Ujamaa Ridgeback, Melbourne

<%@LANGUAGE="JAVASCRIPT" CODEPAGE="1252"%> Ujamaa Ridgeback, Melbourne

HEART MURMURS IN THE RHODESIAN RIDGEBACK
	Breeder Information Originally published in the August/September 1988 newsletter of The Rhodesian Ridgeback Club of Victoria, updated November 2002 HEART MURMURS IN THE RHODESIAN RIDGEBACK A recent diagnosis of a "heart murmur" in a 6 week old pup has prompted this article, The final diagnosis for this pup was aortic stenosis, with a pressure gradient differential of 40 mm (a low-end moderate case) and a reasonable chance of living a normal life (NB this dog lived till 7 years of age). The diagnosis was somewhat of a surprise although I had heard of "heart murmurs" in the breed. The only other case I could recall from my own litters was in fact in the litter of the pups dam. What prompted this article were the following points learnt from this exercise: All heart defects are regarded as inherited. The advice received was not to breed with the affected animal and to avoid the problem re-occurring by not repeating the mating of the sire and dam "Heart murmurs" is a very broad term for a number of conditions, which can then result in the murmur. The murmur may in fact disappear, but the underlying condition may not, and most require surgical correction. A point breeders should consider here is that surgical correction is very expensive. An operation for the most common defect Patent Ductus Arteriosis is approx $600-$800. Other forms of surgical correction which require open heart surgery have variable outcomes and may cost up to $2000 (1991 prices) M B Willis in "Genetics of the Dog" lists a number of heart defects for which genetic predisposition has been shown. These are: Patent Ductus Arteriosus (PDA) This condition is also seen in humans. The patent ductus is a duct between the aorta and the pulmonary artery which generally closes around the time of birth. Persistence of the duct results in higher pressure in the aorta than the pulmonary artery (the artery which takes fresh blood to the lungs). This leads to part of the aortic blood being pumped in the pulmonary artery and subsequent enlargement of the left heart and ascending aorta, resulting in hypertension. The disease is graded in its severity, and a lesser form where there is partial closure of the duct is called Ductus Diverticulum. Diagnosis of PDA requires an experienced veterinary surgeon to listen to the characteristic murmur, and to examine the ECG (electrocardiogram). Surgical correction involves ligation or closure of the duct 2. Pulmonic stenosis. In this condition there is an incomplete emptying at the right ventricle due to a thickening of tissue around the pulmonary valve. 3. Ventricular septum defects This term is used to describe problems with the passage of blood through the ventricles. In a condition known as Tetralogy of Fallot both of the above occur. Surgical correction requires open heart surgery and is therefore very expensive. Subaortic stenosis A narrowing of the outflow area from the left ventricle into the aorta is known as Subaortic stenosis. The severity of this condition can be graded by inserting a catheter into the heart, which measures the pressure gradient between the left ventricle and the aorta. The narrowing of the opening slows down the emptying of the left ventricle which leads to hypertrophy of the left ventricle. Severe cases are associated with fainting and sudden death.Other conditions which have been seen and which probably have a genetic basis are Persistent aortic arch, Atrial septal defects and Triscupid or Mitral valve insufficiency.My advice to other breeders is for pups with moderate to severe heart murmurs, consider culling these animals. The alternative is an expensive diagnostic procedure and even more expensive surgery. The pup which was mentioned in this article grew into a fine looking animal and died at the age of 7- but "paced itself" throughout its life. The diagnostic process caused temporary paralysis around the eye and poor swallowing for about a month. However diagnostic procedures have improved considerably since then. Reference:MB Willis (1989) Genetics of the Dog. HF Witherby Ltd London A good article on diagnosis of cardiac conditions; http://www.usask.ca/wcvm/canine/ Diagram of the canine heart from http://www.ahaf.org/hrtstrok/about/AnatomyHeart.htm Glossary of Terms Aorta – the main artery of the body, which receives blood from the left ventricle. Inferior vena cava – the main vein returning blood from the feet, legs, pelvic region and abdomen back to the heart. Left ventricle – the left lower chamber of the heart that pumps oxygenated blood to the body. Pulmonary trunk – carries blood low in oxygen from the right atrium to the lungs. Right atrium – the right upper chamber of the heart that receives blood low in oxygen from the body and then pumps it to the right ventricle. Left atrium (not in diagram) – the left upper chamber of the heart that receives oxygenated blood from the lungs via the pulmonary veins and then pumps it to the left ventricle. Right ventricle – the right lower chamber of the heart that pumps blood low in oxygen to the lungs via the pulmonary arteries. Superior vena cava – the main vein returning blood from the upper extremities, neck and head back to the heart.

