A proof-of-concept study evaluating cardiac compression techniques for cardiopulmonary resuscitation in laying hens (Gallus gallus).

OBJECTIVE: To determine in adult chickens which of 3 CPR techniques, sternal compressions (SC), SC with interposed caudal coelomic compressions (ICCC), or lateral compressions (LC), results in the highest mean systolic (SAP), diastolic (DAP), and mean arterial pressure (MAP) as measured directly from the carotid artery. DESIGN: Prospective, nonblinded, experimental crossover study. SETTING: University teaching hospital laboratory. ANIMALS: Ten retired laying hens. INTERVENTIONS: Birds were sedated, anesthetized, and placed in dorsal recumbency. A carotid artery catheter was placed to directly measure arterial pressure. Ventricular fibrillation was induced with direct cardiac stimulation using a 9-Volt battery. Each bird then received 2 minutes of the 3 different cardiac compression techniques in a random order by 3 different compressors, with the compressor order also randomized. Birds were subsequently administered IV epinephrine, and transthoracic defibrillation was attempted. At the end of experimentation, each bird was euthanized, and simple gross necropsies were performed. Linear mixed models followed by pairwise paired t-tests were performed to evaluate differences in pressures generated by each technique. MEASUREMENTS AND MAIN RESULTS: The primary study outcomes were SAP, DAP, and MAP over 2 minutes of compressions for each compression technique. Pressures from ICCC (SAP: 27.6 ± 5.3 mm Hg, DAP: 18.7 ± 5.2 mm Hg, MAP: 21.7 ± 5.2 mm Hg) were significantly higher than those from LC (SAP: 18.9 ± 5.4 mm Hg, DAP: 11.6 ± 4.1 mm Hg, MAP: 14.1 ± 4.5 mm Hg). Pressures from SC (SAP: 24.5 ± 6.4 mm Hg, DAP: 15.2 ± 4.3 mm Hg, MAP: 18.3 ± 5.0 mm Hg) were not significantly different from ICCC or LC. CONCLUSIONS: External compressions can generate detectable increases in arterial pressure in chickens with ventricular fibrillation. SC with ICCC generated significantly higher arterial pressures than LC. SC alone generated blood pressures that were not significantly different from those generated by SC with ICCC or LC.

Untargeted metabolomic profiling of dogs with myxomatous mitral valve disease and congestive heart failure shows metabolic differences associated with the presence of cardiac cachexia.

OBJECTIVE: To determine the effects of cardiac cachexia on the metabolomic profile in dogs with myxomatous mitral valve disease (MMVD). ANIMALS: 3 groups of dogs with MMVD enrolled between November 30, 2018, and April 7, 2022: (1) Dogs with congestive heart failure (CHF) and cachexia (CHF-cachexia group; n = 10); (2) dogs with CHF that had no cachexia (CHF-no cachexia group; n = 10); and (3) dogs with asymptomatic disease (American College of Veterinary Internal Medicine [ACVIM] Stage B2) with no cachexia (B2 group; n = 10). METHODS: Metabolomic profiles were analyzed from serum samples using ultra-high-performance liquid chromatography-tandem mass spectroscopy. Dogs in the 3 groups were compared, with statistical significance defined as P < .05 with a low false discovery rate (q < .10) and nominal statistical significance defined as P < .05 but q > .10. RESULTS: Numerous metabolites were significantly (n = 201) or nominally significantly (n = 345) different between groups. For example, when comparing the CHF-cachexia vs CHF-no cachexia groups, lipids were the predominant metabolite differences, including many medium- and long-chain dicarboxylates and dicarboxylate acylcarnitines. For comparisons of the CHF-cachexia vs B2 groups and the CHF-no cachexia vs B2 groups, amino acids, nucleotides, and cofactors/vitamins were the predominant metabolite differences. CLINICAL RELEVANCE: Some significant metabolite differences were identified between dogs with and without cardiac cachexia.

A multicenter, retrospective study of cardiac disease in Borzoi dogs.

Borzoi are large, relatively uncommon sighthounds anecdotally reported to suffer from sudden death. This multicenter retrospective cohort study aimed to describe the sample of Borzoi presenting to veterinary cardiologists for evaluation, with records searched from 14 centers across a study period of up to 20 years. The study sample was comprised of 152 client-owned Borzoi, with dogs most commonly presenting for pre-breed screening in 87/152 (52%), followed by evaluation of an arrhythmia in 28/152 (18%). Of the 131/152 (86%) dogs that had an echocardiogram performed, 85/131 (65%) were structurally normal, with 40/85 (47%) structurally normal dogs having trace or mild atrioventricular valve regurgitation. Tricuspid valve dysplasia was the most commonly diagnosed congenital cardiac disease (n = 6). Myxomatous mitral valve disease (n = 12) and dilated cardiomyopathy (n = 13) were diagnosed at similar frequencies, though 92% of valve disease cases were mild. Only 48/152 (32%) Borzoi had a diagnostic electrocardiogram (ECG) and/or a Holter monitor for arrhythmia screening. Despite this, ventricular arrhythmias were identified during the entirety of the available cardiac evaluation including diagnostic ECG, contemporaneous ECG monitoring during the echocardiogram, and/or Holter monitor in 25/131 (19%) dogs in which an echocardiographic diagnosis was available. Of these 25 Borzoi, 76% had minimal or no structural cardiac disease identified, and five had a family history of sudden death. A sudden death outcome was reported in 3/55 (5%) Borzoi with long-term outcome data available. In conclusion, Borzoi commonly have trace or mild atrioventricular valve insufficiencies, and may develop ventricular arrhythmias and dilated cardiomyopathy.

