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1.
OBJECTIVE: To assess heart rate variability (HRV) in Boxers with arrhythmogenic right ventricular cardiomyopathy (ARVC), assess the ability of HRV analysis to identify differences in Boxers on the basis of severity of their arrhythmia, and evaluate the use of HRV to determine whether persistently high sympathetic tone is present in these dogs. DESIGN: Prospective study. ANIMALS: 24 Boxers with ARVC and 10 clinically normal non-Boxer dogs. PROCEDURE: Boxers were categorized as dogs with congestive heart failure (CHF), dogs with < or = 2 ventricular premature complexes (VPCs)/24 h (designated unaffected), or dogs with > 1,000 VPCs/24 h (designated affected). Ambulatory electrocardiography (24 hours) was performed in each dog. Recordings were analyzed for HRV variables at a commercial laboratory; differences in HRV variables among groups were compared with 1-way ANOVA. RESULTS: Compared with control non-Boxer dogs and Boxers without CHF (affected and unaffected Boxers), HRV was reduced in Boxers with CHF. No differences in HRV variables were detected between affected and unaffected Boxers. Inconsistent differences were identified between the control dogs and Boxers without CHF that had various degrees of arrhythmias. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that persistently high sympathetic tone is not a consistent feature of ARVC. Differences in some HRV variables between Boxers without CHF and control dogs suggest that Boxers may have different autonomic control of heart rate, compared with that of clinically normal non-Boxer dogs. The usefulness of HRV analysis appears limited to Boxers with ARVC that have systolic dysfunction and CHF. 相似文献
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OBJECTIVE: To determine whether Boxers with a clinical diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC) have increased plasma concentrations of brain natriuretic peptide (BNP), compared with concentrations in clinically normal dogs. ANIMALS: 13 Boxers with ARVC, 9 clinically normal Boxers, 10 clinically normal non-Boxer dogs, and 5 hound dogs with systolic dysfunction. PROCEDURE: All Boxers were evaluated via 24-hour ambulatory electrocardiography and echocardiography; the number of ventricular premature contractions (VPCs) per 24 hours was assessed. Hound dogs with cardiac pacing-induced systolic dysfunction (positive control dogs) and clinically normal non-Boxer dogs (negative control dogs) were evaluated echocardiographically. Three milliliters of blood was collected from each dog for measurement of plasma BNP concentration by use of a radioimmunoassay. RESULTS: Mean +/- SD plasma BNP concentration for the ARVC-affected Boxers, clinically normal Boxers, negative control dogs, and positive control dogs was 11.0 +/- 4.6 pg/mL, 7.9 +/- 3.2 pg/mL, 11.5 +/- 4.9 pg/mL, and 100.8 +/- 56.8 pg/mL, respectively. Compared with findings in the positive control group, plasma BNP concentration in each of the other 3 groups was significantly different. There was no significant difference in BNP concentration between the 2 groups of Boxers. A significant correlation between plasma BNP concentration and number of VPCs per 24 hours in the ARVC-affected Boxers was not identified. CONCLUSIONS AND CLINICAL RELEVANCE: A significant difference in BNP concentration between Boxers with ARVC and clinically normal Boxers was not identified. Results suggest that BNP concentration may not be an indicator of ARVC in Boxers. 相似文献
3.
Kathy N. Wright Ali A. Mehdirad Paul Giacobbe Tammy Grubb Tacy Maxson 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1999,13(4):361-371
Incessant supraventricular tachyarrhythmias are known to result in myocardial dysfunction indistinguishable from idiopathic dilated cardiomyopathy by current testing methods. This tachycardia-induced cardiomyopathy (TICM), however, is uniquely reversible with adequate rhythm control. Two dogs were presented to The Ohio State University for incessant supraventricular tachycardia (SVT) and echocardiographic signs of dilated cardiomyopathy, later proven to be TICM. A 3rd dog presented for frequent paroxysms of SVT and syncope had echocardiographic signs of mild myocardial systolic dysfunction. All 3 dogs had inadequate rhythm control with multiple antiarrhythmic agents, and 1 dog suffered from recurrent left-sided congestive heart failure. Generalized cardiomegaly was found in 1 dog and left-sided dilatation without concurrent right-sided enlargement in 1 dog. Mild-to-severe left ventricular systolic dysfunction was confirmed echocardiographically in all dogs. A total of 4 atrioventricular accessory pathways (APs) were found during invasive electrophysiologic studies in these 3 dogs. All APs were successfully ablated with radiofrequency energy delivered through a thermistor-tipped catheter. Elimination of AP conduction, and thus orthodromic atrioventricular reciprocating tachycardia, resulted in resolution of all clinical and echocardiographic evidence of TICM in these dogs. This result confirms that the cardiomyopathy was, in fact, reversible TICM. All cardiovascular medications were discontinued, and no complications occurred during a 15-25-month follow-up period. 相似文献
4.
