To characterize the patterns associated with Lorenz plots (LPs) or Poincaré plots derived from the Holter recordings of dogs with various cardiac rhythms.
77 dogs with 24-hour Holter recordings.
A 1-hour period from the Holter recordings from each of 20 dogs without arrhythmias and from each of 57 dogs with arrhythmias (10 each with supraventricular premature complexes, complex supraventricular ectopy, ventricular premature complexes, complex ventricular ectopy, and atrial fibrillation, and 7 with high-grade second-degree atrioventricular block) were used to generate the LPs. Patterns depicted in the LPs were described.
Arrhythmia-free Holter recordings yielded LPs with a Y-shaped pattern and variable silent zones. Recordings with single premature complexes yielded LPs with double side and triple side lobes. Complex ectopy was denoted by dots clustered in the lower left corner of the LPs. The LPs of recordings with atrial fibrillation had fan patterns consistent with a nonlinear relationship between atrial electrical impulses and atrioventricular nodal conduction. The recordings with atrioventricular block yielded LPs with island patterns consistent with variable atrioventricular nodal conduction.
CONCLUSIONS AND CLINICAL RELEVANCE
Distinct LP patterns were identified for common cardiac rhythms of dogs, supportive of nonrandom mechanisms as the cause of most rhythms. Visual interpretation of an LP generated from a Holter recording may aid in determining the arrhythmia type and understanding the arrhythmia's mechanism in dogs and other species.
To compare metabolomic profiles of dogs eating grain-free (GF) versus grain-inclusive (GI) diets (1) for healthy dogs at baseline and (2) for dogs with subclinical cardiac abnormalities at 12 months after a diet change.
Serum samples from 23 dogs eating GF diets and 79 dogs eating GI diets, of which 17 (8 eating a GF diet and 9 eating a GI diet) were reevaluated 12 months after a diet change.
Metabolomic profiles were developed by means of ultrahigh-performance liquid chromatography–tandem mass spectroscopy of serum samples. Baseline results for the GF group were compared with those for the GI group. Dogs from both groups with subclinical cardiac abnormalities were transitioned to a GI, pulse-free, intervention diet, and samples collected 12 months later were compared between diet groups. Statistical significance for biochemical group differences was defined as P < .05 with a false discovery rate (q) < .10.
Baseline differences in lipid metabolism and amino acid metabolism were found between the GF and GI diet groups. There were 46 metabolites that were higher and 82 metabolites that were lower in the GF group (n = 23), compared with the GI group (79). Comparison of the GF (n = 8) and GI (9) groups 12 months after the diet change showed only 6 metabolites that were higher and 11 metabolites that were lower in the GF group, compared with the GI group.
Metabolomic pathway differences between dogs eating GF versus GI diets highlight the important effect of diet in metabolomics analyses. The clinical importance of these differences and how they might relate to cardiac disease in dogs remains undetermined.
To evaluate the frequency of variants in the pyruvate kinase dehydrogenase 4 (PDK4) and titin (TTN) genes in a group of Doberman Pinschers with dilated cardiomyopathy (DCM) and to determine whether there were unique clinical attributes to each variant.
48 Doberman Pinschers with DCM.
Doberman Pinschers with recently diagnosed DCM were identified, and genomic DNA from each was genotyped with a PCR assay for detection of PDK4 and TTN genetic variants. Dogs were grouped on the basis of whether they had the TTN variant alone, PDK4 variant alone, both variants, or neither variant. Descriptive statistics were compiled for dog age, body weight, and left ventricular dimensions and fractional shortening and for the presence of ventricular and supraventricular arrhythmias and heart failure. Results were compared across groups.
Of the 48 dogs, 28 had the TTN variant alone, 10 had both variants, 6 had neither variant, and 4 had the PDK4 variant alone. The mean age was younger for dogs with the PDK4 variant alone, compared with other dogs. However, the number of dogs with the PDK4 variant alone was very small, and there was an overlap in age across groups. No other meaningful differences were detected across groups, and independent genotype-phenotype relationships were not identified.
CONCLUSIONS AND CLINICAL RELEVANCE
Although findings indicated that the TTN variant was most common, 6 dogs had neither variant, and this fact supported the concept of ≥ 1 other genetic contributor to DCM in Doberman Pinschers. Future studies are warranted to evaluate genotype-phenotype relationships in Doberman Pinschers with DCM.
Objective—To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi).
Animals—20 healthy zebras.
Procedures—Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras.
Results—Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean ± SD heart rate of 67 ± 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra.
Conclusions and Clinical Relevance—Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras.