Comparison of anterior mitral line and mitral isthmus line for ablation of mitral annular flutter.

BACKGROUND: Mitral annular flutter (MAF) is the most common left atrial macro-reentrant arrhythmia following catheter ablation of atrial fibrillation (AF). The best ablation approach for this arrhythmia remains unclear. METHODS: This single-center, retrospective study sought to compare the acute and long-term outcomes of patients with MAF treated with an anterior mitral line (AML) versus a mitral isthmus line (MIL). Acute ablation success, complication rates, and long-term arrhythmia recurrence were compared between the two groups. RESULTS: Between 2015 and 2021, a total of 81 patients underwent ablation of MAF (58 with an AML and 23 with a MIL). Acute procedural success defined as bidirectional block was achieved in 88% of the AML and 91% of the MIL patients respectively (p = 1.0). One year freedom from atrial arrhythmias was 49.5% versus 77.5% and at 4 years was 24% versus 59.6% for AML versus MIL, respectively (hazard ratio [HR]: 0.38, confidence interval [CI]: 0.17-0.82, p = .009). Fewer patients in the MIL group had recurrent atrial flutter when compared to the AML group (HR: 0.32, CI: 0.12-0.83, p = .009). The incidence of recurrent AF, on the other side, was not different between both groups (21.7% vs. 18.9%; p = .76). There were no serious adverse events in either group. CONCLUSION: In this retrospective study of patients with MAF, a MIL compared to AML was associated with a long-term reduction in recurrent atrial arrhythmias driven by a reduction in macroreentrant atrial flutters.

Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study.

AIMS: Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs). METHODS AND RESULTS: This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation. CONCLUSION: Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Coupled local mode method for simulating vibrational spectroscopy.

Experimental and theoretical studies have highlighted protonated water clusters (PWCs) as important models of the excess proton in aqueous systems. A significant focus has been characterizing the spectral signatures associated with different excess proton solvation motifs. Accurate vibrational frequency calculations are crucial for connecting the measured spectra to the structure of PWCs. In this paper, we extend and characterize a coupled local mode (CLM) approach for calculating the infrared spectra of PWCs using the H+(H2O)4 cluster as a benchmark system. The CLM method is relatively low cost and incorporates the anharmonicity and coupling of OH vibrations. Here, we demonstrate the accuracy of the technique compared to experiments. We also illustrate the dependence of calculated spectral features on the underlying electronic structure theory and basis sets used in the local mode frequency and coupling calculations.

FDG-PET/CT in colorectal cancer: potential for vascular-metabolic imaging to provide markers of prognosis.

PURPOSE: This study assesses the potential for vascular-metabolic imaging with FluoroDeoxyGlucose (FDG)-Positron Emission Tomography/Computed Tomography (PET/CT) perfusion to provide markers of prognosis specific to the site and stage of colorectal cancer. METHODS: This prospective observational study comprised of participants with suspected colorectal cancer categorized as either (a) non-metastatic colon cancer (M0colon), (b) non-metastatic rectal cancer (M0rectum), or (c) metastatic colorectal cancer (M+). Combined FDG-PET/CT perfusion imaging was successfully performed in 286 participants (184 males, 102 females, age: 69.60 ± 10 years) deriving vascular and metabolic imaging parameters. Vascular and metabolic imaging parameters alone and in combination were investigated with respect to overall survival. RESULTS: A vascular-metabolic signature that was significantly associated with poorer survival was identified for each patient group: M0colon - high Total Lesion Glycolysis (TLG) with increased Permeability Surface Area Product/Blood Flow (PS/BF), Hazard Ratio (HR) 3.472 (95% CI: 1.441-8.333), p = 0.006; M0rectum - high Metabolic Tumour Volume (MTV) with increased PS/BF, HR 4.567 (95% CI: 1.901-10.970), p = 0.001; M+ participants, high MTV with longer Time To Peak (TTP) enhancement, HR 2.421 (95% CI: 1.162-5.045), p = 0.018. In participants with stage 2 colon cancer as well as those with stage 3 rectal cancer, the vascular-metabolic signature could stratify the prognosis of these participants. CONCLUSION: Vascular and metabolic imaging using FDG-PET/CT can be used to synergise prognostic markers. The hazard ratios suggest that the technique may have clinical utility.