Smith CE Freeman LM Rush JE Cunningham SM Biourge V 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(2):265-273
BACKGROUND: Omega-3 fatty acids have been shown to reduce arrhythmia in animal models and people. These effects have not been studied in dogs with spontaneously occurring arrhythmia. HYPOTHESIS: Fish oil will reduce the frequency of ventricular arrhythmia in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC). ANIMALS: Twenty-four Boxers with ARVC were included in this study. METHODS: Asymptomatic Boxers not receiving antiarrhythmic medications were evaluated with echocardiogram and electrocardiogram. Dogs with at least 1 ventricular premature contraction (VPC) received 24-hour ambulatory electrocardiography (AECG) recordings. Dogs with > 95 VPCs in 24 hours were randomized to 1 of 3 treatments: (1) Fish oil, 2 g; (2) Flax oil, 2 g; or (3) sunflower oil, 2 g (Control group), for 6 weeks. Investigators and owners were blinded to the treatment groups. All baseline measurements were repeated after the 6-week supplementation. RESULTS: There were no differences at baseline for age, sex, blood pressure, weight, echocardiographic measurements, or VPCs. Median number of VPCs in 24 hours for all dogs was 543 (range, 96-40,063) at baseline and 193 (range, 6-14,825) after 6 weeks of supplementation. VPCs/24 h were reduced for the Fish oil group (baseline median = 397 [range, 249-10,587]; 6-week median = 162 [range, 16-3,781]; P = .02), but not for the Flax oil (P = .58) or Control (P = .48) groups. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that fish oil, but not flax oil, supplementation for 6 weeks reduces arrhythmia in Boxers with ARVC and that it could be useful in treating this common disease. Further studies are needed to determine optimal dose and duration of treatment. 相似文献
5.
OBJECTIVE: To assess signal-averaged electrocardiography (SAECG) for evaluation of Boxers with arrhythmogenic right ventricular cardiomyopathy (ARVC) and identify dogs at risk for sudden death (SD) or death related to congestive heart failure (CHF). DESIGN: Prospective study. ANIMALS: 94 Boxers with ARVC and 49 clinically normal non-Boxers (controls). PROCEDURE: Boxers were screened for ARVC, and severity was estimated by use of echocardiography, 24-hour ambulatory ECG, and SAECG. Statistical evaluation was performed to identify significant differences in SAECG variables relative to clinical outcome, frequency of ventricular arrhythmias, and systolic function. Sensitivity, specificity, and positive and negative predictive values were evaluated for each SAECG variable for occurrence of SD or death related to CHF. Late potentials were also evaluated as a predictor of cardiac-related death. RESULTS: Differences were detected in SAECG variables on the basis of clinical outcome, systolic function, and frequency of ventricular arrhythmias. More severely affected dogs had significantly more abnormal SAECG findings. The presence of late potentials, defined as 2 abnormal root mean square values (of 4), was associated with high sensitivity, specificity, and negative predictive value for cardiac-related SD or death secondary to CHF CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that SAECG is a useful noninvasive diagnostic test to evaluate dogs affected with ARVC and identify individuals at risk for cardiac-related death. 相似文献
6.
