The cardiac myosin binding protein C mutation identified in Maine Coon cats has not been found in any other breed of cat with HCM, but more recently another myosin binding protein C mutation has been identified in Ragdoll cats with HCM. As in humans, feline HCM is not present at birth but develops over time. It has been identified for the first time in cats as young as 6 months of age and at least as old as 7 years of age.Clinically, cats with hypertrophic cardiomyopathy commonly have a systolic anterior motion (SAM) of the mitral valve (see graphic). Cats with severe HCM often develop left heart failure (pulmonary edema; pleural effusion) because of severe diastolic dysfunction of the left ventricle. They may also develop a left atrial thrombus that embolizes, most commonly, to the terminal aorta creating acute pain and rear limb paralysis (see below). Sudden death can also occur but appears to be uncommon.Ultrasound of the heart (echocardiography) is necessary to diagnose HCM in cats. Measurement of circulating cardiac biomarkers, like N‐terminal‐proBNP (NT‐proBNP) and troponin I (TnI) may be used in cats to strengthen the suspicion of cardiac disease. There is a Point-of-care test for feline NT-proBNP available which can be used at the veterinary clinic when echocardiography is not possible to perform.There is no cure for feline HCM. Many but not all cats have a heart murmur. Many cats that have a heart murmur do not have HCM.
In addition, older individuals and those with other medical problems, for whom surgical myectomy would pose increased procedural risk, would likely benefit from the less-invasive septal ablation procedure.When performed properly, an alcohol septal ablation induces a controlled heart attack, in which the portion of the interventricular septum that involves the left ventricular outflow tract is infarcted and will contract into a scar. There is debate over which people are best served by surgical myectomy, alcohol septal ablation, or medical therapy. Mitral clip
Since 2013, mitral clips have been implanted via catheter as a new strategy to correct the motion of the mitral valve in people with severe obstructive HCM. The device fastens together the mitral valve leaflets to improve the hearts blood outflow. The mitral clip has not yet established the long-term reliability of septal myectomy or alcohol septal ablation, but HCM specialists are increasingly offering the clip as a less-invasive treatment option. Implantable pacemaker or defibrillator
The use of a pacemaker has been advocated in a subset of individuals, in order to cause asynchronous contraction of the left ventricle. Since the pacemaker activates the interventricular septum before the left ventricular free wall, the gradient across the left ventricular outflow tract may decrease. This form of treatment has been shown to provide less relief of symptoms and less of a reduction in the left ventricular outflow tract gradient when compared to surgical myectomy.