27 Aug 2021
Alex Gough MA, VetMB, CertSAM, CertVC, PGCert(Neuroimaging), MRCVS reviews more research in his latest column from Vet Times.
Image: kkolosov / Pixabay
Arrhythmias are frequently intermittent, or vary in nature and severity. Measuring a short ECG in clinic may not capture the full variability of the arrhythmia, and the stress of the clinic may cause non-typical results.
Holter monitoring to give longer, ambulatory ECG recordings is an important technique to overcome these problems. However, the optimum duration of Holter monitoring is not clear.
Longer readings are more costly and may represent more discomfort to the pet by requiring the monitor to be worn for a longer period, while shorter readings may miss important information.
Mavropoulou et al1 performed a retrospective review of 354 48-hour Holter recordings to compare the information obtained in the first 24 hours with the total information obtained. In 25% of cases, an arrhythmia that caused clinical signs was found.
A 48-hour Holter monitor increased the likelihood of documenting an arrhythmia during an event. However, the 48-hour monitoring period only increased the likelihood of documenting an important arrhythmia by 5%, and this was mainly in dogs with supraventricular arrhythmias.
For bradyarrhythmias and ventricular arrhythmias, the extra 24 hours was rarely useful.
Holter monitoring is important for detecting clinically relevant arrhythmias, but for many cases, 24 hours of monitoring is sufficient. However, 48-hour monitoring will document a small number of arrhythmias not found after 24 hours.
Cannabidiol (CBD) is becoming increasingly available, and is being used by some vets and owners for a variety of clinical conditions. Some evidence is now starting to emerge on its safety and efficacy.
Meija et al2 performed a double-blinded, crossover, placebo-controlled study on 23 client-owned dogs to assess the effect of CBD on OA-associated pain. After four weeks of baseline data collection, dogs were randomised to receive either placebo or CBD for six weeks, followed by a crossover to six weeks of the other treatment. Various objective measures such as accelerometry were used as outcome measures.
No differences were noted between the two groups for any of the outcome measures at any time points. However, 2 dogs vomited after CBD administration, and 14 dogs had elevated liver enzymes.
This small study suggests CBD has no benefit in the treatment of OA and that the compound can cause adverse effects.
Splenic haemangiosarcoma is a malignant tumour that often carries a poor prognosis despite optimal treatment.
Masyr et al3 performed a retrospective study of 70 client-owned dogs to identify physical and clinicopathological variables that could aid in predicting prognosis. All dogs were treated with splenectomy and chemotherapy.
Tumour stage was associated with prognosis, and stage three was associated with a markedly worse progression-free interval (PFI) and overall survival time (OST). Perioperative thrombocytopenia was also a negative prognostic indicator associated with shorter PFI and OST.
The authors recommend further research to assess the causal link between thrombocytopenia and prognosis, and then to evaluate whether this could improve treatment.
Measurements in clinical practice can vary within patients for a variety of reasons such as physiological, pathological and analytical factors. Pre-analytic factors that can cause variation include diet, stress, posture at time of sampling and storage of samples.
Saver et al4 performed a study to assess the effect of withholding food on the serum concentrations of cobalamin, folate, trypsin-like immunoreactivity (TLI) and pancreatic lipase immunoreactivity (cPLI). Eleven healthy dogs were included in the study.
Food was withheld for 12 hours and baseline blood samples were collected. Dogs were then fed and blood samples were collected at various time intervals after feeding. The effect of lipaemia was also considered.
Cobalamin concentrations were lower at four and eight hours postprandially compared to baseline, but this was not considered to be clinically important. No substantial differences were noted in folate, TLI or cPLI, but the mild changes in TLI and folate could affect the diagnosis in some cases.
The authors concluded that feeding rarely made a clinically important difference in the serum concentrations of these parameters, but the further processing required for lipaemic samples means it remains prudent to withhold food for eight hours prior to blood sampling for these tests.
Further research is needed into the effect of withholding food on the measured values of the parameters in dogs with gastrointestinal disease.
Feline chronic gingivostomatitis (FCGS) is a common and painful diseases of unknown cause.
Fried et al5 performed a molecular analysis to identify any associations with the disease in cats with FCGS compared to healthy controls and cats with periodontitis. Oral mucosal swabs were taken from 19 control cats and 23 cats with FCGS. The samples were analysed with unbiased metatranscriptomic next-generation RNA sequencing.
The abundance of microbial and host genes were compared between the FCGS cats and the controls, and between FCGS cats that did and did not respond to clinical treatment.
Feline calicivirus (FCV) was the only microbe strongly associated with FCGS, and this virus was detected in 21 of the 23 FCGS cats, but none of the controls.
Puma feline foamy virus was detected in 9/13 FCGS cats that did not respond to treatment, but none of the FCGS cats that responded to tooth extraction. The genes most expressed in FCGS cats compared to controls were those with antiviral activity.
The authors concluded that FCGS has a viral component, with FCV a likely candidate. They noted that many FCV strains are not detected by reverse transcription-PCR analysis. They also postulated that co-infection with puma feline foamy virus may have a negative effect on treatment.
Chihuahuas are known to frequently have persistent fontanelles on the dorsal skull (bregmatic fontanelles).
It has often been considered that this is a clinically unimportant finding, but no studies have described its prevalence or whether it is accompanied by other persistent fontanelles, or whether they are associated with other cranial abnormalities common in the breed such as Chiari-like malformation (CM) and syringomyelia (SM).
Kiviranta et al6 performed a study to describe the number and location of persistent fontanelles in Chihuahuas with and without signs related to CM/SM. Fifty Chihuahuas with and without CM/SM clinical signs were included in the studies; 92% had at least one persistent fontanelle, with a mean of 2.8 persistent fontanelles.
The number of cranial sutures affected by persistent fontanelles and the total area of the open fontanelles was significantly higher in dogs with CM/SM-related clinical signs.
The authors concluded that persistent fontanelles are very common in Chihuahuas and appear at dorsal, later lateral and caudal cranial surfaces. More numerous and larger fontanelles are associated with CM/SM-related signs.
Optimal treatment for heart failure in cats has yet to be conclusively established.
Schober et al7 performed a prospective randomised placebo-controlled double-blind multicentre trial to investigate the effects of pimobendan in cats with hypertrophic cardiomyopathy (HCM) and recent-onset congestive heart failure (CHF) – 83 cats with HCM and recent CHF were included in the study; 30 of these had left ventricular outflow tract obstruction and 53 did not.
Cats received either placebo or pimobendan, although in one case neither was given. All received furosemide, with or without clopidogrel. The primary endpoint was reaching 180 days without requiring an escalation in furosemide dose. No difference in outcome for the two groups was found.
For non-obstructive cats, 32% reached the primary end point compared to 18.2% in the placebo groups, with an odds ratio of 2.12. However, the 95% confidence interval crossed 1.0, implying the results were not significant. The authors concluded that in this study, no benefit of pimobendan for cats with HCM and recent-onset CHF was identified.
Note that some of the drugs mentioned in this article may not be licensed for the purpose described.