COVID-19 Outbreak Among Three Affiliated Homeless Service Sites - King County, Washington, 2020.

On March 30, 2020, Public Health - Seattle and King County (PHSKC) was notified of a confirmed case of coronavirus disease 2019 (COVID-19) in a resident of a homeless shelter and day center (shelter A). Residents from two other homeless shelters (B and C) used shelter A's day center services. Testing for SARS-CoV-2, the virus that causes COVID-19, was offered to available residents and staff members at the three shelters during March 30-April 1, 2020. Among the 181 persons tested, 19 (10.5%) had positive test results (15 residents and four staff members). On April 1, PHSKC and CDC collaborated to conduct site assessments and symptom screening, isolate ill residents and staff members, reinforce infection prevention and control practices, provide face masks, and advise on sheltering-in-place. Repeat testing was offered April 7-8 to all residents and staff members who were not tested initially or who had negative test results. Among the 118 persons tested in the second round of testing, 18 (15.3%) had positive test results (16 residents and two staff members). In addition to the 31 residents and six staff members identified through testing at the shelters, two additional cases in residents were identified during separate symptom screening events, and four were identified after two residents and two staff members independently sought health care. In total, COVID-19 was diagnosed in 35 of 195 (18%) residents and eight of 38 (21%) staff members who received testing at the shelter or were evaluated elsewhere. COVID-19 can spread quickly in homeless shelters; rapid interventions including testing and isolation to identify cases and minimize transmission are necessary. CDC recommends that homeless service providers implement appropriate infection control practices, apply physical distancing measures including ensuring resident's heads are at least 6 feet (2 meters) apart while sleeping, and promote use of cloth face coverings among all residents (1).

Identification of urinary metabolites with potential blood pressure-lowering effects in lentil-fed spontaneously hypertensive rats.

PURPOSE: Urine samples were obtained from a previously completed study that showed lentil consumption attenuates the increase in blood pressure that occurs over time in spontaneously hypertensive rats (SHRs). The objective of the present study was to compare the metabolite profile of the urine samples from control and lentil-fed SHR in relation to the compounds present in lentils but not in other pulses. METHODS: The urine samples were from 17-week-old, male SHR fed semi-purified diet prepared with powder (30 %, w/w) from cooked whole pulses or a pulse-free control diet (n = 8/group) for 4 weeks. Pulse powders, control diet and urine samples were extracted using acetonitrile and analyzed by a high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). RESULTS: Twenty-seven metabolites were significantly different in urine samples from lentil-fed SHR compared to SHR fed control diet, but only 7 were not present in the urine of SHR fed other pulses. Of these metabolites, only citrulline is linked to blood pressure regulation via production of the vasodilator nitric oxide (NO). Several arginine-related compounds that are NO synthase substrates or inhibitors were detected in lentils but not the control diet or other pulse powders. CONCLUSIONS: Consumption of lentils increases the availability of arginine and several related compounds that could potentially elevate production of NO and contribute to the blood pressure-lowering effects of lentil-rich diets.

Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles.

The 1-substituted-4-imino-1,2,3-triazole motif is an established component of coordination compounds and bioactive molecules, but depending on the substituent identity, it can be inherently unstable due to Dimroth rearrangements. This study examined parameters governing the ring-degenerate rearrangement reactions of 1-substituted-4-imino-1,2,3-triazoles, expanding on trends first observed by L'abbé et al. The efficiency of condensation between 4-formyltriazole and amine reactants as well as the propensity of imine products towards rearrangement was each strongly influenced by the substituent identity. It was observed that unsymmetrical condensation reactions conducted at 70 °C produced up to four imine products via a dynamic equilibrium of condensation, rearrangement and hydrolysis steps. Kinetic studies utilizing 1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbaldehyde with varying amines showed rearrangement rates sensitive to both steric and electronic factors. Such measurements were facilitated by a high throughput colorimetric assay to directly monitor the generation of a 4-nitroaniline byproduct.

