GJA1 gene polymorphism is a genetic predictor of recurrence after pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) and recurrence of AF after pulmonary vein isolation (PVI) have been linked to sinus node dysfunction. OBJECTIVE: The purpose of this study was to investigate the association between the heart rate-associated single nucleotide polymorphisms (SNPs) identified in genome-wide association studies and recurrence of AF after PVI. METHODS: In this study, patients with paroxysmal AF who underwent initial PVI, including 522 patients for screening and 172 patients for replication, were recruited and 21 heart rate-associated SNPs identified in genome-wide association studies were genotyped. The association between these SNPs and the recurrence of AF was investigated. RESULTS: Throughout the follow-up period of 21 ± 12 months, 119 patients with paroxysmal AF (22.8%) exhibited AF recurrences in the screening set. The rate of AF recurrence was significantly associated with the minor allele C of the gap junction alpha-1 protein (GJA1) rs1015451 (additive model: odds ratio 2.07; P = 9.32 × 10-7), but not with other SNPs. This association was confirmed in the replication set (allelic model: odds ratio 1.81; P = 2.70 × 10-2). Multivariate analysis revealed that the recurrence of AF after AF ablation was independently related to the GJA1 SNP rs1015451 additive model, duration of AF >1 year, AF from non-pulmonary vein foci, and thicker interventricular septum. CONCLUSION: The GJA1 SNP rs1015451, coding for a gap junction protein (connexin-43), may be considered a novel genetic marker for AF recurrence after PVI.

Plasma MicroRNAs as noninvasive diagnostic biomarkers in patients with Brugada syndrome.

BACKGROUND: Brugada syndrome (BrS) can be diagnosed by a type 1 BrS tracing in a 12-lead electrocardiogram (ECG). However, there are daily variations in the ECGs of BrS patients, which presents a challenge when diagnosing BrS. Although many susceptibility genes have been identified, the SCN5A gene is reportedly the main causative gene of BrS. However, most patients do not have an evidence of genetic predisposition to develop BrS. In addition, the diagnosis and risk stratification for ventricular fibrillation (VF) in patients with BrS presents some problems. Meanwhile, circulating micro RNAs (miRNAs) have drawn increased attention as potential biomarkers of various diseases. We hypothesize that circulating miRNAs may be potential diagnostic biomarkers for BrS. METHODS: We enrolled 70 Japanese BrS patients and 34 controls for the screening cohort. A total of 2,555 miRNA sequences were detected using the 3D-Gene miRNAs labeling kit and 3D-Gene Human miRNAs Oligo Chip. We compared the expression of the miRNAs between the BrS patients and the controls. We validated whether the miRNA were significantly up- or downregulated in the screening cohort using RT-PCR. We also enrolled 72 Japanese BrS patients and 56 controls to replicate these miRNAs. RESULTS: Eight miRNAs (hsa-miR-223-3p, hsa-miR-22-3p, hsa-miR-221-3p, hsa-miR-4485-5p, hsa-miR-550a-5p, hsa-miR-423-3p, hsa-miR-23a-3p, and hsa-miR-30d-5p) were downregulated, and one miRNA (hsa-miR-873-3p) was upregulated by more than 3-fold in BrS patients. The multivariate logistic regression analysis determined that hsa-miR-423-3p, hsa-miR-223-3p, and hsa-miR-23a-3p were independently associated with BrS (P < 0.0001). The AUC based on cross validation was 0.871 with a sensitivity and specificity of 83.5% and 81.1%, respectively. CONCLUSIONS: The plasma miRNAs are potential noninvasive biomarkers of BrS, and the constructed logistic model was useful for discriminating BrS.

Clinical impact of left bundle branch area pacing in heart failure with preserved ejection fraction and mid-range ejection fraction.