Comparison of echocardiography, biomarkers and taurine concentrations in cats eating high- or low-pulse diets.

OBJECTIVES: There are ongoing investigations into diet-associated dilated cardiomyopathy in dogs, but there has been minimal investigation into possible diet-associated dilated cardiomyopathy in cats. The objective of this study was to compare cardiac size and function, cardiac biomarkers and taurine concentrations in healthy cats eating high- vs low-pulse diets. We hypothesized that cats eating high-pulse diets would have larger hearts, lower systolic function and higher biomarker concentrations than cats eating low-pulse diets and that there would be no difference in taurine concentrations between the diet groups. METHODS: Echocardiographic measurements, cardiac biomarkers, and plasma and whole-blood taurine concentrations were compared between cats eating high- and low-pulse commercial dry diets in a cross-sectional study. RESULTS: There were no differences between the high- (n = 21) and low-pulse (n = 31) diet groups with regard to age, sex and breed, but more cats in the high-pulse group were overweight or obese (67% vs 39%; P = 0.05). Diet duration was not different in the groups, but the range was wide (6-120 months). No differences were found between the diet groups for key cardiac measurements, biomarker concentrations, or plasma or whole-blood taurine concentrations. However, there were significant negative correlations between diet duration and measures of left ventricular wall thickness in the high-pulse, but not the low-pulse, diet group. CONCLUSIONS AND RELEVANCE: This study did not detect significant associations between high-pulse diets and cardiac size, function and biomarkers, but the secondary observation of significant negative correlations between time on high-pulse diets and left ventricular wall thickness warrants further evaluation.

Evaluation of automated external defibrillator designed for people in dogs.

OBJECTIVE: To determine if human automated external defibrillators (AEDs) could successfully record cardiac electrical activity in dogs, make appropriate recommendations regarding shock delivery, and characterize skin preparation required for a readable ECG based on dog haircoat characteristics. DESIGN: Prospective study of AED use in dogs conducted between January and March 2021. SETTING: University teaching hospital. ANIMALS: Three groups of client-owned dogs were evaluated. Group 1 consisted of 23 healthy dogs with sinus rhythms, group 2 consisted of 9 dogs with documented cardiac arrhythmias, and group 3 consisted of 9 dogs receiving CPR following naturally occurring cardiopulmonary arrest. MATERIALS AND METHODS: Haircoat characteristics and clipping or ECG paste required to obtain a readable ECG were recorded. The time interval from a readable ECG by the investigator until AED shock advisement was measured. Correctness of shock advice was recorded. Analyses were performed using commercial statistical software. P-values <0.05 were considered significant. RESULTS: The attending veterinarian judged the ECG on the AED to be readable in all dogs. Time to shock advisement in all dogs was median 18 (range: 7-180) seconds. Dogs with heavy, long, or double haircoats required clipping in 24 of 27 (89%) cases to obtain a readable ECG. ECG paste on the AED pad was required in 36 of 40 dogs (90%) in order to obtain a readable ECG. The AED advice for delivery of shock was appropriate in 51 of 52 (98%) queries of the machine across all groups. CONCLUSIONS: Human AEDs can successfully record cardiac electrical activity in dogs. AEDs appropriately recommend delivery of a shock most times, contingent on skin preparation. Dogs with double, long, or heavy haircoats should be clipped prior to pad application. ECG paste will aid AED reading in all haircoat types. Further investigation is warranted into AED use in dogs, particularly in general practices.

Retrospective evaluation of hypertrophic cardiomyopathy in 68 dogs.

BACKGROUND: There is a lack of clinical data on hypertrophic cardiomyopathy (HCM) in dogs. HYPOTHESIS/OBJECTIVES: To investigate signalment, clinical signs, diagnostic findings, and survival in dogs with HCM. ANIMALS: Sixty-eight client-owned dogs. METHODS: Retrospective multicenter study. Medical records were searched between 2003 and 2015. The diagnosis of left ventricular (LV) hypertrophy was made by echocardiographic examination. RESULTS: Three hundred and forty-five dogs with LV hypertrophy were identified, of which 277 were excluded. The remaining 68 dogs were 0.3 to 14 years old and predominantly <10 kg (85%), and without a sex predilection. Twenty-four % were Shih Tzu and 24% terrier breeds. Most (80%) had a systolic heart murmur. Owner-determined exercise intolerance (37%) and syncope (18%) were most commonly reported signs. The majority (84%) of dogs had symmetrical LV hypertrophy, whereas asymmetrical septal and LV free wall hypertrophy was observed in 9% and 6% of dogs, respectively. Isolated basal interventricular septal hypertrophy was not observed. Commonly recorded were systolic anterior motion of the mitral valve (60%) and LV diastolic dysfunction (89% of dogs where diastolic function was evaluated). Six dogs died unexpectedly, and 3 developed congestive heart failure. Known survival times were between 1 day and 114 months after diagnosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Hypertrophic cardiomyopathy in dogs should be considered as a differential diagnosis if LV hypertrophy is identified. Small breed dogs are overrepresented, and it is uncommon for dogs with HCM to develop CHF although sudden death can occur.

