Estenose de valva mitral associada a um trombo na aurícula esquerda em cão / Mitral valve stenosis associated with a left auricle thrombus in a dog

Background: Mitral valve stenosis is a congenital or acquired condition characterized by the narrowing of the orifice of the mitral valve of the heart. It causes flow obstruction and inadequate left ventricular filling, leading to increased left atrial pressure, left atrial and auricle enlargement, pulmonary venous congestion, and left-sided congestive heart failure. Mitral valve stenosis is extremely rare in dogs, and mitral valve stenosis associated with thrombus is even less common in this species. The etiology of thrombus development in mitral valve stenosis in dogs is still not clear. In human beings, mitral valve stenosis associated with thrombus has been related to rheumatic fever. This paper aims to report a case of mitral valve stenosis associated with a left auricle thrombus in a dog.Case: A small mixed-breed, 9-year-old, spayed female dog was received by the emergency service of the veterinary hospital a few hours after a syncopal episode. The dog presented dyspnea, apathy, and appetite loss for a week. At physical examination, the dog had pale and cyanotic mucous membranes, 92 mmHg systolic blood pressure, 7% dehydration, and 36.9°C rectal temperature. Cardiac auscultation revealed tachyarrhythmia and diastolic murmur grade IV/VI on the left cardiac apex. During pulmonary auscultation, bilateral crackles were noted. Electrocardiography showed sinus tachycardia with supraventricular tachycardia episodes, increased P wave amplitude and duration, and increased QRS complex duration. Generalized cardiomegaly was noted in thoracic radiography with enlarged left atrium, left cardiac edge bulging, pulmonary hypertension and congestion signs, as well as areas of pulmonary opacification.[...]

Estenose de valva mitral associada a um trombo na aurícula esquerda em cão / Mitral valve stenosis associated with a left auricle thrombus in a dog

Background: Mitral valve stenosis is a congenital or acquired condition characterized by the narrowing of the orifice of the mitral valve of the heart. It causes flow obstruction and inadequate left ventricular filling, leading to increased left atrial pressure, left atrial and auricle enlargement, pulmonary venous congestion, and left-sided congestive heart failure. Mitral valve stenosis is extremely rare in dogs, and mitral valve stenosis associated with thrombus is even less common in this species. The etiology of thrombus development in mitral valve stenosis in dogs is still not clear. In human beings, mitral valve stenosis associated with thrombus has been related to rheumatic fever. This paper aims to report a case of mitral valve stenosis associated with a left auricle thrombus in a dog.Case: A small mixed-breed, 9-year-old, spayed female dog was received by the emergency service of the veterinary hospital a few hours after a syncopal episode. The dog presented dyspnea, apathy, and appetite loss for a week. At physical examination, the dog had pale and cyanotic mucous membranes, 92 mmHg systolic blood pressure, 7% dehydration, and 36.9°C rectal temperature. Cardiac auscultation revealed tachyarrhythmia and diastolic murmur grade IV/VI on the left cardiac apex. During pulmonary auscultation, bilateral crackles were noted. Electrocardiography showed sinus tachycardia with supraventricular tachycardia episodes, increased P wave amplitude and duration, and increased QRS complex duration. Generalized cardiomegaly was noted in thoracic radiography with enlarged left atrium, left cardiac edge bulging, pulmonary hypertension and congestion signs, as well as areas of pulmonary opacification.[...](AU)

