Spontaneous rupture of the right aortic sinus resulting in a sterile aorto-atrial fistula in a pet rabbit (Oryctolagus cuniculus).

Aortocardiac fistula is a broad term used to describe defects between the aorta and other cardiac chambers that can occur in humans and animals. A 1.5-year-old, 1.7 kg, male castrated Holland lop rabbit (Oryctolagus cuniculus) was presented for a two-week history of a heart murmur with corresponding cardiomegaly on radiographs. Physical examination confirmed a grade-V/VI continuous heart murmur on the right sternal border with a regular rhythm and a gallop sound. Echocardiography revealed an aortic-to-right-atrial fistula causing severe left-sided volume overload. Based on the echocardiographic findings, rupture of the right aortic sinus was suspected. Due to the poor prognosis, euthanasia was elected. On necropsy, a fistula was found connecting the right aortic sinus with the right atrium, without evidence of an inflammatory response nor evidence of an infectious etiology. The sudden onset of a heart murmur supported acquired fistulation from a ruptured aortic sinus (also known as the sinus of Valsalva), though a congenital malformation could not be completely excluded.

Radiation dose during interventional cardiology procedures: portable C-arm vs. a new generation fluoroscopy system.

INTRODUCTION: Occupational exposure to ionizing radiation poses health risks for veterinary interventionalists. There are limited veterinary studies evaluating radiation dose in the cardiac catheterization laboratory. The purpose of this study was to report direct radiation dose exposure to patients during common interventional cardiology procedures and compare these doses between two fluoroscopy units. ANIMALS: One hundred and fifty-four client-owned dogs. MATERIALS AND METHODS: Patient dose during procedures using a portable C-arm were retrospectively analyzed and compared to those performed in a contemporary interventional suite. Fluoroscopy equipment, procedure type, operator, patient weight, fluoroscopy time, dose area product, and air kerma were recorded and statistically modeled using univariable and multivariable linear regression to evaluate the effect of each factor. RESULTS: Patient dose population (154 dogs), comprised 61 patent ductus arteriosus occlusions, 60 balloon pulmonary valvuloplasties, and 33 pacemaker implantations. Patient dose was significantly lower in the group utilizing a newer generation fluoroscopy unit vs. the group utilizing an older portable C-arm, positively correlated with patient weight, and highest during balloon pulmonary valvuloplasties compared to patent ductus arteriosus occlusions or pacemaker implantations (all P<0.010). DISCUSSION: Newer fluoroscopy systems can be equipped with technologies that improve image quality while reducing patient dose and radiation exposure to interventional personnel. CONCLUSIONS: We documented a significant reduction in patient radiation dose using a newer fluoroscopy system as compared to an older portable C-arm for interventional cardiology procedures in animals. Improved knowledge of patient radiation dose factors may promote better radiation safety protocols in veterinary interventional cardiology.

Transcatheter closure of aneurysmal perimembranous ventricular septal defect with the canine duct occluder in two dogs.

Congenital membranous ventricular septal aneurysm has been reported in dogs and can be associated with a perimembranous ventricular septal defect (VSD). The windsock-like ventricular septal aneurysm is formed by tissue of the membranous ventricular septum and portions of the septal leaflet of the tricuspid valve. We report two dogs that underwent transcatheter closure of perimembranous VSD associated with membranous ventricular septal aneurysm using a commercial device marketed for transcatheter closure of patent ductus arteriosus, the canine duct occluder. Partial closure was achieved in the first dog with reduction in left heart dimensions documented on echocardiography both at one day and nine months after procedure. In the second dog, three-dimensional transesophageal echocardiography, cardiac computed tomography, and a three-dimensionally printed whole heart model were used to evaluate feasibility for transcatheter device closure. Complete closure of the VSD was subsequently achieved. Both cases had good short- to medium-term outcomes, no perioperative complications were observed, and both dogs are apparently healthy and receiving no cardiac medications at 34 months and 17 months after procedure. Transcatheter attenuation of perimembranous VSD with membranous ventricular septal aneurysm is clinically feasible using the canine duct occluder, and multimodal cardiac imaging allows accurate assessment and planning prior to transcatheter intervention for structural heart disease in dogs.