Do Format Differences in the Presentation of Information Affect Susceptibility to Memory Distortions? The Three-Stage Misinformation Procedure Reconsidered.

To date most studies within the misinformation paradigm have used the visual presentation of a to-be-remembered event that is later tested verbally or visually. However, the well-established encoding specificity hypothesis predicts that congruence between encoding and test phases should lead to fewer memory errors. In Study 1, we examined the susceptibility to misinformation after encoding original information in 1 of 4 different formats: as a film, slides, and as a written or auditory narrative. All participants were tested verbally, and those who encoded original information pictorially (as a video or slides) were more likely to incorrectly accept verbally suggested information. This might be-a consequence of encoding-retrieval format match. In Study 2, using either verbal or pictorial modality during encoding, postevent information, and test (fully crossed design), we partially supported the encoding-retrieval format match hypothesis; however, auditory presentation of original or postevent information modified the effect, showing that a memory trace created after auditory description was the strongest.

Lentil-based diets attenuate hypertension and large-artery remodelling in spontaneously hypertensive rats.

Hypertension is a major risk factor for CVD, the leading cause of mortality worldwide. The prevalence of hypertension is expected to continue increasing, and current pharmacological treatments cannot alleviate all the associated problems. Pulse crops have been touted as a general health food and are now being studied for their possible effects on several disease states including hypertension, obesity and diabetes. In the present study, 15-week-old spontaneously hypertensive rats (SHR) were fed diets containing 30% w/w beans, peas, lentils, chickpeas, or mixed pulses or a pulse-free control diet for 4 weeks. Normotensive Wistar-Kyoto (WKY) rats were placed on a control diet. Pulse wave velocity (PWV) was measured weekly, while blood pressure (BP) was measured at baseline and week 4. Fasting serum obtained in week 4 of the study was analysed for circulating lipids. A histological analysis was carried out on aortic sections to determine vascular geometry. Of all the pulse varieties studied, lentils were found to be able to attenuate the rise in BP in the SHR model (P< 0·05). Lentils were able to decrease the media:lumen ratio and media width of the aorta. The total cholesterol (TC), LDL-cholesterol (LDL-C) and HDL-cholesterol levels of rats fed the pulse-based diets were found to be lower when compared with those of the WKY rat and SHR controls (P< 0·05). Although all pulses reduced circulating TC and LDL-C levels in the SHR, only lentils significantly reduced the rise in BP and large-artery remodelling in the SHR, but had no effect on PWV. These results indicate that the effects of lentils on arterial remodelling and BP in the SHR are independent of circulating LDL-C levels.

Aeromedical Evacuation, the Expeditionary Medicine Learning Curve, and the Peacetime Effect.

INTRODUCTION: Organizational proficiency increases with experience, which is known as a learning curve. A theoretical peacetime effect occurs when knowledge and skills degrade during peacetime. In this study, the intertheater evacuation system was examined for evidence of a military learning curve and peacetime effect. MATERIALS AND METHODS: Data on medical evacuations from U.S. Central Command occurring between January 1, 2003, and December 31, 2022, were acquired from the TRANSCOM Regulating and Command & Control Evacuation System. Priority mission evacuation time corresponding to peak periods of activity in Iraq and Afghanistan and minimal activity in Afghanistan was analyzed. Any reduction or increase in the delivery time of casualties would be considered a change in proficiency. RESULTS: There was a marginal monthly decline of 0.019 days (27.4 min) to perform a priority evacuation from Iraq (95% confidence interval [CI], 0.009 to 0.028 days, P < .001) and a decline of 0.010 days (14.4 min) from Afghanistan (95% CI, 0.003 to 0.016 days, P = .004) over 40 months from peak monthly average times. There was a monthly marginal increase in priority evacuation average time from Afghanistan of 0.008 days (11.5 min) (95% CI, 0.005 to 0.011, P < .001) between January 2013 and December 2020. The number of monthly evacuations estimated to maintain or improve monthly average evacuation time is approximately 50. CONCLUSIONS: An intertheater aeromedical evacuation system increased in proficiency during periods of conflict and declined during relative peacetime. There is evidence of a peacetime effect on intertheater aeromedical evacuation.