Valor prognóstico da variabilidade da frequência cardíaca e da eletrocardiografia ambulatorial em cães Boxer com cardiomiopatia arritmogênica do ventrículo direito / Prognostic value of heart rate variability and Holter monitoring in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma importante causa de morte súbita em cães da raça Boxer. A validação de fatores prognósticos para essa doença auxiliaria na detecção de animais mais gravemente afetados e sua exclusão dos programas de reprodução. O objetivo deste estudo foi avaliar o valor prognóstico da presença de manifestações clínicas, dos índices de variabilidade de frequência cardíaca (VFC) e das arritmias supraventriculares ou ventriculares registradas à monitorização eletrocardiográfica com Holter na sobrevida de cães Boxer em diferentes estágios da CAVD. Essas variáveis foram analisadas, de forma prospectiva, em 69 cães Boxer, divididos em cinco grupos: cães Boxer controle (grupo CB, <50 VPC/24 horas, n=28), cães Boxer suspeitos (grupo SB, 50 a 300 VPC/24 horas, n=8), cães Boxer com CAVD (grupo ARVC, >300 VPC/24 horas, n=19), cães Boxer com CAVD e disfunção sistólica sem insuficiência cardíaca congestiva (grupo SDB sem ICC, n=6) e com ICC (grupo SDB com ICC, n=8). A análise estatística compreendeu teste ANOVA, correlação de Pearson e análise de riscos proporcionais de Cox. Comparando-se com o grupo CB, não foi encontrada diminuição nos índices de VFC nos grupos SB, ARVC ou SDB sem ICC; por outro lado, o grupo SDB com ICC apresentou diminuição desses índices. Não houve relação entre os índices de VFC e a morte de origem cardíaca; porém, a presença de síncopes com ou sem sinais clínicos de ICC e o número de episódios de taquicardia ventricular (TV) correlacionaram-se com a sobrevida dos animais. Estes resultados permitem concluir que a presença de sinais clínicos de ICC, a presença de síncopes e o número de TV ao Holter apresentam valor prognóstico de sobrevida em cães Boxer com CAVD.(AU)

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in Boxer dogs. Validation of prognostic factors for this disease could help in detecting more severely affected animals and their exclusion from breeding programs. The aims of this study were to evaluate the prognostic significance of presence of symptoms, heart rate variability (HRV) indices and ventricular or supraventricular arrhythmias recorded by Holter monitoring on survival of Boxer dogs with ARVC at different stages. Symptoms, arrhythmias registered on Holter and five HRV indices were prospectively analyzed in 69 client-owned Boxer dogs divided into five groups: control Boxer dogs (CB group, <50 VPC/24 hours, n=28), suspicious Boxers (SB group, 50 to 300 VPC/24 hours, n=8), Boxers with ARVC (ARVC group, >300 VPC/24 hours, n=19), Boxers with ARVC and systolic dysfunction without congestive heart failure (SDB without CHF group, n=6) and with CHF (SDB with CHF group, n=8). Statistical analyses consisted of an ANOVA test, Pearson correlation and Cox's proportional hazards regression. Compared to the CB group, no decrease in HRV indices was found in SB, ARVCB or SDB without CHF groups; otherwise, SDB with CHF group had impaired indices. No relation was found between HRV indices and cardiac-related death, but the presence of syncopes with or without clinical signs of heart failure and number of ventricular tachycardia (VT), were correlated with survival. These results allow us to conclude that the presence of symptoms of heart failure, presence of syncopes and number of VT on Holter examination seem to have prognostic value in Boxer ARVC.(AU)

Valor prognóstico da variabilidade da frequência cardíaca e da eletrocardiografia ambulatorial em cães Boxer com cardiomiopatia arritmogênica do ventrículo direito / Prognostic value of heart rate variability and Holter monitoring in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma importante causa de morte súbita em cães da raça Boxer. A validação de fatores prognósticos para essa doença auxiliaria na detecção de animais mais gravemente afetados e sua exclusão dos programas de reprodução. O objetivo deste estudo foi avaliar o valor prognóstico da presença de manifestações clínicas, dos índices de variabilidade de frequência cardíaca (VFC) e das arritmias supraventriculares ou ventriculares registradas à monitorização eletrocardiográfica com Holter na sobrevida de cães Boxer em diferentes estágios da CAVD. Essas variáveis foram analisadas, de forma prospectiva, em 69 cães Boxer, divididos em cinco grupos: cães Boxer controle (grupo CB, <50 VPC/24 horas, n=28), cães Boxer suspeitos (grupo SB, 50 a 300 VPC/24 horas, n=8), cães Boxer com CAVD (grupo ARVC, >300 VPC/24 horas, n=19), cães Boxer com CAVD e disfunção sistólica sem insuficiência cardíaca congestiva (grupo SDB sem ICC, n=6) e com ICC (grupo SDB com ICC, n=8). A análise estatística compreendeu teste ANOVA, correlação de Pearson e análise de riscos proporcionais de Cox. Comparando-se com o grupo CB, não foi encontrada diminuição nos índices de VFC nos grupos SB, ARVC ou SDB sem ICC; por outro lado, o grupo SDB com ICC apresentou diminuição desses índices. Não houve relação entre os índices de VFC e a morte de origem cardíaca; porém, a presença de síncopes com ou sem sinais clínicos de ICC e o número de episódios de taquicardia ventricular (TV) correlacionaram-se com a sobrevida dos animais. Estes resultados permitem concluir que a presença de sinais clínicos de ICC, a presença de síncopes e o número de TV ao Holter apresentam valor prognóstico de sobrevida em cães Boxer com CAVD.(AU)

