Clinical Significance of Ventricular Premature Contraction Provoked by the Treadmill Test.

Background and Objectives: The treadmill test (TMT) is a predictive tool for myocardial ischemia. Recently, exercise-provoked ventricular premature contracture (VPC) during TMT was shown to have a relation with coronary artery disease and cardiovascular mortality. Therefore, we evaluate clinical correlates of exercise-provoked VPC and compare the predictive power for myocardial ischemia and cardiovascular events. Method: Data of 408 patients (≥18 years of age) who underwent TMT for work up of angina, palpitation, dyspnea, syncope, or arrhythmia between February 2015, and January 2016, were collected with consent at Samsung Medical Center, Seoul, Republic of Korea. Among total of 408 patients, 208 were excluded according to the previous history of PCI or CABG, previous MI, decreased left ventricular ejection fraction lower than 50%, arrhythmia that could affect ST-segment change on ECG. Results: Among 200 patients, 32 (16.0%) developed exercise-provoked VPC (21 patients in the exercise phase, 20 patients in the recovery phase). Of them, 20 patients (10.0%) showed positive TMT, and 4 patients (2.0%) underwent revascularization after TMT. Among 21 patients showing exercise phase VPC, 5 (23.8%) showed positive TMT results. In patients younger than 65 years, exercise phase VPC was associated with positive TMT (odds ratio 6.879, 1.458-32.453) considering demographics and previous medical history in multivariable analysis. Among the 20 patients showing recovery phase VPC, 2 (10.0%) underwent revascularization after TMT. In multivariable analysis, recovery phase VPC was associated with revascularization (odds ratio 9.381, 1.144-76.948) considering age, sex, BMI, and TMT result. Conclusion: VPC during the treadmill test was a useful predictor of myocardial ischemia in this study.

Electrocardiographic predictors of early recurrence of atrial fibrillation.

BACKGROUND: Electrical cardioversion (ECV) is an effective method for restoring sinus rhythm after atrial fibrillation (AF). However, early recurrence of AF occurs in a significant number of patients after ECV. This study aimed to identify electrocardiographic (ECG) predictors of early AF recurrence after ECV. METHODS: A total of 272 patients with persistent AF undergoing successful ECV were consecutively enrolled in this study. We investigated clinical, echocardiographic, and ECG data. The 12-lead ECG parameters were measured during sinus rhythm right after ECV using a digital caliper. The early AF recurrence was defined as recurrence within 2 months. RESULTS: Of the 272 patients, 165 patients (60.7%) experienced an early AF recurrence. Maximum P-wave duration (PWD) in limb leads (OR: 1.086; 95% CI: 1.019-1.157; p = .012) and P-terminal force (PTF) in V1 (OR: 1.019; 95% CI: 1.004-1.033; p = .011) were independent predictors of early AF recurrence after ECV. The optimal cutoff value of the maximum PWD in limb leads for predicting early AF recurrence was 134 ms, characterized by 90.3% sensitivity and 72.0% specificity. Likewise, the optimal cutoff value of PTF in V1 was 50 ms × mm, characterized by 80.0% sensitivity and 64.5% specificity. CONCLUSION: A longer PWD (>134 ms) and a larger PTF (>50 ms × mm) were useful predictors of early recurrence of AF after successful ECV in clinical practice. A more effective rhythm control therapy such as catheter ablation or rate control strategy rather than a repeat ECV should be considered.

Effectiveness of the Early Staged Hybrid Approach for Treatment of Symptomatic Atrial Fibrillation: the Electrophysiology Study Could Be Deferred?

