There are differences in conformation of LAA surrounding structures with variable healing response between WM and ACP after LAA closure in the canine model. WM does not obstruct or impact the LAA adjacent structures, resulting in a favorable surface recovery. In comparison, the disk of ACP could potentially jeopardize LAA neighboring structures and leads to delayed healing.

AimThe aim of this study was to evaluate the haemodynamic correlates of heart sound (HS) parameters such as third HS (S3), first HS (S1), and HS‐based systolic time intervals (HSTIs) from an implantable cardiac device.Methods and resultsTwo unique animal models (10 swine with myocardial ischaemia and 11 canines with pulmonary oedema) were used to evaluate haemodynamic correlates of S1, S3, and HSTIs, namely, HS‐based pre‐ejection period (HSPEP), HS‐based ejection time (HSET), and the ratio HSPEP/HSET during acute haemodynamic perturbations. The HS was measured using implanted cardiac resynchronization therapy defibrillator devices simultaneously with haemodynamic references such as left atrial (LA) pressure and left ventricular (LV) pressure. In the ischaemia model, S1 amplitude (r = 0.76 ± 0.038; P = 0.002), HSPEP (r = −0.56 ± 0.07; P = 0.002), and HSPEP/HSET (r = −0.42 ± 0.1; P = 0.002) were significantly correlated with LV dP/dtmax. In contrast, HSET was poorly correlated with LV dP/dtmax (r = 0.14 ± 0.14; P = 0.23). In the oedema model, a physiological delayed response was observed in S3 amplitude after acute haemodynamic perturbations. After adjusting for the delay, S3 amplitude significantly correlated with LA pressure in individual animals (r = 0.71 ± 0.07; max: 0.92; min: 0.17) as well as in aggregate (r = 0.62; P < 0.001). The S3 amplitude was able to detect elevated LA pressure, defined as >25 mmHg, with a sensitivity = 58% and specificity = 90%.ConclusionsThe HS parameters such as S1, S3, and HSTIs measured using implantable devices significantly correlated with haemodynamic changes in acute animal models, suggesting potential utility for remote heart failure patient monitoring.

BackgroundCanine veterinary patients increasingly benefit from implantation of transvenous pacemakers for bradyarrhythmias. No published data exist examining procedural outcomes of pacemaker implantation performed in the preclinical laboratory. The purpose was to review short term complication, infection, dislodgement, penetration rates, plus overall morbidity following pacemaker implantation in the research setting. A retrospective review of 74 Class A purpose-bred mongrels implanted with active (n = 89) and passive fixation (n = 57) intracardiac leads for dual (n = 72) or single (n = 2) chamber pacing was performed.ResultsAll leads were implanted successfully, meeting electrical implant criteria. Follow-ups typically occurred every 7 days (first month), then at 30 day intervals. Seroma formation was 1.4% and 10.8% at the venotomy and pulse generator site respectively. Overall infection rate was 1.4%. Overall dislodgement rate was 2.1%, (2 passive atrial leads, 1 passive ventricular lead). Overall fractures and insulation defects were zero. Two helix penetrations were noted incidentally post mortem, one at the right atrial appendage and one at the right ventricle (64 dogs, 128 leads evaluated), a 1.6% event rate. Major in-life adverse events were 5.4% (4 of 74 dogs), including 1 infection and 3 lead dislodgements.ConclusionsThis review demonstrates a low complication rate with bradycardia lead implants in the short term (up to 180 days), in a high volume research setting. Lead type, implant technique, surgeon experience, healthy patient population, patient size and follow-up care play a role. This review also suggests active fixation leads in the right atrial appendage of dogs are safe and reliable.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1431-2) contains supplementary material, which is available to authorized users.

201 Background: Despite treatment intensity escalation, the high local recurrence rate for esophageal cancer has frustrated clinicians for decades. Conventional High Dose Rate brachytherapy, particle therapies, and other sophisticated treatment methods are encouraging but often fiscally and/or biologically infeasible. Additionally, these technologies often burden patients with numerous hospital visits, decreasing patient quality of life. Very low dose-rate brachytherapy (vLDR), with sources emitting relatively low energy, can be more cost effective than conventional radiation treatments, particularly in underserved communities, and can replace many hospital visits with one procedure. The dose distribution advantages of vLDR are irrefutable, especially in regard to doses to other tissues. vLDR seeds are currently used regularly in the prostate and have been tested in several other anatomical sites with good safety results. In the present study, a radioactive(RA) stent platform was developed and tested to apply vLDR therapy to cancers of the gastrointestinal (GI) system. Methods: Monte Carlo simulations were used to guide design of a RA esophageal stent. A design was chosen that minimized surface dose variation while using commercially available RA seeds. RA stents loaded with 60 -125 Seed-in Carrier, GE Healthcare were endoscopically placed in the naïve esophagus of 3 Yucatan swine. Previously, mock treatments using dummy seeds were performed in three similar pigs. Stents were left in place for between 4 and 7 weeks and reaction of the mucosa was assessed macroscopically and histologically. Results: Porcine esophageal tissue received doses in the range of 132-160 Gy at the mucosal surface and 39-48 Gy at a distance of 5mm from the stent surface. Tissues were collected at 0, 1 and 10 weeks after stent removal. No macroscopic radiation damage was seen at autopsy and pathological analysis yielded no radiation-related damage in evaluable tissues. Conclusions: In this preliminary study, no local or systemic damage due to radiation was observed after treatment of normal esophageal tissue with a vLDR stent device. Ongoing research aims to determine dose tolerance in esophageal tissue and target application of vLDR in other locations in the GI tract.

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