in the thermodynamic limit and (b) the two rates are comparable. For case (a) we provide a detailed analysis of the phase diagram and the large deviations function of the overall density, G(r). The phase diagram of the nonconserving model, derived from G(r), is found to be different from the conserving one. This difference, which stems from the nonconvexity of G(r), is analogous to ensemble inequivalence found in equilibrium systems with long-range interactions. An outline of the analysis of case (a) was given in an earlier letter. For case (b) we show that, unlike the conserving model, the nonconserving model exhibits a moving density profile in the steady state with a velocity that remains finite in the thermodynamic limit. Moreover, in contrast with case (a), the critical lines of the conserving and nonconserving models do not coincide. These are new features which are present only when the rates of the conserving and nonconserving processes are comparable. In addition, we analyze G(r) in case (b) using macroscopic fluctuations theory. Much of the derivation presented in this paper is applicable to any driven-diffusive system coupled to an external particle bath via a slow dynamics.

MitomiRs, chloromiRs and modelling of the microRNA inhibition

MicroRNAs are non-coding parts of nuclear and mitochondrial genomes, preventing the weakest part of the genetic regulatory networks from being expressed and preventing the appearance of a too many attractors in these networks. They have also a great influence on the chromatin clock, which ensures the updating of the genetic regulatory networks. The post-transcriptional inhibitory activity by the microRNAs, which is partly unspecific, is due firstly to their possibly direct negative action during translation by hybridizing tRNAs, especially those inside the mitochondrion, hence slowing mitochondrial respiration, and secondly to their action on a large number of putative m-RNA targets like those involved in immunetworks; We show that the circuits in the core of the interaction graphs are responsible for the small number of dedicated attractors that correspond to genetically controlled functions, partly due to a general filtering by the microRNAs. We analyze this influence as well as their impact on important functions like the control by the p53 network over the apoptosis/proliferation system and the homeostasis of the energy metabolism. In this last case, we show the role of two kinds of microRNAs, both involved in the control of the mitochondrial genome: (1) nuclear microRNAs, called mitoMirs, inhibiting mitochondrial genes and (2) putative mitochondrial microRNAs inhibiting the tRNAs functioning.

Differential downregulation of telomerase activity by bortezomib in multiple myeloma cells-multiple regulatory pathways in vitro and ex vivo

BACKGROUND

The importance of telomerase in multiple myeloma (MM) is well established; however, its response to bortezomib has not been addressed.

METHODS

The effect of bortezomib on telomerase activity and cell proliferation was evaluated in four MM cell lines and in myeloma cells obtained from eight patients. The mechanism of telomerase regulation on epigenetic, transcriptional, and post-translational levels was further assessed in two selected cell lines: ARP-1 and CAG. Clinical data were correlated with the laboratory findings.

RESULTS

Bortezomib downregulated telomerase activity and decreased proliferation in all cell lines and cells obtained from patients, albeit in two different patterns of kinetics. ARP-1 cells demonstrated higher and earlier sensitivity than CAG cells due to differential phosphorylation of hTERT by PKCα. Methylation of hTERT promoter was not affected. Transcription of hTERT was similarly inhibited in both lines by decreased binding of SP-1 and not of C-Myc and NFκB. The ex vivo results confirmed the in vitro findings and suggested existence of clinical relevance.

CONCLUSION

Bortezomib downregulates telomerase activity in MM cells both transcriptionally and post-translationally. MM cells, both in vitro and in patients, exhibit different sensitivity to the drug due to different post-translational response. The effect of bortezomib on telomerase activity may correlate with resistance to bortezomib in patients, suggesting its potential utility as a pre-treatment assessment.

Little-Parks oscillations in an insulator

We present the results of a magnetoresistance study of the disorder-induced superconductor-insulator transition in an amorphous indium-oxide thin film patterned by a nanoscale periodic array of holes. We observed Little-Parks-like oscillations over our entire range of disorder spanning the transition. The period of oscillations was unchanged and corresponded to the superconducting flux quantum in the superconducting as well as in the insulating phases. Our results provide direct evidence for electron pairing in the insulator bordering with superconductivity.

Coherent quantum phase slip

A hundred years after the discovery of superconductivity, one fundamental prediction of the theory, coherent quantum phase slip (CQPS), has not been observed. CQPS is a phenomenon exactly dual to the Josephson effect; whereas the latter is a coherent transfer of charges between superconducting leads, the former is a coherent transfer of vortices or fluxes across a superconducting wire. In contrast to previously reported observations of incoherent phase slip, CQPS has been only a subject of theoretical study. Its experimental demonstration is made difficult by quasiparticle dissipation due to gapless excitations in nanowires or in vortex cores. This difficulty might be overcome by using certain strongly disordered superconductors near the superconductor-insulator transition. Here we report direct observation of CQPS in a narrow segment of a superconducting loop made of strongly disordered indium oxide; the effect is made manifest through the superposition of quantum states with different numbers of flux quanta. As with the Josephson effect, our observation should lead to new applications in superconducting electronics and quantum metrology.

