marți, 16 iulie 2013

RIGHT HEART DISEASES IN DOG



Banat`s University of

Agricultural Sciences
and Veterinary Medicine
"King Michael of Romania"
from Timisoara



clinical research on right heart disease in adult dog

Daniela Elena Brăslaşu1, Silvia Joiţa1, Simiz Fl.2, Brăslaşu M.C.1

 1. Faculty of veterinary Medicine Bucharest
2. Faculty of veterinary Medicine Timişoara


SUMMARY


                Right - side heart failure is caused by right heart disease.  The symptoms are obvious at the splanchnic level: hepatomegaly, hepatic sensitiveness, ascites, jugular ectasia and only rarely, pleurisy.
          Causes of right heart disease are heartworms, tricuspid valvular disease, right  intracardial or extracardial  tumors, thrombi, right  dilatative cardiomyopathy.
             Diagnosis of right heart disease is performed by clinical examination and is confirmed  by paraclinical methods: X-rays, electrocardiography and echocardiography. Paraclinical examination play an important role in establishing the diagnosis and in evaluating the prognosis.
                This research emphasizes the characteristics of clinical and paraclinical diagnosis of right-side heart disease.
                Key-words: right –side heart failure, heartworms, cardiac tumors, right dilatative cardiomyopathy.

Right ventricle and atrium represent the right heart, which is responsible for pulmonary circulation. Right heart takes over the blood from hepatic and cerebral level and deliver it to the lungs. As a consequence, right heart disease will have an impact on liver, CNS and lung.
Right heart disease also plays an important role as the sinus node is located in the right atrium. The impairment of sinus node can be the cause of severe cardiac arrhythmia.


Materials and methods

Patients evaluation was performed in the Cardiology Department of the Faculty of Veterinary Medicine Bucharest and in the Internal medicine department of the Faculty of Veterinary Medicine Timişoara (5 patients)
Two different X-ray exposures were  performed  for each animal: right/left lateral exposure and dorso - ventral exposure.
Electrocardiography  parameters were: standard leads, 1mV = 5,10 or 20 mm amplitude and 25 or 50 mm/sec  speed of paper rolling.
Echocardiography was performed on standing animals, using right and left parasternal windows and 3.5 or 6 MHz transducers.
Cytological examination for the diagnosis of heartworms and blood serum biochemistry were  also used into the study.


Results and debates

     There are not many symptoms in right heart disease: different degrees of dyspnoea, hepatomegaly with pain – a differential diagnosis is needed to exclude hepatitis – and ascites. Jugular veins examination is possible in short hair breed, otherwise the area has to be clipped.
       In most of the situations , diagnosis of right heart disease has been established when the heart has been evaluated for the diagnosis of ascites and/or dyspnoea.
       Tricuspid degenerative valvulopathy is a disease diagnosed in most of the cases in small breed dogs. This valvulopathy can evolve alone (rarely) or  together with the degenerative mitral valve disease. Clinical diagnosis is  based on systolic murmur on tricuspid valve auscultation area. Most of the times, this sound is shielded by the murmur of mitral valve.
     In many situation, diagnosis of tricuspid valve disease was done by echocardiography, when diagnosing mixomatous mitral valve disease.
    Ultrasound elements that helped the diagnosis were thickening of mitral valve, tricuspid regurgitation (Doppler echocardiography) and secondary changes (right atrium volume increase).


 Degenerative tricuspid valve disease.
The valve is thickened, there is valvular regurgitation
and right atrial dilation (degenerative mitral valve disease it also observed)


Right dilatative cardiomyopathy is an idiopathic disease often found in large breed dogs. Ultrasound diagnosis is based on right ventricle dilation and systolic dysfunction. To have an accurate diagnosis, it is important to make a differential diagnosis from the diseases that can cause  right ventricular dilation (heartworms).



Right dilatative cardiomyopathy in dog.
Notice the important dilation of right ventricle


     Pulmonary hypertension is a consequence of degenerative mitral valve disease (very often) or of chronic lung disease (including chronic heartworms). The disease is often accompanied by dyspnoea, coughing, fatigue, and eventually by thoracic liquids. To confirm the diagnosis, the arterial pressure in pulmonary artery has to be measured. Pulmonary hypertension is considered in advanced condition patients by following the right ventricle dilation and flattening of interventricular septum (normally, there is a concave aspect of the septum towards right ventricle).





