[Reversibility of a critical intraventricular conduction delay under flecainide and lacosamide by sodium bicarbonate]. / Reversibilität einer kritischen intraventrikulären Leitungsverzögerung unter Flecainid und Lacosamid durch Natriumbicarbonat.

The case of a 72-year-old female patient with arrhythmogenic syncope associated with a combination therapy of flecainide and lacosamide is presented. The authors believe in an additive effect of both drugs on myocardial voltage-gated sodium channels with extraordinary QRS widening, exit block with temporary pacing and complete reversibility through infusion of sodium bicarbonate as bail-out therapy.

Use of machine learning and Poincaré density grid in the diagnosis of sinus node dysfunction caused by sinoatrial conduction block in dogs.

BACKGROUND: Sinus node dysfunction because of abnormal impulse generation or sinoatrial conduction block causes bradycardia that can be difficult to differentiate from high parasympathetic/low sympathetic modulation (HP/LSM). HYPOTHESIS: Beat-to-beat relationships of sinus node dysfunction are quantifiably distinguishable by Poincaré plots, machine learning, and 3-dimensional density grid analysis. Moreover, computer modeling establishes sinoatrial conduction block as a mechanism. ANIMALS: Three groups of dogs were studied with a diagnosis of: (1) balanced autonomic modulation (n = 26), (2) HP/LSM (n = 26), and (3) sinus node dysfunction (n = 21). METHODS: Heart rate parameters and Poincaré plot data were determined [median (25%-75%)]. Recordings were randomly assigned to training or testing. Supervised machine learning of the training data was evaluated with the testing data. The computer model included impulse rate, exit block probability, and HP/LSM. RESULTS: Confusion matrices illustrated the effectiveness in diagnosing by both machine learning and Poincaré density grid. Sinus pauses >2 s differentiated (P < .0001) HP/LSM (2340; 583-3947 s) from sinus node dysfunction (8503; 7078-10 050 s), but average heart rate did not. The shortest linear intervals were longer with sinus node dysfunction (315; 278-323 ms) vs HP/LSM (260; 251-292 ms; P = .008), but the longest linear intervals were shorter with sinus node dysfunction (620; 565-698 ms) vs HP/LSM (843; 799-888 ms; P < .0001). CONCLUSIONS: Number and duration of pauses, not heart rate, differentiated sinus node dysfunction from HP/LSM. Machine learning and Poincaré density grid can accurately identify sinus node dysfunction. Computer modeling supports sinoatrial conduction block as a mechanism of sinus node dysfunction.

The Utility of Predictive Modeling and a Systems Process Approach to Reduce Emergency Department Crowding: A Position Paper.

Emergency department (ED) crowding and its main causes, exit block and boarding, continue to threaten the quality and safety of ED care. Most interventions to reduce crowding have not been comprehensive or system solutions, only focusing on part of the care procession and not directly affecting boarding reduction. This position paper proposes that the ED crowding problem can be optimally addressed by applying a systems approach using predictive modeling to identify patients at risk of being admitted to the hospital and uses that information to initiate the time-consuming bed management process earlier in the care continuum, shortening the time during which patients wait in the ED for an inpatient bed assignment, thus removing the exit block that causes boarding and subsequently reducing crowding.

The Minimum Number of Ablation Lines for Complete Isolation of the Pulmonary Veins during Thoracoscopic Ablation for Atrial Fibrillation.

Total thoracoscopic ablation has been recommended as a class IIa indication for atrial fibrillation. However, the optimal number of ablation lines for pulmonary vein isolation has not yet been proposed. This study aimed to report the minimum number of ablation lines required to achieve an intraoperative conduction block. This study included a total of 20 patients who underwent total thoracoscopic ablation from December 2020 to July 2021. The epicardial conduction block was checked after each ablation line of pulmonary vein antral clamping. The median age was 61 years old. The median duration of atrial fibrillation since the first diagnosis was 78 months. Pulmonary vein isolation with bidirectional conduction block was confirmed in 90% of patients. A median of six ablation lines around each pulmonary vein antrum were performed according to our protocol even after the conduction block was verified. The median number of ablations to achieve an exit block was two on the right side and 3.5 on the left side. We found that most conduction blocks were achieved within three ablations around the pulmonary vein antrum. Our results may provide evidence to reduce the number of unnecessary ablation lines in the future.

