QT interval instability and QRS interval dispersion in healthy cats and cats with a hypertrophic cardiomyopathy phenotype.

OBJECTIVES: Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. Electrocardiographic (ECG) analysis can help with the diagnosis of HCM and also in the investigation of the secondary consequences of the disease. This study investigated ECG markers of QT interval variability (total instability [TI], short-term instability [STI], long-term instability [LTI], QT variance [QTv]), mean QT interval (QTa) and QT interval corrected for heart rate (QTac), as well as the duration (QRSd) and dispersion (QRSv) of the QRS interval in healthy cats and in those with HCM. METHODS: Data were collected from 63 domestic cats: 40 in the control group and 23 in the HCM group. Fifty consecutive QT intervals were recorded for all cats and then QTa, QTac, QTv, TI, LTI and STI were calculated. QRSd and QRSv were also obtained for all animals. A Mann-Whitney U-test was used for group comparison. Receiver operating characteristic curves were plotted to evaluate the sensitivity and specificity of all markers for HCM. Logistic regression analysis was performed to assess the risks of cats having HCM, based on the studied indexes. RESULTS: QTa (P <0.01), QTac (P <0.01), QRSd (P <0.01) and STI (P = 0.02) were higher in the HCM group. QTa >158.8 ms, QTac >27.4 ms and QRSd >0.045 s had an accuracy of 77.4%, 68.2% and 80.9%, respectively, in detecting HCM. Logistic regression showed that cats with QTa >158 ms, QTac >27.4 ms and QRSd >0.045 s had a 1.58-, 1,23- and 6.5-fold higher risk, respectively, of developing HCM. CONCLUSIONS AND RELEVANCE: Cats with HCM had higher ventricular instability as assessed by STI and showed a prolongation of the QT and QRS intervals via the QTa, QTac and QRSd markers. These markers show potential as ancillary screening tools for identifying the presence of HCM.

Tpeak-Tend, a novel electrocardiographic marker in cats with hypertrophic cardiomyopathy-a brief communication.

Hypertrophic cardiomyopathy (HCM) is the most common heart disease in feline species. ECG allows assessing parameters that can help in the diagnosis and risk stratification of conditions that occur secondary to this disease. This study aimed to evaluate electrocardiographic markers Tpte and Tpte/QT in leads I, II, III, aVR, aVL and aVF in control and HCM cats. Data were obtained from 63 domestic cats allocated in a Control (n = 40) and an HCM (n = 23) group. Tpte and Tpte/QT of all individuals were measured in all limb leads (I, II, III, aVR, aVL, aVF). We constructed ROC curves to evaluate the sensitivity and specificity of markers to identify HCM-affected cats. Logistic regression analysis was performed to assess the risks of cats having HCM based on Tpte indexes. Tpte in leads II (p < 0.01), aVR (p < 0.01), aVL (p < 0.01), and aVF (p < 0.01) had significantly higher results in the HCM group. Tpte/QT showed no statistical difference between groups in any of the derivations evaluated. A Tpte > 27.5ms in lead aVF showed an accuracy of 83.3% to identify individuals with HCM in our study. Univariable logistic regression reveals that cats with Tpte in aVR and aVF > 27.5ms and in aVL > 26.5ms had 1.28, 12 and 1.16 respectively, more chances of having HCM. The prolongation of Tpte may be a noninvasive electrocardiographic complementary tool to help differentiate patients with and without hypertrophic cardiomyopathy.

Behavioral and cardiovascular effects of a single dose of gabapentin or melatonin in cats: a randomized, double-blind, placebo-controlled trial.

OBJECTIVES: The aim of this study was to verify whether a single oral dose of gabapentin (100 mg) or melatonin (3 mg) given 60 mins before a cardiac evaluation would reduce anxiety without interfering with heart rate (HR), systemic blood pressure (SBP), electrocardiogram (ECG) and echocardiographic indexes. METHODS: Seventy-five client-owned healthy cats underwent two sets of cardiac assessments 60 mins apart, randomly divided into gabapentin, melatonin and placebo groups. The interval between treatment and the second ECG and SBP measurement was 60 mins, and 70 mins for echocardiography. A compliance score (CS) classified the behavior, focusing on the ease of handling. RESULTS: Most variables did not change between the examinations. The placebo group showed more significant changes (SBP, tricuspid annular plane systolic excursion, HR during echocardiography, aortic flow velocity, S' wave from lateral mitral annulus), but they were not considered to be hemodynamically relevant. Gabapentin and melatonin significantly increased the cats' compliance without interfering with cardiac assessment. Eight cats presented with mild sedation, seven after gabapentin and one after melatonin. No major side effects were observed. CONCLUSIONS AND RELEVANCE: Gabapentin tranquilized the cats when it was given 60 mins prior to ECG and SBP measurement, and 70 mins prior to echocardiography, without interfering with systolic echocardiographic indexes. Melatonin also decreased the CS, but without sedation in most cases. The waiting period may have relaxed the cats in the placebo group, resulting in lower SBP measurements. However, this tranquility did not last as some echocardiographic changes signaled a sympathetic predominance.

