Personalized subcutaneous implantable cardioverter-defibrillator sensing vectors generated by mathematical rotation increase device eligibility whilst preserving device performance.

AIMS: Approximately 5.7% of potential subcutaneous implantable cardioverter-defibrillator (S-ICD) recipients are ineligible by virtue of their vector morphology, with higher rates of ineligibility observed in some at-risk groups. Mathematical vector rotation is a novel technique that can generate a personalized sensing vector, one with maximal R:T ratio, using electrocardiogram (ECG) signal recorded from the present S-ICD location. METHODS AND RESULTS: A cohort of S-ICD ineligible patients were identified through ECG screening of ICD patients with no ventricular pacing requirement and their personalized vectors were generated using ECG signal from a Holter monitor. Subcutaneous ICD eligibility in this cohort was then recalculated. In a separate cohort, episodes of arrhythmia were recorded in patients undergoing arrhythmia induction, and arrhythmia detection in standard S-ICD vectors was compared to rotated vectors using an S-ICD simulator. Ninety-two participants (mean age 64.9 ± 2.7 years) underwent screening and 5.4% were found to be S-ICD ineligible. Personalized vector generation increased the R:T ratio in these vectors from 2.21 to 7.21 (4.54-9.88, P < 0.001) increasing the cohort eligibility from 94.6% to 100%. Rotated S-ICD vectors also showed high ventricular fibrillation (VF) detection sensitivity (97.8%), low time to VF detection (6.1 s), and excellent tachycardia discrimination (sensitivity 96%, specificity 88%), with no significant differences between rotated and standard vectors. CONCLUSION: In S-ICD ineligible patients, mathematical vector rotation can generate a personalized vector that is associated with a significant increase in R:T ratio, resulting in universal device eligibility in our cohort. Ventricular fibrillation detection efficacy, time to VF detection, and tachycardia discrimination were not affected by vector rotation.

Chitosan-based agent use for hemostasis after cryptorchidectomy in a horse.

OBJECTIVE: To document marked hemorrhage as a complication of inguinal cryptorchidectomy and its successful treatment with a novel chitosan-based hemostatic agent. STUDY DESIGN: Case report. ANIMALS: One healthy 5-year old quarter horse cryptorchid. METHODS: The horse was presented for routine unilateral cryptorchidectomy after prior hemicastration. An inguinal approach was made to the abdomen, and the right external pudendal artery was lacerated at the level of the internal inguinal ring, requiring multiple anesthetic events over a 2-week period in attempts to control hemorrhage. A chitosan-based hemostatic agent was packed into the wound to gain control. RESULTS: Chitosan granules placed in the wound successfully controlled the hemorrhage, whereas the use of gauze packing alone failed. There were no immediate or long-term complications to the chitosan granules; the horse was doing well 18 months postoperatively, and the client was satisfied with the outcome. CONCLUSION: Major hemorrhage was demonstrated from the external pudendal artery and caused difficulties because it occurred deep within the inguinal canal during an inguinal cryptorchidectomy. A chitosan-based hemostatic agent was successfully used to achieve hemostasis. CLINICAL SIGNIFICANCE: The external pudendal artery should be avoided in the medial commissure of the inguinal canal. The use of chitosan-based hemostatic agents warrants further investigation in horses because these products may be useful for controlling major hemorrhage from various causes in equine practice.

Sacrococcygeal luxation and complete tail amputation following a tail pull injury in a horse.

A 17-year-old Quarter horse mare was presented because of traumatic luxation of the fifth sacral and first coccygeal vertebrae resulting in loss of sensation, motor function, and perfusion of the tail. The case was complicated by an associated tail head hematoma. Due to the severity of the injury, tail amputation was performed at the level of the luxation. Tail amputations in horses at the sacrococcygeal junction following a suspected tail pull injury are infrequently reported in the literature.

