A Modular Communicative Leadless Pacing-Defibrillator System.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (ICD) is associated with fewer lead-related complications than a transvenous ICD; however, the subcutaneous ICD cannot provide bradycardia and antitachycardia pacing. Whether a modular pacing-defibrillator system comprising a leadless pacemaker in wireless communication with a subcutaneous ICD to provide antitachycardia and bradycardia pacing is safe remains unknown. METHODS: We conducted a multinational, single-group study that enrolled patients at risk for sudden death from ventricular arrhythmias and followed them for 6 months after implantation of a modular pacemaker-defibrillator system. The safety end point was freedom from leadless pacemaker-related major complications, evaluated against a performance goal of 86%. The two primary performance end points were successful communication between the pacemaker and the ICD (performance goal, 88%) and a pacing threshold of up to 2.0 V at a 0.4-msec pulse width (performance goal, 80%). RESULTS: We enrolled 293 patients, 162 of whom were in the 6-month end-point cohort and 151 of whom completed the 6-month follow-up period. The mean age of the patients was 60 years, 16.7% were women, and the mean (±SD) left ventricular ejection fraction was 33.1±12.6%. The percentage of patients who were free from leadless pacemaker-related major complications was 97.5%, which exceeded the prespecified performance goal. Wireless-device communication was successful in 98.8% of communication tests, which exceeded the prespecified goal. Of 151 patients, 147 (97.4%) had pacing thresholds of 2.0 V or less, which exceeded the prespecified goal. The percentage of episodes of arrhythmia that were successfully terminated by antitachycardia pacing was 61.3%, and there were no episodes for which antitachycardia pacing was not delivered owing to communication failure. Of 162 patients, 8 died (4.9%); none of the deaths were deemed to be related to arrhythmias or the implantation procedure. CONCLUSIONS: The leadless pacemaker in wireless communication with a subcutaneous ICD exceeded performance goals for freedom from major complications related to the leadless pacemaker, for communication between the leadless pacemaker and subcutaneous ICD, and for the percentage of patients with a pacing threshold up to 2.0 V at a 0.4-msec pulse width at 6 months. (Funded by Boston Scientific; MODULAR ATP ClinicalTrials.gov NCT04798768.).

Efficacy and Safety of an Extravascular Implantable Cardioverter-Defibrillator.

BACKGROUND: The extravascular implantable cardioverter-defibrillator (ICD) has a single lead implanted substernally to enable pause-prevention pacing, antitachycardia pacing, and defibrillation energy similar to that of transvenous ICDs. The safety and efficacy of extravascular ICDs are not yet known. METHODS: We conducted a prospective, single-group, nonrandomized, premarket global clinical study involving patients with a class I or IIa indication for an ICD, all of whom received an extravascular ICD system. The primary efficacy end point was successful defibrillation at implantation. The efficacy objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients with successful defibrillation was greater than 88%. The primary safety end point was freedom from major system- or procedure-related complications at 6 months. The safety objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients free from such complications was greater than 79%. RESULTS: A total of 356 patients were enrolled, 316 of whom had an implantation attempt. Among the 302 patients in whom ventricular arrhythmia could be induced and who completed the defibrillation testing protocol, the percentage of patients with successful defibrillation was 98.7% (lower boundary of the one-sided 97.5% confidence interval [CI], 96.6%; P<0.001 for the comparison with the performance goal of 88%); 299 of 316 patients (94.6%) were discharged with a working ICD system. The Kaplan-Meier estimate of the percentage of patients free from major system- or procedure-related complications at 6 months was 92.6% (lower boundary of the one-sided 97.5% CI, 89.0%; P<0.001 for the comparison with the performance goal of 79%). No major intraprocedural complications were reported. At 6 months, 25 major complications were observed, in 23 of 316 patients (7.3%). The success rate of antitachycardia pacing, as assessed with generalized estimating equations, was 50.8% (95% CI, 23.3 to 77.8). A total of 29 patients received 118 inappropriate shocks for 81 arrhythmic episodes. Eight systems were explanted without extravascular ICD replacement over the 10.6-month mean follow-up period. CONCLUSIONS: In this prospective global study, we found that extravascular ICDs were implanted safely and were able to detect and terminate induced ventricular arrhythmias at the time of implantation. (Funded by Medtronic; ClinicalTrials.gov number, NCT04060680.).

