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Simple Summary: Cardiac output (CO) measurement devices are classified as invasive, minimally invasive, or noninvasive depending on their level of invasiveness for CO data acquisition. Pulmonary artery thermodilution is the 'gold standard' CO technique. This method is more accurate, but its invasiveness possesses risks. Minimally invasive lithium dilution (LiD) is slowly replacing thermodilution as a reference standard in animal research due to its excellent agreement and acceptable performance. Monitoring CO with standard cardiovascular parameters (i.e., blood pressure and heart rate) in anesthetized animals can potentially improve patient care and case outcomes. Hence, we evaluated noninvasive electrical cardiometry (EC)-measured CO and other EC-acquired hemodynamic variables, and analyzed them against CO measured using LiD in healthy, anesthetized dogs during different treatments (dobutamine, esmolol, phenylephrine, and high-dose isoflurane) impacting CO values. Overall, EC showed good agreement with LiD, but it exhibited consistent underestimation when the CO values were higher. The percentage error was low and within published standards, and a good trending pattern was exhibited by EC. The acquired EC variables followed the trends in CO obtained by LiD. EC may be a pivotal tool for monitoring trends in hemodynamics and guiding treatments for cardiovascular anesthetic complications in clinical settings. Numerous cardiac output (CO) technologies were developed to replace the 'gold standard' pulmonary artery thermodilution due to its invasiveness and the risks associated with it. Minimally invasive lithium dilution (LiD) shows excellent agreement with thermodilution and can be used as a reference standard in animals. This study evaluated CO via noninvasive electrical cardiometry (EC) and acquired hemodynamic variables against CO measured using LiD in six healthy, anesthetized dogs administered different treatments (dobutamine, esmolol, phenylephrine, and high-dose isoflurane) impacting CO values. These treatments were chosen to cause drastic variations in CO, so that fair comparisons between EC and LiD across a wide range of CO values (low, intermediate, and high) could be made. Statistical analysis included linear regression, Bland–Altman plots, Lin's concordance correlation coefficient (ρc), and polar plots. Values of p < 0.05 represented significance. Good agreement was observed between EC and LiD, but consistent underestimation was noted when the CO values were high. The good trending ability, ρc of 0.88, and low percentage error of ±31% signified EC's favorable performance. Other EC-acquired variables successfully tracked changes in CO measured using LiD. EC may be a pivotal hemodynamic tool for continuously monitoring circulatory changes, as well as guiding and treating cardiovascular anesthetic complications in clinical settings. [ABSTRACT FROM AUTHOR]

Simple Summary: Using general anesthesia on animals causes significant changes to the heart and blood vessels that disrupt normal cardiovascular performance. Blood pressure (BP) is used for closely monitoring hemodynamics in anesthetized animals. However, BP is affected by various factors and may not always accurately correlate with the total body blood flow. Pulmonary artery thermodilution (PATD) is the gold standard for cardiac output (CO) measurements, but, due to the high risks associated with its invasiveness, it is not performed in clinical settings. This study evaluates noninvasive electrical cardiometry's (EC) performance in measuring CO and other hemodynamic variables in healthy anesthetized dogs during acute blood volume manipulation. The EC measurements consistently underpredict the CO values as compared with PATD, but have a better performance when acute blood loss occurs. Even though the EC readings have a slightly higher error than the accepted error, this method is very good at showing trends in the CO measured using PATD. Other EC-derived variables are able to closely track the changes in the CO measured using PATD. In clinics, noninvasive EC may benefit the patient care quality for anesthetized dogs by monitoring the trends in hemodynamics and guiding anesthetists to diagnose and treat cardiovascular complications. In animals, invasive pulmonary artery thermodilution (PATD) is a gold standard for cardiac output (CO) monitoring, but it is impractical in clinical settings. This study evaluates the agreement between PATD and noninvasive electrical cardiometry (EC) for measuring CO and analyzes the other EC-derived hemodynamic variables in six healthy anesthetized dogs subjected to four different hemodynamic events in a sequential order: (1) euvolemia (baseline); (2) hemorrhage (33% blood volume loss); (3) autologous blood transfusion; and (4) 20 mL/kg colloid bolus. The CO measurements obtained using PATD and EC are compared using Bland–Altman analysis, Lin's concordance correlation (LCC), and polar plot analysis. Values of p < 0.05 are considered significant. The EC measurements consistently underpredict the CO values as compared with PATD, and the LCC is 0.65. The EC's performance is better during hemorrhage, thus indicating its capability in detecting absolute hypovolemia in clinical settings. Even though the percentage error exhibited by EC is 49.4%, which is higher than the standard (<30%), EC displays a good trending ability. Additionally, the EC-derived variables display a significant correlation with the CO measured using PATD. Noninvasive EC may have a potential in monitoring trends in hemodynamics in clinical settings. [ABSTRACT FROM AUTHOR]