Luxation sacrococcygienne et amputation complète de la queue à la suite d'une blessure par traction de la queue chez un cheval. Une jument Quarter horse âgée de 17 ans fut présentée pour cause de luxation traumatique de la cinquième vertèbre sacrée et de la première vertèbre coccygienne résultant en une perte de sensation, de fonction moteur, et de perfusion de la queue. Le cas était compliqué par l'association d'un hématome de la tête de la queue. Compte tenu de la sévérité de la blessure, l'amputation de la queue fut effectuée au site de la luxation. Les amputations de la queue chez les chevaux à la jonction sacrococcygienne à la suite d'une blessure suspectée causée par traction de la queue ne sont rapportées que peu fréquemment dans la littérature.(Traduit par Dr Serge Messier).

Increasing age does not affect time to appropriate therapy in primary prevention ICD/CRT-D: a competing risks analysis.

Aims: To evaluate the impact of age on the clinical outcomes in a primary prevention implantable cardioverter defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) population. Methods and Results: A retrospective, multicentre analysis of patients aged 60 years and over with primary prevention ICD/CRT-D devices implanted between 1 January 2006 and 1 November 2014 was performed. Survival to follow-up with no therapy (T1), death prior to follow-up with no therapy (T2), delivery of appropriate therapy with survival to follow-up (T3), and delivery of appropriate therapy with death prior to follow-up (T4) were measured. In total, 424 patients were eligible for inclusion in the analysis, mean follow-up of 32.6 months during which time 44 patients (10.1%) received appropriate therapy. The sub-hazard ratio (SHR) for the cumulative incidence of appropriate therapy (T3) according to age at implant was 1.00 (P = 0.851; 95% CI 0.96­1.04). The SHR for cumulative incidence of death (T2) according to age at implant was 1.06 (P < 0.001; 95% CI 1.03­1.01). Age at implant, ischaemic aetiology, baseline haemoglobin, and the presence of diabetes mellitus were predictors of all-cause mortality. Conclusion: Age has no impact on the time to appropriate therapy, but risk of death prior to therapy increases by 6% for every year increment. As the ICD population ages, the proportion who die without receiving appropriate therapy increases due to competing risks. Characterizing competing risks predictive of death independent of ICD indication would focus therapy on those with potential to benefit and reduce unnecessary exposure to ICD-related morbidity.

Left and Right Parasternal Sensing for the S-ICD in Adult Congenital Heart Disease Patients and Normal Controls.

BACKGROUND: This study investigated the impact of a right parasternal sensing electrode position on the R- and T-wave amplitudes and the R:T ratio in three subcutaneous implantable cardioverter defibrillator (S-ICD) vectors in patients with adult congenital heart disease (ACHD) and normal controls. METHODS: Conventional left parasternal sensing electrode position and right parasternal sensing electrode positions were used to collect 10-second electrograms, recorded through an 80-electrode body surface mapping technology (Prime ECG™ system, Heartscape Technologies Inc., now Verathon, Columbia, MD, USA). Recordings were made in the supine, prone, left lateral, right lateral, sitting, and standing positions in using both the standard electrode vector position and the right parasternal positions. RESULTS: Forty patients were recruited and 37 patients were used for analysis. Twenty-seven (73%) had complex ACHD; 10 patients had normal hearts and acted as controls. A total of 3,708 data points were analyzed. There were no significant differences in the R:T ratio when measured in ACHD patients in the right compared to the left parasternal lead position. In contrast, there were important differences in the magnitude of the R:T ratio when measured in control patients in the right compared to the left parasternal lead position; in the primary vector, the R:T ratio was greater in right than left by 2.99 (P = 0.0002; 95% confidence interval [CI]: 1.48-4.50) and in the secondary vector, the R:T ratio was smaller in the right than in the left by 0.77 (P = 0.004; 95% CI: -1.58-0.05). CONCLUSION: In selected patients, a right parasternal lead position may provide a useful alternative sensing configuration for the S-ICD.

Quality of Adhesions After Sutured Paramedian vs. Laparoscopic Toggle Abomasopexy in an Ovine Model.