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in Boxer dogs. Validation of prognostic factors for this disease could help in detecting more severely affected animals and their exclusion from breeding programs. The aims of this study were to evaluate the prognostic significance of presence of symptoms, heart rate variability (HRV) indices and ventricular or supraventricular arrhythmias recorded by Holter monitoring on survival of Boxer dogs with ARVC at different stages. Symptoms, arrhythmias registered on Holter and five HRV indices were prospectively analyzed in 69 client-owned Boxer dogs divided into five groups: control Boxer dogs (CB group, <50 VPC/24 hours, n=28), suspicious Boxers (SB group, 50 to 300 VPC/24 hours, n=8), Boxers with ARVC (ARVC group, >300 VPC/24 hours, n=19), Boxers with ARVC and systolic dysfunction without congestive heart failure (SDB without CHF group, n=6) and with CHF (SDB with CHF group, n=8). Statistical analyses consisted of an ANOVA test, Pearson correlation and Cox's proportional hazards regression. Compared to the CB group, no decrease in HRV indices was found in SB, ARVCB or SDB without CHF groups; otherwise, SDB with CHF group had impaired indices. No relation was found between HRV indices and cardiac-related death, but the presence of syncopes with or without clinical signs of heart failure and number of ventricular tachycardia (VT), were correlated with survival. These results allow us to conclude that the presence of symptoms of heart failure, presence of syncopes and number of VT on Holter examination seem to have prognostic value in Boxer ARVC.(AU)

Controle de insuficiência cardíaca congestiva e arritmias ventriculares em um cão com cardiomiopatia dilatada – relato de caso / Control of congestive heart failure with and ventricular arrhythmiasarrhytmias in a dog with dilated cardiomyopathy - case report / Manejo de una insuficiencia cardíaca congestiva y arritmias ventriculares en un perro con cardiomiopatía dilatada - relato de caso

No presente trabalho relata-se o caso de um cão, macho, cocker spaniel americano de onze anos com histórico de dispneia aguda e intolerância ao exercício. O exame eletrocardiográfico evidenciou a presença de arritmias ventriculares, e, por meio do exame ecocardiográfico o paciente foi diagnosticado com cardiomiopatia dilatada e insuficiência cardíaca congestiva. Realizou-se o tratamento, com melhora dos sinais congestivos e das arritmias. Arritmias ventriculares são difíceis de se controlar em pacientes tratados somente para a doença cardíaca de base, sema administração de antiarrítmicos. O paciente atingiu uma sobrevida de quinze meses evidenciando a necessidade de se realizar diagnóstico e tratamento precoces, a fim de se obter uma melhora na expectativa de vida de pacientes cardiopatas.

We report a case of a dog, male, eleven year old, american cocker spaniel with a history of acute dyspnea and exercise intolerance. The electrocardiography examination revealed the presence of ventricular arrhytmias, and, through echocardiographic examination, the patient was diagnosed with dilated cardiomyopathy and congestive heart failure. Treatment was performed, with improvement in congestive signs and arrhytmias. Ventricular arrhytmias are difficult to control in patients treated only for underlying heart disease, without the administration of antiarrythmics. The patient survived for fifteen months, emphasizing the need for early diagnosis and treatment, in order to obtain an improvement in life expectancy of patients with heart disease.