Effects of process changes on emergency department crowding in a changing world: an interrupted time-series analysis.

BACKGROUND: During a 6-year period, several process changes were introduced at the emergency department (ED) to decrease crowding, such as the implementation of a general practitioner cooperative (GPC) and additional medical staff during peak hours. In this study, we assessed the effects of these process changes on three crowding measures: patients' length of stay (LOS), the modified National ED OverCrowding Score (mNEDOCS), and exit block while taking into account changing external circumstances, such as the COVID-19 pandemic and centralization of acute care. METHODS: We determined time points of the various interventions and external circumstances and built an interrupted time-series (ITS) model per outcome measure. We analyzed changes in level and trend before and after the selected time points using ARIMA modeling, to account for autocorrelation in the outcome measures. RESULTS: Longer patients' ED LOS was associated with more inpatient admissions and more urgent patients. The mNEDOCS decreased with the integration of the GPC and the expansion of the ED to 34 beds and increased with the closure of a neighboring ED and ICU. More exit blocks occurred when more patients with shortness of breath and more patients > 70 years of age presented to the ED. During the severe influenza wave of 2018-2019, patients' ED LOS and the number of exit blocks increased. CONCLUSIONS: In the ongoing battle against ED crowding, it is pivotal to understand the effect of interventions, corrected for changing circumstances and patient and visit characteristics. In our ED, interventions which were associated with decreased crowding measures included the expansion of the ED with more beds and the integration of the GPC on the ED.

Revisiting exit block after entrance block: Investigation of ablation index-guided pulmonary vein isolation.

INTRODUCTION: Unidirectional block, left atrium to pulmonary vein (LA-PV) entrance block without PV-LA exit block, has not been fully investigated in the setting of ablation index (AI)-guided pulmonary vein (PV) isolation (PVI). The aim of this study was to investigate unidirectional blocks during AI-guided PVI. METHODS: After achieving entrance block, exit block was evaluated by pacing from the catheter placed in the PV. Local PV musculature capture without conduction to the LA was necessary to prove exit block. RESULTS: In total, 441 PVs (including nine left common PVs) from 113 consecutive patients (mean age: 71 ± 12 years, 77 men, 61 paroxysmal atrial fibrillation cases) who underwent initial AI-guided PVI for atrial fibrillation were studied. Entrance block was achieved in all PVs. of the 247/441 (56%) PVs showing local PV musculature capture, 5/247 (2.0%) showed unidirectional blocks. Three of the five PVs (left superior and inferior PVs in one patient; right superior PV in another patient) showed LA-PV reconnection, requiring additional ablation to achieve bidirectional block during the procedure. Two of the five PVs (left superior and inferior PVs in one patient) showed LA-PV reconnection, and thereafter, LA-PV conduction became blocked again spontaneously, leading to bidirectional block without further ablation during the procedure. CONCLUSION: AI-guided PVI presented a low prevalence of unidirectional block (2%), using entrance block alone as the endpoint of PVI could therefore be justified.

Impact of high frequency stimulation to confirm a complete box isolation in catheter ablation of non-paroxysmal atrial fibrillation.

INTRODUCTION: Pulmonary vein (PV) isolation (PVI) including the left atrial posterior wall (LAPW) (Box-PVI) is proposed as an additional strategy for non-paroxysmal atrial fibrillation (NPAF), however, the efficacy remains controversial. The more reliable and durable the Box-PVI we can create, the better the rhythm outcomes might be than with a conventional PVI alone. This study focused on the potential exit conduction of the box lesion and investigated whether the conventional Box-PVI would be sufficient. METHODS AND RESULTS: We enrolled 350 consecutive patients with NPAF that underwent a conventional encircling Box-PVI and examined whether latent exit conduction and dormant "exit" conduction independently remained on the LAPW and in the PVs using high frequency stimulation (HFS) and an adenosine triphosphate (ATP) injection. All electrograms inside the box lesion were eliminated in all cases, however, HFS inside the box propagated outward in 23 cases (6.6%) without any exit conduction by conventional burst stimulation, and 24 cases (6.9%) exhibited only dormant "exit" conduction of the LAPW. Additional ablation where positive HFSs were observed created a complete bidirectional Box-PVI in 43 (41.3%) of the cases without a first pass Box-PVI. The recurrence rates depended on the groups classified according to the HFS response. CONCLUSION: HFS delivered with an ATP injection on the LAPW and in the PVs following a Box-PVI could not only elucidate true exit block but also identified possible incomplete lesions or connections outside the ablation line, whose elimination could achieve a complete Box-PVI leading to a better rhythm outcome.