OBJECTIVE: To evaluate adhesions created by abomasopexies using either chromic gut or polydioxanone suture through a right paramedian approach and determine whether a laparoscopic toggle technique is an acceptable alternative to open abomasopexy using an ovine model. STUDY DESIGN: Experimental study. ANIMALS: Mature ewes (n=30). METHODS: Ewes received 1 of 3 abomasopexy techniques (n=10): right paramedian approach using chromic gut or polydioxanone, or a laparoscopic toggle technique. After euthanasia 8 weeks postoperatively, adhesions were removed en bloc and adhesion cross-sectional area (width × length) and depth (distance from abdominal wall to abomasum) were measured and given a grade of 0-3 based on the quality of adhesion. Surgical time was recorded and compared for each technique. Significance was set at P≤.05. RESULTS: Abomasopexies performed with either suture material resulted in a significantly larger mean cross-sectional area and higher adhesion grades compared to those performed using the toggle. Width and length of adhesions formed using chromic gut or polydioxanone were not significantly different; however, both were significantly wider and longer than those formed using the toggle. The laparoscopic toggle technique required significantly less surgical time than the sutured techniques. CONCLUSION: Polydioxanone is as effective as chromic gut suture material in inducing abomasal adhesion formation in our sheep model. The clinical significance of the size and grade of adhesions formed is unknown and requires further investigation before the laparoscopic toggle technique can be recommended as a replacement for paramedian abomasopexy in cattle for the treatment of displaced abomasum.

Occurrence of Incisional Complications After Closure of Equine Celiotomies With USP 7 Polydioxanone.

OBJECTIVES: To report the occurrence of, and risk factors associated with, incisional complications of equine ventral median celiotomies closed with USP 7 polydioxanone (7PD). STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Horses (n = 73; 75 celiotomies). METHODS: Medical records (2000-2010) were retrieved and reviewed for horses that had a ventral celiotomy closed with 7PD and survived ≥14 days. Follow-up (>1 year) was obtained from the medical record, owner, or referring veterinarian. Independent variables were selected based on risk factors identified in previous studies, perceived clinical relevance, and if there were adequate data recorded in the medical record. Statistical analysis, including multivariable logistic regression with a forward-building model process, was performed to evaluate variables associated with incisional complications. RESULTS: One or more incisional complication(s) occurred in 19 celiotomies (25.3%) during hospitalization or after discharge including: drainage (25.3%), infection (12.0%), and partial dehiscence (5.3%). Two of 63 horses (3.2%) available for follow-up developed an incisional hernia. Variables associated with incisional complications after multivariate analysis included: number of days hospitalized, surgery time, postoperative colic, and postoperative fever. CONCLUSION: Overall occurrence of incisional herniation after closure of ventral celiotomies with 7PD was low.

Ex vivo comparison of 7 polydioxanone, 2 polyglactin 910 for closure of ventral median celiotomy in horses.

OBJECTIVE: To compare bursting strength and failure mode between ventral median celiotomies closed with USP 7 braided polydioxanone (7PD) or USP 2 polyglactin 910 (2PG). STUDY DESIGN: Ex vivo experimental. ANIMALS: Equine cadavers (n = 10). METHODS: A 25 cm ventral median celiotomy was created in fresh equine cadavers. A 200 L polyurethane bladder was inserted into the abdomen. Celiotomies were closed in a simple continuous pattern with 2 sections of 7PD or 2PG. The bladder was inflated with compressed air until construct failure. The horses' signalment, body weight, suture type, failure mode (suture or abdominal wall), and bursting strength (mmHg) were recorded. Interactions between independent and dependent variables were assessed with statistical tests including linear regression. RESULTS: Failure mode was significantly different by suture type (P = .01). Four of 5 celiotomies closed with 2PG failed at the suture; whereas, 0 celiotomies closed with 7PD failed at the suture. In celiotomies closed with 7PD, increasing age was highly and negatively correlated with bursting strength (r = -0.99). When the effect of age was controlled, 7PD had a significantly higher bursting strength than 2PG (P = .024). CONCLUSION: 7PD has a higher bursting strength compared with 2PG. Suture failure was the main failure mode for 2PG; whereas, all celiotomies closed with 7PD failed at the abdominal wall.

