Arrhythmogenic Right Ventricular Arrhythmogenic Right Ventricular Cardiomyopathy is a disease that affects predominantly the myocardium Boxer. It is characterized by fibrofatty infiltration of right ventricular infarction which causes the appearance of right ventricular extrasystoles and ventricular tachycardia. May be asymptomatic or present with symptoms such as syncope or sudden death. Its diagnosis is mainly based on the findings of Holter monitoring (prolonged electrocardiographic monitoring).
Today we want to share this video by Dr Meurs at the University of Washington.
For those who do not have time or are stuck the English have made a summary of the key points below.
The highlights of the conference:
General:
- - The American cardiologists recommend starting screening tests (Holter) after 3 years and reassess each year
- - normal Holter study in a larger dog ; 4 years old preclude the occurrence of the disease
- - The disease onset usually occurs between 6-8 years
- - echocardiography is unreliable for detection of ARVC.
- - Echocardiography is not good for assessing right ventricular function. The best tool for that is cardiac magnetic resonance.
- - However, in those patients detected by Holter ARVC is advisable to echocardiography to assess the possible involvement of the left ventricle
- - The HRV or heart rate variability (one of the tools offered by Holter monitoring) may be diagnostic but only in advanced stages (when there is heart failure)
to Recover by Holter monitoring :
- - Rarely normal dogs have more than 100 premature ventricular contractions per day pairs or triplets or submit saved.
- - Some animals may present with less than 100 syncopations extrasystole per day if they come in bursts or triplets .
- - There is considerable consensus that the phenomenon of R in t is a serious phenomenon.
- - Boxers with ARVC Some extrasystole may have left home.
- - The genetic test can not replace the Holter
study on the analysis of Holter
- - At least 20 hours readable layout
- - A careful analysis of artifacts
- , - Count the total number of beats detected may help detect if there is too much noise (if less than 70000 detected something wrong)
- , - not uncommon to find a small number of supraventricular in Holter, is more worrying if they are several hundred or at frequencies very fast.
- - A sleeping dog can get to be 20 bpm, in such situations escape beats may occur without clinical significance
- - There 85% of daily variability in the results of Holter so there are animals that can not display nearly extrasystoles during the examination and submit however many more the next day
On the causes of ARVC
- - The presence of EV in puppies under one year is probable cause a virus.
- - often are viruses that cause transient arrhythmias and then disappear. In these cases we find elevated troponin.
- - In 50% of cases a mutation is identified as a cause of ARVC
- - mutations occur predominantly in 5 genes
- - The ARVC in autosomal dominant boxer has
- - The most important mutations affecting the desmosomes that are responsible for the connection between the myocardial cells.
- - The Boxers seem to have a mutation in the gene that encodes a protein called Striatina .
- - The severity of the disease in homozygous carriers greater but not all show the disease
- - penetrance of the mutation is higher in boxers In humans, 72% of animals affected by the disease mutation show
- - Animals with the same genotype show a great variation in disease severity
- - may be other mutations and other unidentified causes can cause ARVC
- - In a study of mutation-positive boxer in the UK population was 81% penetrance
- - is not known what determines the penetrance of the mutation.
- - Positive homozygotes: better not to breed with them, if they have characteristics closely positive parenting with a negative
regard to genetic testing.
- - Most affected animals show the mutation
- , - However, not all the show and all who develop the disease have
- - useful for breeders and to forecast as there are serious differences between
About
treatment
- - thyroid hormone supplementation may worsen arrhythmias in the course of ARVC
- - Risks to show clinical symptoms increase with age (rare to see them before age 6)
- - treatment for dogs with ARVC and asymptomatic depends on the total number of ventricular extrasystoles and their severity
- - are best sotalol or mexiletine. Overall sotatol
- - However there is no evidence to reduce the risk of sudden death
- , - Amiodarone is also indicated, but as at greater risk of side effects is used as 2 nd choice tto