The clinical and economic impact of extended battery longevity of a substernal extravascular implantable cardioverter defibrillator.

INTRODUCTION: The extravascular implantable cardioverter defibrillator (EV ICD) has extended projected battery longevity compared to the subcutaneous implantable cardioverter defibrillator (S-ICD). This study used modeling to characterize the need for generator changes, long-term complications, and overall costs for both the EV ICD and S-ICD in healthcare systems of various countries. METHODS: Battery longevity data were modeled using a Markov model from averages reported in device labeling for the S-ICD and with engineering estimates based on real life usage from EV ICD Pivotal Study patient data to introduce variability. Clinical demographic data were derived from published literature. The primary outcomes were defined as the number of generator replacement surgeries, complications, and total healthcare system costs due to battery depletion over the expected lifetime of patients receiving EV ICD or S-ICD therapy. RESULTS: Average modeled battery longevity was determined to be 7.3 years for the S-ICD versus 11.8 years for the EV ICD. The probability of a complication after a replacement procedure was 1.4%, with an operative mortality rate of 0.02%. The use of EV ICD was associated with 1.4-1.6 fewer replacements on average over an expected patient lifetime as compared to S-ICD and a 24.3%-26.0% reduction in cost. A one-way sensitivity analysis of the model for the US healthcare system found that use of an EV ICD resulted in a reduction in replacement surgeries of greater than 1 (1.1-1.6) along with five-figure cost savings in all scenarios ($18 602-$40 948). CONCLUSION: The longer projected battery life of the EV ICD has the potential to meaningfully reduce long-term morbidity and healthcare resources related to generator changes from the perspective of multiple diverse healthcare systems.

Longitudinal QTc stability and impact of baseline cardiac rhythm on discharge dose in dofetilide-treated patients.

INTRODUCTION: Dofetilide suppresses atrial fibrillation (AF) in a dose-dependent fashion. The protective effect of AF against QTc prolongation induced torsades de pointe and transient post-cardioversion QTc prolongation may result in dofetilide under-dosing during initiation. Thus, the optimal timing of cardioversion for AF patients undergoing dofetilide initiation to optimize discharge dose remains unknown as does the longitudinal stability of QTc . The purpose of this study was to evaluate the impact of baseline rhythm on dofetilide dosing during initiation and assess the longitudinal stability of QTc-all (Bazzett, Fridericia, Framingham, and Hodges) over time. METHODS: Medical records of patients who underwent preplanned dofetilide loading at a tertiary care center between January 2016 and 2019 were reviewed. RESULTS: A total of 198 patients (66 ± 10 years, 32% female, CHADS2 -Vasc 3 [2-4]) presented for dofetilide loading in either AF (59%) or sinus rhythm (SR) (41%). Neither presenting rhythm, nor spontaneous conversion to SR impacted discharge dose. The cumulative dofetilide dose before cardioversion moderately correlated (r = .36; p = .0001) with discharge dose. Postcardioversion QTc-all prolongation (p < .0001) prompted discharge dose reduction (890 ± 224 mcg vs. 552 ± 199 mcg; p < .0001) in 30% patients. QTc-all in SR prolonged significantly during loading (p < .0001). All patients displayed QTc-all reduction (p < .0001) from discharge to short-term (46 [34-65] days) that continued at long-term (360 [296-414] days) follow-ups. The extent of QTc-all reduction over time moderately correlated with discharge QTc-all (r = .54-0.65; p < .0001). CONCLUSION: Dofetilide initiation before cardioversion is equivalent to initiation during SR. Significant QTc reduction proportional to discharge QTc is seen over time in all dofetilide-treated patients. QTc returns to preloading baseline during follow-up in patients initiated in SR.