Resolution of Symptomatic Intermittent Sinoatrial Exit Block Associated With Unstable Angina Following Percutaneous Coronary Intervention.

Bradyarrhythmia commonly occurs because of degenerative fibrosis in the conductive system. Ischemic disease is a rare etiology and limited cases have demonstrated direct evidence of ischemia to the sinus node vessels. We report a 62-year-old Hispanic male with a significant medical history of diabetes mellitus type II (DM II), hypertension, and dyslipidemia who was admitted to our hospital for symptomatic sinoatrial (SA) exit block. Patient had no electrolyte abnormalities and our differential included ischemic vs. fibrotic or infiltrative pathologies, giving symptomatic bradycardia, cardiac chest pain, and high-risk factors for coronary artery disease. We decided to take him for cardiac catheterization which revealed sluggish, pulsatile flow into the SA nodal artery due to severe stenosis of the ostial right coronary along with sever distal left circumflex (LCX) lesion. The flow into the sinus nodal artery (SNA) markedly improved post percutaneous coronary intervention (PCI) of the right coronary artery (RCA) and distal LCX and restoration of flow into SNA. Resolution of his bradyarrhythmia and symptoms post intervention confirmed our suspicious for reversible ischemic sinus node dysfunctions. Therefore, ischemic pathologies should be thought of when other common etiologies are less likely. Coronary angiogram should be considered prior to pacemaker evaluation in these setting to avoid missing reversible causes of bradyarrhythmia.

Validation of a multipolar pulsed-field ablation catheter for endpoint assessment in pulmonary vein isolation procedures.

AIMS: To validate the performance of a multipolar pulsed-field ablation (PFA) catheter compared to a standard pentaspline 3D-mapping catheter for endpoint assessment of pulmonary vein isolation (PVI). PFA for PVI using single-shot devices combines the benefits of high procedural efficacy and safety. A newly available multipolar PFA catheter allows real-time recording of pulmonary vein (PV) signals during PVI. METHODS AND RESULTS: Patients undergoing first PVI using PFA with the standard ablation protocol (eight applications per PV) were studied. Entrance and exit block (10 V/2 ms) were assessed using the PFA catheter. Subsequently, a high-density 3D electroanatomical bipolar voltage map (3D-EAM) was constructed using a standard pentaspline 3D-mapping catheter. Additional PFA applications were delivered only after confirmation of residual PV connection by 3D-EAM. In 56 patients, 213 PVs were targeted for ablation. Acute PVI was achieved in 100% of PVs: in 199/213 (93%) PVs with the standard ablation protocol alone and in the remaining 14 PVs after additional PFA applications. The accuracy of PV assessment with the PFA catheter after the standard ablation protocol was 91% (194/213 veins). In 5/213 (2.3%) PVs, the PFA catheter incorrectly indicated PV-isolation. In 14/213 (6.6%), the PFA catheter incorrectly indicated residual PV-conduction due to high-output pace-capture. Lowering the output to 5 V/1 ms reduced this observation to 0.9% (2/213) and increased the overall accuracy to 97% (206/213). CONCLUSION: A novel multipolar PFA catheter allows reliable endpoint assessment for PVI. Due to its design, far-field sensing and high-output pace-capture can occur. Lowering the pacing output increases the accuracy from 91 to 97%.

An Epicardial Connection With a Unidirectional Conduction Property From the Left Atrium to Pulmonary Vein.

The presence of an epicardial connection between the left-sided pulmonary vein and left atrium was suggested during catheter ablation of atrial fibrillation because of sustainable unidirectional entrance conduction after complete endocardial ablation, centrifugal breakout deep inside the pulmonary vein, and immediate elimination of the conduction by point ablation. (Level of Difficulty: Advanced.).

Lyme carditis manifesting with sinoatrial exit block: a case report.