El presente trabajo relata el caso de un perro Cocker spaniel americano macho, de once años con histórico de disnea aguda e intolerancia al ejercicio físico. El electrocardiograma mostró arritmias ventriculares y la ecocardiografia evidenció la presencia de una cardiomiopatía dilatada yinsuficiencia cardíaca mayor. La enfermedad fue tratada y el paciente mostró mejoría del cuadro congestivo y de las arritmias. Las arritmias ventriculares son difíciles de controlar en pacientes tratados solo por enfermedad cardíaca subyacente, sin la necessidad de administrar medicamentos antiarrítmicos. El animal tuvo una supervivencia de quince meses. Los resultados muestran la importancia de realizar un diagnóstico y un tratamiento precoces, con objetivo de mejorar la expectativa de vida de pacientes con cardiopatías.

Controle de insuficiência cardíaca congestiva e arritmias ventriculares em um cão com cardiomiopatia dilatada relato de caso / Control of congestive heart failure with and ventricular arrhythmiasarrhytmias in a dog with dilated cardiomyopathy - case report / Manejo de una insuficiencia cardíaca congestiva y arritmias ventriculares en un perro con cardiomiopatía dilatada - relato de caso

No presente trabalho relata-se o caso de um cão, macho, cocker spaniel americano de onze anos com histórico de dispneia aguda e intolerância ao exercício. O exame eletrocardiográfico evidenciou a presença de arritmias ventriculares, e, por meio do exame ecocardiográfico o paciente foi diagnosticado com cardiomiopatia dilatada e insuficiência cardíaca congestiva. Realizou-se o tratamento, com melhora dos sinais congestivos e das arritmias. Arritmias ventriculares são difíceis de se controlar em pacientes tratados somente para a doença cardíaca de base, sema administração de antiarrítmicos. O paciente atingiu uma sobrevida de quinze meses evidenciando a necessidade de se realizar diagnóstico e tratamento precoces, a fim de se obter uma melhora na expectativa de vida de pacientes cardiopatas.(AU)

We report a case of a dog, male, eleven year old, american cocker spaniel with a history of acute dyspnea and exercise intolerance. The electrocardiography examination revealed the presence of ventricular arrhytmias, and, through echocardiographic examination, the patient was diagnosed with dilated cardiomyopathy and congestive heart failure. Treatment was performed, with improvement in congestive signs and arrhytmias. Ventricular arrhytmias are difficult to control in patients treated only for underlying heart disease, without the administration of antiarrythmics. The patient survived for fifteen months, emphasizing the need for early diagnosis and treatment, in order to obtain an improvement in life expectancy of patients with heart disease.(AU)

El presente trabajo relata el caso de un perro Cocker spaniel americano macho, de once años con histórico de disnea aguda e intolerancia al ejercicio físico. El electrocardiograma mostró arritmias ventriculares y la ecocardiografia evidenció la presencia de una cardiomiopatía dilatada yinsuficiencia cardíaca mayor. La enfermedad fue tratada y el paciente mostró mejoría del cuadro congestivo y de las arritmias. Las arritmias ventriculares son difíciles de controlar en pacientes tratados solo por enfermedad cardíaca subyacente, sin la necessidad de administrar medicamentos antiarrítmicos. El animal tuvo una supervivencia de quince meses. Los resultados muestran la importancia de realizar un diagnóstico y un tratamiento precoces, con objetivo de mejorar la expectativa de vida de pacientes con cardiopatías.(AU)

Time-domain signal-averaged electrocardiogram in healthy German Shepherd and Boxer dogs / Eletrocardiograma de alta resolução (ECGAR) no domínio do tempo em cães sadios das raças Pastor Alemão e Boxer

Signal-averaged electrocardiogram (SAECG) identifies ventricular late potentials (LP), low-amplitude electrical signals that are markers of slow cardiac conduction in fibrous myocardium, consisting in a predictive factor for sudden death in dogs at risk of sustained ventricular tachycardia. The aim of this study was to establish reference values of SAECG for German Shepherd and Boxer dogs. SAECG was performed in 19 German Shepherd and 28 Boxer client-owned dogs, and parameters analyzed were QRSd (duration of filtered QRS), LAS<40μV (duration of low-amplitude signals in terminal portion of filtered QRS) and RMS40 (root square of mean voltage over the last 40 milliseconds of filtered QRS), with two different filters (25-250 Hz and 40-250 Hz). Statistical analyses was achieved by T Student test (p<0.05) to identify differences between the two groups and between the values obtained with the two filters. No statistical difference was found in SAECG variables between the two breeds with the two different filters (p>0.05). Achieving normal values of SAECG in German Shepherd and Boxer dogs is important to further research late potentials in animals of these breeds with hereditary ventricular tachycardia or arrhythmogenic cardiomyopathy and identification of individuals at high risk of cardiac-related sudden death.(AU)

