Hypertrophic Cardiomyopathy

CARDIOLOGY ()Map CARDIOVASCULAR CONDITIONS (Map)

Hypertrophic cardiomyopathy (cat). Courtesy of T. Scase

Rare in dogs

Common in cats

Signalment

Dogs: Rare

Cats: Pedigrees (e.g. Persians, Maine Coons) & mixed breeds; Occurs in young pedigrees and young to old mixed breeds; Male>Female

Description

Left ventricular concentric hypertrophy without an identifiable cause is known as hypertrophic cardiomyopathy. The ventricular myocardium becomes so thick that the lumen is reduced to a size that is not compatible with maintaining the heart's function as a pump. The left ventricle no longer has the capacity to hold normal volumes of blood during diastole. As a result, the left atrium dilates from the increased pressure and volume of blood backing up into the lungs.

Diagnosis

History & Clinical Signs

-Asymptomatic

-Hindlimb paresis or weakness (saddle thrombus see in cats)

-Signs of left-sided heart failure

Physical Exam:

-Systolic murmur

-Ventricular arrhythmias

Radiography=

-Left atrial enlargement

-Enlarged heart

-Pulmonary congestion & edema

Electrocardiography (ECG)=

-Tall R wave

-Wide QRS

-Ventricular arrhythmias

-Conduction disturbances

-Sinus tachycardia

Echocardiography

-Left ventricular concentric hypertrophy

-Left atrial enlargement

-Mitral valve insufficiency

Treatment

-Treat the individual symptoms

Contraindications: Arterial Vasodilators; Positive Inotrops

Prognosis

-Poor for symptomatic cats