BACKGROUND: Recently, conduction system pacing, including His bundle and left bundle branch area pacing (LBBAP), has emerged as an alternative pacing procedure for right ventricular (RV) pacing. The current study aimed to compare the clinical outcomes of LBBAP and conventional RV midseptal pacing (RVMSP) in patients with heart failure (HF) with preserved ejection fraction (HFpEF) and HF with midrange ejection (HFmrEF) requiring frequency RV pacing due to atrioventricular block (AVB). METHODS: A total of 89 patients with HFpEF and HFmrEF requiring RV pacing due to symptomatic AVB were enrolled between September 2018 and April 2021, among whom 43 and 46 underwent LBBAP and RVMSP, respectively. RESULTS: No significant differences in baseline characteristics were observed between the two groups. The LBBAP group had a significantly shorter paced-QRS duration and paced left ventricular activation time (LVAT) compared to the RVMSP group (123.4 ± 10.4 ms vs. 152.3 ± 12.3 ms, p < .001 and 68.3 ± 10.0 ms vs. 95.2 ± 12.3 ms, p < .001, respectively). The LBBAP group had significantly lower N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels at the 6-month follow-up compared to the RVMSP group [459.6 pg/ml (240.4-678.7) vs. 972.7 pg/ml (629.5-1315.9), p = .01]. More patients in the LBBAP group exhibited a significant improvement in NT-proBNP, defined as a > 50% decreased from baseline levels. CONCLUSION: LBBAP maintains physiological ventricular activation and contributes to greater improvement in NT-proBNP value 6 months after implantation in patients with HFpEF and HFmrEF compared to RVMSP.

Association between left atrial appendage fibrosis and thrombus formation: A histological approach.

INTRODUCTION: Although recent echocardiographic studies have suggested that left atrial appendage (LAA) remodeling contributes to the development of LAA thrombus (LAAT), histological evidence is absent. The objective of this study was to examine clinical parameters and histological findings to clarify the factors involved in LAAT formation. METHODS: A total of 64 patients (no atrial fibrillation [AF], N = 22; paroxysmal AF, N = 16; nonparoxysmal AF, N = 26) who underwent LAA excision during surgery were enrolled. Transthoracic and transesophageal echocardiography were performed before surgery. We evaluated the fibrosis burden (%) in the excised LAA sections with Azan-Mallory staining in patients with a LAAT compared with those without. RESULTS: Patients with paroxysmal and non-paroxysmal AF had a higher LAA fibrosis burden than those without AF (p = .005 and p < .0001, respectively). Among the patients enrolled, 16 had a LAAT and 15 of them had nonparoxysmal AF. Among the nonparoxysmal AF patients, those with a LAAT had significantly higher LAA fibrosis burden than those without (23.8% [14.8%-40.3%] vs. 12.8% [7.4%-18.2%], p = .004) and echocardiographic parameters of the left atrial volume index (R = 0.543, p = .01), LAA depth (R = 0.452, p = .02), and LAA flow velocity (R = - 0.487, p = .01) were correlated with the LAA fibrosis burden. CONCLUSION: This study provided histological evidence that LAA fibrosis is related to LAAT formation. Echocardiographic parameters of LAA remodeling and function were correlated with the LAA fibrosis burden.

Evaluation of the Feasibility and Efficacy of a Novel Device for Screening Silent Atrial Fibrillation (MYBEAT Trial).

BACKGROUND: myBeat is a novel cutaneous patch device that continuously records electrocardiography and automatically detects atrial fibrillation (AF) by using a new algorithm based on RR intervals. We aimed to test the diagnostic ability of this novel device for screening silent AF in asymptomatic patients.Methods and Results:A multicenter randomized prospective clinical study was performed. To be eligible for inclusion in the study, patients had to be ≥65 years of age and have ≥1 of the following risk factors: hypertension, diabetes, heart failure, ischemic heart disease, stroke, and transient ischemic attack. Patients with prior AF, an implantable pacemaker, and previous palpitation or syncope were excluded. The 300 participants were divided into 2 groups, those using myBeat (n=150) or those undergoing 24-h Holter monitoring (control group; n=150), for AF screening. The rate of AF detection was significantly higher in the myBeat than control group (16 [10.7%] vs. 7 [4.7%], respectively; P=0.04). Multivariable logistic regression analysis revealed that prior heart failure was an independent predictor of silent AF (odds ratio 12.07; 95% confidence interval 1.67-86.27; P=0.01). A 7.7-fold difference in silent AF was found between subjects with CHA2DS2-VASc scores of 1 point and those with scores ≥4 points. CONCLUSIONS: The novel patch device using an original algorithm was beneficial for screening of silent AF.

