FAQ

Wanneer en hoe dikwijls moet een dier gescreend worden voor erfelijke hartaandoeningen ?

ACAPULCO'S RICHTLIJNEN VOOR TIMING VAN SCREENING

Er bestaan geen universele richtlijnen en er is geen consensus voor alle ziekten. De richtlijnen kunnen van land tot land verschillen en we zouden willen aanraden om met de locale kennelclub te checken voor de recente reglementering. ACAPULCO volgt de richtlijnen uitgegegeven door de†European Society for Veterinary Cardiology (ESVC), het Britse 'heart testing' schema (http://www.bsava.org.uk/vcs/) and Professor Kittlesonís richtlijnen for HCM in Maine Coons en andere katten.


Gedilateerde cardiomyopathie bij de hond (DCM): indien de dieren gebruikt worden voor de voortplanting is jaarlijkse echocardiographie screening aanbevolen, startende voor de eerste paring tot de dood van het dier omdat de ziekte zich tot op heel late leeftijd kan ontwikkelen.

Hypertrofische cardiomyopathie (HCM) bij katten: indien de katten gebruikt worden voor de voortplanting dan is jaarlijkse screening aanbevolen, startende voor de eerste paring.†Bij de†Main Coones zullen de meeste katers echografische tekenen van de ziekte vertonen bij de leeftijd van 2 en de katinnen bij de leeftijd van 3 jaar.†Desalniettemin kan de ziekte zich ook op latere leeftijd ontwikkelen. De meeste andere raskatten zullen HCM ook op jongere leeftijd ontwikkelen.

Aortastenose (AS) bij de hond: screening kan gebeuren enkel door auscultatie, maar in honden met een graad 1 of 2 hartruis/bijgeruis is†Doppler echocardiografie sterk aanbevolen om een meer objectieve evaluatie te verkrijgen van de snelheid/drukgradiŽnt †ter hoogte van de obstructie via de subcostale benadering. De screening kan op jonge leeftijd al uitgevoerd worden maar voor officiŽle certificatie wordt het best gewacht tot de leeftijd van 1 jaar, waarbij het dier als volwassen wordt beschouwd op hartmorfologisch gebied, want de ziekte ontwikkelt zich en evolueert over de groeiperiode. De screening hoeft niet herhaald te worden omdat aortastenose tendens heeft om in de meeste honden, maar niet alle, stabiel te blijven.

SPECIFIC BRITISH RECOMMENDATIONS FOR BOXER BREEDERS REGARDING SAS (Dr Bruce Catanagh)

A. In the case of adults, ie, over 12 months of age:


1. All stock should be screened by designated cardiologists
- those which are free of heart murmurs (Grade 0) may be considered free of aortic (and pulmonic) stenosis, and suitable for breeding purposes.
- those which have only minor (Grade 1) murmurs may, for the moment, be accepted as normal and therefore suitable for breeding purposes.
2. Stock with Grade 2 murmurs may be rescreened (up to three times).
- those which on any rescreening obtain a Grade 1 score, or are even found to be murmur-free, may be considered suitable for breeding;
- those which are consistently found to have Grade 2 or louder murmurs should normally be discarded for breeding purposes, unless, in the case of bitches, there is no alternative other than to disband the whole of a kennel's breeding stock, when,

1. Selected bitches should be mated only to stud dogs that are considered to be normal (as described above), preferably murmur-free.

2. At most only one or two litters should be taken with the objective of breeding a murmur-free replacement.
In the case of dogs with murmurs consistently no louder than Grade 2, Doppler echocardiography may be a further option. Those with blood velocities below 2.0 m/s may, for the present, be considered suitable for breeding. Other useful Grade 2 dogs might, for the present, be available for stud to a strictly limited number of bitches. These bitches should be murmur-free or have at the most only grade 1 murmurs. Dogs with Grade 3 or louder murmurs should never be considered for breeding purposes, even if they have blood velocities below 2.0 m/s.

3. Bitch owners are strongly advised to use only tested and proven normal dogs at stud.

4. Dog owners are advised to offer only tested and proven normal dogs for stud purposes and ensure, before accepting bitches for service, that their owners are complying with the recommended control procedures. At owners' risk, stud services could be provided for untested, non-show bitches both of whose parents are murmur-free or have only grade 1 murmurs.

