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1.
OBJECTIVE: To determine the prevalence of Doppler echocardiography-derived evidence of pulmonary arterial hypertension (DEE-PAH) in dogs with mitral valve disease (MVD) classified according to the International Small Animal Cardiac Health Council (ISACHC) heart failure classification scheme and various echocardiographic and Doppler indices of MVD severity. DESIGN: Retrospective case series. ANIMALS: 617 dogs examined from 2001 to 2005 with MVD in ISACHC classes I to III. PROCEDURES: Dogs were examined echocardiographically. Criteria used for systolic and diastolic DEE-PAH were detection of high tricuspid (> or = 2.5 m/s) and telediastolic pulmonic (> or = 2.0 m/s) valvular peak regurgitant jet velocities, respectively, by use of continuous-wave Doppler echocardiography. RESULTS: 86 (13.9%) dogs with MVD had a diagnosis of DEE-PAH. Severity and prevalence of DEE-PAH increased with ISACHC class (3.0%, 16.9%, 26.7%, and 72.2% prevalences for ISACHC classes Ia, Ib, II, and III, respectively). A significant correlation between systolic or diastolic pulmonary arterial pressure and left atrial-to-aortic diameter ratio (LA/Ao) was detected. Doppler echocardiography-derived evidence of pulmonary arterial hypertension was detected in 18 dogs with values of LA/Ao within reference range, all of which had moderate (n = 2 dogs) or severe (16) mitral valve regurgitation on color Doppler imaging. CONCLUSIONS AND CLINICAL RELEVANCE: The prevalence and degree of DEE-PAH were related to the severity of MVD. Changes associated with DEEPAH may be detected in early stages of the disease, but only in dogs with severe mitral valve regurgitation.  相似文献   

2.
Background: Tissue Doppler imaging (TDI) including strain and strain rate (SR) assess systolic and diastolic myocardial function.
Hypothesis: TDI, strain, and SR variables of the left ventricle (LV) and the interventricular septum (IVS) differ significantly between dogs with myxomatous mitral valve disease (MMVD) with and without congestive heart failure (CHF).
Animals: Sixty-one dogs with MMVD with and without CHF. Ten healthy control dogs.
Methods: Prospective observational study.
Results: Radial motion : None of the systolic variables were altered and 3 of the diastolic velocities were significantly increased in dogs with CHF compared with dogs without CHF and control dogs. Longitudinal motion : 2 systolic velocities and 3 diastolic velocities were significantly increased in dogs with CHF compared with dogs without CHF and control dogs. Difference in systolic velocity time-to-peak between LV and IVS was significantly increased in dogs with MMVD with and without CHF compared with control dogs. In total, 11 (23%) of 48 TDI and strain variables differed significantly between groups. Left atrial to aortic ratio was positively correlated to early diastolic velocities, percentage increase in left ventricular internal diameter in systole was positively correlated to systolic and diastolic velocities, and mitral E wave to peak early diastolic velocity in the LV basal segment (E/Em) was positively correlated to radial strain and SR.
Conclusions and Clinical Importance: Few TDI and strain variables were changed in dogs with MMVD with and without CHF. Intraventricular dyssynchrony may be an early sign of MMVD or may be an age-related finding.  相似文献   

3.
BACKGROUND: Tissue Doppler Imaging (TDI) or strain (St) imaging could provide sensitive indices for early detection and treatment follow-up of canine dilated cardiomyopathy (DCM). Analysis of TDI and St features in dogs with overt DCM is a prerequisite before using these new criteria in prospective screenings of predisposed families or in clinical trials. HYPOTHESIS: Radial and longitudinal right and left myocardial motion, assessed by TDI and St variables, is altered in dogs with DCM. ANIMALS: Case records for 26 dogs; 14 with DCM and 12 healthy controls of comparable age and weight were reviewed. METHODS: A retrospective analysis was conducted of conventional echocardiography, 2-dimensional color TDI, and St imaging data. RESULTS: The DCM group was characterized by decreases in radial and longitudinal systolic velocity gradients of the left ventricular free wall (LVFW), radial and longitudinal absolute values of peak systolic St of the LVFW, and longitudinal systolic right ventricular (RV) velocities (all P < .001 versus control) associated with longitudinal postsystolic contraction waves in 7/14 dogs. Early diastolic LVFW velocities also were decreased for longitudinal (P < .01) and radial (P < .05) motions. All radial LVFW, longitudinal basal LVFW, and RV systolic velocities were negatively correlated with heart rate (P < .01). CONCLUSIONS AND CLINICAL IMPORTANCE: LV contractility along both the short and long axes is impaired in dogs with spontaneous DCM, as is systolic RV and diastolic LVFW function. These myocardial alterations are associated with an inverse force-frequency relationship. Studies now are needed to determine the comparative sensitivity of TDI and St variables for the early detection of canine DCM.  相似文献   

