Ventricular fibrillation, often referred to as V-fib, represents a severe disorder of the heart’s electrical activity. This condition prevents the heart from effectively pumping blood throughout the body. It is a medical emergency that requires immediate attention to prevent life-threatening complications.
What Happens During V-Fib
During ventricular fibrillation, the heart’s lower chambers, known as the ventricles, experience disorganized electrical signals. Instead of contracting in a coordinated manner to pump blood, these chambers merely quiver erratically. This chaotic activity means the heart cannot circulate blood effectively to the rest of the body. Without proper blood flow, organs, including the brain, are deprived of oxygen, leading to rapid loss of consciousness.
How V-Fib Appears on an ECG
An electrocardiogram (ECG) provides a visual representation of the heart’s electrical activity. On an ECG, V-fib presents as a chaotic, irregular, wavy line. There are no discernible P waves, QRS complexes, or T waves, which are normal heart rhythm components. Instead, the tracing shows continuous, erratic deflections varying in shape, amplitude, and direction.
The electrical activity rate can range from 150 to 500 beats per minute. Depending on wave amplitude, V-fib can be “coarse” (larger waves) or “fine” (smaller waves), with fine V-fib sometimes resembling a near-flatline.
Recognizing V-Fib in a Person
Recognizing V-fib in an individual is important as it often occurs with little warning. The most observable sign is a sudden collapse. This happens because the heart immediately stops pumping blood to the brain and other vital organs. Following collapse, the person becomes unresponsive to any stimuli.
A person experiencing V-fib will also stop breathing normally or may exhibit very shallow, gasping breaths, sometimes called agonal breathing. This abnormal breathing occurs due to lack of oxygen-rich blood reaching the lungs and other body parts. There will be no detectable pulse. These signs together signify a medical emergency requiring immediate intervention.
What to Do When V-Fib Occurs
Immediate action is important when V-fib is suspected. First, call emergency medical services. Then, promptly initiate cardiopulmonary resuscitation (CPR) to circulate blood. Chest compressions should be performed hard and fast, at 100 to 120 compressions per minute, pushing down about 2 inches on the center of the chest.
If an automated external defibrillator (AED) is available, use it as soon as possible. AEDs recognize V-fib and deliver an electrical shock to help restore a normal heart rhythm. Follow the device’s voice prompts, as it guides the user through the steps. Using an AED within the first few minutes significantly increases survival chances. Continue CPR until emergency medical personnel arrive or the person shows signs of responsiveness.