Pulmonary hypertension – flattening of interventricular septum
(2D-Eco, transversal section)


Dirofilariasis is a disease more and more frequently diagnosed in dogs in our country (Bucharest) . Dirophilariasis is considered in right heart dilation (not every right heart dilation is a consequence of dirophilariasis) and diagnosis of larvae is done by cytologic examination – Parasitology Department. Diagnosis of adults is difficult to establish when there is a small number of worms. It is also very important to differentiate  the heartworms from the chordae tendineae, that have a steady position between ventricular walls and tricuspid valve.
      There were 3 cases of Dirophilariosis diagnosed in  Veterinary Cardiology Department from Bucharest, that were confirmed by hematological examination. The ultrasound image was comparable with a straw bundle in the right heart; the worms were floating freely from right atrium  to the right ventricle. Other secondary signs were right ventricular and atrial dilation and pleurisy.


Heartworms in dog.
The are adult worms into right ventricle (transversal section).
There is also an increase of right heart cavities


Heartworms in dog.
The adult worms have the aspect of a straw bundle.
There is also an increase of right heart cavities


       Intracardial echogenic masses can be represented by tumors or by free clots. In both situations, there was a right atrioventricular dilation with echogenic intracardiac masses. It is difficult in  many situations to differentiate the tumors from the clots. The tumors look usually as a steady vascular mass, but in one case, the aspect of the tumor was that of spherical mass, moving between right atrium and ventricle. It was the necropsy examination that confirmed the presence of a pediculate tumor mass.



Intracardial echogenic masses – free clots


Tumors in Right atrium

     Even if these diseases have been diagnosed using echocardiography, electrocardiography also played an important role. Electrocardiography allowed to see the secondary effects at the cardiac level: right bundle branch block, cavities increase and different types of arrhythmia: premature atrial and ventricular beats, atrial fibrilation et al.
      X-rays played an important role for the confirmation of right atrium and ventricular dilation, in the diagnosis of chronic lung disease and of lungs tumors et al.
      Cytological examination and complete blood count has often be used to diagnose heartworms and also to evaluate the general status of the patient (together with serum biochemistry)


Conclusions

1.           Right-side heart disease are primary diseases or can be a consequence of a cardial or a pulmonary disease. Right dilatative cardiomyopathy, tricuspid degenerative valve disease, pulmonary hypertension, tumors, clots and arrhythmia (right bundle branch block) are the causes of right cardiopathyes.

2.           These diseases can cause right heart insufficiency, hepatomegaly, liver sensitiveness, jugular veins congestion, ascites, fatigue and sometimes pleural effusions .

3.           Diagnosis is based on complementary investigations. Besides the diagnosis of right heart dilation, X-ray plays an important role in the diagnosis of lungs disease that can cause pulmonary hypertension with secondary right heart disease.

4.           Electrocardiography is the method used to establish the diagnosis of heart arrhythmia: right bundle branch block, atrial or ventricular premature beats et al.

5.           Echocardiography is the best method to diagnose right heart disease. There is a right ventricular dilation and systolic dysfunction in dilatative cardiomyopathy. Tricuspid valve disease is diagnosed by valve thickening, blood regurgitation (Doppler ultrasonography) and secondary signs (dilation of right atrium and ventricle). In dirophilariasis, adult worms can be seen in the right heart. Pulmonary arterial hypertension could be considered in the situation of interventricular septum flattening.

6.           Complete blood count plays an important role in A) confirmation of dirophilariasis (cytological examination), B) evaluation of general status of the patient and C) Therapy monitoring


Bibliography

Boon June A., Manual of Veterinary Echocardiography. Blackwell Publishing, 2006.
Brăslaşu M.C. (coordonator), Cardiologie veterinară – Diagnosticul bolilor cardiovasculare la animale. Ed. Artprint Bucureşti, 2008.
Gomez A., Unruh H., Mink S.N., Altered left ventricular chamber stiffness and isovolumic relaxation in dogs with chronic pulmonary hypertension caused by emphysema. Circulation, 87, 1, 1993, 247 - 260.
Scansen  B.A., Meurs K.M., Spier A.W., Koplitz S., Baumwart R.D., Temporal variability of ventricular arrhythmias in Boxer dogs with Arrhythmogenic Right Ventricular Cardiomyopathy. J. Vet. Int. Med,m 23, 5, 2009, 1020-1024.
Simiz F., Moţ T., Ciulan D., Morar D., Petruse Cristina, Electrocardiographic parameters analysis in young dogs. Lucr. Ştiinţ., Med. Vet., XLV (4), 2012, pp. 152  – 159.



Scientific Conference
Book of Abstracts, p. 81
2013, Timisoara, Agroprint

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