Aqueous wheat extract (Triticuma estivum) prevents carboplatin-induced myelosuppression and oxidative stress in Wistar rats / Extrato aquoso de trigo (Triticum aestivum) na prevenção da mielossupressão e estresse oxidativo induzidos pela carboplatina em ratos Wistar

ABSTRACT: The present study aimed to evaluate the use of aqueous wheat extracts as an adjunct to antineoplastic therapy with carboplatin. In this study, 32 rats were used which were randomly distributed into 4 groups: G1 - negative control; G2 - control treated with physiological solution; G3 - animals treated with aqueous extract of wheat in the concentration of 100mg/kg; G4 - animals treated with aqueous wheat extract at the concentration of 400mg/kg; 300mg/m² of carboplatin was administered intraperitoneally at day 0 in animals from groups G2, G3, and G4, whereas 1ml of physiological solution was administered by the same route in animals from group G1. Animals were treated daily for 21 days by orogastric gavage according to their respective experimental group. Blood was collected from animals on days 3, 7 and 21 for complete blood count (CBC), biochemistry, and measurement of paraoxonase 1 (PON1) activity. On day 21, animals were euthanized and necropsied. Promising results were obtained regarding oxidative balance in groups G3 and G4. Both presented better PON1 activity in comparison with group G2 (P<0.05). Total leukocyte count of group G4 differed significantly from group G2 (P<0.05) on day 21. Myelogram values of animals from groups G3 and G4 were ​​similar to those from G1; animals from G3 had lower numbers of promyelocytes and increased numbers of erythrocytes and rubriblasts than animals from G2 (P<0.05). In the present experimental study, aqueous wheat extract was safe at the doses used in the animals, and was an effective treatment for myelosuppression and for the prevention of an excessive release of free radicals induced by carboplatin.

RESUMO: O presente estudo avaliou a utilização dos extratos aquosos de trigo como adjuvante a terapia antineoplásica com carboplatina. No estudo foram utilizadas 32 ratas, as quais foram aleatoriamente distribuídas em quatro grupos: G1 - controle negativo; G2 - controle tratado com solução fisiológica; G3 - tratado com extrato aquoso de trigo na concentração de 100mg/kg; G4 - tratado com extrato aquoso de trigo na concentração de 400mg/kg. Administrou-se 300mg/m² de carboplatina por via intraperitoneal no dia 0 nos grupos G2, G3, e G4, enquanto no G1 foi administrado 1mL de solução fisiológica pela mesma via. Os animais foram tratados diariamente durante 21 dias por gavagem orogástrica de acordo com seu respectivo grupo experimental. Foi coletado sangue dos animais nos dias três, sete e 21, para realização de hemograma, testes bioquímicos e mensuração da atividade da paraoxanase 1 (PON1). No dia 21 os animais foram eutanasiados e realizada coleta de medula óssea, rim e fígado. Foram observados resultados promissores com relação ao balanço oxidativo no G3 e G4, pois ambos apresentaram melhor atividade da PON1 em relação ao G2 (P<0,05). Além disso, foi constatado que os mesmos grupos apresentaram contagem de leucócitos totais superiores ao G2 durante todo o período experimental, com G4 diferindo significativamente do G2 (P<0,05) no dia 21. Os mielogramas dos animais do G3 e G4 apresentaram valores análogos ao G1, sendo que o G3 apresentou menor contagem de promielócitos e maior de células eritroides e rubroblastos que o G2 (P<0,05). Nas condições experimentais deste estudo os extratos aquosos de trigo mostraram-se seguros nas doses utilizadas e úteis no tratamento da mielossupressão e liberação excessiva de radicais livres induzidas pelo fármaco carboplatina.