Clinical use of tissue plasminogen activator for systemic thrombolysis in dogs and cats.

INTRODUCTION: Systemic administration of tissue plasminogen activator (tPA) is seldomly reported in dogs and cats. ANIMALS: Client-owned animals receiving tPA (2010-2020). MATERIALS AND METHODS: Medical records of dogs and cats receiving tPA for distant known/suspected thrombus were reviewed. Fourteen dog visits (24 injections) and five cat visits (six injections) were included. RESULTS: Canine known/suspected thrombus included pulmonary thromboembolism (n=6), intracardiac thrombus (n=4), aortic thrombus (n=1), cranial vena cava thrombus (n=2), and femoral and iliac veins thrombus (n=1). Various canine primary diseases were represented, but open-heart surgery was the most common cause. Median time between diagnosis/suspicion of thrombus and tPA injection was 24.5 h (range, 3-150 h). Mean total tPA dose was 1.0±0.78 mg/kg. Clinical improvement occurred in 93% of dogs. Non-fatal complications were reported in 14% of dogs. Dogs' survival to discharge was 78.6% without identifiable non-survivor characteristics. Feline known/suspected thrombus included unilateral feline aortic thromboembolism (FATE) (n=2), bilateral FATE (n=2), and right renal artery thrombus. Feline primary diseases included cardiomyopathy (n=5). Median time between diagnosis/suspicion of thrombus and tPA injection was 4 h (range, 2-17 h) and median total tPA dose was 1.0 mg/kg (range, 0.6-1.4 mg/kg).Clinical improvement occurred during 40% of the visits. All cats (n=3) with acute kidney injury (AKI) at admission developed worsening AKI and reperfusion injury. Of the remaining two visits, one developed a non-fatal AKI. Cats' survival to discharge was 40%. CONCLUSIONS: Systemic thrombolysis with tPA seems to be effective and safe in dogs. More investigation is needed in cats.

Medial insertion of the patent ductus arteriosus characterized by computed tomography angiography in a cat and dog.

Surgical ligation of a left-to-right shunting patent ductus arteriosus was attempted in two animals. In both cases, a young cat and dog, ligation was complicated by poor visualization of the ductus resulting in unsuccessful ligation. Post-operatively, both the cat and dog underwent computed tomography angiography to characterize the location and morphology of the patent ductus arteriosus. In both cases, computed tomography angiography revealed a left-to-right shunting patent ductus arteriosus with an insertion location medial to the left pulmonary artery branch compared to the typical location. We hypothesize that this atypical location resulted in a difficult surgical visualization from the left thoracotomy approach. Transvenous coil embolization of the duct from the external jugular vein was performed in both cases and resulted in successful occlusion. Variations in the medial-lateral insertion of the ductus arteriosus may have consequences for surgical intervention. If an atypical location of a patent ductus arteriosus is suspected on transthoracic echocardiography, computed tomography angiography prior to ligation may be useful to further define ductal location and help guide the surgical approach.

Trifoliate left atrioventricular valve with and without intact septal structures in four dogs: echocardiographic findings and surgical repair.

Trifoliate left atrioventricular (AV) valve with common atrioventricular junction is considered part of the spectrum of atrioventricular septal defect. This valve morphology is typically associated with defects in the AV septum resulting in communication at the atrial or ventricular level, but has also been described as an isolated defect in the setting of a common AV junction without AV septal defect. Trifoliate left AV valve exhibits a line of apposition between the bridging leaflets that is directed toward the inlet interventricular septum, distinguishing it from isolated mitral valve cleft in which the orientation of the bridging leaflets are toward the left ventricular outflow tract. The echocardiographic findings of four dogs with trifoliate left AV valve are described; two with intact septal structures and two with large ostium primum defects. Three dogs underwent open surgical repair using different approaches depending on the presence or absence of a septal defect. One of these underwent concurrent surgical repair for right AV valve dysplasia. One dog with intact septal structures underwent interventional closure of a concurrent patent ductus arteriosus. Current terminology associated with trileaflet left AV valve malformations is reviewed.