Peripheral arterial tone during active standing.

Active standing test is clinically used to detect inadequate sympathetic nervous system response to the orthostasis. Peripheral arterial tone (PAT) is a recently developed technology whereby sympathetic activity can be measured through monitoring the digit arterial pulsatile volume. We aimed to determine the response of PAT to the orthostasis. The PAT and short-time frequency domain heart rate variability (HRV) were simultaneously measured during a 5.5-min active standing test in volunteers. The endpoints were changes in the PAT and ratio of low frequency to high frequency (LH/HF) before and after the postural changes: sitting→standing→sitting again. The blood pressure (BP) was constant throughout the test while the heart rate increased during standing in 54 participants. The natural logarithm of the mean LF/HF increased in the standing position (sitting, standing, and sitting again, mean±standard deviation, 1.3±1.04, 1.73±1.15, and 1.51±0.94; p=0.006), and the natural logarithm of its peak value was the highest also while standing (2.58±1.19, 3.08±1.2, and 2.85±1.05; p=0.007). The mean PAT (487.5±277.7, 314.5±180.4, and 458.1±244.3; p <0.001) and its nadir value (341.8±204.8, 189.4±119.2, and 264.3±157.6; p <0.001) declined during standing, and reascended after sitting again. The percent change before and after the standing in mean PAT was not correlated with that of the mean LF/HF. In conclusion, the PAT changed independently of and inversely with the LF/HF during the orthostatic test while the BP remained constant, possibly reflecting peripheral vasocontraction needed for the BP homeostasis.

Porphyromonas gingivalis and left atrial appendage spontaneous echo contrast in atrial fibrillation ablation candidates.

Atrial fibrillation (AF) is associated with a fivefold risk of stroke and thrombotic embolism, which are usually derived from the left atrial appendage (LAA). Spontaneous echo contrast (SEC) is known as a risk factor for thrombosis. Porphyromonas gingivalis (P. gingivalis) has some prothrombotic effects and plays a key role in periodontitis and oral-systemic disease connection. We aimed to clarify the relationship between P. gingivalis and LAA SEC among AF patients. A total of 569 AF ablation candidates were enrolled in the present study. LAA SEC was categorized into nondense SEC and dense SEC based on transesophageal echocardiography. Serum immunoglobulin G antibody titers of P. gingivalis fimA subtypes (types I-IV) were measured with an enzyme-linked immunosorbent assay. The levels of antibody titers were categorized into high (> mean + 3 standard deviation) and low values. A total of 513 (90%) patients were included in the nondense SEC group, and 56 (10%) were included in the dense SEC group. Multivariate regression analysis revealed that the high-value serum antibody titers of P. gingivalis types II and IV were independently associated with dense SEC [type II: adjusted odds ratio (OR) 2.220; 95% confidence interval (CI) 1.062-4.643; P = 0.02; and type IV: adjusted OR 3.169; 95% CI 1.058-6.657; P = 0.002]. The results revealed that P. gingivalis types II and IV are related to LAA SEC severity among AF patients who receive appropriate anticoagulation therapy.

Minor allele of GJA1 gene polymorphism is associated with higher heart rate during atrial fibrillation.

