Manual vs. automatic assessment of the QT-interval and corrected QT

AIMS

Sudden cardiac death (SCD) is challenging to predict. Electrocardiogram (ECG)-derived heart rate-corrected QT-interval (QTc) is used for SCD-risk assessment. QTc is preferably determined manually, but vendor-provided automatic results from ECG recorders are convenient. Agreement between manual and automatic assessments is unclear for populations with aberrant QTc. We aimed to systematically assess pairwise agreement of automatic and manual QT-intervals and QTc.

METHODS AND RESULTS

A multi-centre cohort enriching aberrant QTc comprised ECGs of healthy controls and long-QT syndrome (LQTS) patients. Manual QT-intervals and QTc were determined by the tangent and threshold methods and compared to automatically generated, vendor-provided values. We assessed agreement globally by intra-class correlation coefficients and pairwise by Bland-Altman analyses and 95% limits of agreement (LoA). Further, manual results were compared to a novel automatic QT-interval algorithm. ECGs of 1263 participants (720 LQTS patients; 543 controls) were available [median age 34 (inter-quartile range 35) years, 55% women]. Comparing cohort means, automatic and manual QT-intervals and QTc were similar. However, pairwise Bland-Altman-based agreement was highly discrepant. For QT-interval, LoAs spanned 95 (tangent) and 92 ms (threshold), respectively. For QTc, the spread was 108 and 105 ms, respectively. LQTS patients exhibited more pronounced differences. For automatic QTc results from 440-540 ms (tangent) and 430-530 ms (threshold), misassessment risk was highest. Novel automatic QT-interval algorithms may narrow this range.

CONCLUSION

Pairwise vendor-provided automatic and manual QT-interval and QTc results can be highly discrepant. Novel automatic algorithms may improve agreement. Within the above ranges, automatic QT-interval and QTc results require manual confirmation, particularly if T-wave morphology is challenging.

Genetic Susceptibility for Atrial Fibrillation in Patients Undergoing Atrial Fibrillation Ablation

BACKGROUND

Ablation is a widely used therapy for atrial fibrillation (AF); however, arrhythmia recurrence and repeat procedures are common. Studies examining surrogate markers of genetic susceptibility to AF, such as family history and individual AF susceptibility alleles, suggest these may be associated with recurrence outcomes. Accordingly, the aim of this study was to test the association between AF genetic susceptibility and recurrence after ablation using a comprehensive polygenic risk score for AF.

METHODS

Ten centers from the AF Genetics Consortium identified patients who had undergone de novo AF ablation. AF genetic susceptibility was measured using a previously described polygenic risk score (N=929 single-nucleotide polymorphisms) and tested for an association with clinical characteristics and time-to-recurrence with a 3 month blanking period. Recurrence was defined as >30 seconds of AF, atrial flutter, or atrial tachycardia. Multivariable analysis adjusted for age, sex, height, body mass index, persistent AF, hypertension, coronary disease, left atrial size, left ventricular ejection fraction, and year of ablation.

RESULTS

Four thousand two hundred seventy-six patients were eligible for analysis of baseline characteristics and 3259 for recurrence outcomes. The overall arrhythmia recurrence rate between 3 and 12 months was 44% (1443/3259). Patients with higher AF genetic susceptibility were younger (P<0.001) and had fewer clinical risk factors for AF (P=0.001). Persistent AF (hazard ratio [HR], 1.39 [95% CI, 1.22-1.58]; P<0.001), left atrial size (per cm: HR, 1.32 [95% CI, 1.19-1.46]; P<0.001), and left ventricular ejection fraction (per 10%: HR, 0.88 [95% CI, 0.80-0.97]; P=0.008) were associated with increased risk of recurrence. In univariate analysis, higher AF genetic susceptibility trended towards a higher risk of recurrence (HR, 1.08 [95% CI, 0.99-1.18]; P=0.07), which became less significant in multivariable analysis (HR, 1.06 [95% CI, 0.98-1.15]; P=0.13).