Transcatheter closure of patent ductus arteriosus in 11 dogs and one cat after incomplete or aborted surgical ligation.

OBJECTIVE: To describe the characteristics and outcomes of transcatheter patent ductus arteriosus (PDA) occlusion after incomplete or aborted surgical ligation in dogs and cats. ANIMALS: Twelve client-owned animals (11 dogs and one cat). MATERIALS AND METHODS: This retrospective study describes data from animals with aborted or incomplete surgical PDA ligation that subsequently underwent transcatheter closure using endovascular methods. Patient demographics, reason for incomplete or aborted surgery, complications, and method of transcatheter occlusion were recorded. Data are presented as mean ± standard deviation or median (interquartile range), where appropriate. RESULTS: For all cases, median age at surgery was 12.2 months (4.9-15.1 months) and at catheterization was 15.4 months (8.9-21.9 months), with 79 days (29-209 days) between surgical and interventional procedures. Median weight at catheterization was 4.5 kg (2.5-12.6 kg). Reasons for failed surgical ligation included hemorrhage during ductal dissection in seven dogs, residual flow in four dogs, and inability to identify the ductus in one cat. Transcatheter closure was successfully performed using a canine duct occluder in eight dogs, transarterial coil embolization in two dogs, and transvenous coil embolization in one dog and one cat. Metallic hemoclips partially obscured angiographic findings in three cases with prior surgical hemorrhage but did not prevent transcatheter closure. In all cases, ductal flow was successfully attenuated, with no or trace residual shunting on angiography and complete occlusion the following day on echocardiography. CONCLUSIONS: When surgery is unsuccessful, either owing to hemorrhage or residual flow, transcatheter closure of PDA is feasible, even in small patients.

Transvenous occlusion of patent ductus arteriosus in a domestic chicken (Gallus gallus).

A 2.5-year-old intact female Marans domestic chicken was presented for lethargy, open beak breathing, and hyporexia. Echocardiography noted left atrial and left ventricular enlargement and computed tomography angiography revealed a type III left-sided patent ductus arteriosus. Retrograde catheterization of the ductus was performed via percutaneous access of the right external jugular vein, and transvenous ductal occlusion was achieved using an 8-mm Amplatzer™ Vascular Plug 4. Transient bradycardia and hypotension occurred during right heart catheterization, which were successfully treated with atropine and epinephrine. A two-week follow-up postoperative cardiac computed tomography scan confirmed appropriate placement of the occluder within the ductus, and echocardiography demonstrated reduced left heart size. The chicken showed an improvement in clinical signs and remains apparently well six months after the intervention. This report describes the computed tomographic findings of a patent ductus arteriosus in an avian species, minimally invasive transvenous closure of this congenital anomaly with a low-profile occlusion device, and the associated challenges and considerations specific to cardiac intervention in an avian patient.

Phase I clinical trial of an antithrombotic drug protocol combining apixaban and clopidogrel in dogs.

INTRODUCTION: Combining an antiplatelet drug, clopidogrel, with the direct oral Factor Xa inhibitor, apixaban, could provide an effective antithrombotic strategy in dogs. Thus, a limited 3 + 3 phase I dose-escalation clinical trial in healthy dogs was conducted to evaluate bleeding (primary end-point) and pharmacodynamic (PD)/pharmacokinetic (PK) parameters (secondary end-point). ANIMALS: Eleven beagle dogs, median body weight 10.2 kg (9.7-10.9 kg), were enrolled. METHODS: Four doses of apixaban (three dogs/dose) administered for eight days. Clopidogrel dose was fixed at 18.75 mg per os (PO) q 24 h with escalation of apixaban dose at 5 mg PO q 12 h, 5 mg PO q 8 h, 10 mg PO q 12 h, and 10 mg PO q 8 h. Laboratory testing included fecal occult blood, coagulation parameters, Factor X activity, apixaban concentration, platelet aggregometry, and thromboelastography on days 1, 3, and 8. RESULTS: Evidence of bleeding was not observed at any dosage. Dose-dependent changes in PD/PK parameters between baseline and 3 h post-medication were observed including a prolongation of prothrombin time, a prolongation of activated partial thromboplastin time, a decrease of Factor X activity level, and increased apixaban concentration. CONCLUSIONS: The combination of apixaban at a dosage range of approximately 0.5 mg/kg PO q 12 h to 1 mg/kg PO q 8 h and clopidogrel at approximately 1.8 mg/kg PO q 24 h did not cause bleeding over a one-week period in healthy dogs. Clinically relevant changes in PD/PK data occur at all dosage levels. This study provides a starting point for longer-term clinical trials to determine safety and efficacy.

