ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04982.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04983.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryEchocardiography encompasses a number of specific imaging techniques. The two‐dimensional (2‐D) echocardiogram is used to identify lesions of the heart and great vessels, assess myocardial function and provide a template for guiding contrast echocardiography, colour‐coded Doppler echocardiography and spectral Doppler studies. M‐mode echocardiography is used to measure cardiac size and ventricular function and can be combined with contrast or colour‐coded Doppler studies for accurate timing of flow events. Pulsed wave and continuous wave Doppler echocardiography display the direction and velocity of red blood cells within the heart and circulation. Continuous wave Doppler studies are used to calculate pressure gradients in the circulation. Any of the Doppler techniques can be used to identify abnormal or high velocity flow responsible for pathologic heart murmurs. Each Doppler format is complementary to the others: colour‐coded Doppler is used to screen large areas for flow disturbances; pulsed wave Doppler can pinpoint regions of abnormal flow; and continuous wave Doppler quantifies the maximal velocities of blood flow across cardiac lesions. Echocardiographic studies are very useful for the diagnosis and assessment of horses with cardiac murmurs, arrhythmias, and poor exercise performance. A number of cardiac disorders can be evaluated by echocardiography, including: cardiac malformation, valvular heart disease, cardiomyopathy, bacterial endocarditis, pericardial effusion, and congestive heart failure. When combined with a careful clinical examination, exercise evaluation and results of electrocardiography, the echocardiogram provides the best overall clinical assessment of the e

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04984.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryCardiac dimensions and indices of cardiac function were measured in 29 clinically normal adult Thoroughbreds (TB) which performed minimal exercise using guided M‐mode and two‐dimensional (2‐D) echocardiography, from a variety of image planes and measurement methods, and standardised imaging planes based on intracardiac anatomical landmarks. The different methods of measuring these variables were compared. The variables which were considered to be most valuable for quantitative echocardiography were measured in a further 9 horses.Comparable measurements of cardiac dimensions can be obtained from a variety of different imaging planes, using either 2‐D or guided M‐mode echocardiography from the left or right side of the chest, although differences in measurement methods must be taken into account. The results of this study give a useful range of dimensions and indices of cardiac function in normal adult TBs for comparison with those recorded from horses with suspected cardiac disease. Comparisons are only valid if there is meticulous attention to correct orientation of imaging planes with regard to internal landmarks and that comparable measurement locations and timing

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04985.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryEchocardiographic examinations were performed on 41 clinically normal small ponies, large ponies and horses. Using standardised two‐dimensional (2‐D) echocardiographic images to guide M‐mode studies, the interventricular septal thickness, left ventricular internal dimension and left ventricular wall in systole and diastole, and aortic diameter in diastole were measured. Normal values for these echocardiographic dimensions were obtained across a wide range of bodyweights. Although there was a trend for echocardiographic dimensions to increase with bodyweight across the whole range of animals examined, little or no linear correlation was found between dimensions and bodyweight within the small pony, large pony and horse g

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04986.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryTwenty‐six horses were sedated with detomidine hydrochloride (Domosedan, SmithKline Beecham Animal Health, Tadworth, Surrey, UK) at a dose of 10 μg/kg bwt, administered i.v. Echocardiograms were recorded before and after sedation, measurements of cardiac dimensions were made and functional indices were calculated. The pre‐ and post sedation values were compared. No significant change was detected following sedation in the ejection time (ET), left ventricular dimension, left atrial diameter at the sinotubular junction at end‐systole or end‐diastole or at the sinus of Valsalva at end‐diastole. Sedation was found to result in a statistically significant increase in end‐systolic left ventricular diameter and internal area and aortic diameter measured at the sinus of Valsalva. Left ventricular free‐wall thickness and interventricular septal thickness at end‐systole, fractional shortening, fractional area change and heart rate were significantly reduced following sedation. A significant increase in pre‐ejection period (PEP), duration of electromechanical systole (EMS) and PEP/ET (ejection

