HOCM - Hypertrophic Obstructive Cardiomyopathy

Incidence :
United states :
1 in 500, is an autosomal dominant lesion, and is the most common genetic cardiac disease[

Definition :
Hypertrophic cardiomyopathy occurs when the wall between the ventricles, called the interventricular septum, enlarges, thus narrowing of the outflow tract happens.
When the high-velocity flow that occurs during ventricular contraction draws the anterior leaflet of the mitral valve into the narrowed outflow tract , thus causing a dynamic obstruction. In these cases, hypertrophic cardiomyopathy is more accurately referred to as Hypertrophic Obstructive Cardiomyopathy or HOCM.

Signs and Symptoms :
Signs :
left atrial dilatation
atrial fibrillation
congestive heart failure
right heart failure

Symptoms :
can be no symptom
angina at rest or during exercise
syncope
breathlessness
palpitations

Pathophysiology :
thickening of the ventricular wall/septum

1) Valvular distortion (myofibrilopathy , mitral regurgitation)
-arrythmias
-atrial dilatation

2) reduce left ventricular compliance
-increase left ventricular filling pressure
-increase left atrial pressure
-increase pulmonary capillaries pressure
>>>> cause left side heart failure/ pulmonary oedema

3)reduce end diastolic volume
-decrease ejection volume
-cause tachycardia

Etiology : -Idiopathic
-heredity disease

Investigation and Diagnosis :
1)Echocardiography-shows septal hypertrophy, left ventricular hypertrophy and a small left ventricular space
2)ECG-display nonspecific ST segment and T wave abnormalities, septal Q waves, atrial fibrillation, or paroxysmal ventricular contractions "PVCs".
3) chest x-ray

Differential Diagnosis : -aortic stenosis
-hypertrophic cardiomypathy

Treatment :
-no cure at the present moment, but aimed at :
>preventing complications
>reduce symptoms
>>>>>>Improve diastolic, slow the heart rate to permit greater diastolic filling.

Pharmacological : - reduce the contractility of the heart and also decrease the heart rate which gives the left ventricle more filling time.
1) beta blocker
2) calcium channel blocker
3) ACE inhibitor

Surgery :
1) septal myomectomy -removal of septal muscle tissue
2) Alcohol Septal Ablation- a small amount of alcohol is injected into the blood vessels supplying thickened areas of the heart muscle in an attempt to cause death of that particular area. This is because alcohol is extremely toxic to the heart muscles. The dead muscles are then replaced by a scar tissue (see the figures below). These changes result in reduction in bulk of the muscle, which in turn relieves obstruction.

Prognosis :
Some people with hypertrophic cardiomyopathy may not have symptoms and live a normal lifespan. Others may get worse over time or rapidly.
People with hypertrophic cardiomyopathy are at higher risk for sudden death than the normal population.
Sudden death can occur at a young age.
Hypertrophic cardiomyopathy is a well-known cause of sudden death in athletes. Almost half of deaths in hypertrophic cardiomyopathy happen during or just after the patient has done some type of physical activity.