BACKGROUND: The efficacy of catheter ablation for persistent atrial fibrillation (AF) remains suboptimal. A hybrid approach of catheter ablation combined with totally thoracoscopic surgical ablation can improve outcomes. In this study, we evaluated the efficacy of the early staged hybrid procedure in hospital stay after totally thoracoscopic ablation compared to the stand-alone totally thoracoscopic ablation. METHODS: Patients who underwent totally thoracoscopic ablation from February 2012 to December 2018 were included in this study. We compared the outcomes of the totally thoracoscopic ablation only group versus the early staged hybrid procedure group. The primary outcome was recurrence of atrial tachyarrhythmia after three months of blanking period. The secondary outcome was repeated unplanned additional electrophysiology study and catheter ablation due to atrial tachyarrhythmia recurrence. RESULTS: A total of 306 patients (mean age, 56.8 ± 8.5 years; 278 [90.8%] males) was included in the study, with 81 patients in the early staged hybrid group and 225 patients in the stand-alone totally thoracoscopic ablation only group. The mean follow-up duration was 30.0 months. Overall arrhythmia-free survival showed no significant difference between the two groups (log-rank P = 0.402). There was no significant difference in the rate of repeat procedure between the two groups (log-rank = 0.11). CONCLUSION: The early staged hybrid procedure after thoracoscopic ablation could not improve the outcome of recurrence of atrial tachyarrhythmia. The second stage of electrophysiology study could be deferred to patients with recurrence of atrial tachyarrhythmia during follow up after totally thoracoscopic ablation.

Clinical Factors Associated with Renal Outcome After Heart Transplantation.

Cardiorenal syndrome (CRS) frequently occurs in end-stage heart failure patients waiting for heart transplantation (HT). Decision-making regarding simultaneous heart and kidney transplantation is an unresolved issue in these patients. We investigated clinical factors associated with renal outcome after HT. A total of 180 patients who received HT from 1996 to 2015 were included. Factors associated with early post-HT chronic kidney disease (CKD, estimated glomerular filtration rate [eGFR] < 60 mL/minute/1.73 m2 within 1 year post-HT), post-HT end-stage kidney disease (ESKD), and significant renal function improvement (%ΔeGFR > 15%) at 1 year post-HT were analyzed. Early post-HT CKD and post-HT ESKD developed in 61 (33.9%) and 8 (4.4%) of 180 patients, respectively. Old age was only independently associated with early post-HT CKD and preexisting CKD tended to be associated with early post-HT CKD. Old age and preexisting CKD were independently associated with post-HT ESKD. Low pre-HT eGFR and preoperative renal replacement therapy were not associated with early post-HT CKD or post-HT ESKD. Young age, low pre-HT eGFR, and high %ΔeGFR 1 month post-HT were independently associated with significant renal function improvement. Preoperative renal function, including preoperative RRT, was not associated with post-HT mortality. In conclusion, preexisting CKD may impact renal outcomes after HT, but preoperative severe renal dysfunction, even that severe enough to require RRT, may not be a contraindication for HT alone. Our data suggest the necessity of early HT in end-stage heart failure patients with CRS and the importance of careful management during the early postoperative period.

Radiofrequency vs. Cryoballoon vs. Thoracoscopic Surgical Ablation for Atrial Fibrillation: A Single-Center Experience.

Background and Objectives: Cryoballoon ablation (CBA) and totally thoracoscopic surgical ablation (TTA) have emerged as alternatives to radiofrequency catheter ablation (RFCA) for atrial fibrillation. In this study, we describe our experience comparing patient characteristics and outcomes of RFCA, CBA, and TTA. Materials and Methods: We retrospectively analyzed data from patients who underwent RFCA, CBA, or TTA. Both atrial fibrillation (AF)- and atrial tachyarrhythmia (ATa)-free survival rates were compared using time to recurrence after a 3-month blanking period (defined by a duration of more than 30 s). All patients were regularly followed using 12-lead ECGs or Holter ECG monitoring. Results: Of 354 patients in this study, 125 underwent RFCA, 97 underwent CBA and 131 underwent TTA. The TTA group had more patients with persistent AF, a larger LA diameter, and a history of stroke. The CBA group showed the shortest procedure time (p < 0.001). The CBA group showed significantly lower AF-free survival at 12 months than the RFCA and TTA groups (RFCA 84%, CBA 74% and TTA 85%, p = 0.071; p = 0.859 for TTA vs. RFCA, p = 0.038 for RFCA vs. CBA and p = 0.046 for TTA vs. CBA). There were no significant differences in ATa-free survival among the three groups (p = 0.270). There were no procedure-related adverse events in the RFCA group, but some complications occurred in the CBA group and the TTA group (6% and 5%, respectively). Conclusions: RFCA and CBA are effective and safe as first-line treatments for paroxysmal and persistent AF. In some high-risk stroke patients, TTA may be a viable option. It is important to consider patient characteristics when selecting an ablation method for AF.

Comparison of three neutralizing broths for environmental sampling of low levels of Listeria monocytogenes desiccated on stainless steel surfaces and exposed to quaternary ammonium compounds.

