Cardiomyopathy

Cardiomyopathy where the word Cardio means heart, Myo means muscle & Pathy means any pathological condition. 

Hence, Cardiomyopathy is a disease process that disrupts the cardiac muscle activity.

It is divided into three parts that is Dilated cardiomyopathy, Hypertrophic cardiomyopathy & Restrictive cardiomyopathy.

The basis for this classification is according to the morphological and hemodynamic characteristics. 

In morphological criteria, we identify the type of Structural abnormalities like whether the heart gets dilated, Hypertrophic etc to classify the cardiomyopathy.

This picture shows the structural changes that are seen in different types of cardiomyopathy.

Dilated Cardiomyopathy, As the word describes that the chambers of the heart is dilatated in this type of cardiomyopathy. This dilatated is seen mostly due to unknown reason but it is also seen due to mutation, as a side-effects of certain drugs, infectious cause and sometimes due to metabolic disorders. In general, all the chambers of heart that is both atria and ventricles gets dilated but left ventricle is largely affected among all chambers. 

Hypertrophic Obstructive Cardiomyopathy, again the word describes that there is some sort of obstruction in heart that cause obstruction in blood pumping. Hence the obstruction should be near the ventricular septum so that it obstructs the blood flow out into the circulation. In general, hypertrophy is seen due to mutation in left ventricles seen either near the subaortic part, midventricular septum or found diffusely over the left ventricle.

Restrictive Cardiomyopathy, here there is a restriction in heart from filling the heart during diastole. The restriction of heart is due to the deposition of abnormal protein that makes the heart stiff and non-compliant that failed to relax normally during diastole.

In Hemodynamic criteria, cardiomyopathy is sub-divided on the basis that whether the cardiomyopathy is due to the systolic dysfunction or diastolic dysfunction.

In Dilated Cardiomyopathy, heart can’t able to pump properly into the systemic circulation leading into a systolic dysfunction. The dysfunctional systolic pump is due to the fact that ventricles of the heart becomes thin and looses its muscle that is required to generate a good contractility force in order to pump blood into the systemic circulation.

In Hypertrophic Obstructive Cardiomyopathy, heart systolic force is up to the mark but heart can’t able to pump blood out into circulation due to obstruction at the left ventricles near the septum separating the two ventricles. This results into a decreased outflow of blood from left ventricles which empedes the blood from filling the left ventricle during diastole and that present as diastolic dysfunction. 

In Restrictive cardiomyopathy, hearts non-compliant stiff ventricles failed to relax during diastole phase and that results into a diastolic dysfunction.

In summary, Contractile function is only reduced in dilated cardiomyopathy as a result ejection fraction is markedly decreased.

Ejection fraction is only seen increased in Hypertrophic obstructive cardiomyopathy which is due to fact that the reduced chamber size generates pressure inside the ventricles of heart which results into a elevated ejection fraction. 

Diastolic dysfunction is seen in both hypertrophic Obstructive cardiomyopathy and restrictive cardiomyopathy.