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This research was intended to identify reference intervals for the radiographic cardiac indices [vertebral heart scale (VHS), radiographic left atrial dimension (RLAD), and vertebral left atrial size (VLAS) of 58 healthy, adult New Zealand white rabbits based on echocardiography. The VHS, VLAS, and RLAD measurements were taken from contrast right lateral (R) and ventrodorsal (VD) thoracic radiographs. The correlations between these radiographic cardiac indices and echocardiographic parameters were then evaluated. The mean values with a reference interval were 7.94±0.31 vertebrae (v) (7.2-8.6 v) for R-VHS and 8.67±0.33 v (7.8-9.2 v) for VD-VHS. The median values with a reference interval were 1.5 v (1-2 v) for VLAS and 1 v (0.7-1.4 v) for RLAD. Body weight and gender had no effect on radiographic cardiac indices. There were positive correlations between all radiographic indices obtained from the R contrast radiographs and the echocardiographic parameters (rs=0.421, P<0.0001). Excellent intraobserver agreement was determined for the radiographic measurement methods (intraclass correlation coefficients =0.818). The contrast thoracic radiography appears to represent a useful technique for the accurate determination of radiographic cardiac indices. The findings can be used as reference values for radiographic cardiac evaluation in both pet and laboratory rabbits. [ABSTRACT FROM AUTHOR]

Abstract Background Predicting progression of myxomatous mitral valve disease (MMVD) in dogs can be challenging. Hypothesis/Objectives The mitral regurgitation severity index (MRSI) will predict time to congestive heart failure (CHF) and all‐cause death in dogs with MMVD. Animals Eight hundred sixty‐nine client‐owned dogs. Methods Retrospective study pooling data from 4 previous samples including dogs with MMVD stage B2 or C. MRSI was calculated as: (heart rate [HR]/120) × left atrium‐to‐aorta ratio (LA:Ao) × (age in years/10) × 100. Alternative MRSI formulas substituting radiographic measures of left atrial size were also calculated. Cox proportional hazard modeling and time‐dependent receiver‐operator characteristic curves quantified prognostic performance. Results For Stage B2 pooled samples, MRSI > 156 was predictive of time to CHF (median 407 vs 1404 days; area under the curve [AUC] 0.68; hazard ratio 3.02 [95% CI 1.9‐4.9]; P 173 was predictive of all‐cause death (median survival 868 vs 1843 days; AUC 0.64; hazard ratio 4.26 [95% CI 2.4‐7.5]; P

Background: Predicting progression of myxomatous mitral valve disease (MMVD) in dogs can be challenging. Hypothesis/Objectives: The mitral regurgitation severity index (MRSI) will predict time to congestive heart failure (CHF) and all‐cause death in dogs with MMVD. Animals: Eight hundred sixty‐nine client‐owned dogs. Methods: Retrospective study pooling data from 4 previous samples including dogs with MMVD stage B2 or C. MRSI was calculated as: (heart rate [HR]/120) × left atrium‐to‐aorta ratio (LA:Ao) × (age in years/10) × 100. Alternative MRSI formulas substituting radiographic measures of left atrial size were also calculated. Cox proportional hazard modeling and time‐dependent receiver‐operator characteristic curves quantified prognostic performance. Results: For Stage B2 pooled samples, MRSI > 156 was predictive of time to CHF (median 407 vs 1404 days; area under the curve [AUC] 0.68; hazard ratio 3.02 [95% CI 1.9‐4.9]; P <.001). MRSI > 173 was predictive of all‐cause death (median survival 868 vs 1843 days; AUC 0.64; hazard ratio 4.26 [95% CI 2.4‐7.5]; P <.001). MRSI showed superior predictive value compared to the individual variables of HR, LA:Ao, and age. Variations of the MRSI equation substituting radiographic vertebral left atrial size for LA:Ao were also significantly predictive of outcome in stage B2. MRSI was not consistently predictive of outcome in Stage C. Conclusions and Clinical Importance: MRSI was predictive of outcome (onset of CHF and all‐cause death) in MMVD Stage B2, demonstrating utility as a useful prognostic tool. Echocardiographic LA:Ao can be effectively replaced by radiographically determined LA size in the MRSI formula. [ABSTRACT FROM AUTHOR]

Staging of myxomatous mitral valve disease (MMVD) requires an echocardiographic examination along with thoracic radiographs. The aims of this study were to calculate mean values for radiographic scores vertebral heart size (VHS), left atrial width (LA Width), radiographic left atrial dimension (RLAD), and vertebral left atrial size (VLAS) in conventional and grayscale inverted images in healthy dogs and dogs with different stages of MMVD, and to find cutoff values for a stage assignment. One hundred fifty dogs in different stages of MMVD and 50 unaffected dogs were evaluated. Radiographic scores, echocardiographic left atrium-to-aorta ratio and normalized left ventricular internal dimension at end-diastole, and results of a clinical examination were obtained. Analyses were performed to evaluate the correlation between radiographic scores and echocardiographic values, to determine cutoff values for a radiographic stage assignment, and to compare measurements in conventional and inverted radiographs. After excluding breed-specific higher VHS, the means of VHS, LA Width , RLAD, and VLAS were similar in the control group and stage B1. All radiographic scores increased in stages B2 and C. The cutoff values identifying heart enlargement, and therefore differentiating stages B1 and B2, were 11.0 for VHS, 1.8 for LA Width , 2.0 for RLAD, and 2.3 for VLAS. Besides RLAD, scores were similar in conventional and inverted radiographs. Cutoff values for the different radiographic scores for stage assignment were calculated. Radiographic cardiac scores using either conventional or inverted grayscale could be a tool to differentiate between different stages of MMVD when echocardiography is unavailable. [ABSTRACT FROM AUTHOR]

Simple Summary: In the present study, different radiographic measurements for evaluating the cardiac size and left atrial size in dogs with and without myxomatous mitral valve disease were evaluated. Veterinarians applied these measurements with different levels of experience to identify heart enlargement in conventional and inverted radiographs. The repeatability and ease of application were evaluated. It was shown that radiographic measurements can identify cardiac enlargement reliably and even potentially stage dogs with myxomatous mitral valve disease if echocardiography is unavailable. The measurements can be performed in conventional and inverted radiographs with reliable results by veterinarians with different degrees of experience. Dogs suffering from Myxomatous Mitral Valve Disease (MMVD) show a potential heart enlargement, especially in the left atrium, detectable by radiography. Due to digital radiography, different radiographic measurements estimate cardiac size quite uncomplicatedly. The Vertebral Heart Size (VHS), Radiographic Left Atrial Dimension (RLAD), Left Atrial Width (LAWidth), and the Vertebral Left Atrial Size (VLAS) used anatomical landmarks for measuring cardiac size in relation to the vertebral column. This study aimed to compare VHS, RLAD, LAWidth, and VLAS measured in conventional and inverted radiographs by veterinarians with different levels of experience in healthy dogs and dogs with MMVD. The reliability and user-friendliness of these measurements were evaluated, and the staging was compared to the echocardiography staging. A total of 50 unaffected dogs and 150 dogs with MMVD in stages B1, B2, and C were assessed. Three veterinarians with different levels of experience examined 200 conventional radiographs and their corresponding inverted radiographs blinded to the echocardiographic and clinical examination results. Analyses were performed to compare the measurements' grading and determine anatomical landmarks with measurement difficulties. Additionally, inter- and intraobserver agreement was assessed using intraclass correlation coefficient, and the agreement between radiographic and echocardiographic staging was compared using the kappa coefficient. The VHS, LAWidth, and VLAS were easier to define than the RLAD. The interobserver agreement was almost perfect for VHS (0.962) and good for the other radiographic measurements (RLAD: 0.778, LAWidth: 0.772, VLAS: 0.858). The VHS assigned the most dogs to the correct stage. However, VHS, RLAD, LAWidth, and VLAS presented an almost perfect intraobserver agreement. The dorsal left atrial margin of the RLAD was the most difficult measurement point to identify. The VHS is the most reproducible radiographic method for measuring the canine heart size and shows the highest agreement with echocardiography. An observer-related influence could be detected for RLAD, LAWidth, and VLAS. [ABSTRACT FROM AUTHOR]