Evaluation of serum cardiac troponin I concentration in Boxers with arrhythmogenic right ventricular cardiomyopathy 总被引：1，自引：0，他引：1
OBJECTIVE: To evaluate serum cardiac troponin I (cTnI) concentrations in Boxers with arrhythmogenic right ventricular cardiomyopathy (ARVC), unaffected (control) Boxers, and control non-Boxers. ANIMALS: 10 Boxers with a clinical diagnosis of ARVC defined by > or = 1,000 ventricular premature complexes (VPCs)/24 h on an ambulatory ECG, 10 control Boxers assessed as normal by the presence of < 5 VPCs/24h, and 10 control non-Boxers. PROCEDURES: Serum was extracted from a blood sample from each dog. Analysis of serum cTnI concentrations was performed. RESULTS: Mean +/- SD serum cTnI concentration was 0.142 +/- 0.05 ng/mL for Boxers with ARVC, 0.079 +/- 0.03 ng/mL for control Boxers, and 0.023 +/- 0.01 ng/mL for control non-Boxers. A significant difference in serum cTnI concentrations was observed among the 3 groups. In the combined Boxer population (ie, Boxers with ARVC and control Boxers), a significant correlation was found between serum cTnI concentration and number of VPCs/24 h (r = 0.78) and between serum cTnI concentration and grade of ventricular arrhythmia (r = 0.77). CONCLUSIONS AND CLINICAL RELEVANCE: Compared with clinically normal dogs, Boxers with ARVC had a significant increase in serum cTnI concentration. For Boxers, correlations were found between serum cTnI concentration and number of VPCs/24 h and between concentration and the grade of arrhythmia. Because of the overlap in serum cTnI concentrations in control Boxers and Boxers with ARVC, future studies should evaluate the correlation of serum cTnI concentration with severity of disease in terms of degree of myocardial fibrofatty changes. 相似文献
7.
OBJECTIVE: To use an index of myocardial performance (IMP) to assess right ventricular function in Boxers with arrhythmogenic right ventricular cardiomyopathy (ARVC). ANIMALS: 22 Boxers (12 Boxers with ARVC diagnosed by the detection of > or = 1,000 ventricular premature complexes (VPCs)/24 h and 10 Boxers with < or = 5 VPCs/24 h (control dogs). Procedures-Pulsed-wave Doppler recordings of tricuspid inflow and pulmonic outflow were acquired. Preejection period (PEP), ejection time (ET), PEP/ET, and IMP were determined for the right ventricle by use of data from separate cardiac cycles. RESULTS: A significant difference was not identified between groups for right ventricular PEP, right ventricular ET, right ventricular PEP/ET, or right ventricular IMP. Right ventricular IMP was not significantly correlated with VPC number (r = 0.21) or VPC grade (r = -0.3) in Boxers with ARVC. CONCLUSIONS AND CLINICAL RELEVANCE: Boxers with ARVC did not have significant differences in right ventricular IMP, compared with results for control Boxers. This would suggest that right ventricular dysfunction does not develop in Boxers with ARVC or that a more severe phenotype of the disease may be necessary for detection of dysfunction. Additional studies that use more sensitive techniques to evaluate myocardial function may be warranted. 相似文献
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9.
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease seen in dogs, cats, and humans. A common entity in Boxers and the related English bulldog, the disease is characterized by fatty or fibrofatty replacement of the myocardium, ventricular arrhythmias, and the potential for syncope or sudden death. In some individuals, concomitant left ventricular involvement results in systolic dysfunction and a progression to congestive heart failure. The clinical and pathological characteristics of ARVC share many similarities in dogs and humans, and Boxers serve as an important spontaneous model of the disease.Although multiple mechanisms have been implicated in the pathogenesis of ARVC, the disease is ultimately considered to be a disorder of the desmosome. Multiple causal genetic mutations have been identified in people, and over 50% of affected humans have an identifiable mutation in desmosomal proteins. To date, only a single genetic mutation has been associated with ARVC in Boxer dogs. Other as-yet-undiscovered genetic mutations and epigenetic modifiers of the disease are likely. Treatment of ARVC in dogs is focused on controlling ventricular arrhythmias and associated clinical signs. This article will review the pathophysiology, clinical diagnosis, treatment, and prognosis of ARVC in the dog. 相似文献
10.