4.
OBJECTIVES: To determine the effect of the route and rate of protamine administration on the amount of protamine that could be delivered before a hemodynamic reaction occurred in dogs. STUDY DESIGN: Prospective randomized experimental study. ANIMALS: Twenty adult mixed-breed dogs weighing 25.1+/-2.5 kg. METHODS: Before vascular surgery, the dogs were heparinized to reach an activated clotting time (ACT) of 300 seconds. After completion of the vascular surgery, protamine was administered intravenously until a hemodynamic reaction was recorded. The 4 groups of dogs were given protamine at 5 mg/min (slow) or 10 mg/min (fast) via the cephalic or the jugular veins. Systemic and pulmonary arterial pressures, central venous pressure (CVP), and pulmonary arterial occlusion pressure (PAOP) were recorded before and after protamine administration. The dose of protamine was recorded when a reaction occurred, which was defined as mean arterial pressure (MAP) <60 mm Hg or mean pulmonary arterial pressure (MPAP) >20 mm Hg or more than double the baseline value. RESULTS: Significant decreases in systolic arterial pressure (SAP), MAP, and diastolic arterial pressure (DAP) and significant increases in systolic (SPAP), mean (MPAP), and diastolic (DPAP) pulmonary arterial pressures were recorded after protamine administration. The cephalic slow group had significantly fewer protamine reactions than other groups (chi-square = 8.57, P = .03, df = 3). Significantly more protamine could be delivered from the cephalic vein (52.5+/-14.5 mg) compared with the jugular vein (37.6+/-16 mg) before a reaction occurred (P = .048). CONCLUSION: The rate of administration did not have an effect on the amount of protamine delivered. Adverse reactions were minimized when protamine was administered via the cephalic vein at a slow rate. CLINICAL RELEVANCE: We would recommend delivering protamine after cardiopulmonary bypass or vascular surgery through a peripheral venous route.  相似文献   

5.
BACKGROUND: Pulmonary hypertension (PH) is commonly diagnosed by Doppler echocardiography (DE) of tricuspid regurgitation (TR). However, TR may be absent or difficult to measure. HYPOTHESIS: Doppler-derived systolic time intervals of pulmonary artery (PA) flow may be used to predict PH in dogs. ANIMALS: Seventy-three healthy dogs and 45 West Highland white terriers (WHWT) with interstitial pulmonary disease (IPD). METHODS: Echocardiographic studies, including determination of right ventricular acceleration time (AT), ejection time (ET), and AT : ET ratio; right ventricular shortening fraction (RV-SF); and TR velocity, were performed. Pulmonary hypertension was defined by TR >3.1 m/s. RESULTS: In healthy WHWT, AT (median, range) was 73 ms (53 to 104) and AT : ET was 0.40 (0.28 to 0.55). AT : ET was minimally affected by age (R2 = 0.04, 95% confidence interval [CI] 0.01-0.07, P < .001) but not by heart rate, body weight, or RV-SF. In all WHWT with TR, AT and AT : ET were inversely related to calculated systolic PA pressure (R2 = 0.52, 95% CI 0.42-0.62, P < .001 and R2 = 0.36, 95% CI 0.29-0.42, P = .001). Clinical cutoffs to predict systolic PH were defined for AT (58 ms; sensitivity [Se] 88% and specificity [Sp] 80%) and AT : ET (0.31; Se 73% and Sp 87%). CONCLUSION AND CLINICAL IMPORTANCE: PH is common in WHWT with IPD. Analysis of right ventricular AT and AT : ET may be predictive of PH and should be particularly useful if TR is absent.  相似文献   

6.
OBJECTIVE: To investigate the relationship between preload and tricuspid valve annulus-derived tissue Doppler imaging (TDI) as an index of right ventricular (RV) filling in dogs. ANIMALS: 7 Beagles. PROCEDURES: Peak systolic RV pressure and RV end-diastolic pressure (RVEDP) were measured in anesthetized dogs. Pulsed Doppler was used to measure tricuspid valve inflow and pulmonary valve outflow velocities. The TDI velocities were measured at the lateral corner of the tricuspid valve annulus. Lactated Ringer's solution was infused at 200 mL/kg/h for 60 minutes via the cephalic vein. RESULTS: IV infusion significantly increased heart rate, RV pressure, and RVEDP. Early diastolic flow (E-wave) and ejection time significantly increased. The myocardial performance index (MPI) significantly decreased. Intravenous infusion significantly increased the ratio of the E'-wave (peak myocardial velocity during early diastole) to the A'-wave (peak myocardial velocity during late diastole; E':A' ratio) and myocardial velocity during systole (S'), early diastole (E'), and late diastole (A'). The TDI-isovolumic relaxation time and TDI-MPI decreased significantly. The RVEDP was correlated with late diastolic flow (A-wave), ratio of the E-wave to the A-wave (E:A ratio), E'-wave, A'-wave, S'-wave (peak myocardial velocity during systole), TDI-isovolumic relaxation time, TDI-MPI, and ratio of the E-wave to the E'-wave (E: E' ratio). The A-wave and E:A ratio and TDI-derived isovolumic relaxation time, S' duration, and E'-wave could predict the RVEDP. CONCLUSIONS AND CLINICAL RELEVANCE: The TDI velocities were affected by RV filling pressure in healthy dogs, whereas other TDI profiles, such as MPI and E':A' ratio, were independent of acute filling abnormalities.  相似文献   

7.
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8.
OBJECTIVE: To identify Doppler echocardiographic (DE) variables that correlate with left ventricular filling pressure (LVFP). ANIMALS: 7 healthy dogs (1 to 3 years old). PROCEDURES: Dogs were anesthetized and instrumented to measure left atrial pressure (LAP), left ventricular pressures, and cardiac output. Nine DE variables of LVFP derived from diastolic time intervals, transmitral and pulmonary venous flow, and tissue Doppler images were measured over a range of hemodynamic states induced by volume loading and right atrial pacing. Associations between simultaneous invasive measures of LVFP and DE measures of LVFP were determined by use of regression analysis. Receiver operating characteristic analysis was used to predict increases in mean LAP on the basis of DE variables. RESULTS: Mean LAP was correlated with several DE variables: the ratio between peak velocity during early diastolic transmitral flow and left ventricular isovolumic relaxation time (peak E:IVRT) during sinus rhythm and during right atrial pacing, IVRT, the ratio between late diastolic transmitral flow velocity and pulmonary venous flow duration, and the interval between onset of early diastolic mitral annulus motion and onset of early diastolic transmitral flow. Cutoff values of 2.20 and 2.17, for peak E:IVRT in dogs with sinus rhythm and atrial pacing predicted increases in mean LAP (> or = 15 mm Hg) with sensitivities of 90% and 100% and specificities of 92% and 100%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Doppler echocardiography can be used to predict an increase in LVFP in healthy anesthetized dogs subjected to volume loading.  相似文献   

9.
It has been described in humans that chronic obstructive bronchitis leads to pathologic changes, especially in the right ventricular myocardium due to hypoxia, which can be assessed by tissue Doppler imaging (TDI). In our study, different TDI techniques, that is, pulsed-wave TDI and color TDI, were evaluated for applicability in different scan planes (apical long-axis view and short-axis view) for the analysis of right ventricular myocardial function in six healthy horses (control) and six horses affected with recurrent airway obstruction (RAO) (RAO group). Tissue Doppler imaging was applicable to all scan planes described. Myocardial movement directions in general and the absolute values of TDI parameters were assessable. Significantly reduced early diastolic filling velocities (E), elevated late diastolic filling velocities (A), thereby decreased E/A quotient, prolonged electromechanical coupling periods between electrocardiograph Q-wave and maximal velocities, and compensatory elevated systolic strain as well as diminished displacement could be observed in horses with RAO compared with the control group. To conclude, equine right ventricular myocardial function is assessable by TDI. Significant changes of right ventricular myocardial function could be demonstrated by TDI in horses with RAO compared with matched healthy controls. The hypothesis that RAO potentially leads to right ventricular dysfunction detectable by TDI before conventional echocardiography changes are evident is supported by this explorative study.  相似文献   

10.
Right ventricular myocardial (RVM) motion is poorly documented. The objective of this study was to determine the variability of RVM velocities by tissue Doppler imaging (TDI) in healthy dogs (study 1), to analyze RVM motion in a large healthy canine population (study 2), and to compare the results with those obtained for the left ventricular free wall. Six healthy Beagle Dogs were monitored in study 1, and 64 healthy dogs of 14 different breeds were monitored in study 2. Velocities were recorded in 2 segments (basal and apical) of the right and left myocardial walls. In study 1, 36 TDI examinations were performed for 4 days, whereas a single TDI examination was performed on each dog in study 2. All velocity profiles included 1 positive systolic wave and 2 negative diastolic waves. The lowest intraday and interday coefficient of variation values of the right TDI variables were observed at the base (3.5-16.1%). The variability of the right apical velocities was much higher, with most coefficient of variation values > 15%. RVM velocities were higher in the basal than in the apical segments (P < .001) and were higher than the left velocities of the corresponding segment (P < .01). Body weight and breed had an effect on only a few right and left TDI variables. TDI provides a repeatable and reproducible method for evaluating basal RV function in the dog. These data also demonstrate the heterogeneity of the myocardial velocities between the left and the right ventricles and between the base and the apex.  相似文献   

11.
OBJECTIVE: To determine left ventricular free wall (LVFW) radial and longitudinal myocardial contraction velocities in healthy dogs via quantitative 2-dimensional color tissue Doppler imaging (TDI). ANIMALS: 100 dogs. PROCEDURE: TDI was used by a single trained observer to measure radial and longitudinal myocardial movement in the LVFW. Radial myocardial velocities were recorded in segments in the endocardial and epicardial layers of the LVFW, and longitudinal velocities were recorded in segments at 3 levels (basal, middle, apical) of the LVFW. RESULTS: LVFW velocities were higher in the endocardial layers than in the epicardial layers. Left ventricular free wall velocities were higher in the basal segments than in the middle and apical segments. Radial myocardial velocity gradients, defined as the difference between endocardial and epicardial velocities, were (mean +/- SD) 2.5 +/- 0.8 cm/s, 3.8 +/- 1.5 cm/s, and 2.3 +/- 0.9 cm/s in systole, early diastole, and late diastole, respectively. Longitudinal myocardial velocity gradients, defined as the difference between basal and apical velocities, were 5.9 +/- 2.2 cm/s, 6.9 +/- 2.5 cm/s, and 4.9 +/- 1.7 cm/s in systole, early diastole, and late diastole, respectively. A breed effect was detected for several systolic and diastolic TDI variables. In all segments, systolic velocities were independent of fractional shortening. CONCLUSIONS AND CLINICAL RELEVANCE: LVFW myocardial velocities decreased from the endocardium to the epicardium and from base to apex, thus revealing intramyocardial radial and longitudinal velocity gradients. These indices could enhance conventional echocardiographic analysis of left ventricular function in dogs. Breed-specific reference intervals should be defined.  相似文献   