CONCLUSIONS

Higher AF genetic susceptibility was associated with younger age and fewer clinical risk factors but not recurrence. Arrhythmia recurrence after AF ablation may represent a genetically different phenotype compared to AF susceptibility.

Determination and Interpretation of the QT Interval

BACKGROUND

Long QT syndrome (LQTS) is associated with potentially fatal arrhythmias. Treatment is very effective, but its diagnosis may be challenging. Importantly, different methods are used to assess the QT interval, which makes its recognition difficult. QT experts advocate manual measurements with the tangent or threshold method. However, differences between these methods and their performance in LQTS diagnosis have not been established. We aimed to assess similarities and differences between these 2 methods for QT interval analysis to aid in accurate QT assessment for LQTS.

METHODS

Patients with a confirmed pathogenic variant in KCNQ1(LQT1), KCNH2(LQT2), or SCN5A(LQT3) genes and their family members were included. Genotype-positive patients were identified as LQTS cases and genotype-negative family members as controls. ECGs were analyzed with both methods, providing inter- and intrareader validity and diagnostic accuracy. Cutoff values based on control population's 95th and 99th percentiles, and LQTS-patients' 1st and 5th percentiles were established based on the method to correct for heart rate, age, and sex.

RESULTS

We included 1484 individuals from 265 families, aged 33±21 years and 55% females. In the total cohort, QT_Tangent was 10.4 ms shorter compared with QT_Threshold (95% limits of agreement±20.5 ms, P<0.0001). For all genotypes, QT_Tangent was shorter than QT_Threshold ( P<0.0001), but this was less pronounced in LQT2. Both methods yielded a high inter- and intrareader validity (intraclass correlation coefficient >0.96), and a high diagnostic accuracy (area under the curve >0.84). Using the current guideline cutoff (QTc interval 480 ms), both methods had similar specificity but yielded a different sensitivity. QTc interval cutoff values of QT_Tangent were lower compared with QT_Threshold and different depending on the correction for heart rate, age, and sex.

CONCLUSION

The QT interval varies depending on the method used for its assessment, yet both methods have a high validity and can both be used in diagnosing LQTS. However, for diagnostic purposes current guideline cutoff values yield different results for these 2 methods and could result in inappropriate reassurance or treatment. Adjusted cutoff values are therefore specified for method, correction formula, age, and sex. In addition, a freely accessible online probability calculator for LQTS ( www.QTcalculator.org ) has been made available as an aid in the interpretation of the QT interval.

High-density Mapping Guided Pulmonary Vein Isolation for Treatment of Atrial Fibrillation - Two-year clinical outcome of a single center experience

Pulmonary vein isolation (PVI) as interventional treatment for atrial fibrillation (AF) aims to eliminate arrhythmogenic triggers from the PVs. Improved signal detection facilitating a more robust electrical isolation might be associated with a better outcome. This retrospective cohort study compared PVI procedures using a novel high-density mapping system (HDM) with improved signal detection vs. age- and sex-matched PVIs using a conventional 3D mapping system (COM). Endpoints comprised freedom from AF and procedural parameters. In total, 108 patients (mean age 63.9 ± 11.2 years, 56.5% male, 50.9% paroxysmal AF) were included (n = 54 patients/group). Our analysis revealed that HDM was not superior regarding freedom from AF (mean follow-up of 494.7 ± 26.2 days), with one- and two-year AF recurrence rates of 38.9%/46.5% (HDM) and 38.9%/42.2% (COM), respectively. HDM was associated with reduction in fluoroscopy times (18.8 ± 10.6 vs. 29.8 ± 13.4 min; p < 0.01) and total radiation dose (866.0 ± 1003.3 vs. 1731.2 ± 1978.4 cGy; p < 0.01) compared to the COM group. HDM was equivalent but not superior to COM with respect to clinical outcome after PVI and resulted in reduced fluoroscopy time and radiation exposure. These results suggest that HDM-guided PVI is effective and safe for AF ablation. Potential benefits in comparison to conventional mapping systems, e.g. arrhythmia recurrence rates, have to be addressed in randomized trials.

Corrigendum: Violent Behavior During Psychiatric Inpatient Treatment in a German Prison Hospital

[This corrects the article DOI: 10.3389/fpsyt.2019.00762.].

Violent Behavior During Psychiatric Inpatient Treatment in a German Prison Hospital

Violent behavior in correctional facilities is common and differs substantially in type, target, implication, and trigger. Research on frequency and characteristics of violent behavior in correctional facilities and psychiatric hospitals is limited. Results from recent research suggest that comorbidity of severe mental disorder, personality disorder, and diagnosis of substance abuse is related to a higher risk of violent behavior. In the Berlin prison hospital, a database was created to collect data from all violent incidences (n=210) between 1997 and 2006 and between 2010 and 2016. In a retrospective, case-control study, we analyzed specific socioeconomic data and psychiatric diagnosis and compared the group of prisoners with violent behavior with randomly selected prisoners of the same department without violent behavior (n = 210). Diagnosis of schizophrenia, non-German nationality, no use of an interpreter, no children, and no previous sentence remained significantly associated with the dependent variable violent behavior. There were no significant differences regarding age and legal statuses. Practical implications for clinical work are discussed.

Multi-ethnic genome-wide association study for atrial fibrillation

Atrial fibrillation (AF) affects more than 33 million individuals worldwide1 and has a complex heritability2. We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF.

Development, preclinical evaluation and validation of a novel quick vascular closure device for transluminal, cardiac and radiological arterial catheterization

Following percutaneous coronary intervention, vascular closure devices (VCDs) are increasingly used to reduce time to ambulation, enhance patient comfort, and reduce potential complications compared with traditional manual compression. Newer techniques include complicated, more or less automated suture devices, local application of pads or the use of metal clips and staples. These techniques often have the disadvantage of being time consuming, expensive or not efficient enough. The VCD failure rate in association with vascular complications of 2.0-9.5%, depending on the type of VCD, is still not acceptable. Therefore, the aim of this study is to develop a self-expanding quick vascular closure device (QVCD) made from a bioabsorbable elastic polymer that can be easily applied through the placed introducer sheath. Bioabsorbable block-co-polymers were synthesized and the chemical and mechanical degradation were determined by in vitro tests. The best fitting polymer was selected for further investigation and for microinjection moulding. After comprehensive haemocompatibility analyses in vitro, QVCDs were implanted in arterial vessels following arteriotomy for different time points in sheep to investigate the healing process. The in vivo tests proved that the new QVCD can be safely placed in the arteriotomy hole through the existing sheath instantly sealing the vessel. The degradation time of 14 days found in vitro was sufficient for vessel healing. After 4 weeks, the remaining QVCD material was covered by neointima. Overall, our experiments showed the safety and feasibility of applying this novel QVCD through an existing arterial sheath and hence encourage future work with larger calibers.

CHA2DS2-VASc score and blood biomarkers to identify patients with atrial high-rate episodes and paroxysmal atrial fibrillation

AIMS

Paroxysmal atrial fibrillation (PAF) is often asymptomatic but nonetheless harmful. We evaluated the performance of disease-related blood biomarkers and CHA2DS2-VASc score to discriminate for PAF in patients with continuous rhythm monitoring.