Abstract Background In the absence of echocardiography, identification of cardiomegaly via thoracic radiography is a necessary criterion for classification of disease severity in dogs with myxomatous mitral valve disease (MMVD). Objective Modified‐vertebral left atrial size (M‐VLAS) facilitates objective radiographic assessment of the left atrium (LA) in 2 dimensions and identifies LA enlargement more accurately than existing methods. Animals Sixty‐four dogs with various stages of MMVD and 6 control healthy dogs. Methods Retrospective case–control study. Medical records were searched for dogs with varying severity of MMVD. Modified‐vertebral left atrial size, vertebral left atrial size (VLAS), vertebral heart size (VHS), and radiographic left atrial dimension (RLAD) were measured from thoracic radiographs and compared with echocardiographically derived measurements. Results Positive correlation to LA/Ao was identified for M‐VLAS (r = 0.77, P

Abstract Background Evaluation of left heart size helps determine disease severity in dogs with myxomatous mitral valve disease (MMVD). Hypothesis/Objectives Determine the ability of radiographic vertebral heart size (VHS) and vertebral left atrial size (VLAS) to predict LHEECHO in dogs with preclinical MMVD. Animals Seventy client‐owned dogs with MMVD and no historical or present clinical or radiographic evidence of congestive heart failure (CHF). Methods Retrospective cross‐sectional study of dogs with same‐day echocardiography and thoracic radiography. Receiver‐operating characteristic (ROC) curves were used to assess the ability of VHS, VLAS, and VHS + VLAS to discern dogs with and without LHEECHO, and clinically relevant cutpoints for these radiographic measurements were selected. Results The ability of VHS and VHS + VLAS to predict LHEECHO was moderate (area under the curve [AUC]VHS = 0.851; 95% CI, 0.762‐0.941; AUCVHS + VLAS = 0.865; 0.783‐0.947), and performance of VLAS and VHS + VLAS was not different from that of VHS alone. A VHS cutpoint of >10.8 had sensitivity = 91.1% (76.3%‐98.1%) and specificity = 69.4% (51.9%‐83.7%) for predicting LHEECHO. A cutpoint of >11.7 had sensitivity = 32.4% (17.4%‐50.5%) and specificity = 97.2% (85.5%‐99.9%) for predicting LHEECHO. Thirty (43%) of the 70 dogs had a VHS value of 10.9 to 11.7. Conclusions and Clinical Importance Vertebral heart size >11.7 identified dogs with LHEECHO and VHS ≤ 10.8 excluded dogs with LHEECHO. A large percentage of dogs had VHS values intermediate to these cutpoints.

Two radiographic measures of the left atrial (LA) size, the vertebral left atrial size (VLAS) and the radiographic left atrial dimension (RLAD), have been described in dogs. The aim of this study was to determine their feasibility and diagnostic value in the prediction of LA enlargement and clinical stage in dogs with myxomatous mitral valve disease (MMVD). 111 client-owned dogs affected by MMVD. Retrospective study. In each dog, VLAS, RLAD, vertebral heart score (VHS), and left atrium-to-aorta-ratio (LA/Ao) were measured. The correlation between VLAS, RLAD, and LA/Ao was evaluated. The diagnostic accuracy of VLAS and RLAD was assessed for the detection of LA enlargement and clinical staging using the receiver operating characteristic curve analysis. A positive correlation was observed between VLAS, RLAS, and LA/Ao (r = 0.816 and r = 0.855, respectively; p<0.0001). Both VLAS (area under the curve [AUC], 0.93; p<0.0001) and RLAD (AUC, 0.98; p<0.0001) showed high diagnostic accuracy in the detection of LA enlargement. In the stage B, the RLAD (AUC, 0.99; cutoff, ≥1.8; sensitivity, 100%; specificity 93%) performed better than VLAS (AUC, 0.90; cutoff, ≥2.4; sensitivity, 66%; specificity 100%) and VHS (AUC, 0.89; cutoff, ≥10.7; sensitivity, 88%; specificity 83%) in the detection of dogs fulfilling the echocardiographic criteria for stage B2. VLAS and RLAD represent useful radiological tools for the detection of LA enlargement in dogs with MMVD. In asymptomatic dogs, the RLAD performs better than VLAS and VHS in the prediction of those fulfilling the echocardiographic criteria for stage B2. [ABSTRACT FROM AUTHOR]