Background: Hyperthyroid cats might have a predisposition to arterial thrombus formation. The mechanism for thrombogenesis currently is unknown but could be associated with systemic hypercoagulability as seen in hyperthyroid humans. Objective: Our purpose was to evaluate markers of hemostasis in hyperthyroid cats compared to healthy cats, and in hyperthyroid cats before and after radioactive iodine treatment (RIT). Animals Twenty‐five cats with hyperthyroidism and 13 healthy euthyroid cats >8 years of age. Methods: Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin (AT), D‐dimers, thrombin‐antithrombin complexes (TAT), von Willebrand Factor antigen (vWF : Ag), and activity of factors VIII and IX were measured. An echocardiogram was performed in all cats. Hemostatic markers and echocardiogram were evaluated again 6 to 9 months after successful RIT in 7 cats. Results: Hyperthyroid cats had higher fibrinogen concentration (P <.0001), AT activity (P <.0001), and vWF : Ag concentration (P =.01) than healthy control cats with all results decreasing significantly post‐RIT. Hyperthyroid cats were not more likely to be in a hypercoaguable state than euthyroid cats (P =.08). Serum T4 concentration was not a predictor of a hypercoagulable state (P =.53). Conclusions and Clinical Importance: Hyperthyroid cats have evidence of altered hemostasis that does not appear to be solely attributable to cardiac abnormalities, but no evidence of a hypercoagulable state. Findings suggest altered hemostasis resolves after RIT. Hyperthyroid cats could have endothelial dysfunction as indicated by increased vWF : Ag which could potentiate thrombogenesis. [ABSTRACT FROM AUTHOR]

Background: Myxomatous mitral valve disease (MMVD) is more prevalent in Cavalier King Charles Spaniels (CKCSs) compared to dogs of other breeds at a given age. Abnormal valvular stress is thought to contribute to the development and progression of MMVD, and a relationship exists between mitral valve (MV) morphology and stress acting on the valve. Objectives: To determine whether the MV morphology of healthy adult CKCSs differs from the morphology of healthy adult dogs of other breeds determined by RT‐3DTTE. Animals Thirty‐five healthy CKCSs and 41 healthy dogs of other breeds. Methods: Prospective cross‐sectional study. Dogs underwent physical examination, conventional echocardiography, and RT‐3DTTE. RT–3DTTE datasets were analyzed using dedicated software for MV morphologic analysis. Morphologic variables were compared between CKCSs and dogs of other breeds. Results: The MV of healthy CKCSs had a smaller annulus height (0.46 ± 0.11 vs. 0.56 ± 0.17; P =.0021), tenting height (0.26 ± 0.12 vs. 0.42 ± 0.18; P <.001), tenting area (0.42 ± 0.15 vs. 0.79 ± 0.34; P <.001), normalized tenting volume (0.09 [0.05–0.13] vs. 0.14 [0.10–0.20]; P <.001), and normalized area of the posterior leaflet (0.57 ± 0.15 vs. 0.66 ± 0.18; P =.016) compared to healthy dogs of other breeds; this results in CKCSs having a flatter MV with reduced tenting, compared to the MV of other breeds. Conclusions and Clinical Importance: These morphologic features could confer a mechanical disadvantage and play a role in the predisposition of CKCSs to the early development of MMVD. [ABSTRACT FROM AUTHOR]

OBJECTIVE To compare cardiac output (CO) measurements by transesophageal echocardiography (TEECO) and esophageal Doppler monitor (EDMCO) with pulmonary artery thermodilution (PATDCO) in anesthetized dogs subjected to pharmacological interventions. The effect of treatments on EDM-derived indexes was also investigated. ANIMALS 6 healthy male dogs (10.8 ± 0.7 kg). METHODS Dogs were anesthetized with propofol and isoflurane, mechanically ventilated, and monitored with invasive mean arterial pressure (MAP), end-tidal isoflurane concentration (ETISO), PATDCO, TEECO, EDMCO, and EDM-derived indexes. Four treatments were administered to all dogs by randomization. Baseline data were collected before each treatment: (1) dobutamine infusion; (2) esmolol infusion; (3) phenylephrine infusion; and (4) ETISO > 3%. Data were collected after 10-minute stabilization and after 30 minutes of washout between treatments. Statistical tests were pairwise t test, Bland-Altman analysis, Lin's concordance correlation (ρc), and polar plot analysis with P < .05 set as significance. RESULTS The mean ± SD relative bias (limits of agreement) for TEECO was 0.35 ± 25.2% (-49.1% to 49.8%) and for EDMCO was -27.2 ± 22.5% (-71.4% to 17%) versus PATDCO. The percent error for TEECO and EDMCO was 27.6% and 44.1%, respectively. The ρc value was 0.82 for TEECO and 0.66 for EDMCO. TEECO and EDMCO showed good trending ability. EDMderived indexes displayed significant changes specific to the drug administered (P < .001). CLINICAL RELEVANCE For minimally invasive CO monitoring, TEE may provide more favorable performance than EDM in clinical settings; however, EDM-derived indexes yield valuable hemodynamic information that reliably follows trends in CO, thus supporting critical decision-making in canine patients. [ABSTRACT FROM AUTHOR]