Smith CE Freeman LM Meurs KM Rush JE Lamb A 《American journal of veterinary research》2008,69(2):195-198
OBJECTIVE: To compare plasma fatty acid concentrations and the relationships of fatty acids to arrhythmias in Boxers versus Doberman Pinschers. ANIMALS: 38 Boxers and 13 Doberman Pinschers. PROCEDURES: Boxers and Doberman Pinschers evaluated via Holter recording and for which a blood sample was available were included. Echocardiograms were performed in 49 of 51 dogs. The number of ventricular premature complexes (VPCs)/24 h was counted and fatty acids analyzed. Plasma fatty acid concentrations and VPCs/24 h, as well as correlations between the 2 variables, were compared between the 2 breeds. RESULTS: Compared with the Doberman Pinschers, Boxers had significantly higher plasma concentrations of gamma-linolenic acid but lower concentrations of arachidonic acid. Total n-6 fatty acids and total polyunsaturated fatty acid concentrations were higher in Doberman Pinschers. There were significant, but weak, positive correlations between VPCs and oleic acid, total n-3 fatty acids, and total n-9 fatty acids in Boxers but not in Doberman Pinschers. CONCLUSIONS AND CLINICAL RELEVANCE: Data suggested that plasma fatty acid concentrations may differ between Boxers and Doberman Pinschers and that the relationship between fatty acid concentrations and VPCs may be different between these 2 breeds. 相似文献
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OBJECTIVE: To determine results of ambulatory electrocardiography in and outcome of overtly healthy Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy. DESIGN: Case series. ANIMALS: 44 overtly healthy (25 male, 19 female) Doberman Pinschers. PROCEDURE: 24-hour ambulatory electrocardiographic (Holter) recordings with > 90% scan quality obtained the same day that echocardiography was performed were reviewed. RESULTS: Holter recordings from 42 of 44 (95%) dogs contained ventricular premature complexes (VPC). Fifteen of 44 (34%) dogs had > 100 VPC, 9 (20%) had > 500 VPC, and 5 (11%) had > 1,000 VPC. Nonsustained (< 30 seconds) ventricular tachycardia was detected in 4 dogs. Eighteen of 27 (67%) dogs with > 100 VPC, any couplets or triplets of VPC, or ventricular tachycardia developed dilated cardiomyopathy within 1 year, compared with 8 of 17 (47%) dogs with < 100 VPC, no couplets or triplets of VPC, and no ventricular tachycardia. Of the 18 dogs that did not develop dilated cardiomyopathy within 1 year, 11 (61%) did so within 3 years. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a high percentage of Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy will be found to have VPC during 24-hour ambulatory electrocardiography and that most will develop echocardiographic abnormalities indicative of cardiomyopathy. 相似文献
13.
Karsten E. Schober Dr MedVet Virginia Luis Fuentes PhD MRCVS 《Veterinary radiology & ultrasound》2001,42(1):52-61
M-mode echocardiography was used to assess apical mitral annulus motion (MAM) in 103 normal dogs and 101 dogs with cardiac disease, to obtain information on systolic left ventricular long axis function. In normal dogs, a close relationship was found between MAM and body weight (r = 0.80, P < 0.001). There was a weak correlation between MAM and heart rate (r = -0.25, P < 0.05), but no correlation between MAM and age or left ventricular shortening fraction (P > 0.05). Mean MAM (95% confidence intervals) were established for normal dogs of differing body weight, and were 0.70 cm (0.65 to 0.75) in dogs < 15 kg, 1.08 cm (1.03 to 1.13) in dogs weighing 15 to 40 kg, and 1.51 cm (1.21 to 1.81) in dogs > 40 kg. "Cut-off" values to define decreased MAM for normal dogs of differing body weight were 0.45 cm (dogs < 15 kg), 0.80 cm (dogs 15-40 kg), and 1.20 cm (dogs > 40 kg). In dogs with cardiac disease, median MAM was normal in mitral valve endocardiosis or aortic stenosis, but significantly decreased (P < 0.05) in dilated cardiomyopathy. All dogs with mitral valve endocardiosis (n = 54) or aortic stenosis (n = 26) had MAM above the above-mentioned "cut-off" values, suggesting normal or increased left ventricular longitudinal systolic shortening, whereas 81% (17/21) of dogs with dilated cardiomyopathy had MAM below the "cut-off" value, indicating decreased long axis systolic function. It is concluded that MAM may be used to evaluate systolic left ventricular long axis performance in dogs and may add useful information on global left ventricular contraction dynamics. 相似文献
14.