12.
OBJECTIVE: To determine left ventricular free wall (LVFW) motions and assess their intra- and interday variability via tissue Doppler imaging (TDI) in healthy awake and anesthetized dogs. ANIMALS: 6 healthy adult Beagles. PROCEDURE: n the first part of the study, 72 TDI examinations (36 radial and 36 longitudinal) were performed by the same observer on 4 days during a 2-week period in all dogs. In the second part, 3 dogs were anesthetized with isoflurane and vecuronium. Two measurements of each TDI parameter were made on 2 consecutive cardiac cycles when ventilation was transiently stopped. The TDI parameters included maximal systolic, early, and late diastolic LVFW velocities. RESULTS: The LVFW velocities were significantly higher in the endocardial than in the epicardial layers and also significantly higher in the basal than in the mid-segments in systole, late diastole, and early diastole. The intraday coefficients of variation (CVs) for systole were 16.4% and 22%, and the interday CV values were 11.2% and 16.4% in the endocardial and epicardial layers, respectively. Isoflurane anesthesia significantly improved the intraday CV but induced a decrease in LVFW velocities, except late diastolic in endocardial layers and early diastolic in epicardial layers. CONCLUSIONS AND CLINICAL RELEVANCE: Left ventricular motion can be adequately quantified in dogs and can provide new noninvasive indices of myocardial function. General anesthesia improved repeatability of the procedure but cannot be recommended because it induces a decrease in myocardial velocities.  相似文献   

13.
OBJECTIVE: To quantify radial and longitudinal left ventricular free wall (LVFW) velocities in dogs during the preclinical phase of Golden Retriever muscular dystrophy (GRMD)-associated cardiomyopathy by use of tissue Doppler imaging (TDI). ANIMALS: 9 dogs with GRMD and 6 healthy control dogs. PROCEDURE: All dogs (< 3 years old) were examined via conventional echocardiography and 2-dimensional color TDI. Myocardial velocities in the LVFW were recorded from right parasternal ventricular short-axis (radial motion) and left apical 4-chamber (longitudinal motion) views. Cardiac assessments via TDI included maximal systolic and early and late diastolic LVFW velocities in the endocardial and epicardial layers (for radial motion) and in the basal and apical segments (for longitudinal motion) (for longitudinal motion), RESULTS:-No notable ventricular dilatation or alteration of inotropism was detected in dogs with GRMD via conventional echocardiography. Compared with healthy dogs, endocardial velocities were significantly decreased in dogs with GRMD, resulting in marked decreases in radial myocardial velocity gradients during systole and early and late diastole. Similarly, basal and apical velocities were significantly decreased in systole and the former also in early diastole, resulting in significant decreases in the 2 corresponding longitudinal myocardial velocity gradients. The radial epicardial and longitudinal late diastolic velocities were comparable in the 2 groups. CONCLUSION AND CLINICAL RELEVANCE: Results indicated that GRMD-associated cardiomyopathy in dogs is associated with early marked dysfunction of both radial and longitudinal LVFW motions. These combined regional myocardial abnormalities might be useful criteria for detection of dilated cardiomyopathy at the preclinical stage of the disease in dogs.  相似文献   

14.
The effects of intravenous (iv) infusion of endotoxin for 60 mins at a cumulative dosage of 0.03 micrograms/kg bodyweight on systemic arterial, right atrial and pulmonary arterial pressures, heart rate, cardiac output, and derived pulmonary vascular resistance and total peripheral vascular resistance were compared to the effects of iv infusion of saline solution in four healthy horses. Heart rate was increased significantly after endotoxin infusion, although diastolic arterial pressure, systolic arterial pressure, electronically averaged arterial pressure, cardiac output, total peripheral resistance, and right atrial pressure did not change significantly. Average pulmonary arterial pressure was increased significantly by endotoxin infusion. This was accompanied by a trend toward increased diastolic pulmonary arterial pressure (P = 0.1), systolic pulmonary arterial pressure (P = 0.08) and pulmonary vascular resistance (P = 0.07). These results suggest that low dosages of endotoxin produce pulmonary hypertension without causing hypotensive, hypodynamic shock.  相似文献   