Evaluation of a program for outpatient sotalol loading with physician and pharmacist monitoring.

BACKGROUND: Dose-dependent QT prolongation with class III antiarrhythmics mandates close monitoring often in an inpatient setting. Outpatient sotalol loading monitor provides an alternative to patients that is cost effective and allows preservation of hospital resources. OBJECTIVES: The objectives for this study include assessing adverse events, assessing patient adherence to monitoring and follow-up, comparing hospital cost and resource utilization, and evaluating patient satisfaction with outpatient sotalol loading program. PRACTICE DESCRIPTION: One pharmacist in the antiarrhythmic clinic at OhioHealth Riverside Methodist Hospital completed 3-day outpatient sotalol loads under a collaborative practice agreement. Clinic services included pharmacotherapy management, medication counseling, and device education. PRACTICE INNOVATION: This service allows pharmacists to provide direct patient monitoring to provide increased patient access. EVALUATION METHODS: All data were collected via the electronic medical record, patient journal documentation, and a patient satisfaction survey. RESULTS: A total of 12 patients completed outpatient sotalol loading; 10 patients started in normal sinus rhythm, and 1 patient was cardioverted during the load. No patients experienced any adverse events during the loading phase. One patient completed a successful dose increase during the loading phase. All 12 patients attended the first visit, completed baseline laboratory tests, and uploaded electrocardiograms for all 3 days. A total of 11 patients were evaluated as a cost comparison for inpatient sotalol loading. On average, outpatient loading cost was $886.30, in comparison with $7571.76 for inpatient loading (P < 0.001). A total of 10 patients completed the satisfaction survey, and all of the patients preferred to complete this in the outpatient setting. CONCLUSION: In this study, 12 patients safely completed outpatient sotalol loading, with an overall decrease in the cost of their care in comparison with inpatient loading. This study showed that pharmacists can serve as physician extenders to continue to provide high-quality and safe care to patients in the antiarrhythmic space.

Cell-associated type I collagen in nondegenerate and degenerate human articular cartilage.

Chondrocytes with abnormal morphology are present in nondegenerate human cartilage suggesting dedifferentiation to a fibroblastic phenotype and production of a mechanically-weakened matrix of unknown composition. We determined the relationship between in situ chondrocyte morphology, chondrocyte clusters, and levels of cell-associated collagen type I. Chondrocyte morphology in fresh femoral head cartilage from 19 patients with femoral neck fracture and collagen type I labelling was identified with Cell TrackerTM fluorescence and immunofluorescence, respectively, in axial/coronal orientations using confocal microscopy with images analysed by ImarisTM . In axial images of grade 0 cartilage, 87 ± 8% were normal chondrocytes with a small (10 ± 6%) abnormal population possessing ≥1 cytoplasmic process. More normal chondrocytes (78 ± 11%) were collagen type I negative than those labelling positively (p < 0.001). For abnormal chondrocytes, 81 ± 14% labelled negatively for collagen type I compared to those labelling positively (19 ± 3%; p = 0.007; N(n)=11(3)). Overall, approximately 9% of the cells in normal cartilage labelled for collagen type I. With degeneration, the percentage of normal chondrocytes decreased (p < 0.001) but increased for abnormal cells (p = 0.036) and clusters (p = 0.003). A larger percentage of normal, abnormal and clustered chondrocytes now demonstrated collagen type I labelling (p = 0.004; p = 0.009; p = 0.001 respectively). Coronal images exhibited increased (p = 0.001) collagen type I labelling in the superficial zone of mildly degenerate cartilage with none in the mid or deep zones. These results show that collagen type I was identified around normal and abnormal chondrocytes in nondegenerate cartilage, which increased with degeneration. This suggested the presence of mechanically weak fibro-cartilaginous repair tissue in otherwise macroscopically nondegenerate human cartilage which progressed with degeneration as occurs in osteoarthritis.