Atrial fibrillation (AF) tachycardia causes heart failure and requires more attention. The genetic background of individual heart rate (HR) variations during AF are unclear. We hypothesized that HR-associated single nucleotide polymorphisms (SNPs) reported in Genome-Wide Association Studies (GWAS) are also associated with HR during AF. We enrolled patients with persistent AF (311 for screening and 146 for replication) who underwent AF ablation and were genotyped for the 21 h-associated SNPs reported in GWAS. The patients underwent 24-h Holter monitoring before AF ablation and electrophysiological study after AF ablation during sinus rhythm. Only the GJA1 SNP rs1015451 (T>C) was significantly associated with total HR (TT 110,643 ± 17,542 beats/day, TC 116,350 ± 19,060 beats/day, CC 122,163 ± 25,684 beats/day, P = 8.5 × 10-4). We also confirmed this significant association in the replication set. The intra-atrial conduction was faster in AF patients with the GJA1 minor allele than in those without it. Multivariate analysis revealed the presence of a GJA1 SNP rs1015451 additive model, female gender, lower left ventricular ejection fraction, and higher 1:1 atrioventricular nodal conduction were independently associated with higher HR during AF. The GJA1 SNP might be a new genetic marker for AF tachycardia.

Increased Urinary Liver-Type Fatty Acid-Binding Protein Level Predicts Major Adverse Cardiovascular Events in Patients With Hypertension.

BACKGROUND: Urinary liver-type fatty acid-binding protein (L-FABP) has been known as a potential biomarker for acute kidney injury. It has also been suggested to have an effective predictive value for cardiovascular mortality in patients with diabetes or critically ill condition. Therefore, this study aimed to examine the ability of urinary L-FABP in predicting mid-term cardiovascular morbidity and mortality in patients with hypertension. METHODS: Urinary L-FABP levels in stable outpatients without diabetes who were treated with antihypertensive drugs were measured, and a 5-year follow-up was planned. The primary end-point was a combination of acute heart failure requiring hospitalization, myocardial infarction, stroke, and cardiovascular death. The secondary end-point was kidney disease progression defined as a relative decline in the estimated glomerular filtration rate of ≥30% from the baseline. RESULTS: A total of 197 patients were recruited. Primary and secondary end-points occurred in 24 (12.2%) and 42 (21.3%) patients, respectively, during a median follow-up of 5.7 years. Patients with urinary L-FABP levels higher than the upper limit (8.4 µg/g creatinine) were more likely to reach the primary (30.43% vs. 9.77%; P = 0.003) and secondary end-points (56.52% vs. 16.67%; P < 0.001) than those with urinary L-FABP levels within the normal limits. Urinary L-FABP level was independently associated with both primary (hazard ratio (HR) 1.21; P = 0.03) and secondary end-points (HR 1.19; P = 0.02). CONCLUSIONS: This study demonstrated that increased urinary L-FABP levels may predict adverse cardiovascular events and renal dysfunction progression even among stable nondiabetic patients with hypertension.

Predicting atrial fibrillation using a combination of genetic risk score and clinical risk factors.

BACKGROUND: Atrial fibrillation (AF) has a genetic basis, and environmental factors can modify its actual pathogenesis. OBJECTIVE: The purpose of this study was to construct a combined risk assessment method including both genetic and clinical factors in the Japanese population. METHODS: We screened a cohort of 540 AF patients and 520 non-AF controls for single nucleotide polymorphisms (SNPs) previously associated with AF by genome-wide association studies. The most strongly associated SNPs after propensity score analysis were then used to calculate a weighted genetic risk score (WGRS). We also enrolled 1018 non-AF Japanese subjects as a validation cohort and monitored AF emergence over several years. Finally, we constructed a logistic model for AF prediction combining WGRS and clinical risk factors. RESULTS: We identified 5 SNPs (in PRRX1, ZFHX3, PITX2, HAND2, and NEURL1) associated with AF after Bonferroni correction. There was a 4.92-fold difference in AF risk between the highest and lowest WGRS calculated using these 5 SNPs (P = 2.32 × 10-10). Receiver operating characteristic analysis of WGRS yielded an area under the curve (AUC) of 0.73 for the screening cohort and 0.72 for the validation cohort. The predictive logistic model constructed using a combination of WGRS and AF clinical risk factors (age, body mass index, sex, and hypertension) demonstrated better discrimination of AF than WGRS alone (AUC = 0.84; sensitivity 75.4%; specificity 80.2%). CONCLUSION: This novel predictive model of combined AF-associated SNPs and known clinical risk factors can accurately stratify AF risk in the Japanese population.