BACKGROUND: An effective environmental sampling method involves the use of a transport/neutralizing broth with the ability to neutralize sanitizer residues that are collected during sampling and to maintain viability of stressed Listeria monocytogenes (Lm) cells. RESULTS: We applied Lm onto stainless steel surfaces and then subjected Lm to desiccation stress for 16-18 h at room temperature (RT, 21-24 °C). This was followed by the subsequent application of Whisper™ V, a quaternary ammonium compound (QAC)-based sanitizer, diluted to 400 ppm and 8000 ppm of active quat, for 6 h. We then sampled Lm with sponges pre-moistened in three transport broths, Dey/Engley (D/E) broth, Letheen broth and HiCap™ broth, to generate environmental samples that contained sanitizer residues and low levels of stressed Lm, which were subsequently analyzed by an enrichment-based method. This scheme conformed with validation guidelines of AOAC International by using 20 environmental test portions per broth that contained low levels of Lm such that not all test portions were positive (i.e., fractional positive). We showed that D/E broth, Letheen broth and HiCap™ broth performed similarly when no quat or 400 ppm of quat was applied to the Lm contaminating stainless steel surfaces. However, when 8000 ppm of quat was applied, Letheen broth did not effectively neutralize the QAC in the samples. These comparisons were performed on samples stored under three conditions after collection to replicate scenarios of sample transport, RT for 2 h, 4 °C for 24 h and 4 °C for 72 h. Comparisons under the three different scenarios generally reached the same conclusions. In addition, we further demonstrated that storing Letheen and HiCap™ broths at RT for two months before sampling did not reduce their capacity to neutralize sanitizers. CONCLUSIONS: We developed a scheme to evaluate the ability of transport broths to neutralize QAC sanitizers. The three transport broths performed similarly with a commonly used concentration of quat, but Letheen broth could not effectively neutralize a very high concentration of QAC. The performance of transport broths was not significantly affected under the assessed pre-sampling and post-sampling storage conditions.

Effectiveness and safety of high-power and short-duration ablation for cavotricuspid isthmus ablation in atrial flutter.

BACKGROUND: Despite many studies on new tools and strategies for cavotricuspid isthmus (CTI) ablation, there is an unmet need to improve the CTI ablation procedure. Recently, high-power short-duration (HPSD) ablation has been widely used for pulmonary vein (PV) isolation in atrial fibrillation. We evaluated the effectiveness and safety of HPSD for CTI ablation in atrial flutter (AFL). METHODS: Eighty-four patients who underwent CTI ablation with or without simultaneous PV isolation between January 2018 and February 2019 were enrolled in this prospective cohort study. We compared procedural characteristics, periprocedural complications, and recurrence of atrial tachyarrhythmia (ATa) between the HPSD group (50 W for 15 s) and conventional group (30 W for 60 s). RESULTS: A total of 84 patients were divided into the HPSD (n = 42) and conventional (n = 42) groups. Bidirectional CTI block was achieved in all patients and 95% achieved bidirectional block after the first-line ablation in both groups. Although there was no difference in the total number of ablation lines between the two groups (1.17 ± 0.7 vs 1.38 ± 0.8, P = .067), HPSD ablation significantly reduced total ablation time compared to the conventional group (236.0 ± 85.6 vs 534.2 ± 235.2 s, P < .001). One pericardial tamponade was reported in the HPSD group. During the mean follow-up of 9.3 ± 4.8 months, CTI-dependent AFL recurrence occurred in one patient in the HPSD group. Recurrence of ATa developed in 14 patients with no significant difference between the groups. CONCLUSION: Our study demonstrates that HPSD CTI ablation is safe and can shorten procedure time.

Megalocytic interstitial nephritis following acute pyelonephritis with Escherichia coli bacteremia: a case report.

Megalocytic interstitial nephritis is a rare form of kidney disease caused by chronic inflammation. We report a case of megalocytic interstitial nephritis occurring in a 45-yrold woman who presented with oliguric acute kidney injury and acute pyelonephritis accompanied by Escherichia coli bacteremia. Her renal function was not recovered despite adequate duration of susceptible antibiotic treatment, accompanied by negative conversion of bacteremia and bacteriuria. Kidney biopsy revealed an infiltration of numerous histiocytes without Michaelis-Gutmann bodies. The patient's renal function was markedly improved after short-term treatment with high-dose steroid.

