Ventricular fibrillation is a life-threatening condition in which the heart loses its normal rhythm and quivers uncontrollably. In ventricular fibrillation, the heart is no longer able to pump blood out of the lower chambers or ventricles. According to the National Institutes of Health, ventricular fibrillation results in sudden cardiac death if urgent care is not received. Disruption of the normal electrical rhythm of the heart can be caused by a variety of diseases that affect the heart, particularly those that leave scars on the heart.
Heart Attack
According to the NIH, heart attacks are the most common cause of ventricular fibrillation. A heart attack occurs when the blood supply of a segment of the heart is interrupted resulting in death of that part of the heart. According to MayoClinic.com, the scar from a heart attack can disrupt the flow of rhythmic electrical waves through the heart, resulting in ventricular fibrillation. Blood supply to the heart can be interrupted by narrowing of the coronary arteries by atherosclerosis, coronary artery disease or a blood clot lodged in a branch of the coronary arteries. Smoking, high blood pressure and diabetes are some of the risk factors for heart attacks.
Previous Heart Disease
Previous disease in the heart with formation of scar tissue could disrupt the well-regulated electrical functioning of the heart muscles, leading to ventricular fibrillation. Cardiomyopathy, a disease of the heart muscles, is one such previous heart condition mentioned by the NIH as a predisposing factor to the development of ventricular fibrillation. Congenital heart diseases such as tetralogy of Fallot, coarctation of the aorta and large ventricular septal defects can overwork the heart and weaken the heart muscles, leading to the development of ventricular fibrillation. Having had heart diseases such as rheumatic heart disease and angina pectoris with cardiac ischemia can also result in ventricular fibrillation.
Direct Injury to the Heart
Direct physical injury to the heart from surgery, motor vehicle accidents, gun-shots or sports-related injuries can lead to ventricular fibrillation. Electrocution can seriously damage the heart muscles leading to the development of ventricular fibrillation at the moment of exposure or later on from scar tissue formed in the damaged heart muscles.
The heart muscles are also directly affected by illicit drugs such as metamphetamines and cocaine. Certain medications and toxic chemicals such as ephedrine, tricyclic antidepressants, anticholinergics and insecticides can also lead to the development of ventricular fibrillation, especially in high doses or suicide attempts.
Other Possible Causes
According to the National Heart, Lung and Blood Institute, chemical imbalances affecting the blood levels of certain ions can affect the heart, leading to ventricular fibrillation. The ions that can influence this development are calcium, potassium and magnesium.
Shock from dehydration or hemorrhage can lead to reduced blood flow to the heart. According to the NIH, this could also result in ventricular fibrillation.