15.
Pulsed tissue Doppler imaging (pulsed TDI) has been demonstrated to be useful for the estimation of left ventricular (LV) systolic and diastolic functions in various human cardiac diseases. The objectives of this study were to investigate the relationship between pulsed TDI and LV function by using cardiac catheterization in healthy dogs and to evaluate the clinical usefulness of pulsed TDI in dogs with spontaneous mitral regurgitation (MR). The peak early diastolic velocity (E'), peak atrial systolic velocity (A'), and peak systolic velocity (S') were detectable in the velocity profiles of the mitral annulus in all the dogs. In the healthy dogs, S' and E' were correlated with LV peak +dP/dt and -dP/dt, respectively. E' was lower in dogs with MR than in dogs without cardiac diseases. E/E' in the MR dogs with decompensated heart failure was significantly increased in comparison with those with compensated heart failure. The sensitivity and specificity of the E/E' cutoff value of 13.0 for identifying decompensated heart failure were 80% and 83%, respectively. In addition, E/E' was significantly correlated with the ratio of left atrial to aortic diameter. These findings suggest that canine pulsed TDI can be applied clinically for estimation of cardiac function and detection of cardiac decompensation and left atrial volume overload in dogs with MR.  相似文献   

16.
OBJECTIVES: To obtain reference arterial blood pressure values from Kangal dogs, a local giant breed found in Turkey. METHODS: Arterial blood pressure measurements were obtained from 48 healthy Kangal dogs using oscillometric and Doppler techniques. The ages of the dogs ranged from two to 96 months, with a mean (sd) age of 36 (16) months. RESULTS: The effect of age on systolic, diastolic and mean arterial pressures determined by the oscillometric technique and on systolic pressure determined by the Doppler technique was significant (P<0.001). Blood pressure was found to be higher in mature dogs compared with that in immature dogs. The effect of sex and the interaction between age and sex were not significant (P>0.05). There was a direct relationship between age and oscillometric systolic, diastolic and mean arterial pressures and Doppler systolic arterial blood pressure both in the whole group and the immature group (P<0.05). Correlation between age and systolic arterial blood pressure measured either by oscillometric or Doppler techniques was not significant in the mature group. CLINICAL SIGNIFICANCE: The Kangal dog is bred in various countries including Turkey. It is known that giant breed dogs, such as the Kangal dog, are predisposed to cardiovascular disease. Canine arterial blood pressure values are highly breed and age dependent, so a reference value for any other breed is inappropriate for Kangal dogs. Therefore, it is important to measure arterial blood pressure of Kangal dogs.  相似文献   

17.
Hypertrophic cardiomyopathy (HCM) in cats is characterized by concentric left ventricular (LV) hypertrophy and both diastolic and systolic dysfunction. Although impaired cardiac function detected by tissue Doppler imaging (TDI) in cats with HCM was previously reported, reference ranges of TDI in normal cats and cats with HCM have been reported as widely variable. Two-dimensional speckle tracking echocardiography (STE) was useful for assessment of cardiac function in human patients with HCM, but clinical utility was not known in cats. The aim of this study was to assess global and segmental LV myocardial function using STE in cats with HCM whose TDI variables were within the reference range. A total of 35 cats of different breeds were enrolled in this study. The HCM group (n=22) was cats diagnosed as HCM without left atrial enlargement and with normal TDI measurements. HCM cats were further divided into a segmental hypertrophy (S-HCM) group and a diffuse hypertrophy (D-HCM) group. The control group consisted of 13 clinically healthy cats. No cats in any group showed any clinical symptoms. Conventional echocardiography, TDI, and global and segmental STE indices were evaluated and compared between groups. Only the longitudinal strain rate during early diastole was significantly decreased in both HCM groups, even in all segments including those without hypertrophy in S-HCM group. This study suggests that STE parameters are the more sensitive variables compared with conventional TDI parameters to detect early myocardial diastolic dysfunction in cats with HCM.  相似文献   