Thread-like Bone Cement in the Right-side Heart and Pulmonary Arteries Causing Diffuse Pulmonary Embolism as a Late Complication.

Pulmonary embolism (PE) is usually associated with deep vein thrombosis (DVT) in the lower extremities. However, foreign bodies in the pulmonary arteries can rarely cause PE without evidence of DVT. In this report, we present a case of diffuse PE associated with a migrated thread-like structure of the right-side heart and pulmonary arteries in a 70 year-old woman. The patient underwent several episodes of percutaneous vertebroplasty (PV) to treat compression fractures. The thread-like foreign bodies were identified as the bone cement injected during the previous PV procedures. We present this case study to emphasise that clinicians should consider the possibility of PE as a late complication, especially those with a history of PV.

Assessing the Utility of Acoustic Radiation Force Impulse in the Evaluation of Non-Alcoholic Fatty Liver Disease with Severe Obesity or Steatosis.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) encompasses a heterogeneous spectrum ranging from simple steatosis to fibrosis and cirrhosis. Fibrosis, associated with long-term overall mortality and liver-related events, requires evaluation. Traditionally, liver biopsy has been the gold standard for diagnosing fibrosis. However, its invasive nature, potential complications, and sampling variability limit widespread use. Consequently, various non-invasive tests have been developed as alternatives for diagnosing fibrosis in NAFLD patients. AIM: This study aimed to compare the accuracy of non-invasive tests (NITs) and evaluate the diagnostic accuracy of acoustic radiation force impulse (ARFI), one of the point shear wave techniques, compared to conventional methods, assessing its effective role in diagnosis. METHODS: This is a retrospective study; a total of 136 patients diagnosed with fatty liver disease through ultrasonography were enrolled. The anthropometric data of the patients were collected on the day of admission and blood tests, measurements of ARFI, and a point shear test were conducted using abdominal ultrasound; a biopsy was performed the following day. In addition, we calculated the aspartate aminotransferase-to-platelet ratio index (APRI) index based on four factors (FIB-4) and the NAFLD fibrosis score (NFS). Subsequently, we assessed the diagnostic accuracy of NITs within various subgroups based on the extent of obesity, steatosis, or NAFLD activity score. RESULTS: ARFI has been shown to have the highest diagnostic value among various NITs, with AUROC values of 0.832, 0.794, 0.767, and 0.696 for ARFI, APRI, FIB-4, and NFS, respectively. In the morbidly obese subgroup, the AUROC values of ARFI, APRI, FIB-4, and NFS were 0.805, 0.769, 0.736, and 0.674. In the group with severe steatosis or non-alcoholic steatohepatitis (NASH), the AUROC values were 0.679, 0.596, 0.661, and 0.612, respectively, for severe steatosis and 0.789, 0.696, 0.751, and 0.691, respectively, for NASH. CONCLUSIONS: In conclusion, ARFI is not affected by various factors and maintains diagnostic accuracy compared to serum NITs. Therefore, we can recommend ARFI as a valuable diagnostic test to screen for advanced fibrosis in patients with NAFLD.

Variability of Transrectal Shear Wave Elastography in a Phantom Model.

Purpose: This study aimed to assess the variability of transrectal shear wave elastography (SWE) using a designed phantom. Materials and Methods: In a phantom, the SWE values were examined by two radiologists using agarose and emulsion silicone of different sizes (1, 2, and 3 cm) and shapes (round, cubic) at three depths (1, 2, and 3 cm), two region of interest (ROI) and locations (central, peripheral) using two ultrasound machines (A, B from different vendors). Variability was evaluated using the coefficient of variation (CV). Results: The CVs decreased with increasing phantom size. Significant changes in SWE values included; agarose phantom at 3 cm depth (p < 0.001; machine A), 1 cm depth (p = 0.01; machine B), emulsion silicone at 2 cm depth (p = 0.047, p = 0.020; both machines). The CVs increased with increasing depth. Significant changes in SWE values included; 1 cm agarose (p = 0.037, p = 0.021; both machines) and 2 cm agarose phantom (p = 0.047; machine A). Significant differences in SWE values were observed between the shapes for emulsion silicone phantom (p = 0.032; machines A) and between ROI locations on machine B (p ≤ 0.001). The SWE values differed significantly between the two machines (p < 0.05). The intra-/inter-operator agreements were excellent (intraclass correlation coefficient > 0.9). Conclusion: The phantom size, depth, and different machines affected the variability of transrectal SWE.

Evaluation of the Persistence and Characterization of Listeria monocytogenes in Foodservice Operations.

Listeria monocytogenes is a major foodborne pathogen that can contaminate food products and colonize food-producing facilities. Foodservice operations (FSOp) are frequently responsible for foodborne outbreaks due to food safety practices failures. We investigated the presence of and characterized L. monocytogenes from two FSOp (cafeterias) distributing ready-to-eat meals and verified FSOp's compliance with good manufacturing practices (GMP). Two facilities (FSOp-A and FSOp-B) were visited three times each over 5 months. We sampled foods, ingredients, and surfaces for microbiological analysis, and L. monocytogenes isolates were characterized by phylogenetic analyses and phenotypic characteristics. GMP audits were performed in the first and third visits. A ready-to-eat salad (FSOp-A) and a frozen ingredient (FSOp-B) were contaminated with L. monocytogenes, which was also detected on Zone 3 surfaces (floor, drains, and a boot cover). The phylogenetic analysis demonstrated that FSOp-B had persistent L. monocytogenes strains, but environmental isolates were not closely related to food or ingredient isolates. GMP audits showed that both operations worked under "fair" conditions, and "facilities and equipment" was the section with the least compliances. The presence of L. monocytogenes in the environment and GMP failures could promote food contamination with this pathogen, presenting a risk to consumers.

Transvenous lead extraction using the TightRail mechanical rotating dilator sheath for Asian patients.

The need for transvenous lead extraction (TLE) is increasing worldwide including in Asia-Pacific regions. However, supporting evidence for TightRail, a relatively new rotating mechanical dilator sheath, is still lacking in Asian patients. The efficacy and safety of TLE using TightRail performed between March 2018 and June 2021 were evaluated in 86 consecutive patients with 131 leads. The mean lead age was 11.7 ± 7.3 (range, 1.0-41.4) years. Clinical and complete procedural success using TightRail were achieved in 93.0% and 89.5% of 86 patients, respectively, with 6 min of median fluoroscopic time and 9.3% of major complication rate: death (1.2%), cardiac tamponade (3.5%), severe tricuspid regurgitation (3.5%), and stroke (1.2%). However, in 46 patients with longest lead age ≤ 10 years, clinical/complete success and major cardiac complication rates turned out better as 97.8%, 95.7%, and 2.2%, respectively. Additionally, when patients were divided into 3 groups: the first 28, second 29, and the last 29 patients, there was a clear trend toward better efficacy and safety outcomes with more experience with TightRail (Ptrend < 0.05). Longest lead age > 10 years was closely associated with TLE-related major cardiac complication (P = 0.046) with 85.7% sensitivity, 57.0% specificity, 15.0% positive predictive value, and 97.8% negative predictive values. In conclusion, TLE using TightRail may be effectively and safely performed by experienced operators for Asian patients with the longest lead age ≤ 10 years. However, as TightRail is a potentially aggressive tool, special attention should be paid to patients with longer lead dwelling times (e.g., > 10 years).

Effect of distal access catheter tip position on angiographic and clinical outcomes following thrombectomy using the combined stent-retriever and aspiration approach.

