What causes Heart Failure ? 

Conditions that damage or overwork the heart muscle can cause heart failure. Over time, the heart weakens. It isnt able to fill with and/or pump blood as well as it should. As the heart weakens, certain proteins and substances might be released into the blood. These substances have a toxic effect on the heart and blood flow, and they worsen heart failure.
                
Causes of heart failure include:
                
Coronary heart disease
                
Diabetes
                
High blood pressure
                
Other heart conditions or diseases
                
Other factors
                

                
Coronary Heart Disease
                
Coronary heart disease is a condition in which a waxy substance called plaque builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart muscle.
                
Plaque narrows the arteries and reduces blood flow to your heart muscle. The buildup of plaque also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow. Coronary heart disease can lead to chest pain or discomfort calledangina, aheart attack, and heart damage.
                

                
Diabetes
                
Diabetes is a disease in which the bodys blood glucose (sugar) level is too high. The body normally breaks down food into glucose and then carries it to cells throughout the body. The cells use a hormone called insulin to turn the glucose into energy.
                
In diabetes, the body doesnt make enough insulin or doesnt use its insulin properly. Over time, high blood sugar levels can damage and weaken the heart muscle and the blood vessels around the heart, leading to heart failure.
                

                
High Blood Pressure
                
Blood pressure is the force of blood pushing against the walls of the arteries. If this pressure rises and stays high over time, it can weaken your heart and lead to plaque buildup.
                
Blood pressure is considered high if it stays at or above 140/90 mmHg over time. (The mmHg is millimeters of mercurythe units used to measure blood pressure.) If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher.
                

                
Other Heart Conditions or Diseases
                
Other conditions and diseases also can lead to heart failure, such as:
                
Arrhythmia. Happens when a problem occurs with the rate or rhythm of the heartbeat.
                
Cardiomyopathy.Happens when the heart muscle becomes enlarged, thick, or rigid.
                
Congenital heart defects. Problems with the hearts structure are present at birth.
                
Heart valve disease. Occurs if one or more of your heart valves doesnt work properly, which can be present at birth or caused by infection, other heart conditions, and age.
                

                
Other Factors
                
Other factors also can injure the heart muscle and lead to heart failure. Examples include:
                
Alcohol abuse or cocaine and other illegal drug use
                
HIV/AIDS
                
Thyroid disorders (having either too much or too little thyroid hormone in the body)
                
Too much vitamin E
                
Treatments for cancer, such as radiation and chemotherapy