Ex vivo comparison of bursting strength of ventral median and right ventral paramedian celiotomies in horses.

OBJECTIVE: To compare bursting strength and failure mode between ventral median (VM) and right ventral paramedian (RVP) celiotomies closed with 1 section of USP 7 braided polydioxanone (7PD). STUDY DESIGN: Ex vivo experimental. ANIMALS: Equine cadavers (n = 12). METHODS: A 25 cm VM or RVP (positioned 5 cm lateral to the linea alba) celiotomy was created in fresh equine cadavers. A 200 L polyurethane bladder was inserted into the abdomen. Celiotomies were closed in a simple continuous pattern with 1 section of 7PD. The bladder was inflated with compressed air until construct failure. Horse signalment, body weight, celiotomy type, failure mode (suture or abdominal wall), failure location (adjacent or remote from the celiotomy), and bursting strength (mmHg) were recorded. Interactions between independent and dependent variables were assessed with statistical tests including linear regression. RESULTS: Increasing age (P = .002) and Quarter horse-type breed (P = .01) had a negative effect on bursting strength. When age and breed were controlled, RVP celiotomies had a lower bursting strength compared with VM celiotomies (P = .039). None of the celiotomies failed at the suture. CONCLUSION: VM celiotomies have a greater bursting strength than RVP celiotomies when age and breed are controlled. Celiotomy bursting strength decreases with increasing age and is lower in Quarter horse-type breeds compared with non-Quarter horse-type breeds.

Laminar epidermal hyperplasia and hyperkeratosis in an equine hoof.

A 6-year-old Canadian Warmblood gelding was presented for suspicion of keratoma growth, based on a history of recurring abscesses in the right front foot. Radiographic examination and computed tomography identified 2 bilaterally symmetrical, laminar epidermal ingrowths adhered to the hoof wall at the level of the lateral and medial heels.

Hyperplasie épidermique laminaire et hyperkératose dans un sabot équin. Un hongre Canadian Warmblood âgé de 6 ans a été présenté en raison de soupçons relativement à la croissance de kératomes, basés sur des antécédents d'abcès récurrents dans le pied avant droit. Un examen radiographique et une tomodensitométrie ont identifié 2 tissus épidermiques laminaires bilatéralement symétriques qui adhéraient à la paroi du sabot au niveau des talons latéraux et médiaux.(Traduit par Isabelle Vallières).

Computational fluid dynamic analysis of upper airway procedures in equine larynges.

Introduction: Computational fluid dynamics (CFD) has proven useful in the planning of upper airway surgery in humans, where it is used to anticipate the influence of the surgical procedures on post-operative airflow. This technology has only been reported twice in an equine model, with a limited scope of airflow mechanics situations examined. The reported study sought to widen this application to the variety of procedures used to treat equine recurrent laryngeal neuropathy (RLN). The first objective of this study was to generate a CFD model of an ex-vivo box model of ten different equine larynges replicating RLN and four therapeutic surgeries to compare the calculated impedance between these procedures for each larynx. The second objective was to determine the accuracy between a CFD model and measured airflow characteristics in equine larynges. The last objective was to explore the anatomic distribution of changes in pressure, velocity, and turbulent kinetic energy associated with the disease (RLN) and each surgical procedure performed. Methods: Ten equine cadaveric larynges underwent inhalation airflow testing in an instrumented box while undergoing a concurrent computed tomographic (CT) exam. The pressure upstream and downstream (outlet) were measured simultaneously. CT image segmentation was performed to generate stereolithography files, which underwent CFD analysis using the experimentally measured outlet pressure. The ranked procedural order and calculated laryngeal impedance were compared to the experimentally obtained values. Results and discussion: The CFD model agreed with the measured results in predicting the procedure resulting in the lowest post-operative impedance in 9/10 larynges. Numerically, the CFD calculated laryngeal impedance was approximately 0.7 times that of the measured calculation. Low pressure and high velocity were observed around regions of tissue protrusion within the lumen of the larynx. RLN, the corniculectomy and partial arytenoidectomy surgical procedures exhibited low pressure troughs and high velocity peaks compared to the laryngoplasty and combined laryngoplasty/corniculectomy procedures. CFD modeling of the equine larynx reliably calculated the lowest impedance of the different surgical procedures. Future development of the CFD technique to this application may improve numerical accuracy and is recommended prior to consideration for use in patients.