HotBalloon ablation of atrial fibrillation in patients with dextrocardia and situs inversus by "mirror image" approach.

A 51-year-old man with dextrocardia and complete situs inversus who presented with palpitation as a result of drug refractory paroxysmal atrial fibrillation (AF) was referred to our hospital for catheter ablation. Pulmonary vein isolation (PVI) was performed using the HotBalloon technique. We were able to accomplish AF ablation safely and easily using 180 degree-inversed mirror images of X-ray fluoroscopy. We have reported successful PVI for AF with dextrocardia using HotBalloon and mirror image of X-ray fluoroscopy without any complication for the first time.

Improvement in the Reliability of AOAC Official Method 2012.15 for Iodine.

Background: Reliable measurements of iodine are essential for ensuring the quality of infant formula. The AOAC Official Method 2012.15 for iodine tends to produce higher results in the presence of carbon remaining in the final test solution after digestion with alkaline dissolution. This is partly because of the lack of countermeasures for signal enhancement induced by coexisting carbon in Method 2012.15. Objective: To obtain more reliable values for infant formulas, we undertook an experiment. Methods: We modified the protocol by adding carbon in the form of methanol to both the standard solutions and the final test solutions. Comparisons of the enhancement factor for iodine-127 were used to find the optimized concentration of methanol from 0-10%. Results: Optimization of the additional carbon showed that a 5% methanol minimum was necessary for a constant ratio of iodine. The results exhibited good linearity (coefficient of determination >0.999), and the LOQ was 0.19 µg/100 g for the reconstituted final product with a methanol concentration of 5%. The intermediate precision RSD was <3.76%, and the recovery factor was 97.5-104.2% for infant formula distributed in several countries and a special formula distributed in Japan. Conclusions: This demonstrates that 5% methanol, when added to standard and final solutions, acts as an effective matrix matching agent. Highlights: This modified method produces more accurate iodine quantification in infant formulas and special formulas in which there is incomplete digestion of the matrix.

Improvement of Versatility and Analytical Range of AOAC Official Method 2015.06 for Selenium.

AOAC Official Method 2015.06 is not applicable for infant formula without selenium addition because of lack of sensitivity. In addition, Method 2015.06 specifies hydrogen gas as the cell gas of inductively coupled plasma (ICP)-MS instruments. There are only a few manufacturers who have formally adopted hydrogen gas. To expand the applicability of Method 2015.06 for infant formulas with lower selenium content and for ICP-MS instruments that do not use hydrogen gas as the cell gas, we modified the conditions of Method 2015.06. The results exhibited a good linearity (coefficient of determination >0.999) when the range of standard concentration was set from 0.4 to 16.0 µg/L and the cell gas was replaced with helium gas. The measurement precision was improved to an intermediate precision RSD value of 3.49%, and the recovery factor was 103.1%. This study demonstrates that helium gas can be used as the cell gas (easing restrictions in selecting an ICP-MS instrument) and expands the applicability of this method to infant formula samples with lower selenium content by modifying the sample preparation method.

Intercomparison of γ-spectrometry analysis of radionuclides between China and Japan in 2012-2013.