METHODS AND RESULTS

Clinical data and blood samples were obtained from patients with dual-chamber pacemakers selected according to the absence (no_AHRE) or presence of Atrial High-Rate Episodes (AHRE) >6 min in recent device history (case-control approach). We included 93 patients (n = 49 AHRE, n = 44 no_AHRE). In a subgroup with high AHRE burden and confirmed PAF 15 biomarkers were evaluated (n = 19 AHRE-AF vs. n = 20 no_AHRE). Significantly regulated biomarkers were then tested in all patients to distinguish no_AHRE from AHRE (receiver operating characteristics analysis). Hsp27, TGFβ1, cystatin C, matrix metalloproteinases MMP-2,-3,-9, albumin, and serum uric acid were not altered in the subgroup. Tissue inhibitors of metalloproteinases (TIMP) -1,-2,-4; NT-proANP, NT-proBNP, IL-6 and serum amyloid protein A were significantly different in AHRE vs. no_AHRE (subgroup and whole cohort), with best discriminatory performance for TIMP-4. Biomarkers performed better than CHADS2-VASc for AHRE discrimination. Intracardial electrograms and medical history from seven AHRE patients suggested atrial tachycardia and not AF (AHRE-AT). Four of the most relevant regulated biomarkers (TIMP-4, TIMP-2, SAA, NT-proBNP) behaved similarly in AHRE-AT and AHRE-AF. NT-proBNP >150 pg/mL indicated an odds ratio of 12.9 for AHRE. Combining two biomarkers significantly improved discrimination of AHRE.

CONCLUSION

TIMP-4, NT-proANP, NT-proBNP were strongest associated with PAF and AHRE. The discriminatory performance of CHADS2-VASc for PAF was increased by addition of selected biomarkers.

Intrajugular balloon catheter reduces air embolism in vitro and in vivo

Background

Neurosurgical procedures requiring a sitting position may put the patient at risk of a potentially life-threatening air embolism. Transient manual jugular venous compression limits further air entry in this situation. This study presents an alternative technique aimed at reducing the risk of air embolism.

Methods

In an in vitro model, an intrajugular balloon catheter was inserted to demonstrate that this device prevents air embolism. In an in vivo study, this device was bilaterally placed into jugular vessels in pigs. Using an ultrasound technique, blood flow was monitored and jugular venous pressure was recorded before and during cuff inflation. Air was applied proximally to the inflated cuffs to test the hypothesis that this novel device blocks air passage.

Results

In vitro, the intrajugular balloon catheter reliably prevented further air entry (n=10). Additionally, accumulated air could be aspirated from an orifice of the catheter (n=10). In vivo, inflation of the catheter balloon completely obstructed venous blood flow (n=8). Bilateral inflation of the cuff significantly increased the proximal jugular venous pressure from 9.8 (2.4) mm Hg to 14.5 (2.5) mm Hg (n=8, P<0.05). Under conditions mimicking an air embolism, air passage across the inflated cuffs was prevented and 78 (20%) (n=6) of the air dose could be aspirated by the proximal orifice of the catheter.

Conclusions

These findings may serve as a starting point for the development of intrajugular balloon catheters designed to reduce the risk of air embolism in patients undergoing neurosurgery in a sitting position.

Preclinical evaluation of the thrombogenicity and endothelialization of bare metal and surface-coated neurovascular stents

BACKGROUND AND PURPOSE

Stent-assisted coiling is routinely used for the endovascular treatment of complex or wide-neck intracranial aneurysms. However, in-stent thrombosis, thromboembolic events, and ischemic complications remain a major concern associated with stent implants. Therefore, a novel low-profile neurovascular stent with a bare metal surface was investigated with regard to thrombogenicity and endothelialization and compared with the same stent coated with albumin or heparin.

MATERIALS AND METHODS

The bare metal and heparin- or albumin-coated stents were loaded in heparin-coated tubing, which was then filled with heparinized human blood (n = 5) and circulated at 150 mL/min and 37°C for 60 minutes. Before and after circulation, measurement of various inflammation and coagulation markers and scanning electron microscopy were performed. Endothelialization of the stents was investigated in an in vitro model including human umbilical vascular endothelial cells.

RESULTS

Our results showed that platelet loss and platelet activation and activation of the coagulation cascade, which are induced by the bare metal stents, were significantly reduced by heparin or albumin coating. Adverse effects on erythrocytes, leukocytes, and the complement cascade were not induced by the bare metal or coated stents. Moreover, the bare metal and albumin-coated stents showed good endothelialization properties.