BACKGROUND: Lyme disease is the most common vector-borne disease in North America and Europe. Infection with the spirochete Borrelia burgdorferi complex can involve cardiac tissue causing Lyme carditis (LC). Due to the infection of conductive tissue, LC typically presents with varying degrees of atrioventricular conduction block. Here, we provide the first evidence that conductive tissue of the sinus node can be involved in LC resulting in higher degree sinoatrial (SA) block with concomitant syncope. CASE SUMMARY: We report the case of an otherwise healthy 31-year-old female presenting with LC manifesting with SA exit block causing asystole over 12 s with concomitant syncope. Signs of SA block completely resolved with antibiotic treatment with a third-generation cephalosporin. The patient did not require permanent pacemaker implantation and had no sinus pauses after 12 months of follow-up as confirmed via implantable loop recorder. CONCLUSION: The possibility of LC in patients with sinus node dysfunction should be considered, as adequate antibiotic therapy can spare patients from potentially unnecessary pacemaker implantation.

How the coronavirus disease 2019 pandemic changed the patterns of healthcare utilization by geriatric patients and the crowding: a call to action for effective solutions to the access block.

The geriatric population constitutes a large slice of the population of Western countries and a class of fragile patients, with greater deaths due to COVID-19. The patterns of healthcare utilization change during pandemic disease outbreaks. Identifying the patterns of changes of this particular fragile subpopulation is important for future preparedness and response. Overcrowding in the emergency department (ED) can occur because of the volume of patients waiting to be seen, delays in patient assessment or treatment in the ED, or impediments to leaving the ED once the treatment has been completed. Overcrowding has become a serious and growing issue globally, which represents a serious impediment to healthcare utilization. To estimate the rate of ED visits attributable to the outbreak and guide the planning of strategies for managing ED access or after the outbreak of transmittable respiratory diseases. This observational study was based on a retrospective review of the epidemiological and clinical records of patients aged > 75 years who visited the Foundation IRCCS Policlinic San Matteo during the first wave of COVID-19 outbreak (February 21 to May 1, 2020; pandemic group). The analysis methods included estimation of the changes in the epidemiological and clinical data from the annual baseline data after the start of the COVID-19 pandemic. Outcome measures and analysis: Primary objective is the evaluation of ED admission rate change and ED overcrowding. Secondary objectives are the evaluation of modes of ED access by reason and triage code, access types, clinical outcomes (such as admission and mortality rates). During the pandemic, ED crowding increased dramatically, although the overall number of patients decreased, in the face of a percentage increase in those with high-acuity conditions, because of changes in patient management that have prolonged length of stay (LOS) and increased rates of access block. Overcrowding during the COVID-19 pandemic can be attributed to the Access Block. Access Block solutions are hence required to prevent a recurrence of crowding to any new viral wave or new epidemic in the future.

Reducing Crowding in Emergency Departments With Early Prediction of Hospital Admission of Adult Patients Using Biomarkers Collected at Triage: Retrospective Cohort Study.

BACKGROUND: Emergency department crowding continues to threaten patient safety and cause poor patient outcomes. Prior models designed to predict hospital admission have had biases. Predictive models that successfully estimate the probability of patient hospital admission would be useful in reducing or preventing emergency department "boarding" and hospital "exit block" and would reduce emergency department crowding by initiating earlier hospital admission and avoiding protracted bed procurement processes. OBJECTIVE: To develop a model to predict imminent adult patient hospital admission from the emergency department early in the patient visit by utilizing existing clinical descriptors (ie, patient biomarkers) that are routinely collected at triage and captured in the hospital's electronic medical records. Biomarkers are advantageous for modeling due to their early and routine collection at triage; instantaneous availability; standardized definition, measurement, and interpretation; and their freedom from the confines of patient histories (ie, they are not affected by inaccurate patient reports on medical history, unavailable reports, or delayed report retrieval). METHODS: This retrospective cohort study evaluated 1 year of consecutive data events among adult patients admitted to the emergency department and developed an algorithm that predicted which patients would require imminent hospital admission. Eight predictor variables were evaluated for their roles in the outcome of the patient emergency department visit. Logistic regression was used to model the study data. RESULTS: The 8-predictor model included the following biomarkers: age, systolic blood pressure, diastolic blood pressure, heart rate, respiration rate, temperature, gender, and acuity level. The model used these biomarkers to identify emergency department patients who required hospital admission. Our model performed well, with good agreement between observed and predicted admissions, indicating a well-fitting and well-calibrated model that showed good ability to discriminate between patients who would and would not be admitted. CONCLUSIONS: This prediction model based on primary data identified emergency department patients with an increased risk of hospital admission. This actionable information can be used to improve patient care and hospital operations, especially by reducing emergency department crowding by looking ahead to predict which patients are likely to be admitted following triage, thereby providing needed information to initiate the complex admission and bed assignment processes much earlier in the care continuum.

