Changes in echocardiographic variables of left ventricular size and function in a model of canine normovolemic anemia

Left heart dimensions in anemic cats and dogs before and after blood transfusion

Background

Whether anemic cats and dogs with increased left heart dimensions are at higher risk of transfusion‐associated circulatory overload, and the effect of blood transfusion on left heart dimensions in naturally occurring anemia is unknown.

Hypothesis/objectives

To evaluate the effect of blood transfusion on left heart dimensions in clinically relevant anemia.

Animals

Twenty dogs and 20 cats presenting to a university veterinary teaching hospital.

Methods

In this prospective observational study, anemic dogs and cats requiring blood transfusion were included. Packed cell volume (PCV), total solids, and echocardiography were performed before and within 24 hours of blood transfusion. Signalment, bodyweight, disease process, transfusion duration and volume, and prior treatments were recorded. Nonparametric statistics were reported as median [range]. Post hoc Bonferroni correction set significance at P < .006.

Results

After transfusion, PCV increased in cats (12% [6–16] to 18% [10‐33], P = .001) and dogs (14% [7–24] to 25% [9‐37], P = .001), heart rate decreased in dogs (104 bpm [86‐166] to 87 bpm [56‐138], P < .001), and fractional shortening decreased in cats (57.1% [36.0‐84.7] to 41.0% [28.1‐69.6], P = .002) and dogs (33.79% [19.33‐62.79] to 31.89% [19.06‐51.47], P = .006). Left ventricular internal diameter in systole increased in cats (6.5 mm [2.7‐9.8] to 7.9 mm [5.3‐11.1], P = .001). Normalized left ventricular internal diameter in diastole (1.48 [1.25‐1.79] to 1.57 [1.33‐2.00], P = .001) and systole (0.87 [0.58‐1.19] to 1.00 [0.74‐1.36], P = .001) increased in dogs. Incidence of volume overload did not differ before (14/20 cats, 70%; 9/20 dogs, 45%) or after (12/20 cats, 60%; 11/20 dogs, 55%) transfusion (P = .64).

Conclusions and clinical importance

Blood transfusion is well tolerated when signs of volume overload are present before transfusion.

Pregnancy Effect on Echocardiographic Parameters in Great Dane Bitches

Simple Summary

In women, as well as in bitches, pregnancy is associated with the adaptation of the left ventricular function. Pregnancy mainly represents a status of increased volume load of the maternal heart driven by the need to supply an adequate blood flow through an augmented uterine perfusion to the developing fetuses. Consequently, cardiac morpho-functional changes are expected. Cardiac morphology and function in pregnant bitches that would develop complications may differ from those with a normal outcome. Thus, the assessment of the maternal cardiovascular function may be a useful screening tool to detect pregnancy complications in dogs. Few studies investigated the cardiac maternal adaptation in different gestational ages in dogs. Breed is a known source of variation in echocardiographic values; hence, the cardiac performance during pregnancy may also be prone to a breed-related variation. For these purposes, due to possible breed-related variations in cardiac parameters and function, and to the specific predisposition for myocardial diseases, echocardiographic changes along pregnancy in healthy Great Dane bitches were evaluated. A significant effect of the age of gestation on the increase of functional and diastolic parameters and on the decrease of systolic parameters was reported.

Abstract

Pregnancy is associated with adaptation of the left ventricular (LV) function. Due to differences between breeds in baseline echocardiographic values and specific predispositions for myocardial diseases, breed-specific echocardiographic parameters may be helpful to evaluate whether the systolic function varies during pregnancy. This study enrolled nine healthy Great Dane bitches with uncomplicated pregnancy. Echocardiographic M-mode and B-mode data were collected before ovulation and within 7 days of the predicted parturition term. Evaluated parameters were: LV dimension in diastole (LVd) and systole (LVs), end-diastolic (EDVI) and end-systolic (ESVI) volumes indexed to body surface area (BSA), end-diastolic (EDV) and end-systolic (ESV), end-point-septal-separation (EPSS), left atrium to aortic root ratio (LA/Ao), sphericity index (SI), ejection fraction (EF), fractional shortening (FS), stroke volume (SV), heart rate (HR), and cardiac output (CO). The ANOVA showed a statistical effect of the age of gestation (p < 0.01) on the increase of diastolic dimensions and functional parameters and on the decrease of systolic dimensions. The CO increase parallels the rise in SV and HR (p < 0.01). No statistical differences were observed for EPSS, LA/Ao, and SI. The changes in cardiac chambers and function are likely to reflect maternal adaptation to allow the fetal development in uncomplicated pregnancy. The present study provides specific echocardiographic values in uncomplicated pregnancy of Great Danes, showing that the systolic function is enhanced and that the increase in preload, observed during gestation, is the likely mechanism.