A biomechanical comparison of a novel two-loop suture technique and two sutures for laryngoplasty in the horse.

OBJECTIVES: Evaluation of the strength of the novel suture technique by comparison with a 2-interrupted suture technique. SAMPLE: 40 equine larynges. PROCEDURES: 40 larynges were used; 16 laryngoplasties were performed using the currently accepted 2-suture technique and 16 using the novel suture technique. These specimens were subjected to a single cycle to failure. Eight specimens were used to compare the rima glottidis area achieved with 2 different techniques. RESULTS: The mean force to failure, as well as the rima glottidis area of both constructs, were not significantly different. The cricoid width did not have a significant effect on the force to failure. CLINICAL RELEVANCE: Our results suggest that both constructs are equally strong and can achieve a similar cross-sectional area of the rima glottidis. Laryngoplasty ("tie-back") is currently the treatment of choice for horses with exercise intolerance due to recurrent laryngeal neuropathy. Failure to maintain the expected degree of arytenoid abduction post-surgery occurs in some horses. We believe this novel 2-loop pulley load-sharing suture technique can help achieve and, more importantly, maintain the desired degree of abduction during surgery.

Investigation of a progressive facial deformity and stridor in an adult horse with a bone sequestrum and subsequent sinonasal abscess.

Advanced diagnostic imaging and histopathological investigation were performed in an adult horse with chronic facial swelling due to a bone sequestrum and abscessation. In contrast to other cases, there were no draining tracts, difficulty eating, weight loss, head shaking, or fistula formation between the oral cavity and the maxillary sinus.

Computed tomographic geometrical analysis of surgical treatments for equine recurrent laryngeal neuropathy.

OBJECTIVES: To characterize the 3-D geometry of the equine larynx replicating laryngeal hemiplegia and 4 surgical interventions by use of CT under steady-state airflow conditions. Secondly, to use fluid mechanic principles of flow through a constriction to establish the relationship between measured airflow geometries with impedance for each surgical procedure. SAMPLE: 10 cadaveric horse larynges. PROCEDURES: While CT scans were performed, inhalation during exercise conditions was replicated for each of the following 5 conditions: laryngeal hemiplegia, left laryngoplasty with ventriculocordectomy, left laryngoplasty with ipsilateral ventriculocordectomy and arytenoid corniculectomy, corniculectomy, and partial arytenoidectomy for each larynx while CT scans were performed. Laryngeal impedance was calculated, and selected cross-sectional areas were measured along each larynx for each test. Measured areas and constriction characteristics were analyzed with respect to impedance using a multilevel, mixed-effects model. RESULTS: Incident angle, entrance coefficient, outlet coefficient, friction coefficient, orifice thickness, and surgical procedure were significantly associated with upper airway impedance in the bivariable model. The multivariate model showed a significant influence of incident angle, entrance coefficient, and surgical procedure on impedance; however, the orifice thickness became nonsignificant within the model. CLINICAL RELEVANCE: Laryngeal impedance was significantly associated with the entrance configuration for each procedure. This suggested that the equine upper airway, despite having a highly complex geometry, adheres to fluid dynamic principles applying to constrictions within pipe flow. These underlying flow characteristics may explain the clinical outcomes observed in some patients, and lead to areas of improvement in the treatment of obstructive upper airway disease in horses.

Evaluation of ethyl alcohol for use in a minimally invasive technique for equine proximal interphalangeal joint arthrodesis.