18.
Gated radionuclide ventriculography was evaluated as a noninvasive method of quantifying right ventricular function in dogs with experimentally induced congestive heart failure. Gated radionuclide ventriculography measurements of right ventricular function (right ventricular ejection fraction, right ventricular average emptying rate, and right ventricular average filling rate) were related to standard hemodynamic and echocardiographic measurements. Congestive heart failure was induced by rapid ventricular pacing in eight normal dogs. Hemodynamic, echocardiographic, and gated radionuclide ventriculography measurements were obtained before and after development of biventricular failure. Congestive heart failure resulted in significant changes in all hemodynamic, echocardiographic, and gated radionuclide ventriculography measurements with the exception of systemic arterial pressure. Right ventricular ejection fraction was inversely related to pulmonary artery systolic, diastolic, and mean pressure, and right ventricular average emptying rate was inversely related to the pulmonary artery systolic, diastolic, and mean pressure. Right ventricular ejection fraction was inversely related to left ventricular filling pressure, (pulmonary capillary wedge pressure). Neither the echocardiographic measurements of right ventricular size (right ventricular internal diastolic dimension) nor the right ventricular end-diastolic pressure were related to right ventricular ejection fraction and right ventricular average emptying rate. However, echocardiographic measurements of right ventricular dimension were related to right ventricular filling pressure. The gated radionuclide ventriculography indexes of right ventricular function, right ventricular ejection fraction and right ventricular average emptying rate, are affected by afterload but unaffected by preload, whereas the echocardiographic measurement of right ventricular dimension is related to preload. Gated radionuclide ventriculography provides right ventricular data which is unique from that obtained by standard echocardiographic imaging. Also, gated radionuclide ventriculography has potential value as a noninvasive means of estimating a change in pulmonary artery pressure.  相似文献   

19.
Background: Pulmonary arterial hypertension (PAH) in dogs carries a poor prognosis. Sildenafil increases exercise capacity and improves hemodynamics in people with PAH. Hypothesis/Objectives: Dogs receiving sildenafil will have lower pulmonary arterial pressure, increased exercise capacity, and better quality of life (QOL) than dogs receiving placebo. Animals: Thirteen dogs with echocardiographic evidence of PAH. Methods: Prospective short‐term, randomized, placebo controlled, double‐blind, crossover study. Dogs with PAH were randomly allocated to receive sildenafil or placebo for 4 weeks, followed by the alternative treatment for 4 weeks. Results: Dogs receiving sildenafil had a significantly lower estimated pulmonary arterial pressure (median, 56 mmHg; range, 34–83 mmHg) than at baseline (median, 72 mmHg; range, 61–86 mmHg; P= .018), but not significantly lower than those receiving placebo (median, 62 mmHg; range, 49–197 mmHg). Exercise capacity was significantly greater in dogs receiving sildenafil than those receiving placebo (mean activity count per minute: 101 ± 47 versus 74 ± 32; P= .05). QOL scores were significantly higher in dogs receiving sildenafil than dogs receiving placebo. Conclusions and Clinical Importance: Sildenafil decreases systolic pulmonary arterial pressure from baseline in dogs with PAH and is associated with increased exercise capacity and QOL when compared to treatment with placebo.  相似文献   

20.
BACKGROUND: Age and heart rate have effects on myocardial velocities as assessed by color tissue Doppler imaging (TDI) in people. A similar phenomenon has been identified when left ventricular velocities are assessed in cats. To date, the effects of age and heart rate on tricuspid annular velocities of cats have not been assessed. OBJECTIVES: This study was designed to determine the relationships between age and heart rate and tricuspid annular velocities in cats as assessed by 2-dimensional (2D) color TDI. ANIMALS: Fifty healthy nonsedated cats with age range from 3 months to 19 years old were studied. METHODS: Tricuspid annular velocities were obtained with 2D color TDI. Effects of age and heart rate on tricuspid annular velocities were evaluated by simple linear regression. The strength of the linear relationship was determined by using coefficient of determination (R2). RESULTS: A significant weak negative relationship was found between age and peak early diastolic annular velocity (E'; R2 = 0.135, P = .018). No significant relationships between age and right ventricular (RV) systolic TDI values were found. Diastolic and systolic TDI parameters were not affected by heart rate with the exception of deceleration rate of early diastolic motion (DR; R2 = 0.100, P = .025). CONCLUSIONS AND CLINICAL IMPORTANCE: Age and heart rate have minimal effects on tricuspid annular velocities. The present study provides reference ranges for tricuspid annular velocities in healthy cats and information for assessing the clinical utility of color TDI for evaluation of RV function in cats.  相似文献   

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