Evaluation of heart rate variability and behavior of electrocardiographic parameters in dogs affected by chronic Monocytic Ehrlichiosis

Canine Monocytic Ehrlichiosis (CME) is a systemic disease prevalent in the entire world caused by the obligate intracellular bacteria Ehrlichia canis. The occurrence of myocarditis with a high prevalence of arrhythmias in dogs affected by this disease in the cytopenic phase has already been proven. This study aims to evaluate the concentrations of CK MB, cTnI and NT-proBNP in dogs affected by Ehrlichia canis in the chronic phase since the intense stimulation of the immune system can lead to myocarditis; to evaluate if the condition can lead to arrhythmic events and, if so, define their frequency and classification through conventional and ambulatory electrocardiogram tests (Holter method) for a period of 24 hours; to analyze heart rate variability in the time domain and whether the condition can lead to autonomic imbalance; and to determine the survival rate of affected dogs, identifying possible risk factors for mortality at this stage of the disease. For this purposes, we evaluated clinical, hematological and biochemical data, as well as the concentrations of cardiac biomarkers Creatine Kinase-MB (CK MB), Cardiac Troponin I (cTnI) and N-terminal pro-peptide natriuretic type B (NT-proBNP). We also analyzed conventional and ambulatory electrocardiography (24-hour Holter) and heart rate variability (HRV) in 20 dogs afflicted by cytopenic CME in the chronic phase of the disease (G1) and compared the results with a control group comprised of ten healthy dogs (G2). G1 was monitored during the treatment for 28 days, during which eight (8) of the 20 infected dogs died (40%). Anorexia, vomiting, fatigue, hypoalbuminemia, heart murmurs and increased concentrations of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were common clinical signs. The mean concentrations of cTnI and CKMB were significant (0.24 ng / mL ± 0.5, 229 ± 205 IU / mL) in comparison to the control group (0.042 ± 0.07 ng / mL, 126 ± 46.12 IU / mL). No significant differences were observed between NT-proBNP concentrations in G1 (135.46 ± 29.7) and G2 (138.28 ± 19.77). Nine of the twenty dogs (45%) presented a high frequency of arrhythmias during 24-hour recording, ranging from first and second-degree atrioventricular block, ventricular and supraventricular ectopic events and sinus tachycardia. No sinus pause was observed. One dog had 120 episodes of unsustained ventricular tachycardia and two episodes of sustained ventricular tachycardia. The short-term and long-term HRV data, represented by SDNN (ms), SDANN (ms) and pnn50 (%) were also significant lower (83 ± 65, 56.05 ± 37.3 and 14.56 ± 20, respectively) in comparison to the healthy animals (268 ± 74.6, 168.3 ± 39.14 and 55.87 ± 12.8, respectively). These results suggest that cytopenic CME is characterized by an arrhythmogenic component and intense stimulation of the sympathetic autonomic nervous system in the heart, reflecting an imbalance in the activity of the ANS.

Comparison of myocardial damage among dogs at different stages of clinical leishmaniasis and dogs with idiopathic chronic kidney disease

