首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
OBJECTIVE: To evaluate cardiac electrical function in dogs with tick toxicity. DESIGN: A prospective clinical investigation of 39 client-owned dogs treated for naturally occurring tick toxicity. PROCEDURE: An ECG was performed on each dog on several occasions; at admission to hospital with tick toxicity, 24 h later, at discharge from hospital when clinically normal and approximately 12 months later. RESULTS: The mean QT interval corrected for heart rate (QTc) was prolonged at admission, 24 h and at discharge compared to the QTc measured 12 months later. T wave morphology was altered in dogs at admission. All other parameters were within normal limits. CONCLUSIONS: The prolonged QTc interval and altered T wave morphology of dogs with tick toxicity reflects delayed cardiac repolarisation and is comparable with long QT syndrome (LQTS) in people who are predisposed to polymorphic ventricular tachycardia and sudden death. Resolution of ECG changes lagged behind clinical recovery.  相似文献   

2.
Background: A lack of information on normal heart rhythm at maximal effort hampers investigation of poor performance and sudden death in Standardbred racing. Hypothesis/Objective: To characterize rhythm variations during scheduled racing in clinically normal Standardbred horses. Animals: Two hundred and eighty‐eight Standardbred horses competing in 40 scheduled races at a Southern Ontario racetrack. Methods: Observational study, convenience sampling: Heart rhythm was monitored by ECG from harnessing to postrace recovery and assessed visually and by examining heart rate intervals. Rhythm variations were used as response variables in multivariate analysis of race records detailing signalment, race, and race outcome. Results: Monitoring involved 345 individual horse or race events. Occasional, isolated premature cycles, only, occurred during the race. Postrace, sudden cardiac slowing (punctuated deceleration [PD]) appeared in 42 events (12.2%). Only premature ventricular complexes were exhibited in 40 events postrace (11.6%), whereas 55 (15.9%) exhibited complex ventricular arrhythmias (CVA) including torsades‐like polymorphic ventricular tachycardia, 34.5% of these being closely associated with PD (odds ratio = 8). Predispositions to CVA were found for horses parked at the 1/2 mile (odds ratio = 3), and trotters breaking in the stretch (odds ratio = 38). Horses spontaneously reverted to sinus rhythm and no sudden death events were encountered. Conclusions and Clinical Importance: Arrhythmias occur frequently in racing Standardbreds during cardiac deceleration, often associated with sudden, rapid increases in vagal tone. Circumstances imposing unusual demand and racing at the trot appear to predispose. Findings provide insight into possible mechanisms of sudden death.  相似文献   

3.
Background: Ventricular tachyarrhythmias occur in association with cardiac and extracardiac disorders in many species of animals, but information identifying concurrent disorders in cats with such arrhythmias is scarce. Methods: We investigated coexisting diseases by retrospectively evaluating medical records of cats with ventricular tachyarrhythmias seen during a 51‐month period at 1 institution. For comparative purposes, we evaluated records of dogs with similar arrhythmias during the same time period. All cats and dogs had premature ventricular complexes, accelerated idioventricular rhythm, ventricular tachycardia, or some combination of these arrhythmias, and all had undergone echocardiography during the same visit that led to the diagnosis of ventricular tachyarrhythmia. Results and Conclusions: Most (102/106; 96%) cats had at least 1 echocardiographically apparent abnormality concurrent with ventricular tachyarrhythmias. Ventricular tachyarrhythmias in cats were most commonly associated with myocardial disease (eg, left ventricular concentric hypertrophy [n = 66], restrictive or unclassified cardiomyopathy [n = 17], and dilated cardiomyopathy [n = 6]). When comparing dogs and cats that had ventricular tachyarrhythmias and were diagnosed on the same clinical service of the same institution, an echocardiographically apparent cardiac lesion was seen more often in cats (102/106, 96%) than in dogs (95/138, 69%) (P < .001).  相似文献   

4.
There is growing evidence that dilated cardiomyopathy may be a major cause of death in captive Livingstone's fruit bats (Pteropus livingstonii). Therefore, the primary aim of this prospective, exploratory study was to examine whether a systematic cardiac ultrasound protocol is feasible in this critically endangered species and to report basic measures of cardiac structure and function from a cohort of apparently healthy bats. A secondary aim was to test the effect posture (dorsal recumbency vs. roosting) has upon cardiac function in this species. Transthoracic echocardiograms, including 2D, Doppler, and tissue Doppler measures of cardiac structure and function were completed as part of routine health examinations for bats at a single center (n = 19). Bats were then grouped by age and disease status and the mean and range data reported for each group. In healthy adult bats, with the exception of a reduction in heart rate (P ≤ 0.05), right atrial systolic area (P ≤ 0.05), and right ventricular velocity during atrial contraction, there were no significant changes in cardiac structure or function in response to the roosting position. However, in the bats presenting with dilated cardiomyopathy the current data suggest that left ventricular ejection fraction is improved while roosting. Further work is required to confirm our initial findings, generate diagnostic reference intervals, and explore the causes of dilated cardiomyopathy in this species.  相似文献   