CONCLUSIONS

Albumin and heparin coatings clearly improve the thrombogenicity of the stents and thus may represent fundamental progress in the treatment of intracranial aneurysms. Moreover, preclinical evaluation of neurovascular stents under physiologic conditions supports and accelerates the development of more biocompatible neurovascular stents.

Evolution of the optical releasers for aggressive behavior in cave-dwelling Astyanax fasciatus (Teleostei, Characidae)

Epigean and blind cave-dwelling populations of the characid Astyanax fasciatus differ in their agonistic behavior. Epigean specimens are characterized by intense aggressive behavior and territoriality in the laboratory, whereas the blind cave fishes are rarely aggressive and have totally lost the territorial behavior. These behavioral changes are genetically based. In the present study, a comparative analysis of the optical releasers for aggressive behavior has been performed in both epigean and cave-dwelling populations. It was expected that the regression of aggressive behavior should be accompanied by the regression of the genetically fixed optical releasers for aggression in the cave specimens. For the analysis of cave fishes, well-eyed F1-hybrids of cave and epigean specimens (Pachon × Teapao) as well as phylogenetically young cave specimens (Micos) selected for large eyes, have been used. In epigean specimens, aggression is most intensely released by a combination of the signals 'natural shape' and 'locomotion'. The cave populations exhibit a partial regression of the releaser 'natural shape'. 'Locomotion', however, has become a more effective releaser for aggression in cave fishes than it has in their epigean relatives. The results are discussed with respect to their evolutionary significance.

Automatic cell segmentation in strongly agglomerated cell networks for different cell types

This paper presents a method of separating cells that are connected to each other forming clusters. The difference to many other publications covering similar topics is that the cell types we are dealing with form clusters of highly varying morphology. An advantage of our method is that it can be universally used for different cell types. The segmentation method is based on a growth simulation starting from the nuclei areas. To start the evaluation, the cells need to be made visible with a histological stain, in our case with the May-Grünwald solution. After the staining process has been completed, the nuclei areas can be distinguished from the other cell areas by a histogram backprojection algorithm. The presented method can, in addition to histological stained cells, also be applied to fluorescent-stained cells.

Pentacoordinate silicon(IV): cationic, anionic and neutral complexes derived from the reaction of NHC→SiCl4 with highly Lewis acidic (C2F5)2SiH2

Addition of NHC→SiCl4 to the highly Lewis acidic bis(pentafluoroethyl)silane ((C2F5)2SiH2) afforded the salt [(NHC)2SiCl2H][(C2F5)2SiCl3] with pentacoordinate silicon in the cation and the anion. The anion represents the first example of a chlorosilicate structurally characterized in the solid state. In this reaction, the long sought pentacoordinate NHC-adduct of silicochloroform was identified as an intermediate and its crystal structure is presented.

Expression of antimicrobial peptides and toll-like receptors is increased in tinea and pityriasis versicolor

In superficial tinea and pityriasis versicolor, the causative fungi are for the most part confined to the stratum corneum which is barely reached by leukocytes. Therefore, a role of non-cellular components in the epidermal antifungal defence was suggested. To investigate the presence of such factors in these infections, the expression of human beta defensins 2 and 3 (hBD-2, hBD-3), RNase 7, psoriasin, toll-like receptors 2, 4 and 9 (TLR2, TLR4 and TLR9) and dectin 2 was analysed by use of immunostainings in skin biopsies. We found that hBD2, hBD3, psoriasin, RNase7, TLR2 and TLR4 were significantly more often expressed in distinct layers of lesional epidermis as compared with uninfected epidermis. In both infections but not in normal skin, hBD2 and hBD3 were commonly expressed within the stratum corneum and in the stratum granulosum. Similarly, psoriasin was seen more often in the upper skin layers of both infections as compared with normal skin. No significant differences between normal and infected skin were found for the expression of TLR9 and dectin 2. Our findings clearly show the expression of specific antimicrobial proteins and defence-related ligands in superficial tinea as well as in pityriasis versicolor, suggesting that these factors contribute to fungal containment.