Military Blood Supply and Distribution in USCENTCOM.

In expeditionary environments, the consistent availability of blood for casualty care is imperative yet challenging. Responding to evidence and the specific needs of its expeditionary context, the US Central Command (USCENTCOM) prioritized supplying stored low titer O whole blood (LTOWB) to its units from March, 2023 onward. A strategy was devised to set minimal LTOWB on-hand supply benchmarks, determined by the number of operating beds and point of injury teams. This transition led to a 54% reduction in orders for packed red blood cells. As a countermove, the Armed Services Blood Program (ASBP) enhanced LTOWB production at a conversion rate 2:1 from packed red blood cell to LTOWB. Consequently, there was a decline in expired blood products, and fulfillment rates for blood requests are projected to reach 100% consistently. This paper delves into the intricacies of the expeditionary blood supply, the rationale behind the LTOWB transition, the devised allocation strategy, and the subsequent impacts of this change.

The USCENTCOM Walking Blood Bank Performance Benchmark and Anticipated Benefit of Universal Low Titer Type O Screening.

The walking blood bank (WBB) is a system for emergency blood acquisition from nearby donors if a patient's blood needs exceed the immediate supply. USCENTCOM medical units will perform a walking blood bank if immediate blood requirements exceed the local supply. A benchmark WBB performance time was needed to provide a training goal for military WBB exercises. An expeditionary WBB performance time benchmark was created from prospective measurements of USCENTCOM medical unit performance times over 9 months. The mean total time, and new performance benchmark, for a WBB in USCENTCOM was 41.4 min +/- 13.2 min. USCENTCOM time from donor arrival to a transfusable unit mean time was 34.4 +/- 12.1 min. Expeditionary medical units conducting a WBB should expect to meet or exceed the provided benchmark.

Bipolar ablation involving coronary venous system for refractory left ventricular summit arrhythmias.

Background: Catheter ablation of premature ventricular complexes (PVCs) and ventricular tachycardia (VT) from the left ventricular summit (LVS) may require advanced ablation techniques. Bipolar ablation from the coronary veins and adjacent endocardial structures can be effective for refractory LVS arrhythmias. Objective: The aim of this study was to investigate the outcomes of bipolar ablation performed between the coronary venous system and adjacent endocardial left ventricular outflow tract (LVOT) or right ventricular outflow tract (RVOT). Methods: This multicenter study included consecutive patients with LVS PVC/VT who underwent bipolar ablation between the anterior interventricular vein (AIV) or great cardiac vein (GCV) and the endocardial LVOT/RVOT after failed unipolar ablation. Ablation was started with powers of 10-20 W and uptitrated to achieve an impedance drop of at least 10%. Angiography was performed in all cases to confirm a safe distance (>5 mm) of the catheter from the major coronary arteries. Results: Between 2013 and 2023, bipolar radiofrequency ablation between the AIV/GCV and the adjacent LVOT/RVOT was attempted in 20 patients (4 female; age 57 ± 16 years). Unipolar ablation from sites of early activation (AIV/GCV, LVOT, aortic cusps, RVOT) failed to effectively suppress the PVC/VT in all subjects. Bipolar ablation was delivered with a maximum power of 30 ± 8 W and total duration of 238 ± 217 s and led to acute PVC/VT elimination in all patients. No procedural-related complications occurred. Over a follow-up period of 30 ± 24 months, the freedom from arrhythmia recurrence was 85% (1 recurrence in the VT group and 2 in the PVC group). PVC burden was reduced from 22% ± 10% to 4% ± 8% (P <.001). Conclusion: In cases of LVS PVC/VT refractory to unipolar ablation, bipolar ablation between the coronary venous system and adjacent endocardial LVOT/RVOT is safe and effective if careful titration of power and intraprocedural angiography are performed to ensure a safe distance from the coronary arteries.

Feasibility, Efficacy, and Safety of Fluoroless Ablation of VT in Patients With Structural Heart Disease.