Dilated cardiomyopathy (DCM), characterized by chamber dilatation and myocardial systolic and diastolic dysfunction, is one of the most common heart diseases in dogs. The clinical diagnosis is based on findings on echocardiographic and Doppler examinations, with the active exclusion of other acquired or congenital heart diseases. However, the echocardiographic criteria for the diagnosis of DCM are not wholly specific for the disease, and histologic examination may be necessary for final diagnosis. Review of reports on histologic findings in dogs with clinically diagnosed DCM reveals two histologically distinct forms of DCM: 1) cardiomyopathy of Boxers and Doberman Pinschers, corresponding to the "fatty infiltration-degenerative" type and 2) the form seen in many giant, large-, and medium-sized breeds, including some Boxers and Doberman Pinschers, classified as the "attenuated wavy fiber" type of DCM. The histologic changes of the attenuated wavy fiber type of DCM may precede clinical and echocardiographic signs of heart disease, thus indicating an early stage of DCM. 相似文献
15.
J D Thomason M S Kraus K K Surdyk T Fallaw C A Calvert 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2008,22(4):931-936
BACKGROUND: Syncope is a recognized problem in Boxers and often is the result of rapid ventricular tachycardia (VT). Affected dogs may have echocardiographic evidence of dilated cardiomyopathy, but frequently have normal echocardiograms. Although VT is probably the most common cause of syncope in Boxers, neurocardiogenic bradycardia can also occur. OBJECTIVE: We describe 7 Boxers with comorbid VT and neurocardiogenic bradycardia, wherein the syncope was secondary to bradycardia rather than VT. ANIMALS: Seven Boxers were selected from a larger population of Boxers with Holter-documented VT because these dogs had documented bradycardia at the time of syncope. METHODS: Retrospective study. RESULTS: Although all dogs had Holter-documented VT, the etiology of the syncopal episodes was consistent with neurocardiogenic bradycardia. CLINICAL IMPORTANCE: Neurocardiogenic bradycardia or VT can occur as isolated problems in Boxers. In some Boxers, VT and potential or manifest neurocardiogenic bradycardia coexist. The administration of a beta-blocker or sotalol to such dogs can aggravate or precipitate neurocardiogenic bradycardia-related syncope. 相似文献
16.
Calvert CA Jacobs G Pickus CW Smith DD 《Journal of the American Veterinary Medical Association》2000,217(9):1328-1332
OBJECTIVE: To identify, by means of 24-hour ambulatory electrocardiography, electrocardiographic abnormalities in overtly healthy Doberman Pinschers in which results of echocardiography were abnormal. DESIGN: Clinical case series. ANIMALS: 56 (35 male, 21 female) overtly healthy Doberman Pinschers with echocardiographic evidence of cardiomyopathy on initial examination that subsequently died of cardiomyopathy. PROCEDURE: Twenty-four-hour ambulatory electrocardiographic (Holter) recordings obtained at the time of initial examination were reviewed. For all dogs, scan quality was > 90%. RESULTS: Initial Holter recordings of all 56 dogs contained ventricular premature contractions (VPC). Thirty-six (65%) dogs had > 1,000 VPC/24 h, 17 (31%) had > 5,000 VPC/24 h, and 11 (19%) had > 10,000 VPC/24 h. Fifty-four (96%) dogs had couplets of VPC, 37 (66%) had triplets of VPC, and 36 (64%) had episodes of nonsustained (< 30 seconds) ventricular tachycardia. Number of VPC/24 h during the initial Holter recordings was positively correlated with numbers of couplets and triplets of VPC and number of ventricular escape beats and negatively correlated with left ventricular fractional shortening. Twenty-eight dogs died suddenly prior to the putative onset of congestive heart failure. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that along with echocardiography, 24-hour ambulatory electrocardiography can be used to help identify overtly healthy Doberman Pinschers with cardiomyopathy. 相似文献
17.
Loureiro J Smith S Fonfara S Swift S James R Dukes-McEwan J 《The Journal of small animal practice》2008,49(11):578-586
Objective : The aims of this study were (i) to evaluate echocardiographic findings and myocardial function including pulsed wave tissue Doppler imaging in dogs with naturally occurring dynamic left ventricular outflow tract obstruction and (ii) to investigate the clinical outcome and response to therapy in these dogs. Methods : Two cases were retrospectively reviewed and three cases were prospectively evaluated including clinical findings, diagnostic test results (including standard Doppler echocardiography and pulsed wave tissue Doppler imaging), response to treatment and outcome. The two retrospective cases received no treatment. Other cases were treated with a β‐blocker. Results : All dogs had a variable intensity left apical systolic murmur. Concentric left ventricular hypertrophy, systolic anterior motion of the mitral valve and scimitar‐shaped left ventricular outflow tract Doppler flow profile were present in all cases. Pulsed wave tissue Doppler imaging interrogation of the interventricular septum revealed E′/A′ reversal in all but one patient. Regression of left ventricular hypertrophy and total resolution of the dynamic left ventricular outflow tract obstruction were observed in all cases. Clinical Significance : Young dogs are affected with a possible terrier breed predisposition. Dynamic left ventricular outflow tract obstruction may be distinguished from canine hypertrophic cardiomyopathy as progressive resolution of echocardiographic abnormalities was documented. Pulsed wave tissue Doppler imaging abnormalities provide further evidence for significant diastolic dysfunction associated with the hypertrophy. 相似文献
18.