O eletrocardiograma de alta resolução (ECGAR) identifica os potenciais tardios (PT), sinais elétricos de baixa amplitude considerados marcadores de condução cardíaca lenta de áreas fibrosadas do miocárdio, cuja presença consiste em fator preditivo de morte súbita em cães com taquicardia ventricular sustentada. O objetivo deste estudo foi o estabelecimento de valores de referência para o ECGAR de cães Boxer (n=28) e Pastor Alemão (n=19). Os seguintes parâmetros do ECGAR foram analisados: dQRS (duração do QRS filtrado), LAS<40μV (duração dos sinais de baixa amplitude no final do QRS filtrado) e RMS40 (raiz quadrada da voltagem média do final do QRS filtrado), com dois tipos diferentes de filtro (25-250 Hz e 40-250 Hz). Análise estatística foi realizada por meio do teste T de Student (p<0,05) para identificar diferenças entre os dois grupos e entre os valores obtidos com os dois filtros. Não foram encontradas diferenças significativas entre as variáveis de ECGAR nas duas raças estudadas com os dois diferentes filtros (p>0,05). A obtenção dos valores de normalidade de ECGAR em cães dessas raças auxiliará na realização de futuras pesquisas de potenciais tardios em animais com taquicardia ventricular hereditária ou cardiomiopatia arritmogênica, bem como na identificação dos indivíduos com alto risco de morte súbita de origem cardíaca.(AU)

Arrhythmogenic Right Ventricular Cardiomyopathy in Two Dogs

Arrhythmogenic right ventricle cardiomyopathy (ARVC) is a rare primary heart condition recognized in dogs. It is an inherited disease more commonly described in Boxer dogs. Clinically, ARVC is characterized by ventricular tachyarrhythmias and histopathologically by fibrofatty replacement, mostly on the right ventricle. This report describes the gross and histopathological findings from a female adult Boxer and from a male adult mixed breed dog, presenting signs of heart failure and marked infiltration of adipose tissue replacing cardiomyocytes, predominantly in the epicardium and myocardium of the right ventricle.

Arrhythmogenic Right Ventricular Cardiomyopathy in Two Dogs

Arrhythmogenic right ventricle cardiomyopathy (ARVC) is a rare primary heart condition recognized in dogs. It is an inherited disease more commonly described in Boxer dogs. Clinically, ARVC is characterized by ventricular tachyarrhythmias and histopathologically by fibrofatty replacement, mostly on the right ventricle. This report describes the gross and histopathological findings from a female adult Boxer and from a male adult mixed breed dog, presenting signs of heart failure and marked infiltration of adipose tissue replacing cardiomyocytes, predominantly in the epicardium and myocardium of the right ventricle.(AU)

Flutter atrial e taquicardia ventricular em cão com síndrome dilatação e vólvulo / gástrico / Atrial flutter and ventricular tachycardia in dog with gastric-dilation volvulus Complex