Background: In the absence of echocardiography, identification of cardiomegaly via thoracic radiography is a necessary criterion for classification of disease severity in dogs with myxomatous mitral valve disease (MMVD). Objective: Modified‐vertebral left atrial size (M‐VLAS) facilitates objective radiographic assessment of the left atrium (LA) in 2 dimensions and identifies LA enlargement more accurately than existing methods. Animals Sixty‐four dogs with various stages of MMVD and 6 control healthy dogs. Methods: Retrospective case–control study. Medical records were searched for dogs with varying severity of MMVD. Modified‐vertebral left atrial size, vertebral left atrial size (VLAS), vertebral heart size (VHS), and radiographic left atrial dimension (RLAD) were measured from thoracic radiographs and compared with echocardiographically derived measurements. Results: Positive correlation to LA/Ao was identified for M‐VLAS (r = 0.77, P <.001), VLAS (r = 0.76, P <.001), RLAD (r = 0.75, P <.001), and VHS (r = 0.67, P <.001). Receiver operating characteristic analyzes provided an area under the curve of 0.97 (95% CI, 0.94‐1.00) for M‐VLAS, which was superior to VHS (0.90, 95% CI, 0.94‐1.00, P =.03) in identifying dogs with LA/Ao ≥1.6. A cut‐off value of ≥3.4 vertebrae using M‐VLAS provided 92.7% sensitivity and 93.1% specificity in predicting LA enlargement. Conclusions and clinical importance: M‐VLAS, which is superior to VHS, offers an accurate and repeatable way to radiographically identify LA enlargement in dogs with MMVD. [ABSTRACT FROM AUTHOR]

Background: Evaluation of left heart size helps determine disease severity in dogs with myxomatous mitral valve disease (MMVD). Hypothesis/Objectives: Determine the ability of radiographic vertebral heart size (VHS) and vertebral left atrial size (VLAS) to predict LHEECHO in dogs with preclinical MMVD. Animals Seventy client‐owned dogs with MMVD and no historical or present clinical or radiographic evidence of congestive heart failure (CHF). Methods: Retrospective cross‐sectional study of dogs with same‐day echocardiography and thoracic radiography. Receiver‐operating characteristic (ROC) curves were used to assess the ability of VHS, VLAS, and VHS + VLAS to discern dogs with and without LHEECHO, and clinically relevant cutpoints for these radiographic measurements were selected. Results: The ability of VHS and VHS + VLAS to predict LHEECHO was moderate (area under the curve [AUC]VHS = 0.851; 95% CI, 0.762‐0.941; AUCVHS + VLAS = 0.865; 0.783‐0.947), and performance of VLAS and VHS + VLAS was not different from that of VHS alone. A VHS cutpoint of >10.8 had sensitivity = 91.1% (76.3%‐98.1%) and specificity = 69.4% (51.9%‐83.7%) for predicting LHEECHO. A cutpoint of >11.7 had sensitivity = 32.4% (17.4%‐50.5%) and specificity = 97.2% (85.5%‐99.9%) for predicting LHEECHO. Thirty (43%) of the 70 dogs had a VHS value of 10.9 to 11.7. Conclusions and Clinical Importance: Vertebral heart size >11.7 identified dogs with LHEECHO and VHS ≤ 10.8 excluded dogs with LHEECHO. A large percentage of dogs had VHS values intermediate to these cutpoints. [ABSTRACT FROM AUTHOR]