OBJECTIVE: To determine whether intra-articular 70% ethyl alcohol alone (IAEA) or in combination with 2 percutaneously placed transarticular lag screws (EA-TLS) would result in arthrodesis of the equine proximal interphalangeal (PIP) joint. STUDY DESIGN: Experimental. ANIMALS: Healthy horses (n=6), aged 1.5-3 years, free of lameness, diagonally paired front and hind PIP joints. METHODS: Six milliliters 70% ethyl alcohol was injected into randomly selected diagonally paired front and hind PIP joints. Thirty days later, 2 parallel 5.5 mm cortical screws were inserted in lag fashion across the hind PIP joints and the limbs were cast. Horses were confined for 60 days after surgery before free exercise was permitted. Serial lameness examinations were performed at 1, 6, and 10 months. Radiographs of the PIP joints were obtained before injection with alcohol (front, hind PIP joints), at 6 and 10 months (front PIP joints) and 1, 3, 6, and 10 months (hind PIP joints). At 10 months, horses were euthanatized and gross and histopathologic examination of the treated joints was performed. RESULTS: Horses had variable cartilage thinning (more severe in hind PIP joints) and dorsal bone proliferation. One front and 1 hind PIP joint were fused 10 months after alcohol injection. CONCLUSIONS: Ethyl alcohol injected alone or in combination with percutaneously placed transarticular lag screws failed to reliably produce fusion of the PIP joint.

Pain during cardiac implantable electronic device implantation.

In order to evaluate the extent and causes of pain during cardiac implantable electronic device (CIED) implantation in our hospital, a prospective audit over a 23-month period using a patient selfreporting questionnaire was undertaken. In total, 599 procedures were reported, 52.9% for de novo pacemaker implantation and 23.4% for high-energy devices (cardiac resynchronisation therapy defibrillator [CRT-D], implantable cardiac defibrillator [ICD], subcutaneous ICD). Overall, the median pain score was 2/10 (interquartile range 2-4). In total, 61.6% (367/599) reported no pain or mild pain (pain scores 0-3/10), 27.7% (165/599) reported moderate pain (pain score of 4-6/10) and 10.7% (64/599) reported severe pain (pain score of 7-10/10) during the procedure. Significant preimplant worry (odds ratio [OR] 2.13, 95% confidence interval [CI] 1.22 to 3.73) and higher lidocaine doses (OR 1.06, 95%CI 1.00 to 1.11) were associated with severe patient-reported pain. In conclusion, most patients underwent CIED implantation with minimum stress and maximum comfort. An important minority reported severe pain during the procedure. Optimising surgical technique and interventions targeted at reducing pre- and peri-implant worry, particularly in women, and especially in those receiving ICDs, warrants further investigation to reduce patient-reported pain during CIED implantation.

Crystal structures of phosphine-supported (η5-cyclo-penta-dien-yl)molybdenum(II) propionyl complexes.

Three cyclo-penta-dienylmolybdenum(II) propionyl complexes featuring tri-aryl-phosphine ligands with different para substituents, namely, dicarbon-yl(η5-cyclo-penta-dien-yl)propion-yl(tri-phenyl-phosphane-κP)molybdenum(II), [Mo(C5H5)(C3H5O)(C18H15P)(CO)2], (1), dicarbon-yl(η5-cyclo-penta-dien-yl)propion-yl[tris-(4-fluoro-phen-yl)phosphane-κP]molybdenum(II), [Mo(C5H5)(C3H5O)(C18H12F3P)(CO)2], (2), and dicarbon-yl(η5-cyclo-penta-dien-yl)propion-yl[tris-(4-meth-oxy-phen-yl)phosphane-κP]molybdenum(II) dichloromethane solvate, [Mo(C5H5)(C3H5O)(C21H21O3P)(CO)2]·CH2Cl2, (3), have been prepared from the corresponding ethyl complexes via phosphine-induced migratory insertion. These complexes exhibit four-legged piano-stool geom-etries with mol-ecular structures quite similar to each other and to related acetyl complexes. The extended structures of the three complexes differ somewhat, with the para substituent of the tri-aryl-phosphine of (2) (fluoro) or (3) (meth-oxy) engaging in non-classical C-H⋯F or C-H⋯O hydrogen-bonding inter-actions. The structure of (3) exhibits modest disorder in the position of one Cl atom of the di-chloro-methane solvent, which was modeled with two sites showing approximately equivalent occupancies [0.532 (15) and 0.478 (15)].