Prospective study of dilated cardiomyopathy in dogs eating nontraditional or traditional diets and in dogs with subclinical cardiac abnormalities.

BACKGROUND: Recent studies have investigated dogs with presumed diet-associated dilated cardiomyopathy (daDCM), but prospective studies of multiple breeds are needed. HYPOTHESIS/OBJECTIVES: To evaluate baseline features and serial changes in echocardiography and cardiac biomarkers in dogs with DCM eating nontraditional diets (NTDs) or traditional diets (TDs), and in dogs with subclinical cardiac abnormalities (SCA) eating NTD. ANIMALS: Sixty dogs with DCM (NTD, n = 51; TDs, n = 9) and 16 dogs with SCA eating NTDs. METHODS: Echocardiography, electrocardiography, and measurement of taurine, cardiac troponin I, and N-terminal pro-B-type natriuretic peptide were performed in dogs with DCM or SCA. Diets were changed for all dogs, taurine was supplemented in most, and echocardiography and cardiac biomarkers were reassessed (3, 6, and 9 months). RESULTS: At enrollment, there were few differences between dogs with DCM eating NTDs or TDs; none had low plasma or whole blood taurine concentrations. Improvement in fractional shortening over time was significantly associated with previous consumption of a NTD, even after adjustment for other variables (P = .005). Median survival time for dogs with DCM was 611 days (range, 2-940 days) for the NTD group and 161 days (range, 12-669 days) for the TD group (P = .21). Sudden death was the most common cause of death in both diet groups. Dogs with SCA also had significant echocardiographic improvements over time. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with DCM or SCA previously eating NTDs had small, yet significant improvements in echocardiographic parameters after diet changes.

Retrospective study of dilated cardiomyopathy in dogs.

BACKGROUND: The United States Food and Drug Administration is investigating possible diet-associated dilated cardiomyopathy (DCM) in dogs and cats. OBJECTIVES: To retrospectively review DCM cases for signalment, diet information, echocardiographic changes, and survival. ANIMALS: Client-owned dogs (n = 71). METHODS: Medical records of dogs diagnosed with DCM between January 1, 2014 and September 30, 2018 were reviewed. Dogs were grouped into "traditional" or "nontraditional" diet categories and whether or not diet was changed after diagnosis. RESULTS: For dogs eating nontraditional diets, those that had their diets changed had a larger percentage decrease in normalized systolic left ventricular internal dimension (P = .03) and left atrial:aorta ratio (P < .001) compared to those that did not have their diets changed. Survival time was significantly longer for dogs with DCM eating nontraditional diets that had their diets changed (median survival, 337 days; range, 9-1307 days) compared to dogs eating nontraditional diets that did not have their diets changed (median survival, 215 days; range, 1-852 days; P = .002). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with DCM eating nontraditional diets can experience improvement in cardiac function after diet change but additional research is needed to examine possible associations between diet and DCM.

A pilot study investigating circulating trimethylamine N-oxide and its precursors in dogs with degenerative mitral valve disease with or without congestive heart failure.

BACKGROUND: Pathophysiologic mechanisms for the development and progression of degenerative mitral valve disease (DMVD) remain elusive. Increased concentrations of circulating trimethylamine N-oxide (TMAO) and its precursors choline and l-carnitine are associated with the presence and severity of heart disease in people. OBJECTIVES: To determine if differences exist in plasma concentrations of TMAO, choline, or l-carnitine among dogs with DMVD and congestive heart failure (CHF), dogs with asymptomatic DMVD, and healthy control dogs. ANIMALS: Thirty client-owned dogs: 10 dogs with CHF secondary to DMVD, 10 dogs with asymptomatic DMVD, and 10 healthy control dogs. METHODS: A pilot cross-sectional study in which echocardiography was performed and fasting plasma concentrations of TMAO, choline, and l-carnitine (total and fractions) were measured. RESULTS: TMAO (P = .03), total l-carnitine (P = .03), carnitine esters (P = .05), and carnitine esters to free carnitine ratio (E/F ratio; P = .05) were significantly higher in dogs with CHF compared to those with asymptomatic DMVD. TMAO (P = .02), choline (P = .01), total l-carnitine (P = .01), carnitine esters (P = .02), free carnitine (P = .02), and E/F ratio (P = .009) were significantly higher in dogs with CHF compared to healthy controls. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with CHF secondary to DMVD had higher concentrations of TMAO compared to both asymptomatic DMVD dogs and healthy controls. Larger prospective studies are warranted to determine if TMAO plays a role in the development or progression of DMVD or CHF.