HEART MURMURS IN THE RHODESIAN RIDGEBACK

Breeder Information

Originally published in the August/September 1988 newsletter of The Rhodesian Ridgeback Club of Victoria,

updated November 2002

HEART MURMURS IN THE RHODESIAN RIDGEBACK

A recent diagnosis of a "heart murmur" in a 6 week old pup has prompted this article, The final diagnosis for this pup was aortic stenosis, with a pressure gradient differential of 40 mm (a low-end moderate case) and a reasonable chance of living a normal life (NB this dog lived till 7 years of age). The diagnosis was somewhat of a surprise although I had heard of "heart murmurs" in the breed. The only other case I could recall from my own litters was in fact in the litter of the pups dam. What prompted this article were the following points learnt from this exercise:

All heart defects are regarded as inherited. The advice received was not to breed with the affected animal and to avoid the problem re-occurring by not repeating the mating of the sire and dam

"Heart murmurs" is a very broad term for a number of conditions, which can then result in the murmur. The murmur may in fact disappear, but the underlying condition may not, and most require surgical correction. A point breeders should consider here is that surgical correction is very expensive. An operation for the most common defect Patent Ductus Arteriosis is approx $600-$800. Other forms of surgical correction which require open heart surgery have variable outcomes and may cost up to $2000 (1991 prices)

M B Willis in "Genetics of the Dog" lists a number of heart defects for which genetic predisposition has been shown. These are:

Patent Ductus Arteriosus (PDA)

This condition is also seen in humans. The patent ductus is a duct between the aorta and the pulmonary artery which generally closes around the time of birth. Persistence of the duct results in higher pressure in the aorta than the pulmonary artery (the artery which takes fresh blood to the lungs). This leads to part of the aortic blood being pumped in the pulmonary artery and subsequent enlargement of the left heart and ascending aorta, resulting in hypertension. The disease is graded in its severity, and a lesser form where there is partial closure of the duct is called Ductus Diverticulum. Diagnosis of PDA requires an experienced veterinary surgeon to listen to the characteristic murmur, and to examine the ECG (electrocardiogram). Surgical correction involves ligation or closure of the duct

2. Pulmonic stenosis.

In this condition there is an incomplete emptying at the right ventricle due to a thickening of tissue around the pulmonary valve.

3. Ventricular septum defects

This term is used to describe problems with the passage of blood through the ventricles. In a condition known as Tetralogy of Fallot both of the above occur. Surgical correction requires open heart surgery and is therefore very expensive.

Subaortic stenosis

A narrowing of the outflow area from the left ventricle into the aorta is known as Subaortic stenosis. The severity of this condition can be graded by inserting a catheter into the heart, which measures the pressure gradient between the left ventricle and the aorta. The narrowing of the opening slows down the emptying of the left ventricle which leads to hypertrophy of the left ventricle. Severe cases are associated with fainting and sudden death.Other conditions which have been seen and which probably have a genetic basis are Persistent aortic arch, Atrial septal defects and Triscupid or Mitral valve insufficiency.My advice to other breeders is for pups with moderate to severe heart murmurs, consider culling these animals. The alternative is an expensive diagnostic procedure and even more expensive surgery. The pup which was mentioned in this article grew into a fine looking animal and died at the age of 7- but "paced itself" throughout its life. The diagnostic process caused temporary paralysis around the eye and poor swallowing for about a month. However diagnostic procedures have improved considerably since then.

Reference:MB Willis (1989) Genetics of the Dog. HF Witherby Ltd London

A good article on diagnosis of cardiac conditions;

http://www.usask.ca/wcvm/canine/

Diagram of the canine heart from http://www.ahaf.org/hrtstrok/about/AnatomyHeart.htm

Glossary of Terms

Aorta – the main artery of the body, which receives blood from the left ventricle.

Inferior vena cava – the main vein returning blood from the feet, legs, pelvic region and abdomen back to the heart.

Left ventricle – the left lower chamber of the heart that pumps oxygenated blood to the body.

Pulmonary trunk – carries blood low in oxygen from the right atrium to the lungs.

Right atrium – the right upper chamber of the heart that receives blood low in oxygen from the body and then pumps it to the right ventricle.

Left atrium (not in diagram) – the left upper chamber of the heart that receives oxygenated blood from the lungs via the pulmonary veins and then pumps it to the left ventricle.

Right ventricle – the right lower chamber of the heart that pumps blood low in oxygen to the lungs via the pulmonary arteries.

Superior vena cava – the main vein returning blood from the upper extremities, neck and head back to the heart.

Breeder Information

HEART MURMURS IN THE RHODESIAN RIDGEBACK

Patent Ductus Arteriosus (PDA)

2. Pulmonic stenosis.

3. Ventricular septum defects

Subaortic stenosis