Canine leishmaniasis (CanL) is a systemic disease caused by the protozoan parasite Leishmania infantum. Myocarditis in CanL has been described previously in CanL by histopathological analysis of post-mortem specimens and by evaluation of cardiac troponin I (cTnI) levels. However, the degree of myocardial damage at different stages of CanL and the role that concurrent azotaemia plays in this myocardial injury are unknown. The aim of this study was to prospectively evaluate and compare the presence of myocardial injury in dogs at different stages of clinical CanL and in dogs with severe idiopathic chronic kidney disease (CKD) by measuring cTnI. Forty-eight dogs were included in the study, divided into four groups: (1) group A (10 healthy dogs); (2) group B (17 dogs with CanL without renal azotaemia, classified as mild to severe in the LeishVet scheme); (3) group C (11 dogs with CanL and renal azotaemia, classified as very severe in the LeishVet scheme); and (4) group D (10 dogs with idiopathic CKD). Dogs in group C had significantly higher cTnI than dogs in groups B and D, although cTnI was also elevated in these groups. Dogs in group A had normal cTnI values. Dogs in groups D and C had similar renal IRIS classification scorers. Severe lymphoplasmocytic myocarditis and a positive real time PCR of L. infantum DNA were observed in all dogs in group C. Dogs with very severe CanL exhibit more myocardial injury than dogs with milder CanL or dogs with idiopathic CKD.

Serum cardiac troponin I concentrations decrease following treatment of primary immune-mediated haemolytic anaemia

OBJECTIVES

The measurement of serum cardiac troponin I concentrations in dogs with a range of non-primary cardiac illnesses suggests that cardiac myocyte damage is commonplace. Dogs with primary immune-mediated haemolytic anaemia have increased serum cardiac troponin I concentrations at the time of diagnosis. However, it is unclear whether biochemical evidence of cardiac myocyte damage improves following successful treatment of anaemia.

METHODS

A haematology profile was performed and serum cardiac troponin I concentrations were measured in 19 dogs with primary immune-mediated haemolytic anaemia before and after treatment.

RESULTS

The haematocrit increased significantly (P = 0 · 0001) following treatment of primary IMHA (median pre: 0 · 13 L/L, median post: 0 · 33 L/L). The serum cardiac troponin I concentrations decreased significantly (P < 0 · 05) after treatment (median pre: 0 · 26 ng/mL, median post: 0 · 16 ng/mL).

CLINICAL SIGNIFICANCE

Serum cardiac troponin I concentration decreases following successful treatment of primary immune-mediated haemolytic anaemia. The clinical and prognostic significance of serum cardiac troponin I concentrations before and after treatment in dogs with primary immune-mediated haemolytic anaemia merits further investigation.

Echocardiographic and Doppler assessment of maternal cardiovascular function in normal and abnormal canine pregnancies

The objective was to verify maternal hemodynamic differences between normal and abnormal pregnancies in dogs. Brucella-negative pregnant bitches (n = 31) were retrospectively classified into abnormal (which had either their pregnancy interrupted between Days 52 and 60 or perinatal death of more than 50% of the litter; n = 14) and normal (which had delivered healthy puppies at term; n = 17). These dogs were evaluated with echocardiography every 10 days from Days 0 to 60 of gestation (Day 0 = estimated day of LH peak). Systolic blood pressure was also assessed. At Day 50 of gestation, left ventricular free wall in systole increased in the normal but not in the abnormal group (P < 0.01). In contrast, end systolic stress (P < 0.01) and systolic blood pressure (P < 0.01) diminished only in normal animals. We concluded that signs of altered maternal cardiovascular adaptation to pregnancy may be predictors of obstetrical complications in dogs.

Ultrasonographic assessment of maternal cardiac function and peripheral circulation during normal gestation in dogs

The aim of this study was to describe changes in cardiac morphology, systolic function and some peripheral hemodynamic parameters during normal pregnancy in dogs. Twenty healthy bitches, 10 pregnant (PG) and 10 non-pregnant controls (CG), were evaluated every 10 days using echocardiography from day 0 of the estrus cycle to parturition or to day 65 for the PG and CG groups, respectively. Systolic blood pressure (SBP) and uterine artery resistance index (RI) were also assessed. Throughout the study, the shortening fraction and cardiac output increased up to 30% vs. 5% (P<0.01) and 45% vs. 2% (P<0.01) in the PG and CG groups, respectively. In contrast, SBP and RI diminished up to 20% vs. 1% (P<0.01) and 29% vs. 0% (P<0.01) in the PG and CG groups, respectively. In conclusion, a decrease in afterload, an increase in cardiac output and cardiac hypertrophy appear to be the result of the hemodynamic modifications occurring during pregnancy in dogs.