Editorial Commentary: Raising the Osmolarity of Arthroscopic Irrigating Solutions May Be Chondroprotective: We Must Be Kind to Joints During Arthroscopy!

The irrigation of joints during arthroscopic procedures typically uses a non-physiological solution. This replaces the natural synovial fluid and rapidly subjects the connective tissues to an alien hypo-osmotic environment in which cartilage cells are far more sensitive to iatrogenic injury. Raising the osmolarity of the irrigating solution may be a simple, safe, and effective chondroprotective strategy.

Conditional deletion of E11/podoplanin in bone protects against load-induced osteoarthritis.

BACKGROUND: Subchondral bone (SCB) thickening is one of the earliest detectable changes in osteoarthritic joints and is considered a potential trigger for subsequent articular cartilage degeneration. In this manuscript, we examine whether disruption to the SCB osteocyte network contributes to the initiation and pathogenesis of osteoarthritis. METHODS: We examined expression patterns of the glycoprotein E11/podoplanin by immunohistochemical labelling in murine, human and canine osteoarthritis models. We also examined the effects of twice-weekly administration of Bortezomib, a proteasome inhibitor which stabilises osteocyte E11 levels, to C57/BL6 wild-type male mice (1 mg/kg/day) for 8 weeks after surgical destabilisation of the medial meniscus. By inducing osteoarthritis-like changes in the right knee joint of 12-week-old male E11 hypomorphic mice (and corresponding controls) using a post-traumatic joint loading model, we also investigated whether a bone-specific E11 deletion in mice increases joint vulnerability to osteoarthritis. Articular cartilage degradation and osteophyte formation were assessed by histology and in line with the OARSI grading system. RESULTS: Our studies reveal increased E11 expression in osteocytes of human and canine osteoarthritic SCB. We found that Bortezomib administration had no effect on surgically-induced osteoarthritis, potentially due to a lack of the expected stabilisation of E11 in the SCB. We also found, in concordance with our previous work, wild-type mice exhibited significant load-induced articular cartilage lesions on the lateral femoral condyle (p < 0.01) and osteophyte formation. In contrast, E11 hypomorphic mice did not develop osteophytes or any corresponding articular lesions. CONCLUSIONS: Overall, these data suggest that an intact osteocyte network in the SCB contributes to the development of mechanically-driven osteoarthritis. Further, the data presented here indicate that the molecular pathways that preserve the osteocyte network, such as those driven by E11, may be targeted to limit osteoarthritis pathogenesis.

The clustering and morphology of chondrocytes in normal and mildly degenerate human femoral head cartilage studied by confocal laser scanning microscopy.