5. Stock incidentally identified as having heart abnormalities other than aortic stenosis, eg, cardiomyopathy or pulmonic stenosis, should not be considered for breeding purposes.

B. In the case of young stock, ie, under 12 months of age:

Puppies aged 6 - 12 months can usefully be tested in the same manner as adults but the results must be interpreted with discretion. Because aortic stenosis develops progressively it cannot be assumed that those that are free of murmurs or have only grade 1 murmurs will be found to be so as adults; their prospects may nevertheless be considered relatively good. On the other hand, those found to have grade 2 or louder murmurs are unlikely to become suitable prospects for breeding purposes, and may be at risk of developing the clinical effects of aortic stenosis in later life. The testing of puppies is strongly recommended. Their retesting as adults is essential, however.

SPECIFIC BRITISH RECOMMENDATIONS FOR NEWFOUNDLAND BREEDERS REGARDING SAS (Dr Jo Dukes-McEwan)

In subaortic stenosis there may be NO murmur in a young pup. As the pup grows and the heart grows, the abnormality below the valve remains constant, so it becomes proportionately worse with ageing. This is the reason that dogs should be over 12 months old for the results of official heart testing to be recorded or published. Although it is sensible to get pups checked, they must be re-examined at over 12 months old. There is a possibility that SAS does become more severe up until 24 months of age, but then remains reasonably constant.
It has been shown (Jo Dukes-McEwan) that some Newfoundlands, being broad-chested, possibly over-weight, and tending to pant, have NO audible heart murmur. There is evidence of SAS on echo-Doppler. This shows that the sensitivity of heart testing by the stethoscope alone is insufficient to detect all cases of SAS (although it will certainly detect the more severe cases). This is the reason why dogs used at stud should be echo-Dopplered for SAS. Stud dogs are potentially responsible for many more progeny than bitches.
Dogs which had a heart murmur detected at 12 months old will mature and may put on a lot of weight and then the murmur becomes undetectable. Similarly, dogs with no heart murmur detected may lose a lot of weight, and then one becomes apparent.
Sub-aortic stenosis is the main congenital heart disease of concern in Newfoundland dogs. Confirmation of diagnosis by echo-Doppler is based on a Doppler recording of a peak aortic velocity exceeding 1.7 metres per second in a relaxed dog. The blood flow through the aortic valve is normally much less than 1.7 m/s. Increased velocity is associated with increased turbulence of blood. These are both factors in creating a heart murmur. The abnormal flow is a consequence of a narrowed (stenotic) area affecting the aortic valve or caused by a fibrous ridge below the valve.


SPECIFIC BRITISH RECOMMENDATIONS FOR MITRAL VALVE DISEASE IN CAVALIER KING CHARLES SPANIELS

Mitral valvular endocardiosis (MVD) in Cavalier King Charles Spaniels (CKCS): while it is extremely doubtful the disease will ever be irradicated from the Cavalier King Charles Spaniel completely, the hope of breeders is to move the age of onset back as late in life as possible. So many breeders will have their dogs checked annually for evidence of a heart murmur (via auscultation) and breed mature dogs which are unaffected. By breeding older Cavaliers who are clear of a murmur until as late as possible in life it is hoped that the age of onset will also move back as well.
The suggested protocol at present in many countries is to try to breed females who are older than 2 1/2 years of age and clear (with parents with clear heart certificates, issued at 5 (five) years or older), to males who are at least 2Ĺ (two and a half) years old with a clear heart (with parents with clear heart certificates issued at 5 (five) years of age or older). To use an older stud dog with a clear certificate issued as late in life as possible is highly desirable.
Please remember, dogs do not have to have a clear heart to be used as stud. It is the dogs with early onset murmurs (under five years of age) that are strongly advised not to use for breeding. It is strongly advised that breeding stock under five years of age is limited to those with clear heart certificates. Breeders should aim at raising the age of onset of MVD by selecting breeding stock with a good heart record. Club guide-lines are based on current recommendations of Geneticists and Cardiologists, and may be updated and reissued as further research information becomes available.
Testing is merely a breeder's tool to try to establish a dog's health at any point in time. It does not mean that dog may not develop a heart murmur 3 months onwards or that he will not produce puppies with Mitral Valve Disease.