Repeat balloon valvuloplasty for dogs with recurrent or persistent pulmonary stenosis.

INTRODUCTION/OBJECTIVES: Pulmonary stenosis (PS) is a common congenital defect in the dog. Severe valvar PS can be treated with balloon valvuloplasty (BV) to reduce obstruction severity and improve clinical signs. Repeat BV is often unnecessary, as restenosis is uncommon. Repeated pulmonary BV in people is generally successful and safe, but outcomes in dogs with recurrent or persistent stenosis have not been reported. The objectives of this study were to retrospectively evaluate outcomes of repeat BV in dogs. ANIMALS, MATERIALS, AND METHODS: Medical records and stored echocardiographic images were reviewed from dogs that received repeat BV for pulmonary valvar restenosis or persistent stenosis. Echocardiographic variables included maximum systolic ejection velocity (PVmax), velocity-derived maximal pressure gradient (PGmax) and velocity time integral (VTI) across the pulmonary valve, and ratios of pulmonic to aortic maximum velocity (PVmax/AVmax) and VTI (VTIPV/VTIAV). RESULTS: Twenty-three dogs were included; one underwent three BV procedures. The median time between BV procedures was 18.3 months (interquartile range, 6.3-43.6). One dog died during repeat BV, but no others experienced adverse effects. Reductions in PVmax, PGmax, and VTIPV after initial and repeat BV were 1.85 m/s, 76.2 mmHg, and 44.7 cm and 1.33 m/s, 55.6 mmHg, and 30.2 cm, respectively (all p < 0.01). Differences between pre-BV and post-BV PVmax, PGmax, VTIPV, PVmax/AVmax, and VTIPV/VTIAV were not different comparing initial to repeat BV (all p > 0.10). CONCLUSIONS: Repeat BV for recurrent or persistent PS is well tolerated and effective in a majority of dogs.

A pilot study evaluating cutting and high-pressure balloon valvuloplasty for dysplastic pulmonary valve stenosis in 7 dogs.

INTRODUCTION: This case series describes early experience and technical aspects of cutting balloon dilation followed by high-pressure balloon pulmonary valvuloplasty in dogs with dysplastic pulmonary valve stenosis. ANIMALS: Seven client-owned dogs were enrolled in this study. METHODS: Dogs were prospectively enrolled based on echocardiographic diagnosis of severe pulmonary valve dysplasia, defined as marked valve thickening with variable degrees of annular hypoplasia or subvalvar fibrous obstruction and a peak echocardiography-derived transpulmonary pressure gradient higher than 100 mmHg. Preinterventional and postinterventional hemodynamic data and transthoracic pressure gradients were obtained for all dogs. Recheck echocardiography varied in timing by client convenience, with maximum follow-up 35 months after intervention. RESULTS: No intraprocedural or periprocedural mortality was observed. The only major complication was partial avulsion of a cutting blade related to exceeding recommended burst pressure of the device, which was not associated with obvious clinical consequence. Invasive hemodynamic measurements demonstrated an average reduction of 46% in peak systolic right ventricular-to-pulmonary artery pressure gradient (range, 31-77%). The echocardiographic results 24 h after procedure demonstrated an average reduction in pressure gradient of 43% (range, 20-66%), with late follow-up demonstrating an average reduction of 35% (range, 10-57%) compared with preprocedural echocardiography. CONCLUSIONS: This procedure is a feasible therapeutic transcatheter intervention for dogs with dysplastic pulmonary valves and appears safe in this small cohort. The ideal selection criteria and rate of restenosis for this procedure is under investigation, and long-term follow-up and a large, randomized, controlled study are necessary to demonstrate efficacy.

