Check out this overview from Simon Swift MA VetMB CertSAC DipECVIM-CA (Cardiology) MRCVS and Liz Bode BVSc PhD DipECVIM-CA (Cardiology) MRCVS for Vetlexicon’s Canis service.
Hypertrophic cardiomyopathy (HCM) and hypertrophic obstructive cardiomyopathy (HOCM) are rare diseases in the dog, however HOCM has been observed in Pointers and Terriers and has been suggested to be predisposed, although most cases are sporadic. There are too few cases in the UK to allow breed predilections to be identified.
The disease is characterized by an asymmetrically thick left ventricle with a normal to small left ventricular chamber. The increased wall thickness decreases the afterload and results in a stiff chamber. Clinical signs include a systolic heart murmur over left base or apex, often exacerbated at exercise or by use of short acting agents that increase contractility or reduce afterload. Arrhythmia and gallop rhythm may also be noted. However, some may show no clinical signs.