Understanding your Condition

Causes of Heart Failure

There are many potential causes for heart failure. One of the most common causes of Heart Failure is a heart attack. Heart attacks can damage and weaken the heart, reducing the ability of the heart to pump blood to the body. If severe enough, this damage can cause heart failure. As mentioned before, even though heart attacks can be related to or the cause of heart failure, a heart attack is not the same as a heart failure.

Another common cause is cardiomyopathy, which is a type of cardiac disease that affects the heart muscle. Cardiomyopathy can be caused by many conditions like drug or alcohol use, metabolic disorders (such as high blood pressure, obesity or diabetes), viral infections or autoimmune conditions.

Causes of Heart Failure High Blood Pressure Arrhythmias (such as atrial fibrillation) Genetic Heart Defects Hypertrophy (thickening and stiffening of the muscle) Valvular Heart Disease HIV/AIDS Heart Attack /Coronary Artery Disease Abuse of street drugs like cocaine Excessive Alcohol Intake Viral Heart Disease (myocarditis)

Diagnosis of Heart Failure: What tests might I need?

As needed, the diagnosis of heart failure may require several scans or investigations. Your doctor will go over the specifics of any particular diagnostic screening you may need. The following is a list of some of the most common tests that heart failure patients may need:

Physical Exam
  • Come prepared knowing your symptoms, medical and family history!
  • Measurements of blood pressure, height & weight and listening to heart & lungs stethescope
  • Be completely honest! It's your health!
Blood Test
  • Blood tests may be ordered from a lab
  • Measurements of substances like sodium, albumin and creatinine can indicate the health of organs that may be effected by HF
  • Biomarkers like BNP might also be used for diagnosis of HF
Chest X-Ray (CXR)
  • Chest X-rays are performed in radiology labs
  • Chest x-rays can show whether the heart is enlarged (like in systolic heart failure)
  • Chest x-rays can also show fluid or congestion in the lungs
Electrocardiocgram (ECG)
  • During an ECG, electrodes are placed on the chest and detect the electric signals in the heart
  • This can indicate prior heart attacks, and abnormal heartbeats (like atrial fibrillation)
  • They can also be used to detect whether the left ventricle is thickened/enlarged
  • Electrocardiocgram testing at CCCC
Echocardiogram (Echo)
  • An echo machine bounces sound waves off the heart to examine its structure and motion of fluids like blood
  • This can be used to measure the structure of the heart (how thick/rigid the walls are) and how well the heart pumps (ejection fraction) as well as the structure and function of valves
  • Echocardiography testing at CCCC
Stress Test
  • In a stress test, you will exercise on a treadmill while equipment measures your heart
  • Stress tests examine the response of the heart to exertion and whether blood flow to the heart is impaired
  • Stress tests help determine what kind of exercise is appropraiate
  • Stress testing at CCCC
Nuclear Imaging (MIBI/MUGA)
Cardiac Catheterization / Angiogram
  • A very thin tube called a catheter is inserted into a blood vessel and threaded towards the heart
  • A dye is released that is visible by x-ray
  • The movement of the dyed fluid throughout the heart can show blocked or narrowed arteries as well as how much blood is flowing through the heart
  • Cardiac Catheterization Lab at St. Mary's General Hospital

Symptoms of Heart Failure:

Symptoms from heart-failure can vary from person-to-person; no two people will have identical symptoms. Below is a list of some the most common symptoms for heart failure. Heart failure symptoms can wax and wane over time. Use this as a guide to heart failure symptoms, but also seek out professional help and guidance.

Confusion, Poor Memory, Dizziness & Nausea Shortness of Breath (Dyspnea), Coughing & Wheezing Rapid Weight Gain Swelling of Legs and Ankles Cold Hands and Feet Chest Heaviness, Discomfort or Pain, Irregular Pulse Tenderness or Swelling of Abdomen & Loss of Appetite Chronic Lack of Energy & Tiredness, Increased Urination Especially at Night

Severity of Heart Failure Symptoms:

There are different degrees (known as classes) of severity of heart failure as defined by the New York Heart Association:

Chart showing 4 levels of severity

Difference between Class of Heart Failure & Grade of Ventricle

One common source of confusion for patients and family members is the symptom NYHA class of heart failure and the grade of left ventricular function. These are independent measures of the severity of heart failure and may not necessarily correlate with each other.

The grade of LV (left ventricle) function refers to the actual physiological performance of the left ventricle which can often, but not always correlate to the degree of symptoms. LV function is measured by ejection fraction, which measures the percentage of blood in the left ventricle that is pumped out. In other words, if 60% of the blood in the left ventricle is pumped out as the heart beats and 40% remains in the left ventricle, the ejection fraction would be 60%.

LV function can be graded, with Grade I referring to healthy ventricular function (with an ejection fraction ≥55%) and a Grade IV referring to severely reduced ventricular function (with an ejection fraction ≤30%). As mentioned before, someone may have a severely weakened and impaired Grade IV ventricle with minimal symptoms (NYHA Class I or II). Likewise, a patient may have a relatively healthy LV function but still experience NYHA Class III or IV symptoms.

Types of Heart Failure

Heart failure can affect either side of the heart:

Diagram of blood flow going through lungs -> left atrium -> left ventricle -> body -> right atrium -> right ventricle -> lungs
  1. The left side of the heart is responsible for pumping blood to the body that came from the lungs. During left sided heart failure, the heart muscle can’t pump blood sufficiently to the body, leaving fluid backed up in the lungs. This can cause a shortness of breath and fluid buildup. Because the left heart is not pumping blood effectively enough to the rest of the body including the brain, left-sided heart failure can cause fatigue and dizziness, and sometimes confusion.
  2. The right side of the heart is responsible for pumping blood to the lungs that came from the body. Right sided heart failure is sometimes caused by left-sided heart failure because the backed up blood in the lungs forces the right side of the heart to pump harder than it normally would to compensate. This additional stress can result in damage and weakness (or failure) or the right side of the heart. Blood can therefore become backed up in the body, resulting in swelling of blood in the legs and ankles, abdomen and GI tract.
Wondering why the image is reversed? This is because our reference frame is from an outside point of reference, looking in.

There are two major types of heart failure which are very different and thus require different treatment:

HFpEF (Diastolic) Heart Failure

Diagram of a heart with labels for Aorta, thick, stiff heart muscle and right and left ventricles

HFreF (Systolic) Heart Failure

Diagram of a heart with a label for thin, weak heart muscle
  1. HFreF (Systolic) Heart Failure (also known as Heart Failure with Reduced Ejection Fraction) is when the heart muscle loses the ability to pump with enough muscle power or force. This type of heart failure is more common and occurs when the heart muscle is weak, thin and enlarged.
  2. HFpEF (Diastolic) Heart Failure (also known as Heart Failure with Preserved Ejection Fraction) is when the heart muscle contracts normally and can still be strong enough to force blood out of the ventricle normally. However, due to stiffness and thicker walls, the left ventricle loses the ability to relax normally during the resting period between each heartbeat. This means that less blood is able to fill the heart, leading to less blood being pumped out to organs in the body

Note: Ejection Fraction is a measure of the percentage of blood in the ventricles that the heart pumps out. In Systolic heart failure, the ventricle is typically filled up with blood, but due to muscle weakness it is unable to pump out all of the blood.

Cambridge Cardiac Care
150 Hespeler Rd.
Cambridge, Ontario N1R 6V6
CCC Educational Events

Apr 22, 2017 Healthy Heart Day

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