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04987.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryReference values were established for selected Doppler derived variables from a group of 40 normal Thoroughbred and Thoroughbred cross horses. Standard two‐dimensional (2‐D) images used for guiding the Doppler sampling site allowed accurate alignment with flow. Tricuspid inflow velocities during rapid filling (E) and atrial contraction (A) were significantly higher when recorded from a right parasternal angled view than from a right parasternal long‐axis view. In 8 horses the tricuspid inflow peak A velocity was higher than the peak E velocity. The peak acceleration of blood flow was higher (P=0.000) in the aorta (mean 8.01 m/s/s) than in the pulmonary artery (4.45 m/s/s). Significant differences were also noted in the pre‐ejection period, ejection time and acceleration time between the 2 vessels. Horses with functional ejection murmurs had lower peak aortic acceleration and a longer acceleration time than horses without flow murmurs. Horses with filling murmurs over the left hemithorax had a significantly higher peak mitral E velocity than horses without such murmurs. Measurements from Doppler waveforms were repeatable and may prove useful in assessing ventricular function in this

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04988.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryColour flow Doppler echocardiography is a technique that is used with two‐dimensional (2‐D) echocardiography to study blood flow patterns in the heart and blood vessels. This method was used to define normal flow patterns and to evaluate valvular function in 40 clinically normal Thoroughbred and Thoroughbred cross horses. Flow patterns from 10 standardised echocardiographic images were described in relation to anatomic landmarks and timing during the cardiac cycle. Consistent intracardiac flow patterns were identified in the normal horses. High velocity flow signals or regurgitant jets were recorded at the tricuspid (77.5%), mitral (67.5%), aortic (47.5%) and pulmonary valves (40%) in clinically normal horses. Most of these signals were transient, and many were associated with valve closure.This study demonstrates that colour flow Doppler echocardiography is a sensitive technique for the detection of intracardiac flow in horses. It will provide a basis by which to compare studies in horses suspected of having valvular heart dise

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04989.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryColour flow Doppler echocardiographic examinations were performed on 15 horses; 10 Thoroughbreds and 5 Standardbreds; 9 mares, 5 geldings and 1 stallion; mean ± s.d. 3.4 ± 1.1 years. Cardiac murmurs were audible in 12 horses (80%), but these had characteristics consistent with functional murmurs in all horses. A standardised two‐dimensional (2‐D) and M‐mode echocardiographic examination was unremarkable in all horses except that aortic valve prolapse was identified in 3 horses, tricuspid valve prolapse in 2 horses and mitral valve prolapse was present in one horse. Colour flow Doppler echocardiography revealed laminar antegrade flow in most sites but variance was noted in the right ventricular outflow tract in some horses. Small regurgitant jets associated with the aortic valve were seen in 12 horses (80%), with the tricuspid valve in 7 horses (46%), with the pulmonary valve in 4 horses (26%) and the mitral valve in 4 horses (26%). It was concluded that with colour flow Doppler echocardiography, as in other species, small regurgitant jets could be detected in many normal

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04990.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryTransoesophageal Doppler echocardiography was performed in 7 Thoroughbred horses anaesthetised with halothane. The procedure was performed on 4 occasions under standard conditions. On one occasion dobutamine hydrochloride was infused at 4 μg/kg/min for 20 min. Recordings of aortic blood velocity, obtained using high pulsed repetition frequency Doppler echocardiography (HPRF), were used to derive maximum acceleration (dv/dtmax), maximum velocity (Vmax), left ventricular ejection time (ET), pre‐ejection period (PEP), velocity time integral (VTI) and cardiac output (CO).The coefficient of variation and 95% confidence intervals were narrower for the Doppler variables than for those obtained from cardiac catheterisation. For each horse the anaesthetic to anaesthetic repeatability of the Doppler indices of left ventricular function, exceeded that of maximum rate of rise of left ventricular pressure (LVdp/dtmax). The horse to horse variability was significant for heart rates Vmax, dv/dtmax, and VTI. After dobutamine infusion there were significant changes in all measured variables except heart rate, VTI and CO. The % change that occurred exceeded the predicted 95% confidence intervals for single measurements in all significantly affected variables. This suggests Doppler indices of cardiac performance may be useful to assess changes in haemodynamic function.Passage of the probe into the oesophagus was not associated with serious adverse effects. Mild serous nasal discharge was visible for up to 24 h after the horses recovered from anaesthesia. Mild nasal haemorrhage occurred on 5 occasions during probe insertion. It is concluded that transoesophageal Doppler echocardiography provides a minimally invasive, continuous method for monitoring left ventricular systolic performance in anaesthetised hors

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1995.tb04991.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY