Weak Heart Types, Causes and Symptoms

All too often we refer to heart diseases as a weak heart. However, this does not accurately describe the type of heart disease, its severity of the symptoms that may be associated with it. Some types are more serious than others but eventually all heart diseases can be life threatening. The causes of a weak heart can vary and sometimes it is not the entire heart that is dysfunctional or diseased but just one or more parts of it.

Causes of a Weak Heart

A weak heart simply means that the heart cannot function as effectively as it should. Since its function is to distribute blood throughout the body, a weak heart ultimately affects all organs in acquiring sufficient blood that is rich in oxygen and nutrients. The heart is a muscular pump. Blood that is low in oxygen enters the right side of the heart where it is then sent to the lungs for oxygenation. The blood rich in oxygen comes from the lungs to the left side of the heart from where it is distributed to the rest of the body.

A complex electrical condition system in the heart wall initiates and distributes electrical impulses in a manner that allows the heart to beat. One part of the heart beats first and then the other so as to allow the heart to allow blood to enter and then push it out all in a coordinated manner. Valves prevent the backflow of blood against the normal direction of flow. Collectively these parts work together to maintain normal blood circulation. A weak heart means that one or more of these components are dysfunctional.

Insufficient Blood Supply to the Heart

The heart muscle is constantly working (contracting and relaxing) throughout life in order to pump blood. It also needs an adequate blood supply to provide the muscles with oxygen and nutrients. The blood to the muscular wall of the heart is carried by the coronary arteries. When the arteries become diseased like with atherosclerosis (fatty plaques narrowing the artery) then insufficient blood reaches the heart muscles. This is also known as coronary artery disease (CAD) and is one of the leading causes of heart attacks across the globe.

coronary angiogram


Coronary artery disease is usually silent (without noticeable symptoms) for months or years. When the narrowing is severe enough, the following symptoms may be present:

  • Central chest pain (cardiac pain) during physical exertion or psychological stress.
  • Nausea that is sometimes mistaken for indigestion or acid reflux.
  • Dizziness often accompanied by shortness of breath.
  • Tingling or pain in the jaw, arm or abdomen usually on the left side.

Death of a Portion of the Heart

A myocardial infarction (heart attack) is where a portion of the heart muscle dies. This often occurs as a result of coronary artery disease where there is a complete blockage when a fatty plaque ruptures and a clot forms at the site. It can also when blood circulation to the heart is insufficient even if there is no significant narrowing or blockage of the coronary arteries. Depending on the size of the infarct and access to medical care, a heart attack can be fatal.

Heart Attack


  • Central chest pain radiating to the jaw, upper abdomen or more commonly the arm (usually the left side)
  • Excessive sweating
  • Dizziness and sometimes fainting
  • Difficulty breathing
  • Nausea and sometimes vomiting
  • Anxiety
  • Confusion

Abnormal Heart Rate and Rhythm

The rate and rhythm at which the heart beats is determined by the activity in the electrical conduction system of the heart. When it is disrupted in some way there may be abnormalities in the rate and rhythm of the heartbeat. This is known as an arrhythmia. Some arrhythmias may be harmless while others can be life-threatening. The heart can fail with certain arrhythmias. It can also lead to the formation of blood clots which may then block the blood flow to the brain thereby leading to a stroke.


Arrhythmias may be silent meaning that there are no noticeable signs and symptoms.

  • Fluttering sensation in the chest with or without chest pain.
  • Rapid heart rate (tachycardia) or slow heart rate (bradycardia)
  • Shortness of breath even without physical activity
  • Dizziness and fainting (sometimes)

Abnormal Heart Muscle

Cardiomyopathy is a condition where the heart muscle is abnormal. There are different types – dilated, hypertrophic and restrictive. The abnormalities may include enlargement of a portion of the heart (dilated), thickening of the heart muscle (hypertrophic) or where the heart tissue becomes rigid (restrictive). The causes are diverse, including hypertension, alcohol and drug abuse, cancer treatments like radiation therapy and chemotherapy, genetic conditions, prior heart attacks, heart valve disease, nutritional deficiencies, endocrine disorders, pregnancy, infections and autoimmune diseases.


  • Chest pain
  • Cough
  • Fatigue
  • Shortness of breath even at rest
  • Leg and/or abdominal swelling
  • Dizziness and fainting
  • Abnormal heart beat

Enlarged Heart

Cardiomegaly is a condition where the heart enlarges. It is not a disease but a complication of several conditions. Cardiomegaly usually arises when the heart has to work harder either because it is weak, cannot function normally or there is insufficient oxygen reaching all parts of the body as may occur with anemia. The condition can persist for years or even decades without severely compromising a person’s life. In the long run it can be fatal.


Often there are no signs and symptoms in the early stages and the enlargement may only be identified during investigations like a chest x-ray.

  • Chest pain
  • Shortness of breath
  • Abnormal heart rate (arrhythmia)
  • Swelling of the legs, abdomen or throughout the body.
  • Fainting may sometimes occur in severe cases.

Failing Heart

Cardiac failure is where the heart cannot pump sufficient blood to meet the body’s needs.  It can arise for many different reasons like with a heart attack, heart valve defects, hypertension, congenital heart defects, arrhythmias and infections of the heart. Heart failure is also a long term complication of diseases like diabetes, thyroid disorders, HIV and other chronic or severe acute conditions. It can affect only one side of the heart or both sides.


  • Weakness and fatigue
  • Difficulty breathing
  • Swelling
  • Rapid heart rate
  • Persistent cough
  • Chest pain

Defective Heart Valves

The heart valves ensure that blood flows through the heart in one direction. The valves open and close at different times in the cardiac cycle. Heart valve defects arise for different reasons. Sometimes it is present from birth (congenital). The signs and symptoms of heart valve disease varies depending on the type.

Heart Valves

Congenital Heart Disease

Congenital heart diseases are present from birth and there are many different types. These types of heart disease may not always cause symptoms. Sometimes there are no symptoms in childhood despite being present from birth and only manifest in adulthood. At other times there are severe symptoms from the time of birth and it can even lead to life-threatening complications.

Please note that any information or feedback on this website is not intended to replace a consultation with a health care professional and will not constitute a medical diagnosis. By using this website and the comment service you agree to abide by the comment terms and conditions as outlined on this page