PURPOSE: Mechanical thrombectomy using the stent-retriever in conjunction with the distal access catheter may improve the rates of successful revascularization and clinical outcomes in patients with acute stroke. We aimed to compare two different thrombectomy techniques, according to the position of the distal access catheter tip in the combined stent-retriever and aspiration approach. METHODS: In this retrospective study, patients with middle cerebral artery occlusion treated with the combined technique were divided into two groups based on the tip position of the distal access catheter: distal group (catheter placed adjacent to the thrombus) and proximal group (catheter placed in the cavernous segment of the internal carotid artery below the ophthalmic artery). Baseline characteristics, angiographic results, and clinical outcomes were compared. RESULTS: Eighty-three patients (distal group, n = 45; proximal group, n = 38) were included. Higher complete reperfusion was observed in the distal group (unweighted analysis: 66.7% vs. 42.1%, p = 0.025; weighted analysis: 74.0% vs. 28.8%; p = 0.002). In the multivariate analysis, the distal tip position was independently associated with complete reperfusion (unweighted analysis: aOR, 4.10; 95% CI, 1.40-11.98; p = 0.01; weighted analysis: aOR, 5.20; 95% CI, 1.72-15.78; p = 0.004). The distal group also showed more favorable clinical outcomes and early neurological improvement (unweighted analysis: 62.2% vs. 55.3%; p = 0.521, 60% vs. 50%; p = 0.361, respectively; weighted analysis: 62.7% vs. 61.1%; p = 0.877, 66% vs. 45.7%; p = 0.062, respectively). However, more arterial dissections were observed in the distal group (8.9%, n = 4 vs. 2.6%, n = 1; p = 0.36). In the distal group, one patient with vascular injury died due to complications. No cases of emboli in new territory were observed. CONCLUSIONS: Distal tip position of the distal access catheter has a significant impact on reperfusion in patients with acute ischemic stroke. However, there was also a higher rate of vascular injury as the catheter was advanced further. If advancement to the target lesion is too difficult, placing it in the cavernous internal carotid artery may be a viable method without complications.

Long-term outcome of totally thoracoscopic surgical ablation in atrial fibrillation: A single-center experience.

BACKGROUND: Totally thoracoscopic ablation (TTA) is a minimally invasive and safe alternative to radiofrequency catheter ablation (RFCA) for patients with atrial fibrillation (AF). It has evolved over the last decades, but data are limited. The aim of this study was to report the long-term efficacy and safety of TTA through a single center experience. METHODS: We retrospectively analyzed all consecutive patients who underwent TTA for AF from February 2012 to December 2018. All patients were followed every 3 months after operation with 12-lead ECG and 24-hour Holter ECG monitoring. The late recurrence of AF was defined as any atrial tachyarrhythmia (ATa) sustained more than 30 s from 3 months after surgery. RESULTS: Of the total 408 patients undergoing TTA, 265 were analyzed in this study (17% paroxysmal, persistent or long standing persistent 83%, mean age 56 ± 9 years). During the mean follow-up duration 23 ± 18 months, ATa-free survival rate was 74%, 64%, 58%, 51% and 51% at 1,2,3,4 and 5 years, respectively. At the last follow-up, 75% of patients had sinus rhythm with or without additional intervention. The overall complication rate was 4.5% (12 events) and four patients (1.5%) had a stroke during follow-up. CONCLUSIONS: TTA could be effective treatment option for AF. It had a very low risk of complication and could reduce stroke incidence. Further studies are needed to improve treatment strategy.

Total thoracoscopic ablation in patients with atrial fibrillation and left ventricular dysfunction.

OBJECTIVE: To evaluate the effectiveness and safety of totally thoracoscopic ablation (TTA) in patients with left ventricular (LV) dysfunction for treatment of atrial fibrillation (AF) refractory to antiarrhythmic drug (AAD) therapy. METHODS: Between January 2012 and December 2018, 31 patients underwent TTA with drug-refractory AF and preoperative left ventricular ejection fraction (LVEF) <50% were included. Of the 31 patients, 8 received additional catheter ablation with an electrophysiologic study within 3 months after TTA. The rhythm outcome was obtained by 12-lead electrocardiography or 24-hour Holter monitoring. RESULTS: The patient cohort had a mean age of 54.9 ± 9.0 years and consisted of 51.6% with persistent AF (n = 16), 45.2% with long-standing persistent AF (n = 14), and 3.2% with paroxysmal AF (n = 1). No patients died during the follow-up period. Compared with baseline, mean postoperative LVEF at 3 months (interquartile range [IQR], 2-6 months) increased significantly (from 39.7 ± 6.1% to 53.6 ± 9.3%; P < .001). At 25 months (IQR, 14-45 months), LVEF was sustained or further improved (from 39.7 ± 6.1% to 58.1 ± 7.5%; P < .001). The rate of sinus rhythm state was 93.5% (29 of 31), and freedom from arrhythmias off AADs after the final procedure was 61.3% (19 of 31) at a median follow-up of 32 months (IQR, 24-54 months). CONCLUSIONS: TTA is a safe and effective procedure that improves LV function and restores sinus rhythm in AF patients with LV dysfunction.