Dilatable pulmonary artery banding for ventricular septal defect: surgical technique and case report of three cats.

Pulmonary artery banding (PAB) is a viable but underreported palliative option for hemodynamically significant ventricular septal defect in small animals. A significant challenge associated with PAB is judging the degree of band tightening, which can be further complicated when animals are immature and still growing at the time of PAB. If a pulmonary artery band is overtightened or becomes progressively too tight after surgery, the result can be reversal of shunt flow with potentially devastating consequences. Placement of a band that could be percutaneously dilated using a balloon catheter affords a minimally invasive option for partially or completely relieving the band should it become too tight after PAB. This report describes a surgical technique for placement of a dilatable pulmonary artery band, reviews guidelines for tightening the band, and reports the outcome of three cats undergoing the procedure. All three cats showed evidence of reduced hemodynamic load after PAB for a period of up to three years after PAB.

Cor triatriatum dexter in 17 dogs.

OBJECTIVES: The objective of this study was to report the signalment, presentation, clinical and imaging findings, interventions, and outcomes in a group of dogs with cor triatriatum dexter (CTD). ANIMALS: Seventeen client-owned dogs. METHODS: Medical records were reviewed retrospectively for signalment, history, physical examination findings, imaging and diagnostic findings, presence of concurrent congenital cardiac defects, description of interventional procedures, therapy information, and outcomes. RESULTS: Age at presentation ranged from two to 110 months, with 10 of 17 dogs (59%) aged <12 months. There was an equal distribution between the sexes. Peritoneal effusion was the most common presenting complaint, in 10 of 17 dogs (59%). The CTD was an isolated finding in 3 of 17 dogs (18%); the remaining 14 of 17 (82%) dogs had concurrent cardiac disease, with congenital anomalies present in 12 of 17 (70%). All except one of these 12 dogs had at least one additional condition affecting the right heart. Tricuspid valve dysplasia was the most common congenital comorbidity, present in 9 of 17 dogs (53%). Seven dogs (41%) underwent interventional treatment of their CTD. In 7 of 17 (41%) cases, the CTD was considered to be incidental and the dogs were asymptomatic; therefore, no interventions were performed. The remaining three cases were euthanized or lost to follow-up. CONCLUSIONS: Cor triatriatum dexter in dogs is commonly seen in association with other right-sided congenital cardiac anomalies and may be an incidental finding. Dogs with CTD obstructing right atrial inflow can have a good outcome after intervention. Dogs with no clinical signs associated with the CTD may remain asymptomatic into adulthood.

Bidirectional flow across a perforate cor triatriatum dexter in a dog with concurrent pulmonary, tricuspid, and mitral valve dysplasia.

A 10-week-old male intact mixed breed dog presented for evaluation of suspected right-sided congestive heart failure. Echocardiographic imaging revealed a perforate cor triatriatum dexter (CTD), along with pulmonary valve stenosis and tricuspid and mitral valve dysplasia. In typical CTD cases, there is unidirectional blood flow across the dividing membrane, from the caudal into the cranial right atrial chambers. Owing to right-sided pressure alterations caused by the concurrent valvar defects, color Doppler imaging demonstrated bidirectional flow across the CTD membrane.

Upper rate behavior in six dogs with dual-chamber pacemakers.