Sparsity-based single-shot subwavelength coherent diffractive imaging

Coherent Diffractive Imaging (CDI) is an algorithmic imaging technique where intricate features are reconstructed from measurements of the freely diffracting intensity pattern. An important goal of such lensless imaging methods is to study the structure of molecules that cannot be crystallized. Ideally, one would want to perform CDI at the highest achievable spatial resolution and in a single-shot measurement such that it could be applied to imaging of ultrafast events. However, the resolution of current CDI techniques is limited by the diffraction limit, hence they cannot resolve features smaller than one half the wavelength of the illuminating light. Here, we present sparsity-based single-shot subwavelength resolution CDI: algorithmic reconstruction of subwavelength features from far-field intensity patterns, at a resolution several times better than the diffraction limit. This work paves the way for subwavelength CDI at ultrafast rates, and it can considerably improve the CDI resolution with X-ray free-electron lasers and high harmonics.

Phase diagram and density large deviations of a nonconserving ABC model

The effect of particle-nonconserving processes on the steady state of driven diffusive systems is studied within the context of a generalized ABC model. It is shown that in the limit of slow nonconserving processes, the large deviation function of the overall particle density can be computed by making use of the steady-state density profile of the conserving model. In this limit one can define a chemical potential and identify first order transitions via Maxwell's construction, similarly to what is done in equilibrium systems. This method may be applied to other driven models subjected to slow nonconserving dynamics.

Surface Band Gaps and Superexchange Interaction in Transition Metal Oxides

In this paper, we discuss the change in the band gap of charge transfer insulators for different surface terminations. We have calculated the Madelung potential of the unreconstructed (100) surfaces of the rocksalt structured TM-O compounds (TM = Mn, Fe, Co and Ni). We also considered possible step defects on a (100) surface. The presented results are calculated in both the purely ionic case (TM2+O2−) and in the strong ligand p - cation 4s, phybridization (TM1+O1−) case. In both cases the charge transfer gap, Δ, for the surface is reduced compared to the bulk value. As a consequence of this reduction there is a large increase of the surface superexchange interaction, Jsur, and a decrease of the band gap.

High prevalence of malignant melanoma in Israeli patients with Parkinson's disease

The risk of melanoma is higher in patients with Parkinson's disease (PD) than in the general population. Whether the association is disease related or treatment related is unclear. The objective of this study was to assess melanoma prevalence in PD patients in Israel using active dermatologic screening. Consecutive patients with idiopathic PD were recruited by 12 Israeli centers. A movement disorder specialist assessed the severity of PD and obtained a medical, neurological, and medication history. Subsequently, a dermatologist assessed melanoma risk factors, recorded a dermatologic history, proactively performed a whole-body skin examination, and biopsied suspicious skin lesions. Of the enrolled patients (n = 1,395, mean age 69.5 ± 10.6 years, mean PD duration 7.3 ± 6.0 years), 95.3% were treated with dopaminergic agents. Biopsies revealed 8 patients with melanoma in situ and 1 with invasive malignant melanoma; 14 patients reported a melanoma prior to enrollment. The observed 5-year limited duration prevalence of melanoma in PD patients was 4.4 times greater (95% CI 2.6-7.6) than expected from melanoma prevalence in an age- and sex-matched cohort from the Israel National Cancer Registry. The increase was accounted for by an elevated prevalence of melanoma in situ [relative risk 12.5 (95% CI 6.7-23.2)]. Occurrence of melanoma did not correlate with levodopa therapy or time of onset of PD. Melanoma prevalence in PD patients was higher than expected in the general Israeli population. This was not related to levodopa treatment. PD patients should be actively screened for melanoma on a routine basis.

Hormone replacement therapy and WONCA/COOP functional status: a cross-sectional population-based study of women in Israel

BACKGROUND

Current indications for hormone replacement therapy (HRT) for menopausal women include symptom relief, but recent studies have raised concerns about the safety of HRT. Little data are available on the effect of HRT on functional status of women taking hormonal preparations after menopause.

OBJECTIVE

To assess the association between hormonal replacement therapy and functional status in menopausal women.

METHODS

A cross-sectional survey, population-based study of 682 menopausal women between the ages of 50 and 70 years registered with six family physicians in central Israel. The main outcome measure was the functional status measured by the WONCA/COOP charts.

RESULTS

A total of 587 women (86%) completed questionnaires. Univariate analysis showed an association between current use of HRT and improved functional status. However this association was diminished in a regression analysis which controlled for sociodemographic status and health variables. The contribution of HRT to functional status was small but was found to be significant in the domains of general health status (1.9%, p<0.002), sleep (0.9%, p<0.044), physical activities (2.1%, p<0.001) and feelings (1.0%, p<0.033). The contribution of HRT to daily activities, social activities, change in health status and pain was not significant.

CONCLUSIONS

HRT use had a small contribution to improved functional status in half of the domains measured by the WONCA/COOP charts.