Earliest activation time is a good predictor of successful ablation of idiopathic outflow tract ventricular arrhythmias.

BACKGROUND: In idiopathic outflow tract ventricular arrhythmias (OT-VAs), identifying the site with the earliest activation time (EAT) using activation mapping is critical to eliminating the arrhythmogenic focus. However, the optimal EAT for predicting successful radiofrequency catheter ablation (RFCA) has not been established. HYPOTHESIS: To evaluate the association between EAT and successful RFCA in idiopathic OT-VAs and to determine the optimal cut-off value of EAT for successful ablation. METHODS: We retrospectively analyzed patients undergoing RFCA for idiopathic OT-VAs at a single center from January 2015 to December 2019. RESULTS: Acute procedural success was achieved in 168 patients (87.0%). Among these patients, 158 patients (81.9%) were classified in the clinical success group according to the recurrence of clinical VAs during median (Q1, Q3) follow-up (330 days [182, 808]). EAT was significantly earlier in the clinical success group compared with the recurrence (p = .006) and initial failure (p < .0001) groups. The optimal EAT cut-off value predicting clinical success was -30 ms in the right ventricular outflow tract (RVOT) with 77.4% sensitivity and 96.4% specificity. In all cases of successful ablation in the left ventricular outflow tract (LVOT), EAT in the RVOT was not earlier than -29 ms. CONCLUSIONS: EAT in patients with successful catheter ablation was significantly earlier than that in patients with recurrence and initial failure. EAT earlier than -30 ms could be used as a key predictor of successful catheter ablation as well as an indicator of the need to shift focus from the RVOT to the LVOT.

The Persistence of Bacterial Pathogens in Surface Water and Its Impact on Global Food Safety.

Water is vital to agriculture. It is essential that the water used for the production of fresh produce commodities be safe. Microbial pathogens are able to survive for extended periods of time in water. It is critical to understand their biology and ecology in this ecosystem in order to develop better mitigation strategies for farmers who grow these food crops. In this review the prevalence, persistence and ecology of four major foodborne pathogens, Shiga toxin-producing Escherichia coli (STEC), Salmonella, Campylobacter and closely related Arcobacter, and Listeria monocytogenes, in water are discussed. These pathogens have been linked to fresh produce outbreaks, some with devastating consequences, where, in a few cases, the contamination event has been traced to water used for crop production or post-harvest activities. In addition, antimicrobial resistance, methods improvements, including the role of genomics in aiding in the understanding of these pathogens, are discussed. Finally, global initiatives to improve our knowledge base of these pathogens around the world are touched upon.

Characterization of Mobile Genetic Elements Using Long-Read Sequencing for Tracking Listeria monocytogenes from Food Processing Environments.

Recently developed nanopore sequencing technologies offer a unique opportunity to rapidly close the genome and to identify complete sequences of mobile genetic elements (MGEs). In this study, 17 isolates of Listeria monocytogenes (Lm) epidemic clone II (ECII) from seven ready-to-eat meat or poultry processing facilities, not known to be associated with outbreaks, were shotgun sequenced, and among them, five isolates were further subjected to long-read sequencing. Additionally, 26 genomes of Lm ECII isolates associated with three listeriosis outbreaks in the U.S. and South Africa were obtained from the National Center for Biotechnology Information (NCBI) database and analyzed to evaluate if MGEs may be used as a high-resolution genetic marker for identifying and sourcing the origin of Lm. The analyses identified four comK prophages in 11 non-outbreak isolates from four facilities and three comK prophages in 20 isolates associated with two outbreaks that occurred in the U.S. In addition, three different plasmids were identified among 10 non-outbreak isolates and 14 outbreak isolates. Each comK prophage and plasmid was conserved among the isolates sharing it. Different prophages from different facilities or outbreaks had significant genetic variations, possibly due to horizontal gene transfer. Phylogenetic analysis showed that isolates from the same facility or the same outbreak always closely clustered. The time of most recent common ancestor of the Lm ECII isolates was estimated to be in March 1816 with the average nucleotide substitution rate of 3.1 × 10-7 substitutions per site per year. This study showed that complete MGE sequences provide a good signal to determine the genetic relatedness of Lm isolates, to identify persistence or repeated contamination that occurred within food processing environment, and to study the evolutionary history among closely related isolates.