A retrospective search was conducted to evaluate the diagnostic accuracy of the vertebral heart score (VHS) and other related radiographic indices in the detection of cardiac enlargement associated with different cardiac disorders in the cat. One hundred and five cats with a complete echocardiographic examination and radiographic examination of the thorax with at least two orthogonal views were enrolled. Eighty-three cats had different cardiac disorders, 72 with left-sided cardiac disorders (LSCD) and 11 with right-sided cardiac disorders; 22 cats were free of cardiovascular abnormalities. Measurements of VHS and cardiac long and short axes on lateral (L) and dorsoventral or ventrodorsal radiographs were obtained. Receiver operating characteristic curves were calculated to evaluate the diagnostic accuracy of each radiographic index in differentiating between cats with cardiac disorders or cats with LSCD and cats without cardiac abnormalities and, among cats with LSCD, between those with no or mild left atrial enlargement (LAE) or those with moderate-to-severe LAE and healthy cats. The L-VHS at the cut-off of 7.9 had high diagnostic accuracy in distinguishing cats with LSCD and moderate-to-severe LAE from healthy cats, but all the other radiographic indices were moderately accurate in distinguishing between cats with overall cardiac disorders or LSCD, either with no or mild LAE and moderate-to-severe LAE, and healthy cats. The considered radiographic indices were also moderately accurate in predicting different degrees of LAE in cats with LSCD. Radiographic indices are reasonably specific, but less sensitive predictors of cardiac enlargement in cats with heart disorders. [ABSTRACT FROM PUBLISHER]

Simple Summary: Assessing enlargement of the left atrium (one of the four cardiac chambers) is extremely important for gaining information about dogs' heart disease, their prognosis, and directing treatment. However, people with different levels of experience may be required to make this assessment, and we don't know how observers with different experiences perform in making this assessment. In this study, five observers with different levels of experience evaluated the left atrium of 36 dogs in a blinded fashion (i.e., unaware of each other measurements, or of the identity of the dog), compared to two cardiologists. We then used statistical analysis to evaluate repeatability, reproducibility, accuracy of the measurements, and the capacity of correctly identifying left atrial enlargement. We found that the measurements performed by observers with more experience where more similar to the cardiologists' measurements, and that combining more than one technique for measuring the left atrium can improve accuracy of the identification of left atrial enlargement. Assessment of left atrial (LA) sizes in dogs informs clinical staging, risk assessment, treatment decisions, and prognosis. The objective of this study was to assess the diagnostic performance of observers with different levels of experience measuring the LA with three different techniques. Echocardiographic images from 36 dogs with different degrees of left atrial enlargement (LAE) were retrospectively retrieved, anonymized and measured in a blinded fashion by a veterinary student, a first-year cardiology resident, a third-year cardiology resident, and two board-certified veterinary cardiologists. The LA to aortic root ratio (LA:Ao), LA antero-postero diameter indexed to body weight (LAiAPD) and left atrial area were measured. Inter- and intra-observer intraclass correlation coefficients (ICCs) were calculated for all three variables. Bland–Altman plots and accuracy in identification of LAE were calculated for the three least experienced observers using LA:Ao and LAiAPD. Intra- and interobserver ICCs were greater than 0.9 for every variable. The observer with least experience had significant positive bias and a tendency to overestimate larger measurements using LA:Ao, but not using LAiAPD. The accuracy of identification of LAE also increased with the increasing level of experience and was higher for LAiAPD compared to LA:Ao. Combining both methods for identification of LAE, further increased accuracy. [ABSTRACT FROM AUTHOR]

OBJECTIVE To investigate the relationship between invasively measured stroke volume (SV) and (1) esophageal Dopplerderived indices such as stroke distance (StrokeD), flow time corrected (FTc), stroke distance variation (SDV), and peak velocity variation (PVV); and (2) arterial load (AL) variables during evaluation of fluid responsiveness (FR) in anesthetized dogs undergoing sudden hemodynamic shifts in blood volume. ANIMALS 6 healthy male dogs. PROCEDURES Dogs were anesthetized with isoflurane, ventilated mechanically, and instrumented to undergo sequential, nonrandomized experimental stages. The dogs transitioned from normovolemia (NORMO-BL) to hypovolemia (30% blood loss; HYPO-30), followed by autologous blood transfusion, and then to hypervolemia (colloid bolus). During each stage, SV was quantified using pulmonary artery thermodilution and its relationship with StrokeD, FTc, SDV, and PVV; and AL variables such as effective arterial elastance (Ea), dynamic arterial elastance (Eadyn), and total arterial compliance (Ca) were established. RESULTS As SV decreased significantly during HYPO-30 compared to NORMO-BL, there was a significant (P < .001) decrease in StrokeD, FTc, and Ca, with simultaneous increases in SDV, PVV, Ea, and Eadyn. Upon restoration of blood volume, these values stabilized closer to NORMO-BL. A significant (P < .001) correlation was observed between SV and StrokeD, FTc, Ea, Eadyn, and Ca. CLINICAL RELEVANCE Minimally invasive StrokeD, FTc, SDV, and PVV act as SV surrogates and help assess FR during different blood volume stages in healthy dogs. During hypovolemia-induced hypotension, Ea, Eadyn, and Ca may be able to guide therapeutic decisions favoring improvement in blood pressure and SV. [ABSTRACT FROM AUTHOR]