What is Congestive Heart Failure (CHF)?
How common is CHF
How serious is CHF
What are the causes of CHF?
What are the symptoms or complaints of CHF?
How does the body respond to CHF?
What is Diastolic heart failure?
How is CHF diagnosed?
How is CHF treated?
What is diastolic heart failure or CHF? The left ventricle (LV) or major pumping chamber of the heart empties during systole (pronounced sis-tull-e). The filling process of the LV is known as diastole (pronounced die-as-tull-e). Traditionally, CHF usually refers to failure or weakness of the pumping or systolic action of the heart. However, CHF can also occur in patients who have well preserved systolic function but have problems with diastole or filling of the LV.
The walls of the LV are made up of fairly "elastic" muscle which stretches when it is filled up with blood returned by the body. The LV becomes stiffer and less elastic when it is severely thickened as a result of long standing, uncontrolled high blood pressure or certain types of heart disease such as hypertrophic (pronounced hi-per-trow-fic) cardiomyopathy (pronounced car-dee-o-my-op-a-thee). Stiffness of the LV can also be caused by a disease known as restrictive cardiomyopathy.
With increased stiffness of its walls, the LV requires a higher volume of blood to stretch it adequately. In other words, less blood will not be able to stretch and fill the LV. To understand this concept, let us compare the elasticity or filling of a balloon to that of an automobile tire. A balloon can be inflated with air with the use relatively low pressure.
On the other hand, the flat automobile tire on the left requires a considerably greater amount of pressure to inflate it. Now imagine if you will that the balloon and tire are both of the same size or volume. The air pressure within the balloon will be far less than that of the automobile tire. In other words the pressure within diastole or filling of the LV is far greater when its walls are very stiff.
The high pressure is reflected back to the lungs, the right ventricle and to the body. As the pressure rises, the lungs, legs, etc., become congested in a manner similar to that of CHF caused by weakness of the heart muscle. This is known as diastolic failure of the heart and can be seen even when the pumping ability of the heart is well preserved.
How is CHF diagnosed? The diagnosis of CHF is first suspected when the patient provides a history and complains about fatigue, shortness of breath, swelling and weight gain. Physical examination by the physician helps to strengthen the suspicion or even confirm the diagnosis. At this time, the physician will usually order an EKG (to determine if there is evidence of a prior heart attack, signs of increased wall thickness, irregular heart beats, etc.). A chest x-ray will show if the heart is enlarged and whether or not the lungs are congested or filled with fluid. An echocardiogram is an extremely important test that helps determine the size, thickness and function of the various heart chambers and valves. It also helps estimate pressure within the lungs and determine whether or not the patients volume of blood is excessive. Based upon the above evaluation, the physician may order a Holter monitor if irregular heart beats are suspected or seen, a stress test (regular, echocardiographic, nuclear or chemical) if coronary disease is suspected or even recommend cardiac catheterization.