An intercomparison of γ-spectrometry measurement and analysis was organized by the Japan Chemical Analysis Center (JCAC), the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention (NIRP, China CDC), and the Radiation Monitoring Technical Center of Ministry of Environmental Protection, Chinese (RMTC). The main objective of this study was to assess the γ-spectrometry measurement and analysis technology. The JCAC completed the collection and preparation of soil and powdered rice samples. Three laboratories compared the measurement of seven radionuclides that included two samples of (214)Pb, (214)Bi, (208)Tl, (228)Ac, (40)K, (137)Cs, and (134)Cs with γ-spectrometry. During the studies conducted at the laboratory, the calculated value En was found to be the total uncertainty data of the reported activity. Except (134)Cs in powdered rice sample, the calculated En between each of the two laboratories was <1. The measurement results are acceptable except (134)Cs; therefore, measurement results in the three laboratories were consistent within a certain range except in the case of (134)Cs. Although there is a need to improve the accuracy of measurements and analysis of (134)Cs, an intercomparison was conducted of the tested levels on radionuclide analyzed in the three laboratories.

Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident.

Soil deposition density maps of gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident were constructed on the basis of results from large-scale soil sampling. In total 10,915 soil samples were collected at 2168 locations. Gamma rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that of June 14, 2011 by considering the intrinsic decay constant of each nuclide. Finally the deposition maps were created for (134)Cs, (137)Cs, (131)I, (129m)Te and (110m)Ag. The radioactivity ratio of (134)Cs-(137)Cs was almost constant at 0.91 regardless of the locations of soil sampling. The radioactivity ratios of (131)I and (129m)Te-(137)Cs were relatively high in the regions south of the Fukushima NPP site. Effective doses for 50 y after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from the other radioactive nuclides.

Multilocus variable-number of tandem repeat analysis (MLVA) for Clostridium tyrobutyricum strains isolated from cheese production environment.

Clostridium tyrobutyricum is a gram-positive spore-forming anaerobe that is considered as the main causative agent for late blowing in cheese due to butyric acid fermentation. In this study, multilocus variable-number of tandem repeat (VNTR) analysis (MLVA) for C. tyrobutyricum was developed to identify the source of contamination by C. tyrobutyricum spores in the cheese production environment. For each contig constructed from the results of a whole genome draft sequence of C. tyrobutyricum JCM11008(T) based on next-generation sequencing, VNTR loci that were effective for typing were searched using the Tandem Repeat Finder program. Five VNTR loci were amplified by polymerase chain reaction (PCR) to determine their number of repeats by sequencing, and MLVA was conducted. 25 strains of C. tyrobutyricum isolated from the environment, raw milk, and silage were classified into 18 MLVA types (DI=0.963). Of the C. tyrobutyricum strains isolated from raw milk, natural cheese, and blown processed cheese, strains with identical MLVA type were detected, which suggested that these strains might have shifted from natural cheese to blown processed cheese. MLVA could be an effective tool for monitoring contamination of natural cheese with C. tyrobutyricum in the processed cheese production environment because of its high discriminability, thereby allowing the analyst to trace the source of contamination.

Changes of radionuclides in the environment in Chiba, Japan, after the Fukushima nuclear power plant accident.

Damage to the Fukushima nuclear power plant caused by the 11 March 2011 earthquake and tsunami off the northeast coast of Japan resulted in the release into the environment of radioactive material. Airborne radioactive material was detected in metropolitan areas near Tokyo, and increases in radiation dose rate were observed at many locations. In this study, repeated measurements with the in situ Ge system were performed in Chiba City, which is about 220 km south of Fukushima. Increases in radiation dose rate were recorded on 15, 16, and 21 March, with a maximum of 0.5 µGy h(-1). This level is clearly higher than natural background in Japan. Airborne (99)Mo, (99m)Tc, (129m)Te, (129)Te, (132)Te, (131)I, (132)I, (133)I, (133)Xe,(133m)Xe, (135)Xe, (134)Cs, (136)Cs, (137)Cs, and (140)La were detected. Environmental radioactive contamination in the metropolitan area occurred mainly on 21 March by rainfall. The initial rates of decrease in radiation dose rate generally reflected radiological decay according to their physical (radiological) half-lives. However, the in situ half-lives of the long-lived radionuclides such as (134)Cs and (137)Cs reflected environmental dispersal rather than radiological decay.