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 retrospectively evaluate neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) as a biomarker for severity and short-term outcomes of congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD) in dogs.
47 dogs with CHF secondary to MMVD, 47 dogs with presumptive preclinical MMVD, and 47 control dogs.
Medical record data (signalment, physical examination findings, medical treatments instituted, American College of Veterinary Internal Medicine MMVD stage, length of hospitalization, outcome, and hospital re-presentation due to CHF) from March 2012 through March 2022 for each dog were collected. Statistical analyses were performed with Mann-Whitney, Spearman correlation, and Fisher exact tests.
NLR (but not PLR) was significantly higher in dogs with CHF secondary to MMVD (6.41) compared to presumptive preclinical MMVD dogs (4.66; P < .001) and control dogs (3.95; P < .001). Dogs with higher NLR and PLR received significantly higher cumulative dosages of loop-diuretic therapy during hospitalization (ρ = 0.3, P = .04; and ρ = 0.4, P = .02, respectively). There was a positive association between NLR and duration of oxygen supplementation within the CHF group (ρ = 0.4; P = .01).
The increased diuretic dose and time receiving oxygen supplementation may represent increased disease severity for which NLR (and to a lesser extent PLR) may serve as a readily available marker. The data presented provide information regarding some of the systemic inflammatory changes seen in CHF secondary to MMVD in dogs. Future research should include prospective, longitudinal studies to provide insight into the long-term prognostic value of NLR and PLR in dogs with CHF.
To characterize features of myxomatous mitral valve disease (MMVD) in Miniature Schnauzers and Yorkshire Terriers.
69 Miniature Schnauzers and 65 Yorkshire Terriers, each with MMVD.
Medical record data for each dog were collected; the study period was January 2007 through December 2016. If available, radiographic data were evaluated, and a vertebral heart scale score was assigned for each dog. Statistical analysis was performed with Student t and Fisher exact tests.
Compared with Yorkshire Terriers, the prevalence of MMVD was significantly higher in Miniature Schnauzers and affected dogs were significantly younger at the time of diagnosis. Miniature Schnauzers were significantly more likely to have mitral valve prolapse and syncope, compared with Yorkshire Terriers. Yorkshire Terriers were significantly more likely to have coughing and have had previous or current treatment with cardiac medications, compared with Miniature Schnauzers. There was no statistical difference between breeds with regard to abnormally high vertebral heart scale scores or radiographic evidence of congestive heart failure.
CONCLUSIONS AND CLINICAL RELEVANCE
With regard to MMVD, features of the disease among Miniature Schnauzers and Yorkshire Terriers were similar, but there were also a few discernable differences between these 2 breeds and from historical findings for dogs with MMVD of other breeds. Clinical signs at the time of diagnosis differed between the 2 breeds, which may have reflected concurrent breed-specific conditions (sick sinus syndrome or airway disease [eg, tracheal collapse]). Future work should include prospective studies to provide additional information regarding the natural progression of MMVD in these dog breeds.