Chondrocytes are the major cell type present in hyaline cartilage and they play a crucial role in maintaining the mechanical resilience of the tissue through a balance of the synthesis and breakdown of extracellular matrix macromolecules. Histological assessment of cartilage suggests that articular chondrocytes in situ typically occur singly and demonstrate a rounded/elliptical morphology. However, there are suggestions that their grouping and fine shape is more complex and that these change with cartilage degeneration as occurs in osteoarthritis. In the present study we have used confocal laser scanning microscopy and fluorescently labelled in situ human chondrocytes and advanced imaging software to visualise chondrocyte clustering and detailed morphology within grade-0 (non-degenerate) and grade-1 (mildly degenerate) cartilage from human femoral heads. Graded human cartilage explants were incubated with 5-chloromethylfluorescein diacetate and propidium iodide to identify the morphology and viability, respectively, of in situ chondrocytes within superficial, mid- and deep zones. In grade-0 cartilage, the analysis of confocal microscope images showed that although the majority of chondrocytes were single and morphologically normal, clusters (i.e. three or more chondrocytes within the enclosed lacunar space) were occasionally observed in the superficial zone, and 15-25% of the cell population exhibited at least one cytoplasmic process of ~ 5 µm in length. With degeneration, cluster number increased (~ 50%) but not significantly; however, the number of cells/cluster (P < 0.001) and the percentage of cells forming clusters increased (P = 0.0013). In the superficial zone but not the mid- or deep zones, the volume of clusters and average volume of chondrocytes in clusters increased (P < 0.001 and P < 0.05, respectively). The percentage of chondrocytes with processes, the number of processes/cell and the length of processes/cell increased in the superficial zone of grade-1 cartilage (P = 0.0098, P = 0.02 and P < 0.001, respectively). Processes were categorised based on length (L0 - no cytoplasmic processes; L1 < 5 µm; 5 < L2 ≤ 10 µm; 10 < L3 ≤ 15 µm; L4 > 15 µm). With cartilage degeneration, for chondrocytes in all zones, there was a significant decrease (P = 0.015) in the percentage of chondrocytes with 'normal' morphology (i.e. L0), with no change in the percentage of cells with L1 processes; however, there were significant increases in the other categories. In grade-0 cartilage, chondrocyte clustering and morphological abnormalities occurred and with degeneration these were exacerbated, particularly in the superficial zone. Chondrocyte clustering and abnormal morphology are associated with aberrant matrix metabolism, suggesting that these early changes to chondrocyte properties may be associated with cartilage degeneration.

Minimally invasive calcaneal osteotomy: A cadaveric and clinical evaluation.

BACKGROUND: A cadaveric and clinical study was performed to assess whether a minimally invasive technique is a potentially safer alternative compared to a calcaneal osteotomy through an open lateral approach. METHODS: Cadaveric: A minimally invasive calcaneal osteotomy (MICO) was performed on nine cadaveric specimens. These were examined to identify any nerve injury and to quantify the displacement achieved with the osteotomy. Clinical: A retrospective review of a sequential case series of medializing MICO's performed by the senior author between October 2011 and November 2014 was undertaken. RESULTS: Cadaveric: Neurological structures remained uninjured in all specimens. The distance of the sural nerve and the main trunk of the tibial nerve to the superior limb of the oblique osteotomy was 6.2±4.8mm (range 0-14mm) and 7.3±3.6mm (range 4-12mm), respectively. The mean coronal shift achieved was 16.7±3.4mm (range 12-21mm). Clinical: The senior author carried out 35 medializing MICO procedures. Radiological and clinical union occurred in all 35 cases (100%). There were no neurovascular or wound complications. CONCLUSION: Minimally invasive calcaneal osteotomy offers a safe alternative to an open procedure with promising clinical results.

Comparative evaluation of clinical performance of different kind of occlusal splint in management of myofascial pain.

PURPOSE: To determine the efficacy of hard, liquid, and soft splints in the management of myofascial pain dysfunction syndrome. MATERIALS AND METHODS: In this randomized clinical trial, 45 patients with myofascial pain were diagnosed and were randomly assigned into three groups of 15 patients each. Group 1 - subjects were given hard splint, Group 2 - soft splint, and Group 3 - liquid oral splint for 3 months. Subjective pain analysis using Modified Symptom Severity Index (Mod-SSI) and objective pain analysis muscle palpation was performed at 7 days, 1 month, 2 months, and 3 months after splint insertion. The changes in mean pain value by both methods, in all three groups, were analyzed with Tukey test and Kruskal-Wallis H-test, respectively (P < 0.05). RESULTS: Both Mod-SSI and palpation scores showed statistically significant reduction in pain for all three groups at the end of 3 months. However, the hard splints proved to be very effective in a shorter period of time, followed by liquid splints and finally soft splints. CONCLUSION: The result of this study advocates the use of any one of the three types of the occlusal splints in the therapeutic management of myofascial pain due to temporomandibular disorders.

Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial.

Clinical outcomes of catheter ablation for atrial fibrillation (AF) are suboptimal due, in part, to challenges in achieving durable lesions. Although focal point-by-point ablation allows for the creation of any required lesion set, this strategy necessitates the generation of contiguous lesions without gaps. A large-tip catheter, capable of creating wide-footprint ablation lesions, may increase ablation effectiveness and efficiency. In a randomized, single-blind, non-inferiority trial, 420 patients with persistent AF underwent ablation using a large-tip catheter with dual pulsed field and radiofrequency energies versus ablation using a conventional radiofrequency ablation system. The primary composite effectiveness endpoint was evaluated through 1 year and included freedom from acute procedural failure and repeat ablation at any time, plus arrhythmia recurrence, drug initiation or escalation or cardioversion after a 3-month blanking period. The primary safety endpoint was freedom from a composite of serious procedure-related or device-related adverse events. The primary effectiveness endpoint was observed for 73.8% and 65.8% of patients in the investigational and control arms, respectively (P < 0.0001 for non-inferiority). Major procedural or device-related complications occurred in three patients in the investigational arm and in two patients in the control arm (P < 0.0001 for non-inferiority). In a secondary analysis, procedural times were shorter in the investigational arm as compared to the control arm (P < 0.0001). These results demonstrate non-inferior safety and effectiveness of the dual-energy catheter for the treatment of persistent AF. Future large-scale studies are needed to gather real-world evidence on the impact of the focal dual-energy lattice catheter on the broader population of patients with AF. ClinicalTrials.gov identifier: NCT05120193 .

Management of Lisfranc Injuries: A Critical Analysis Review.

¼: There is a spectrum of midtarsal injuries, ranging from mild midfoot sprains to complex Lisfranc fracture-dislocations. ¼: Use of appropriate imaging can reduce patient morbidity, by reducing the number of missed diagnoses and, conversely, avoiding overtreatment. Weight-bearing radiographs are of great value when investigating the so-called subtle Lisfranc injury. ¼: Regardless of the operative strategy, anatomical reduction and stable fixation is a prerequisite for a satisfactory outcome in the management of displaced injuries. ¼: Fixation device removal is less frequently reported after primary arthrodesis compared with open reduction and internal fixation based on 6 published meta-analyses. However, the indications for further surgery are often unclear, and the evidence of the included studies is of typically low quality. Further high-quality prospective randomized trials with robust cost-effectiveness analyses are required in this area. ¼: We have proposed an investigation and treatment algorithm based on the current literature and clinical experience of our trauma center.

Relationship between Surpoint Tag Index, a Radiofrequency Ablation lesion quality indicator, and Atrial wall thickness in Cavotricuspid isthmus Ablations exhibiting bidirectional block.

BACKGROUND: An RFA lesion quality indicator, Surpoint Tag Index® (TI) incorporates key factors: power, time, and contact force, impacting lesion quality. TI accurately estimates lesion depth in animal studies. However, the relationship between TI and in-vivo atrial wall thickness in patients exhibiting bidirectional block remains unknown. OBJECTIVE: To describe the relationship between atrial wall thickness and TI in CTI exhibiting bidirectional block. METHODS: Data from 492 RFA lesions from 25 patients undergoing PVI and CTI ablations in SR with point-by-point RF lesions (<45 W) utilizing a Thermocool Smarttouch® SF ablation catheter and CARTO-3 mapping were retrospectively analyzed. Operators were blinded to TI data and CTI thickness. CTI thickness was obtained using ICE images on Cartosound pre-ablation. Durable lesions were defined as part of a lesion set exhibiting bidirectional block of >30 min. RESULTS: In lesions exhibiting bidirectional block, the thinnest (1-2 mm; 5% lesions) and thickest (8-10 mm; 6% lesions) portions of the CTI correlated with the lowest (429 ± 75) and highest (516 ± 64) TI. The bulk of thickness (2-6 mm; 80%) correlated with a TI of 455 ± 72 (p = 0.001). There was a weak but positive correlation between TI and CTI thickness (r = 0.2; p ≤ 0.01). Examined in sectors, the anterior 1/3rd CTI was the thickest (4.8 ± 1.9 mm) but correlated with a similar TI value (479 ± 75 vs. 471 ± 70; p = 0.34) as the thinner middle 1/3rd (3.8 ± 1.7 mm; p ≤ 0.0001). CONCLUSION: A mean TI value of 455 correlates with bidirectional block across the bulk of CTI with lower and higher values needed for the thinner and thicker portions, respectively. Tissue composition, aside from wall thickness, influences TI values for the creation of the bidirectional block.

