Contrast Echocardiography in two-dimensional left ventricular measurements: comparison with 256-row multi-detector computed tomography as a reference standard in Beagles

Anomalous origin of the right coronary artery from the pulmonary artery in a Staffordshire Bull Terrier

An asymptomatic 17-month-old, 18.5-kg, male Staffordshire Bull Terrier was referred due to a heart murmur. Examination revealed a grade 3/6 left apical systolic and right apical 3/6 heart murmur. Echocardiography showed volume overload of the left ventricle and mild systolic dysfunction with a left-right flow over the interventricular septal region. Cardiac gated computed tomography revealed anomalous origin of the right coronary artery from the pulmonary artery, an extensive network of collateral blood vessels connected the right and left coronary arteries, with bronchial and left intercostal arteries also connected to the network of collateral blood vessels, markedly enlarged right and left coronary arteries and left coronary sinus. With varied presentation, coronary anomalies are difficult to recognise and classify and to the best of our knowledge this is the first case of anomalous origin of the right coronary artery from the pulmonary artery diagnosis in the dog.

Clinical utility of a new protocol of cardiac computed tomography in dogs

OBJECTIVES

The characteristics of non-electrocardiography- and electrocardiography-gated multidetector computed tomography have not been extensively studied in veterinary clinics but it can be useful for cardiac imaging. This study aimed to ascertain the differences between non-electrocardiography and electrocardiography gating methods and to establish their clinical utility based on patient history.

METHODS

Six client-owned dogs (two with patent ductus arteriosus, two with heart base tumour, one with pericardial mesothelioma, and one with normal health) were included in this study. All the dogs were examined using a non-electrocardiography-gated scan, followed by a retrospective electrocardiography-gated scan. Images were reviewed to determine the optimal scan timing and R-R interval in non-electrocardiography- and electrocardiography-gated images, respectively, for detailed coronary artery imaging, diagnostic quality of the best coronary artery visualisation in non-electrocardiography- and electrocardiography-gated images through visual assessment of the main coronary artery branches, and branching patterns of the left coronary artery. Further, we compared the size and margin demarcation of the heart or pericardial lesions in non-electrocardiography- and electrocardiography-gated images obtained from patients with heart or pericardial tumours.

RESULTS

The optimal scan timing and R-R interval were the second-scan timing and end-diastole (70%-90%), respectively. Second-scan non-electrocardiography-gated images allowed coronary artery evaluation, indicating high-grade quality in visual assessment, except for the septal branch. Electrocardiography-gated images, but not non-ECG-gated images, clearly revealed pericardial nodules in two dogs.

CLINICAL SIGNIFICANCE

Our findings suggest the respective clinical utilities of non-electrocardiography- or electrocardiography-gated imaging using high-slice cardiac computed tomography based on patient history.

Reproducibility of geometric and flow-based echocardiographic measurements used for quantification of left ventricular total and forward stroke volume in healthy dogs

BACKGROUND

Cardiac structure and function in dogs are commonly assessed using echocardiography. A variety of linear, area, and flow-based measurements can be used to calculate left ventricular (LV) total stroke volume (TSV) and forward stroke volume (FSV), but the reproducibility of many of these measurements has not been fully studied. We hypothesized that survey of echocardiographic variables would identify those with high reproducibility and inform future investigation of different methods to measure LV TSV and FSV.

METHODS

The reproducibility of 25 geometric and flow-based echocardiographic measurements was prospectively evaluated in 23 healthy dogs by two experienced observers. Reproducibility (i.e., interobserver agreement) was described using intraclass correlation coefficients. The reproducibility of various methods to calculate LV TSV and FSV was explored.

RESULTS

Reproducibility was generally good to excellent. Variables of LV width, length, and area and aortic and sinotubular junction diameter and velocity time integral were among measures with the highest reproducibility. Measurements of mitral annular diameter and mitral inflow velocity time integral possessed lower reproducibility. Calculation of LV TSV using measurements involved in the cube and bullet formulas demonstrated higher reproducibility than the Simpson's method of disks or mitral inflow methods. Calculation of LV FSV using LV outflow tract and aortic diameters from the right parasternal view generally demonstrated higher reproducibility compared with the left-sided view.

CONCLUSIONS

The reproducibility of many simple geometric and flow-based echocardiographic measurements is high. Comparison of the reliability of different measurement informs future investigation of echocardiographic methods to determine LV TSV and FSV in dogs.