INTRODUCTION: This report provides clinical examples of upper rate behavior in dogs with dual-chamber pacemakers, with suggestions for programming alterations to avoid detrimental upper rate behavior. ANIMALS: Six dogs with dual-chamber pacemakers displaying upper rate behavior at upper atrial tracking rates. METHODS: Medical records of dogs with dual-chamber pacemakers with evidence of upper rate behavior were reviewed retrospectively from two institutions. Two of the six dogs were followed prospectively, and 24 h Holter monitors were placed to evaluate upper rate behavior correlated to programming settings. RESULTS: Pacemaker Wenckebach or 2:1 atrioventricular block was documented in four of six dogs, and automatic mode switch was documented in two of six dogs. Twenty-four-hour Holter monitors placed on two dogs after pacemaker optimization documented a pacemaker Wenckebach window at increased atrial rates with neither dog reaching their respective 2:1 block point throughout the recording period. CONCLUSIONS: Clinicians who implant dual-chamber pacemakers should be aware of upper rate behavior in animal species with high heart rates. Optimal programming of dual-chamber pacemakers can be achieved by selecting programmed timing intervals to limit deleterious upper rate behavior and create a more physiologic ventricular response at maximum tracking rates.

Echocardiographic Estimates of Right Ventricular Systolic Function in Dogs with Myxomatous Mitral Valve Disease.

BACKGROUND: Right ventricular (RV) dysfunction independently predicts outcomes in human myxomatous mitral valve disease (MMVD). There is limited information regarding RV systolic function in dogs with MMVD. HYPOTHESIS: Right ventricular systolic function differs among stages of disease, decreasing in decompensated MMVD. ANIMALS: Thirty-sixclient-owned dogs with MMVD not receiving oral cardiovascular medications. METHODS: Prospective clinical study. Dogs were categorized according to disease severity as ACVIM Stage B1, B2, or C. Seven echocardiographic indices of RV systolic function were measured. Groups were compared by 1-way ANOVA and Tukey's HSD test. Frequencies of cases with cardiac remodeling falling outside previously established reference intervals were compared using Fisher's exact test. Intra- and interobserver measurement variability was calculated for each RV function index. RESULTS: The indices TAPSE (P = 0.029), RV StL (P = 0.012), and RV StRL (P = 0.041) were significantly different between groups. A greater proportion of B2 dogs (7 of 12) had TAPSE values above reference intervals compared with B1 (2 of 12) or C (2 of 12) dogs (P = 0.027). Measurement variability of TAPSE, RV S', and RV StG was clinically acceptable. CONCLUSIONS AND CLINICAL IMPORTANCE: Right ventricular systolic function differs between stages of MMVD, increasing in stage B2, and declining in stage C. The prognostic importance of RV function indices, particularly TAPSE, might be worth evaluating in dogs with MMVD.

Comparison of cardiac measurements by multi-detector computed tomography angiography and transthoracic echocardiography in English bulldogs.

INTRODUCTION: Transthoracic echocardiography (TTE) is the primary tool for the assessment of cardiac structure and function in dogs but is challenging in English bulldogs due to dorsoventral compression of the thorax, obesity, and narrow intercostal spaces. Multi-detector computed tomography angiography (CTA) may overcome the conformational obstacles of cardiac imaging in this breed. ANIMALS: Eleven client-owned English bulldogs. MATERIALS AND METHODS: Prospective clinical trial with paired analysis of TTE and CTA studies. RESULTS: Eight of the 25 linear cardiac dimensional measurements were significantly different between TTE and CTA (p<0.033). Intraobserver agreement was strong with average coefficients of variation (CV) of 5.34% for TTE and 2.50% for CTA. Interobserver agreement CV averaged 6.5% for TTE and 8.75% CTA. Ejection fraction, stroke volume, and end-systolic volume were significantly different between modalities (all p<0.002). No significant difference was present between end-diastolic volume for TTE compared with CTA. DISCUSSION: High-quality cardiac angiographic studies were accomplished using CTA without the use of general anesthesia in English bulldogs. Multi-detector computed tomography angiography and TTE are not interchangeable modalities in the clinical setting. CONCLUSION: Multi-detector-CT ECG-gated cardiac angiography is possible in sedated, non-intubated English bulldogs. Differences were found between some cardiac dimensions as measured by TTE in the awake dog and compared with sedated CTA, indicating the two methodologies are not equivalent. Sedated, non-intubated CTA yielded high-quality imaging with strong intraobserver and interobserver measurement repeatability in English bulldogs.