Impact of a dedicated atrial fibrillation clinic on diagnosis-to-ablation time.

Background: Outcomes following catheter ablation (CA) for atrial fibrillation (AF) improve as the diagnosis-to-ablation time (DAT) shortens. Use of a protocol-based integrated care model through a dedicated atrial fibrillation clinic (AFC) may serve to standardize treatment pathways and decrease DAT. Objective: To evaluate the DAT and clinical characteristics of patients with AF referred from an AFC vs a conventional electrophysiology clinic (EC). Methods: Retrospective analysis was completed in consecutive patients undergoing index AF ablation at Riverside Methodist Hospital in 2019 with minimum 1 year follow-up. Patients were categorized based off their CA referral source (AFC vs EC) and where the initial visit following index diagnosis of AF occurred (AFC vs EC). Results: A total of 182 patients (mean age 65 years, 64% male) were reviewed. Patients referred from an AFC (21%) had a median DAT of 342 days (interquartile range [IQR], 125-855 days) compared to patients referred from EC (79%) with a median DAT of 813 days (IQR, 241-1444 days; P = .01). Patients with their index visit following AF diagnosis occurring in the AFC (9%) had significantly shorter median DAT (127 days [IQR, 95-188 days]) compared to EC (91%) (789 days [IQR, 253-1503 days]; P = .002). Patients with DAT <1 year had lower AF recurrence than patients with DAT >1 year (P = .04, hazard ratio = 0.58, 95% confidence interval 0.3418-1.000). Conclusion: DAT is a modifiable factor that may affect CA outcomes. Significant reductions in DAT were observed in patients evaluated through a dedicated AF clinic.

Lead Macrodislodgement of a Subcutaneous Implantable Cardioverter-Defibrillator Results in a Reel Problem.

Lead macrodislodgement is a rare complication of cardiac implantable electronic devices associated with patient-related risk factors. This paper outlines a case of reel syndrome secondary to device manipulation 3 months after subcutaneous implantable cardioverter-defibrillator implantation and describes the challenges with lead macrodislodgement diagnosis, mechanisms, and management. (Level of Difficulty: Beginner.).

Hinge location and apical drill holes in opening wedge high tibial osteotomy: A finite element analysis.

At the time of medial opening wedge high tibial osteotomy (HTO) to realign the lower limb and offload medial compartment knee osteoarthritis, unwanted fractures can propagate from the osteotomy apex. The aim of this study was to use finite element (FE) analysis to determine the effect of hinge location and apical drill holes on cortical stresses and strains in HTO. A monoplanar medial opening wedge HTO was created above the tibial tuberosity in a composite tibia. Using the FE method, intact lateral hinges of different widths were considered (5, 7.5, and 10 mm). Additional apical drill holes (2, 4, and 6 mm diameters) were then incorporated into the 10 mm hinge model. The primary outcome measure was the maximum principal strain in the cortical bone surrounding the hinge axis. Secondary outcomes included the force required for osteotomy opening, minimum principal strain, and mean cortical bone stresses (maximum principal/minimum principal/von Mises). Larger intact hinges (10 mm) were associated with higher cortical bone maximum principal strain and stress, lower minimum principal strain/stress, and required greater force to open. Lateral cortex strain concentrations were present in all scenarios, but extended to the joint surface with the 10 mm hinge. Apical drill holes reduced the mean cortical bone maximum principal strain adjacent to the hinge axis: 2 mm hole 6% reduction; 4 mm 35% reduction; and 6 mm 55% reduction. Incorporating a 4-mm apical drill hole centered 10 mm from the intact lateral cortex maintains a cortical bone hinge, minimizes cortical bone strains and reduces the force required to open the HTO; thus improving control.

