I have been debating writing this post for weeks and have successfully deferred it in favor of other posts. This morning, following a conversation with myheartspecialist, I decided to tackle the subject. My hesitance was borne from the magnitude of the subject. For now, the approach will be for a general overview of diastolic heart failure and we can get more specific in future posts should the need arise.
Before we go to far, there are two definitions that we should address.
*Heart failure – This is the clinical syndrome where your body is unable to distribute enough blood flow to meet your body’s needs, or at least it cannot meet those within normal parameters and pressures. Heart failure is often called congestive heart failure or CHF for short.
**Ejection fraction – This is the percentage of blood that your heart pumps with each heart beat. A normal heart usually evacuates a little more than half of its volume with each heartbeat. This means that the ejection fraction will be greater than 50%. Most of the time when your physician is speaking of ejection fraction, he/she is referring to the left ventricle.
Diastolic heart failure, is when you have heart failure* with a near normal (preserved) ejection fraction**. This type of heart failure is related more to the heart’s inability to relax than to its inability to squeeze. Diastole is the period of the cardiac cycle when the heart relaxes and blood enters the heart before being ejected. It is somewhat like loading a cannon. Each time the cannon is fired it has to be reloaded. The internal combustion engine of your car may be a more apt analogy but I will need to think about it further. Regardless, what would happen if you had trouble reloading your cannon? You would have all kinds of trouble wouldn’t you?
A heart with diastolic dysfunction is extra-stiff much like the brand new balloon that my kids want me to inflate. I have to huff and puff extra hard to get air into it. The brand new balloon requires a higher than normal pressure to appropriately fill it just like an extra stiff heart. The stiff heart requires more time to fill with blood and sometimes requires higher intracardiac pressures (pressures within the heart). Faster or irregular heart rates (such as atrial fibrillation) can negatively affect your heart’s ability to function at peak efficiency.
How do we diagnose diastolic heart failure? There are two main characteristics in diastolic heart failure: 1) you have to have heart failure. 2) you have a near normal ejection fraction in the setting of a stiff heart.
The diagnosis of heart failure is primarily clinical and is characterized by the following:
- Shortness of breath
- Difficulty lying flat because of shortness of breath
- Waking in the middle of the night gasping for breath. Often times you may want to sit up in bed.
- Persistent cough or wheezing
- Edema or fluid build-up
- Weakness or easy fatigue
- Poor appetite or nausea
- Abnormally fast heart rate.
- Enlarged neck veins suggestive of elevated pressure within your heart
- An enlarged heart or signs of fluid on a chest x-ray.
- If your doctor is unsure about the diagnosis, then additional testing such as plasma BNP or NT pro-BNP, and cardiopulmonary exercise testing may be in order.
The second requirement is confirmation of a normal or near normal ejection fraction. There are a number of methods to evaluate the ejection fraction including echocardiography, nuclear testing, ventriculography at the time of catheterization, cardiac MRI and cardiac CT. Findings such as thickened heart walls, an enlarged left atrium and stiff heart muscle support the diagnosis. Other causes of heart failure not directly related to the muscle must be excluded. Echocardiography is the most utilized tool because of its accessibility, ability to evaluate the aforementioned supportive findings and lack of radiation.
If you have been diagnosed with diastolic heart failure there are four main objectives for treatment:
- Excellent control of your blood pressure
- If you have atrial fibrillation or an abnormally fast heart rate, your heart rate should be controlled.
- Treat your symptoms of heart failure
- If you have significant coronary artery disease then blockages should that are contributing to your symptoms should be addressed.
Later we will discuss some of the treatment options in more detail.
- Heart Failure: How Much Salt Can I Eat? (blog.myheart.net)