BACKGROUND: Catheter ablation of ventricular tachycardia (VT) typically requires radiation exposure with its potential adverse health effects. A completely fluoroless ablation approach is achievable using a combination of electroanatomical mapping and intracardiac echocardiography. Nonetheless, data in patients undergoing VT ablation are limited. OBJECTIVES: This study aimed to determine the feasibility, efficacy, and safety of VT ablation in patients with structural heart disease using a zero-fluoroscopy approach. METHODS: This multicenter study included consecutive patients with ischemic and nonischemic cardiomyopathy undergoing fluoroless VT ablation. Patients requiring epicardial access or coronary angiography were excluded. RESULTS: Between 2017 and 2023 a total of 198 patients (aged 66.4 ± 13.4 years, 76% male, 48% ischemic) were included. Most patients (95.4%) underwent left ventricular (LV) mapping and/or ablation, which was conducted via transseptal route in 54.5% (n = 103), via retrograde aortic route in 43.4% (n = 82), and using a combined approach in 2.1% (n = 4). Two-thirds of patients had a cardiac device, including a biventricular device in 15%; 2 patients had a LV assist device, and 1 patient had a mechanical aortic valve prosthesis. The mean total procedural time was 211 ± 70 minutes, and the total radiofrequency time was 30 ± 22 minutes. During a follow-up period of 22 ± 18 months, the freedom from VT recurrence was 80%, and 7.6% of patients underwent a repeated ablation. Procedural-related complications occurred in 6 patients (3.0%). CONCLUSIONS: Fluoroless ablation of VT in structural heart disease is feasible, effective, and safe when epicardial mapping/ablation is not required.

The External Auditory Canal: Examination and Evaluation.

The external auditory canal is a highly specialized skin appendage whose primary purpose is to provide a pathway for the transmission of sound to the tympanic membrane and beyond. It is also a frequent source of symptoms for our patients. Sources of pain, hearing loss, tinnitus, itching, and other sensations can be inferred from an appropriate history. This should be followed by a thorough cleaning of the ear, so that a thorough examination can be performed.

Deductive Electrocardiographic Analysis of Left Ventricular Summit Arrhythmias.

The left ventricular summit is a source of idiopathic ventricular arrhythmias and presents distinct challenges for mapping and ablation. These arrhythmias are typically targeted from the distal coronary venous system or most often from endocardial vantage points such as the left coronary cusp, basal left ventricle or septal right ventricular outflow tract. In this article, we review the electrocardiographic patterns that suggest a possible origin from the left ventricular summit and the features that may help to predict the most likely site of successful ablation.

Follow the Wax: The Natural Protection of the Ear Canal and Its Biome.

The external canal is a unique environment that has an elaborate mechanism for self-cleaning and protection. The fundamental basis of this is the epithelial migration of the desquamating layers of the keratinizing epithelium that lines the entire canal and ear drum. This migratory movement results in a "conveyor belt" effect where the dead skin is moved out of the bony ear canal to the cartilaginous portion, where it is lifted off with the help of glandular skin secretions and the hairs of the canal to form what we call "ear wax." The ear wax has numerous protective properties and is essential to the health of the external ear. The protective properties are due to chemical properties of the wax, in addition to intrinsic chemical secretions by the sebaceous and cerumen apocrine glands. The protection also comes from a diverse population of organisms that exist in the external ear that are usually saprophytic, commensal, and symbiotic, but in some cases, they can become parasitic and pathologic. Detection and quantification of the members of this biome has been difficult, and their overall role in the normal biome of the ear and their transition into pathogens remain an area of active research and investigation.

Fungal Infections of the External Auditory Canal and Emerging Pathogens.

Fungal infections of the external auditory canal can range from common (otomycosis) to life threatening (necrotizing otitis externa). Proper identification of fungal pathogens is necessary to guide appropriate therapy, and a high index of suspicion for fungal causes of ear canal disease is critical. Fungal pathogens may be an especially important cause of ear canal disease in certain populations, including patients with diabetes, patients recently treated with antibiotics, and immunosuppressed patients. Opportunistic fungal infections of the ear canal are an emerging concern.