Optimization and Validation of a Human Ex Vivo Femoral Head Model for Preclinical Cartilage Research and Regenerative Therapies.

OBJECTIVE: Articular cartilage is incapable of effective repair following injury or during osteoarthritis. While there have been developments in cartilage repair technologies, there is a need to advance biologically relevant models for preclinical testing of biomaterial and regenerative therapies. This study describes conditions for the effective ex vivo culture of the whole human femoral head. DESIGN: Fresh, viable femoral heads were obtained from femoral neck fractures and cultured for up to 10 weeks in (a) Dulbecco's modified Eagle's medium (DMEM); (b) DMEM + mixing; (c) DMEM + 10% human serum (HS); (d) DMEM + 10% HS + mixing. The viability, morphology, volume, and density of fluorescently labelled in situ chondrocytes and cartilage surface roughness were assessed by confocal microscopy. Cartilage histology was studied for glycosaminoglycan content using Alcian blue and collagen content using picrosirius red. RESULTS: Chondrocyte viability remained at >95% in DMEM + 10% HS. In DMEM alone, viability remained high for ~4 weeks and then declined. For the other conditions, superficial zone chondrocyte viability fell to <35% at 10 weeks with deeper zones being relatively unaffected. In DMEM + 10% HS at 10 weeks, the number of chondrocytes possessing cytoplasmic processes increased compared with DMEM (P = 0.017). Alcian blue labeling decreased (P = 0.02) and cartilage thinned (P ≤ 0.05); however, there was no change to surface roughness, chondrocyte density, chondrocyte volume, or picrosirius red labeling (P > 0.05). CONCLUSIONS: In this ex vivo model, chondrocyte viability was maintained in human femoral heads for up to 10 weeks in culture, a novel finding not previously reported. This human model could prove invaluable for the exploration, development, and assessment of preclinical cartilage repair and regenerative therapies.

Percutaneous reduction and fixation of low energy Lisfranc injuries results in better outcome compared to open reduction and internal fixation: Results from a matched case-control study with minimum 12 months follow up.

BACKGROUND: Percutaneous fixation of Lisfranc injuries is potentially less invasive to traditional open techniques but evidence of any clinical benefit is lacking. The aim of this study is to compare the clinical outcomes of percutaneous reduction and internal fixation (PRIF) of low energy Lisfranc injuries with a matched, control group of patients treated with ORIF. METHODS: Over a seven-year period (2012-2019), 16 consecutive patients with a low energy Lisfranc injury (Myerson B2-type) were treated with PRIF. Patient demographics, injury mechanism and radiological outcomes were recorded within a prospectively maintained database at the institution. This study sample was matched for age, sex and mechanism of injury to a control group of 16 patients with similar low energy Lisfranc injuries (Myerson B2-type) treated with ORIF. Clinical outcome was compared using the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score and Manchester Oxford Foot Questionnaire (MOXFQ). RESULTS: At a mean follow up of 43 months (95% CI 35.6 - 50.4), both the AOFAS and MOXFQ scores were significantly higher in the PRIF group compared to the control ORIF group (AOFAS 89.1vs 76.4, p=0.03; MOXFQ 10.0 vs 27.6, p=0.03). There were no immediate postoperative complications in either group. There was no radiological evidence of midfoot osteoarthritis in the PRIF group, three patients in the ORIF group developed midfoot osteoarthritis (p=0.2). CONCLUSIONS: PRIF of low energy Lisfranc injures is a safe, minimally invasive technique and is associated with better mid-term clinical outcomes compared to ORIF.