Background: Gastric-dilation volvulus complex (GDV) is an acute condition characterized by dilation of the stomach associated with rotation around its mesenteric axis. Cardiac arrhythmias, especially of ventricular origin are frequently found in animals with GDV. Ventricular tachycardia is characterized by three or more ventricular premature complexes in sequence. Atrial flutter is a supraventricular arrhythmia uncommon in dogs, characterized by rapid atrial rate and altered atrial depolarization resulting in bidirectional saw-toothed atrial complexes. The aim of this work is describe the cardiac arrhythmias and electrocardiographic patterns observed in a postoperative period of seven days in a dog with GDV syndrome. Case: A 2-year-old female dog of Fila Brasileiro breed was presented to veterinary hospital due to an acute onset of abdominal distension. Clinical findings included hyperemic mucous membranes, capillary refill time of less than two seconds, normal sounds in cardiac auscultation, heart rate of 160 beats per min, tachypnea, normal femoral pulses and an increased abdominal volume compatible with accumulation of gas. The surgical procedure was the treatment of choice for correction of GDV syndrome. The stomach was dilated, rotated 180 degrees clockwise and possibly with a necrotic area. The spleen was congested and infarcted. During surgery, the patient had a period of low oximetry and two isolated ventricular premature complexes, treated with lidocaine in bolus. In the postoperative period, the electrocardiographic monitoring revealed the presence of two types of arrhythmia. Ventricular tachycardia occurred one day after surgery, being treated with lidocaine in bolus and constant rate infusion. On the third day, the dog developed atrial fl utter, treated with digoxin. On the fourth day, cardiac rhythm returned to normal and showed no further changes up to 7 days after surgery, when the dog was discharged. Discussion: The presence of cardiac arrhythmias in the postoperative period is one of the factors that makes the prognosis worse in dogs with GDV. The etiological mechanism of cardiac arrhythmias in this syndrome has not been elucidated. Among the possibilities are myocardial ischemia, release of myocardial depressant factors, release of catecholamines, electrolyte imbalances and acidosis. Ventricular tachycardia is a relatively common arrhythmia in cases of GDV, which can progress to ventricular fibrillation, the leading cause of deaths from cardiac arrhythmia in dogs with the disease. Among supraventricular arrhythmias, atrial premature complexes were reported, however atrial flutter was not described before in this syndrome. Moreover, the dog developed cardiac arrhythmia until about 72 h after surgery, unlike another reports. An electrocardiographic pattern changed was the size of the P wave, suggesting left atrial enlargement, but thoracic radiography showed a normal-sized cardiac silhouette. Moreover, the animal showed T wave amplitude greater than 25% of the R wave amplitude, which may be related to low oximetry observed at the start of surgery, possible electrolyte imbalances or be physiological. The present case reinforces the importance of electrocardiographic monitoring in the postoperative GDV, including a period of up to 72 h after surgery. Moreover, it is concluded that atrial flutter may be another type of arrhythmia caused by secondary changes of GDV syndrome and confirms the effectiveness of antiarrhythmic therapy with lidocaine in cases of ventricular tachycardia.(AU)

Flutter atrial e taquicardia ventricular em cão com síndrome dilatação e vólvulo / gástrico / Atrial flutter and ventricular tachycardia in dog with gastric-dilation volvulus Complex

Background: Gastric-dilation volvulus complex (GDV) is an acute condition characterized by dilation of the stomach associated with rotation around its mesenteric axis. Cardiac arrhythmias, especially of ventricular origin are frequently found in animals with GDV. Ventricular tachycardia is characterized by three or more ventricular premature complexes in sequence. Atrial flutter is a supraventricular arrhythmia uncommon in dogs, characterized by rapid atrial rate and altered atrial depolarization resulting in bidirectional saw-toothed atrial complexes. The aim of this work is describe the cardiac arrhythmias and electrocardiographic patterns observed in a postoperative period of seven days in a dog with GDV syndrome. Case: A 2-year-old female dog of Fila Brasileiro breed was presented to veterinary hospital due to an acute onset of abdominal distension. Clinical findings included hyperemic mucous membranes, capillary refill time of less than two seconds, normal sounds in cardiac auscultation, heart rate of 160 beats per min, tachypnea, normal femoral pulses and an increased abdominal volume compatible with accumulation of gas. The surgical procedure was the treatment of choice for correction of GDV syndrome. The stomach was dilated, rotated 180 degrees clockwise and possibly with a necrotic area. The spleen was congested and infarcted. During surgery, the patient had a period of low oximetry and two isolated ventricular premature complexes, treated with lidocaine in bolus. In the postoperative period, the electrocardiographic monitoring revealed the presence of two types of arrhythmia. Ventricular tachycardia occurred one day after surgery, being treated with lidocaine in bolus and constant rate infusion. On the third day, the dog developed atrial fl utter, treated with digoxin. On the fourth day, cardiac rhythm returned to normal and showed no further changes up to 7 days after surgery, when the dog was discharged. Discussion: The presence of cardiac arrhythmias in the postoperative period is one of the factors that makes the prognosis worse in dogs with GDV. The etiological mechanism of cardiac arrhythmias in this syndrome has not been elucidated. Among the possibilities are myocardial ischemia, release of myocardial depressant factors, release of catecholamines, electrolyte imbalances and acidosis. Ventricular tachycardia is a relatively common arrhythmia in cases of GDV, which can progress to ventricular fibrillation, the leading cause of deaths from cardiac arrhythmia in dogs with the disease. Among supraventricular arrhythmias, atrial premature complexes were reported, however atrial flutter was not described before in this syndrome. Moreover, the dog developed cardiac arrhythmia until about 72 h after surgery, unlike another reports. An electrocardiographic pattern changed was the size of the P wave, suggesting left atrial enlargement, but thoracic radiography showed a normal-sized cardiac silhouette. Moreover, the animal showed T wave amplitude greater than 25% of the R wave amplitude, which may be related to low oximetry observed at the start of surgery, possible electrolyte imbalances or be physiological. The present case reinforces the importance of electrocardiographic monitoring in the postoperative GDV, including a period of up to 72 h after surgery. Moreover, it is concluded that atrial flutter may be another type of arrhythmia caused by secondary changes of GDV syndrome and confirms the effectiveness of antiarrhythmic therapy with lidocaine in cases of ventricular tachycardia.