Effect of Body Position, Exercise, and Sedation on Estimation of Pulmonary Artery Pressure in Dogs with Degenerative Atrioventricular Valve Disease.

BACKGROUND: Severity of pulmonary hypertension (PH) in dogs is related to clinical signs and prognosis. HYPOTHESIS/OBJECTIVES: We hypothesized that Doppler echocardiographic (DE) indices of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are influenced by independent factors that create clinically important variability of DE-based estimates of PH in dogs. ANIMALS: Thirty-eight client owned dogs with naturally acquired degenerative atrioventricular valve disease and tricuspid regurgitation (TR). METHODS: Dogs were prospectively enrolled, and target variables were acquired during 4 echocardiographic study periods (lateral recumbency, standing, lateral recumbency after a 6-minute walk test [6MWT], and lateral recumbency after sedation with butorphanol 0.25 mg/kg IM). Statistical methods included repeated measures ANOVA, mixed model analysis, and Chi-squared test of association. RESULTS: There was a significant increase in peak TR flow velocity (TRFV; P < 0.01) after sedation in 78% of dogs, with TRFV increasing by >0.4 m/s in 42% of dogs, independent of stroke volume. A significant effect of study period on DE-estimated PVR was not found (P = 0.15). There were negligible effects of sonographer, body position, and 6MWT on echocardiographic variables of PH. Clinically relevant cyclic variation of TRFV was found. There was an association between estimation of right atrial pressure based on subjective assessment and estimation based on cranial vena cava collapsibility (P = 0.03). CONCLUSIONS AND CLINICAL IMPORTANCE: The increase in TRFV observed with sedation could change assessment of PH severity and impact prognostication and interpretation of treatment response. Further studies with invasive validation are needed.

Survival time with pacemaker implantation for dogs diagnosed with persistent atrial standstill.

OBJECTIVES: To evaluate survival time in dogs with persistent atrial standstill after pacemaker implantation and to compare the survival times for cardiac-related vs. non-cardiac deaths. Secondary objectives were to evaluate the effects of breed and the presence of congestive heart failure (CHF) at the time of diagnosis on survival time. ANIMALS: Twenty dogs with persistent atrial standstill and pacemaker implantation. METHODS: Medical records were searched to identify dogs diagnosed with persistent atrial standstill based on electrocardiogram that underwent pacemaker implantation. Survival after pacemaker implantation was analyzed using the Kaplan-Meier method. RESULTS: The median survival time after pacemaker implantation for all-cause mortality was 866 days. There was no significant difference (p=0.573) in median survival time for cardiac (506 days) vs. non-cardiac deaths (400 days). The presence of CHF at the time of diagnosis did not affect the survival time (P=0.854). No difference in median survival time was noted between breeds (P=0.126). CONCLUSIONS: Dogs with persistent atrial standstill have a median survival time of 866 days with pacemaker implantation, though a wide range of survival times was observed. There was no difference in the median survival time for dogs with cardiac-related deaths and those without. Patient breed and the presence of CHF before pacemaker implantation did not affect median survival time.

Unilateral absence of an external jugular vein in two English bulldogs with pulmonary valve stenosis.

Two English bulldogs referred for interventional palliation of severe pulmonary valve stenosis were incidentally diagnosed with unilateral absence of an external jugular vein (left in one case, right in the other) by computed tomography and Doppler ultrasound. The right internal jugular vein also could not be visualized in the dog with absence of the left external jugular vein. Cervical venous anomalies can impact diagnostic or interventional venous catheterization procedures such as balloon pulmonary valvuloplasty. Additionally, absence of an external jugular vein may impact central venous catheter placement. Absence of an external jugular vein should be considered in dogs when the external jugular vein cannot be easily palpated. Ultrasound or computed tomography may help identify jugular venous anatomy and confirm anomalies.