Heart Failure in HCM

HCM, by definition is a form of heart failure - the heart fails to work "normally".  This term should not be mistaken for a drastic situation - a normal life is possible with heart failure.  It is important to remember that there are forms and degrees of heart failure. 

Diastolic heart failure:

Diastolic heart failure occurs when the lower left chamber (left ventricle - LV) is not able to fill properly with blood during the diastolic (filling) phase. The amount of blood pumped out to the body is less than normal. In HCM, due to smaller LV cavity size this impairment can lead to symptoms of shortness of breath, fatigue or dizziness.
What happens to the heart?
Diastole is the phase of your heartbeat when your heart relaxes and fills with blood. Diastolic dysfunction means that your left ventricle cannot relax properly during diastole. As a result, your ventricle doesn't fill with enough blood before it pumps. If diastolic dysfunction is severe enough, it can lead to heart failure.
Diastolic heart failure happens because the left ventricle's muscle becomes too stiff or thickened. To compensate for stiff heart muscle. Over time, this increased filling causes blood to build up inside the left atrium and eventually into the lungs, which leads to fluid congestion, which can lead to shortness of breath and fluid retention throughout the body.
Diastolic heart failure may not lower the heart's ejection fraction as drastically as systolic dysfunction can.  Ejection fraction is a measurement of how well the heart is pumping out blood. This ejection fraction is typically lower in people who have systolic heart failure. However, in diastolic heart failure, your left ventricle may pump well during systole; it is just not filling with enough blood during diastole. Your ventricle may have a normal ejection fraction, but it has less blood inside it to pump out. As a result, your ventricle pumps out less blood with each beat. Doctors sometimes call it heart failure with preserved ejection fraction.

Systolic heart failure:

Systolic heart failure happens when the left ventricle (LV) doesn't pump blood out to the body as well as normal. This is more uncommon in HCM and it is believed to occur in about 5% of those with HCM, however it is possible many people may have avoided the detection of HCM and first seek medical attention in this phase of HCM, which may also thin the walls and look similar to a Dilated Cardiomyopathy or DCM.
What happens to the heart?
Systolic heart failure typically affects the left ventricle. Systole is the pumping action of the heart or the “squeeze”.  
It's called systolic heart failure because the left ventricle doesn't squeeze forcefully enough during systole, which is the phase of your heartbeat when your heart pumps blood.  The LV can enlarge and walls can thin.
Tests may show a low ejection fraction.  This means that your left ventricle isn't working as well as normal. Doctors sometimes call it heart failure with reduced ejection fraction.

Congestive Heart Failure

This is really a nonspecific term which means the heart is pumping inadequately to meet the bodies needs.   This causes a build up of fluid (causing swelling or edema).   Left untreated this can be a dangerous situation.  It is advised that those with HCM who notice a significant weight gain in a short period of time consult with their physician.   Both diastolic and systolic heart failure can lead to congestive heart failure.  

When Heart Failure is uncontrollable, what happens?

When the heart fails by being too weak (systolic), too stiff (diastolic) and in the presents of either causing congestive heart failure aggressive medications can be used.   If medications fail to control the failure devices can be used depending on the structure of the heart.   If these devices fail heart transplantation may need to be considered.  It is VERY important to remember that less then 5% of those with HCM will ever need to consider this option.