Cunningham SM Rush JE Freeman LM Brown DJ Smith CE 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2008,22(4):924-930
BACKGROUND: Boxer dogs are routinely screened by echocardiography to exclude congenital and acquired heart disease. Individuals of a given breed may span a large range of body sizes, potentially invalidating linear regression of M-mode measurements against body weight. Echocardiographic ratio indices (ERIs) provide a novel method of characterizing echocardiographic differences between Boxers and other dog breeds. HYPOTHESIS: ERIs obtained from overtly healthy Boxer dogs presented for cardiac screening will be different from ERIs established for normal non-Boxer dogs, and those differences will be unrelated to aortic velocity or systolic blood pressure. ANIMALS: Eighty-one Boxers with no outward clinical signs of heart disease were studied. METHODS: All dogs were examined by 2-dimensional, M-mode, and Doppler echocardiography. M-mode measurements were used to perform ERI calculations, and the indices in Boxers were compared between Boxers with varying severity of arrhythmia and those of normal non-Boxer dogs. RESULTS: Differences in weight-based ERIs, which reflect increased thickness of the left ventricular free wall (LVW) and interventricular septum (IVS) and smaller aortic size, were found in overtly healthy Boxer dogs compared with normal non-Boxer dogs. ERIs of left atrial and LV cavity size in overtly healthy Boxers were not significantly different from those of non-Boxer dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Boxer dogs may have an increased relative thickness of the LVW and IVS that is independent of aortic size, aortic velocity, or arterial blood pressure, and this morphology should be taken into consideration when screening Boxers by echocardiography. 相似文献
19.
Kraus MS Moïse NS Rishniw M Dykes N Erb HN 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(2):153-158
The QRS amplitude and polarity were determined in 12-lead electrocardiograms recorded from 22 Boxers with ventricular arrhythmias. Eighty-one percent (18/22) of dogs displayed a positive QRS morphology in the caudoventral leads (II, III, and aVF) and 77% (17/22) of dogs displayed a positive QRS morphology in the left precordial leads (V2-V6). In leads I and V1, the polarity of the QRS complex was variable (positive or negative). To determine if these morphologic features were suggestive of ventricular complexes arising from the right or left ventricle, a comparison was made to the QRS complexes in a pace-mapping study performed in 7 healthy mixed-breed dogs. A total of 3 right and 4 left ventricular sites were paced. None of the left ventricular paced sites resulted in a QRS morphology similar to the most common spontaneous ventricular arrhythmia in the Boxers. In contrast, QRS morphology in each of the 3 right ventricular sites was similar to that observed in the Boxers (P < .033). Each of these produced positive deflections in the caudoventral and left precordial leads, but both positive and negative QRS complexes were observed in leads I and V1 only when the right ventricular septum was paced. This finding suggested that the right ventricular septum might be a site of origin for the ventricular rhythm observed in the Boxers because in the Boxers the polarity of leads I and V1 also varied. Pacing the right ventricular outflow tract always resulted in a negative QRS complex in lead 1, whereas pacing the right ventricular apex always resulted in a positive QRS complex in lead I and a negative QRS complex in V1. However, these locations cannot be excluded as possible sites of origin for the spontaneous ventricular arrhythmias in the Boxers because the arrhythmias could be originating from both of these locations. The spontaneous ventricular arrhythmia of the Boxer is most similar to that of paced ventricular rhythms arising from the right ventricle. More precise localization to a region of the right ventricle such as outflow tract, septal, or apical could not be made. 相似文献
20.
S.M. Cunningham B.D. Aona K. Antoon J.E. Rush B.A. Barton 《Journal of Veterinary Cardiology》2018,20(5):343-353