Comparação entre a lidocaína e a acupuntura no tratamento da taquicardia ventricular induzida com dopamina em equinos anestesiados com halotano / Comparative study between lidocaine and acupunture in the treatment of ventricular tachycardia induced by dopamine in horses anesthetized with halothane

Os efeitos da lidocaína e da acupuntura nos pontos bilaterais associados ao pericárdio 6 (Pc6-Neiguan) e ao coração 7 (C7-Shenmen), no tratamento da taquicardia ventricular (TV) induzida por dopamina em equinos anestesiados com halotano, foram avaliados e comparados. Seis equinos, distribuídos em três grupos: grupo-controle (GC), grupo tratado com acupuntura (GA) e grupo tratado com lidocaína (GL), foram anestesiados três vezes cada, com intervalo de uma semana entre cada anestesia. Avaliaram-se os parâmetros cardiovasculares (frequência cardíaca, pressão arterial e eletrocardiografia), os respiratórios (frequência respiratória, capnografía, saturação de hemoglobina e hemogasometria) e o escore de recuperação. A dose arritmogênica da dopamina (DAD) foi determinada a partir da infusão de 70µg/kg/min IV durante 10 minutos, sem interrupção, preenchendo o critério arritmogênico: quatro ou mais complexos ventriculares prematuros seguidos, com duração de pelo menos 15 segundos ou TV sustentada. O tempo médio de aparecimento da DAD ou da TV foi de 6,05±0,45 minutos nos animais não tratados, e a TV se reverteu espontaneamente aos 2,7±0,2 minutos. O grupo tratado com acupuntura reverteu a TV no tempo médio de 1,8±0,2 (P<0,05) em relação ao grupo tratado com lidocaina 1,3±0,2 (P<0,01). Os tratamentos mostraram-se eficientes na reversão TV.(AU)

The effects of lidocaine and acupuncture in the associated bilateral points, i.e. pericardium 6 (Pc 6- Neiguan) and heart 7 (H7 - Shenmen), on the ventricular tachycardia (VT) induced by dopamine were evaluated in horses anesthetized with halothane. Six horses were distributed in three groups: control group (CG), acupuncture treated group (AG), and lidocaine treated group (LG). They were anesthetized three times each one using halothane with one week interval between each anesthesic procedure. Cardiovascular (heart rate, arterial pressure, and ECG) and respiratory (respiratory rate, capnometry, hemoglobin saturation, and blood gas analysis) parameters and recovery score were evaluated. The arrhythmogenic dose of dopamine (ADD) was determined by the infusion of 70mg/kg/min during 10 minutes without interruption fulfilling the arrhythmogenic criterion by the presence of four or more ectopic ventricular contractions during at least 15 seconds or maintained VT. The mean time for the occurrence of ADD or VT was 6.05 ± 0.45 minutes in no treated animals and the VT reverted spontaneously in 2.7 ± 0.2 minutes. The group treated with acupuncture reverted the VT in a mean time of 1.8 ± 0.2 (P<0.05) compared to the group treated with lidocaine 1.3±0.2 (P<0.01), both of them were efficacious for the treatment of VT.(AU)