Models Predicting Hospital Admission of Adult Patients Utilizing Prehospital Data: Systematic Review Using PROBAST and CHARMS.

BACKGROUND: Emergency department boarding and hospital exit block are primary causes of emergency department crowding and have been conclusively associated with poor patient outcomes and major threats to patient safety. Boarding occurs when a patient is delayed or blocked from transitioning out of the emergency department because of dysfunctional transition or bed assignment processes. Predictive models for estimating the probability of an occurrence of this type could be useful in reducing or preventing emergency department boarding and hospital exit block, to reduce emergency department crowding. OBJECTIVE: The aim of this study was to identify and appraise the predictive performance, predictor utility, model application, and model utility of hospital admission prediction models that utilized prehospital, adult patient data and aimed to address emergency department crowding. METHODS: We searched multiple databases for studies, from inception to September 30, 2019, that evaluated models predicting adult patients' imminent hospital admission, with prehospital patient data and regression analysis. We used PROBAST (Prediction Model Risk of Bias Assessment Tool) and CHARMS (Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modeling Studies) to critically assess studies. RESULTS: Potential biases were found in most studies, which suggested that each model's predictive performance required further investigation. We found that select prehospital patient data contribute to the identification of patients requiring hospital admission. Biomarker predictors may add superior value and advantages to models. It is, however, important to note that no models had been integrated with an information system or workflow, operated independently as electronic devices, or operated in real time within the care environment. Several models could be used at the site-of-care in real time without digital devices, which would make them suitable for low-technology or no-electricity environments. CONCLUSIONS: There is incredible potential for prehospital admission prediction models to improve patient care and hospital operations. Patient data can be utilized to act as predictors and as data-driven, actionable tools to identify patients likely to require imminent hospital admission and reduce patient boarding and crowding in emergency departments. Prediction models can be used to justify earlier patient admission and care, to lower morbidity and mortality, and models that utilize biomarker predictors offer additional advantages.

The Association between Discharge Delay from Intensive Care and Patient Outcomes.

Rationale: ICU discharge delay occurs when a patient is considered ready to be discharged but remains in the ICU. The effect of discharge delay on patient outcomes is uncertain.Objectives: To investigate the association between discharge delay and patient outcomes including hospital mortality, readmission to ICU, and length of hospital stay after ICU discharge.Methods: Data were accessed from the Australian and New Zealand Intensive Care Society Adult Patient Database between 2011 and 2019. Descriptive analyses and hierarchical logistic and Cox proportional hazards regression were used to examine association between discharge delay and adjusted outcomes. Patients were stratified and analyzed by categories of mortality risk at ICU admission.Measurements and Main Results: The study included 1,014,540 patients from 190 ICUs: 756,131 (75%) were discharged within 6 hours of being deemed ready, with 137,042 (13%) discharged in the next 6 hours; 17,656 (2%) were delayed 48-72 hours; 31,389 (3.1%) died in hospital; and 45,899 (4.5%) patients were readmitted to ICU. Risk-adjusted mortality declined with increasing discharge delay and was lowest at 48-72 hours (adjusted odds ratio, 0.87; 95% confidence interval, 0.79-0.94). The effect was seen in patients with predicted risk of death on admission to ICU of greater than 5% (adjusted odds ratio, 0.77; 95% confidence interval, 0.70-0.84). There was a progressive reduction in adjusted odds of readmission with increasing discharge delay.Conclusions: Increasing discharge delay in ICUs is associated with reduced likelihood of mortality and ICU readmission in high-risk patients. Consideration should be given to delay the discharge of patients with high risk of death on ICU admission.