5.
We examined Bartonella prevalence in 281 bat flies collected from 114 eastern bent-wing bats (Miniopterus fuliginosus) in Japan and phylogenetically analyzed with other bat fly and bat strains. The bat flies were identified as Penicilidia jenynsii (PJ; n = 45), Nycteribia allotopa (NA; n = 157), and novel Nycteribia species (NS; n = 79). Bartonella DNAs were detected in 31.7 % (89/281) of bat flies by PCR targeting the citrate synthase (gltA) gene. The prevalence of Bartonella DNA among the bat flies was 47.1 % (74/157) in NA, 15.2 % (12/79) in NS, and 6.7 % (3/45) in PJ. Bartonella bacteria were also isolated from two NA and one NS. A phylogenetic analysis of the gltA sequences revealed that bat fly-associated strains were classified into three lineages and the same lineages of Bartonella were commonly detected from both Nycteribia bat flies and Miniopterus bats. These results suggest that Nycteribia bat flies are potential vectors for transmitting Bartonella among Miniopterus bats.  相似文献   

6.
Although the cardiovascular and respiratory effects of halothane and isoflurane have been documented in a variety of common mammalian laboratory animals, they have not been investigated in birds. In this study, the effects of halothane and isoflurane anesthesia on respiratory rate, heart rate, heart rhythm, and mean arterial pressure in adult Pekin ducks were evaluated. Both anesthetics significantly increased heart rate and depressed blood pressure and respiration. Halothane induced a more profound alteration in heart rate and respiratory rate. With the ducks under halothane anesthesia, abnormal cardiac rhythms included ventricular fibrillation, ventricular bigeminy, and multifocal ventricular rhythms. Other than cardiac tachycardia, isoflurane induced no changes in cardiac rhythm.  相似文献   

7.
  相似文献   

8.
BACKGROUND: Although atrial arrhythmias are clinically important in horses, atrial electrophysiology has been incompletely studied. HYPOTHESES: Standard electrophysiologic methods can be used to study drug effects in horses. Specifically, the effects of diltiazem on atrioventricular (AV) nodal conduction are rate-dependent and allow control of ventricular response rate during rapid atrial pacing in horses undergoing quinidine treatment. ANIMALS: Fourteen healthy horses. METHODS: Arterial blood pressure, surface electrocardiogram, and right atrial electrogram were recorded during sinus rhythm and during programmed electrical stimulation at baseline, after administration of quinidine gluconate (10 mg/kg IV over 30 minutes, n = 7; and 12 mg/kg IV over 5 minutes followed by 5 mg/kg/h constant rate infusion for the remaining duration of the study, n = 7), and after coadministration of diltiazem (0.125 mg/kg IV over 2 minutes repeated every 12 minutes to effect). RESULTS: Quinidine significantly prolonged the atrial effective refractory period, shortened the functional refractory period (FRP) of the AV node, and increased the ventricular response rate during atrial pacing. Diltiazem increased the FRP, controlled ventricular rate in a rate-dependent manner, caused dose-dependent suppression of the sinoatrial node and produced a significant, but well tolerated decrease in blood pressure. Effective doses of diltiazem ranged from 0.125 to 1.125 mg/kg. CONCLUSIONS AND CLINICAL IMPORTANCE: Standard electrophysiologic techniques allow characterization of drug effects in standing horses. Diltiazem is effective for ventricular rate control in this pacing model of supraventricular tachycardia. The use of diltiazem for rate control in horses with atrial fibrillation merits further investigation.  相似文献   

9.
The objective of this study was to evaluate the electrocardiographic alterations in the cardiac rhythm in dogs treated with levamisole hydrochloride over a period of 24 hours. Thirty-six mixed-breed dogs, both male and female, all clinically healthy, were used in the experiment. The dogs were divided into 6 groups with 6 dogs in each group, according to dosage and route of administration. The Holter test was initiated immediately after the treatment, and was maintained for 24 hours. In the group treated with 10 mg/kg by way of subcutaneous injection, one of them showed ventricular premature complexes, sometimes isolated and other times in pairs, and ventricular tachycardia, concentrated mainly in the first hour after administration of the drug. In the group of 6 animals treated subcutaneously with 25mg/kg, four showed isolated ventricular premature complexes, ventricular bigeminy and trigeminy, mainly during the first 2 hours after administration of the drug. All the animals in the other groups showed sinus arrhythmia followed by sinus arrest. The disturbances in the cardiac rhythm observed in clinically healthy animals treated with levamisole hydrochloride, indicate that it is preferable to avoid subcutaneous administration of levamisole hydrochloride and that the oral administration of the drug should be done with caution.  相似文献   

10.
Although bats are one of the largest groups within the class Mammalia and may carry several zoonotic diseases, basic information about their hematology is limited. In this study, hematocrit (Hct), total white blood cell counts (TWBC; leukocytes), and differential white blood cell counts (DWBC) of free-ranging Neotropical bats were quantified. Blood samples from 255 bats representing 26 species from the families of Emballonuridae (3 species; 33 individuals), Molossidae (2 species; 26 individuals), Mormoopidae (1 species; 1 individual), Phyllostomidae (18 species; 180 individuals), and Vespertilionidae (2 species; 15 individuals) were collected in a Caribbean lowland rainforest of Costa Rica. Hct was measured after centrifugation of microhematocrit capillaries, TWBCs were performed using the Unopette system and a hemocytometer, and DWBCs were performed on eosin methylene blue stained blood films. Hct of bats ranged between 51.8 +/- 0.7% for Phyllostomus discolor (n = 27) and 65.8 +/- 2.2% for Molossus sinaloae (n = 6). Bat species of the same taxonomic family had comparable TWBCs; these were lower for insectivorous emballonurid, molossid, and vespertilionid bat species than for mostly phytophagous phyllostomid bat species. However, Ectophylla alba (Phyllostomidae) exhibited exceptionally low TWBCs (836 +/- 166 /microl; n = 10); this was less than half of the TWBCs of all other bat species, which ranged from 1,714 +/- 297/microl for Molossus bondae (n = 20) to 7,339 +/- 1,503/microl for Trachops cirrhosus (n = 6). Species with higher TWBCs tended to have lower Hct values. Overall, blood cell morphology was similar to other mammalian species. A large number of polychromatophilic erythrocytes and differences in lymphocyte morphology were noted. This study provides important hematological values for Neotropical bat species and significantly expands the knowledge on basal physiological measurements of Chiroptera.  相似文献   

11.
QT-interval dispersion (QT dispersion) is a marker of the inhomogeneity of ventricular repolarisation. In human beings an increase in QT dispersion has been linked to sudden death and arrhythmias in several cardiac diseases. In dogs it has yet to be evaluated, and this study aimed to establish a normal reference range for QT dispersion and to assess the effects of cardiac disease upon it. Ten-lead ECGS were recorded from 81 dogs at two hospitals; satisfactory traces were obtained from 68 dogs, 32 of them normal and 36 with cardiac disease. The mean (sd) QT dispersion was 20.8 (18.2 ms) and the mean heart rate-corrected QT dispersion was 26.1 (23.6 ms). There was no significant effect of cardiac disease. The accuracy of the results may be questioned owing to the identification of several potential errors in the measurements.  相似文献   

12.
A successful and safe methodology for the subcutaneous insertion of passive integrated transponder (PIT) tags in a small- to medium-sized bat (average mass 9 g) under isoflurane-induced anaesthesia is described. Passive integrated transponder (PIT) tagging had no significant impact on the rate of recapture, body condition index (BCI) (bodyweight/forearm length) and reproductive success of tagged individuals, and no visible injuries or health problems were observed in any of the recaptured bats. Tagging success, in terms of retention and function, was 92 per cent (n=61) by the third year of using the method. Sixteen per cent (n=39) of bats tagged during the three-year study period were not producing positive scans with the microchip reader when recaptured after previously successful tag insertion, indicating that the tags were either working their way out of the bats or ceasing to function.  相似文献   

13.
OBJECTIVE: To develop a clinically useful model for predicting QT interval duration as a function of heart rate in healthy cats. ANIMALS: 20 healthy cats. PROCEDURE: For all cats, results of a physical examination, electrocardiography, and echocardiography were normal. Twenty-four hour heart rate and rhythm data were collected by means of ambulatory electrocardiography. Hourly ECG segments were obtained from the 24-hour recordings. Mean heart rate and the mean of 5 QT interval measurements were calculated for each of 479 usable ECG segments. Analysis of covariance was used to develop models to describe variability in QT interval duration. RESULTS: Prediction equations (R2 = 0.81) including terms for heart rate, (heart rate)2, age group (1 to 4 vs 8 to 14 years old), and their interactions were developed. Sex, individual cat, and time of day were of little value in predicting QT interval duration. A simplified prediction equation without age group (R2 = 0.71) also was developed and had better predictive ability than reported correction formulas for QT interval duration. CONCLUSIONS AND CLINICAL RELEVANCE: Prediction equations with 95% prediction intervals for expected QT interval duration in healthy cats were generated. Abnormal QT interval duration can be associated with cardiac electrical instability, yet QT interval duration is greatly influenced by heart rate. Results of the present study provide reference ranges for expected QT interval duration as a function of heart rate in healthy cats.  相似文献   

14.
We previously reported that D0870 induced QT prolongation and sudden death due to torsades de pointes (TdP) in dogs and that catecholamines played an important part in the development of the sudden death. In the present study, we analyzed in detail the ambulatory electrocardiographic recordings obtained from the just-mentioned study to elucidate the mechanism of the onset of TdPs and conducted an in vitro study using isolated canine Purkinje fibers to assess the effect of D0870 on repolarization. The hearts with TdPs observed before the sudden death showed a higher sinus rate for 5 and 10 sec before the onset, a shorter coupling interval, and a higher ventricular tachycardia rate compared with those having the non-sustained TdPs. These findings suggest that D0870-induced fatal TdPs may be provoked by a triggered activity developed from delayed after depolarizations. In contrast, as the pause-dependent, non-sustained TdPs in bradycardia showed a typical "short-long-short" sequence, they may be developed from early afterdepolarization . Moreover, the results of the in vitro study supported our contention that D0870 induced QT prolongation in a reverse use-dependent manner in vivo and suggested that it may inhibit not only rapidly activating delayed rectifier potassium current (Ik(r)) but also L-type Ca current (I(ca-L)).  相似文献   

15.
A 16‐year‐old Arab mare was referred for treatment of a tachydysrhythmia detected on electrocardiogram by the referring veterinarian. Monomorphic, narrow‐complex ventricular tachycardia (VT) was confirmed by electro‐cardiogram in a normal base‐apex configuration. Subsequent diagnostic testing, including echocardiography and measurement of plasma cardiac troponin concentration, did not reveal a definitive cause for the dysrhythmia. Conversion of VT to ventricular bigeminy occurred following treatment with magnesium sulfate and lidocaine hydrochloride, administered intravenously. Treatment with orally administered propranolol subsequently led to conversion to sinus rhythm with intermittent ventricular premature complexes (VPCs). Oral prednisolone treatment was also initiated to address the possibility that VT resulted from underlying myocarditis. The mare was discharged with oral propranolol, a tapering course of prednisolone, and exercise restriction. Follow‐up cardiac examination 6 weeks later revealed persistent, intermittent VPCs and reversion to VT occurred during exercise. Sinus rhythm with intermittent VPCs was re‐established following the administration of lidocaine. The mare was again discharged with oral propranolol therapy, which was subsequently replaced with oral sotalol. Sudden death occurred 4 weeks later but a post mortem examination was not performed.  相似文献   

16.
The well recognized cardiac effects of severe hyperkalemia include progressive rhythm and conduction disturbances such as bradycardia, spiked and narrow T waves, widening QRS complex, widening and flattening P wave, disappearance of the P wave, and cardiac arrest. Paradoxically, a heart rate greater than 200 beats/min may coexist with hyperkalemia in some cats. This report describes three cats with moderate to severe hyperkalemia and concurrent rapid heart rate. In each cat, the serum potassium (K(+)) concentration was > or =7.5 mEq/dl with a concurrent heart rate > 200 beats/min. In each cat, nine-lead electrocardiograms demonstrate an absence of P waves and a wide-complex tachycardia. Hyperkalemia should be considered in the differential diagnosis when a feline electrocardiogram demonstrates a wide-complex tachycardia without identifiable P waves.  相似文献   

17.
Ventricular Arrhythmias in Dogs Undergoing Splenectomy: A Prospective Study   总被引：1，自引：0，他引：1  
Fifty dogs undergoing splenectomy for splenic masses (n = 40), torsion of the splenic pedicle (n = 5), and immune-mediated disease (n = 5) were evaluated preoperatively and postoperatively for ventricular arrhythmias and the relationship between ventricular arrythmia and splenic disease. The ability of 1 -minute electrocardiograms recorded every 6 hours (ECGs/q6hr) to detect ventricular arrythmia was compared with continuous 48-hour Holter monitoring. Based on continuous Holter monitoring, splenectomized dogs had a high incidence (22 of 50) of rapid ventricular tachycardia. The incidence of rapid ventricular tachycardia was significantly higher in dogs with ruptured splenic masses (16 of 23) than without rupture (1 of 17) ( P < .001). When the results of ECG/q6hr were compared with the results of continuous Holter monitoring, ECG/q6hr was normal in 29% (4 of 14) of dogs with rapid ventricular tachycardia at > 3,000 ventricular extrasystoles (VE)/hr; 50% (4 of 8) of dogs with rapid ventricular tachycardia at 1,000 to 3,000 VE/hr and 100% (6 of 6) of dogs with 10 to 300 VE/hr without rapid ventricular tachycardia. Although dogs undergoing splenectomy had a high incidence of ventricular arrythmias, one-minute ECGs/q6h were unreliable for detection of ventricular arrythmias even when high-frequency extrasystoles occurred.  相似文献   

18.
A 5-year-old, 29-kg, female Labrador retriever developed tachypnea, tachycardia, and ataxia following ingestion of approximately 48 mg/kg of phenylpropanolamine. Initial diagnostic tests showed multiform ventricular tachycardia, left ventricular dilatation with a focal dyskinetic region in the dorsal interventricular septum, and elevations in creatinine kinase and cardiac troponin I. All abnormalities resolved within 6 months. The transient electrocardiographic, echocardiographic, and biochemical abnormalities were consistent with myocardial necrosis from infarction or direct catecholamine-induced myocardial toxicity.  相似文献   

19.
Tocainide was administered to 23 cardiomyopathic Doberman Pinschers at doses of 15 to 25 mg/kg tid. These doses produced peak (2–hour) serum concentrations of 6.2 to 19.1 mg/L and trough (8–hour) serum concentrations of 2.3 to 11.1 mg/L. Anorexia and gastrointestinal disturbances occurred in 8 dogs (35%) at doses (15.6 to 25.0 mg/kg) that were not different from those (16.0 to 26.0 mg/kg) received by dogs that did not experience toxicity. Doses producing peak serum concentrations that were either greater or less than 14 mg/L were not different. Likewise, doses producing trough values that were either greater or less than 6 mg/L were not different. The mean dose that produced peak serum concentrations of 10 to 13.6 mg/L and trough concentrations of 4.2 to 10.0 mg/L was 17.9 mg/kg, and was associated with anorexia in 4 dogs. Mean peak serum concentrations associated with toxicity (14.4 mg/L) were significantly higher ( P = .02) than dogs not experiencing toxicity (11.8 mg/L). Serious adverse effects occurred in 7 of 12 dogs (58%) receiving tocainide for longer than 4 consecutive months. Progressive corneal endothelial dystrophy occurred in 3 dogs. Although a causal effect could not be proven, 6 dogs experienced renal dysfunction during treatment. Drug doses in these 7 dogs were similar to those received by other dogs. At least a 70% reduction of the total numbers of ventricular premature contractions occurred in 80% of dogs treated, and ventricular tachycardia was eliminated in 90% of affected dogs by the time of the first post-treatment Holter recording. Long-term control of ventricular tachyarrhythmias was difficult to achieve in some dogs when the left ventricular shortening fraction was less than approximately 17%. J Vet Intern Med 1996;10:235–240. Copyright © 1996 by the American College of Veterinary Internal Medicine .  相似文献   

20.
For obtaining the preliminary data on the pathogenesis of sudden death in calves naturally heavily infected with Strongyloides papillosus, we monitored 8 Holstein calves experimentally infected with the larvae on electrocardiographic and pneumographic changes. Six calves died suddenly on days 11 to 17 after infection. Sinus tachycardia had been recorded continuously since 1 to 6 days before death. Heart rates increased gradually until death. Since 1 or 2 days before death, various patterns of tachyarrhythmia and bradyarrhythmia had been observed among patterns of sinus tachycardia. Arrhythmias included serious ventricular premature beat, paroxysmal ventricular tachycardia, complete atrioventricular block and so on. The terminal pattern observed suddenly in all of the cases was ventricular arrhythmias consisting of serial ventricular tachycardia, flutter and fibrillation, which were followed by respiratory arrest. Abnormal pneumograms were not obtained before the terminal ventricular fibrillation. Two of 8 calves recovered from the infection, only one of which showed sinus arrest and the second degree of atrioventricular block transiently. We concluded that calves heavily infected with the larvae died due to sudden cardiac arrest.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号