Table of ContentsView AllTable of ContentsWhat Happens During Ventricular Fibrillation (VFib)?VFib vs. AFibVentricular Fibrillation SymptomsCauses and Risk Factors of VFibHow Is VFib Diagnosed?VFib TreatmentCan VFib Be Prevented?When to Seek Emergency Care
Table of ContentsView All
View All
Table of Contents
What Happens During Ventricular Fibrillation (VFib)?
VFib vs. AFib
Ventricular Fibrillation Symptoms
Causes and Risk Factors of VFib
How Is VFib Diagnosed?
VFib Treatment
Can VFib Be Prevented?
When to Seek Emergency Care
Ventricular fibrillation, called VFib or VF, is an extremely dangerousarrhythmia. It causes the heart’s lower chambers to twitch (fibrillate), preventing blood from being pumped out of the heart to the brain and other vital organs within the body.
VFib results in cardiac arrest within seconds and death soon after if not treated with chest compressions anddefibrillation(delivering an electric shock to restore the heart’s normal rhythm).
This article explores VFib, including how it develops and its symptoms and treatment. It will also briefly review the differences between VFib and other arrhythmias likeatrial fibrillation(AFib) andventricular tachycardia(V-tach).
Jackyenjoyphotography / Getty Images
To best understand VFib, you must first understand what happens when the heart is innormal sinus rhythm. Theheart is a muscular organwith two upper chambers (right and left atria) and two lower chambers (right and left ventricles).
Ventricular Fibrillation
During a normal heartbeat:
In ventricular fibrillation, electrical impulses do not begin in the SA node or travel through the heart in a coordinated, deliberate manner.
Instead, in VFib, multiple electrical impulses originate within different areas of the ventricles, causing the ventricles to twitch and quiver uncontrollably and chaotically.
As a result of the ventricles twitching, they cannot do their job and pump blood to the rest of the body, leading tosudden cardiac arrestwithin seconds and, in severe cases, death.
The Heart’s Electrical System: Anatomy and Function
Atrial fibrillation, or AFib, is an arrhythmia that originates in the atria, not the ventricles, as in ventricular fibrillation.
As a result of the atria quivering in AFib, blood is not strongly pumped into the ventricles, often causing a sensation of the heart fluttering or pounding in the chest. Also, due to blood pooling in the atria,blood clotscan develop and cause astrokeif they travel to the brain.
While VFib is dangerous, causing sudden cardiac arrest, AFib is not generally considered life-threatening. AFib is also more common than VFib, affecting up to 6 million adults in the United States.
V-Tach vs. VFib
Ventricular tachycardia (V-tach) and ventricular fibrillation are rapid arrhythmias originating in the heart’s lower chambers instead of the SA node.
However, while multiple electrical signals within the ventricles are produced and spread simultaneously in VFib, an area within the left or right ventricle typically generates the electrical impulse in V-tach.
Also, the ventricles quiver irregularly in VFib, whereas the ventricles usually contract regularly in V-tach.
Lastly, VFib is always life-threatening, leading to cardiac arrest and death if not treated immediately. In contrast, V-tach is only considered life-threatening when sustained (lasting more than 30 seconds).
V-Tach vs. VFib: Differences and Similarities
The ventricles in VFib twitch erratically and are, therefore, unable to pump blood to the rest of the body, leading to sudden cardiac arrest (SCA) within seconds.
Sudden cardiac arrest means the heart’s electrical system malfunctions, causing the heart to suddenly stop beating. If not treated immediately, death will occur within minutes.
Symptoms and signs of sudden cardiac arrestinclude:
Ventricular fibrillation has multiple potential causes, with aheart attackbeing a common one.
A heart attack—known medically as amyocardialinfarction—occurs when a part of the heart is damaged or dies when its blood supply is blocked.
Symptoms of a Heart AttackSymptoms of a heart attack vary, although common ones include:Pain or discomfort in the center or left side of the chestShortness of breathDizzinessSweatingNauseaIf you are experiencing heart attack symptoms, call 911 or seek medical care immediately.
Symptoms of a Heart Attack
Symptoms of a heart attack vary, although common ones include:Pain or discomfort in the center or left side of the chestShortness of breathDizzinessSweatingNauseaIf you are experiencing heart attack symptoms, call 911 or seek medical care immediately.
Symptoms of a heart attack vary, although common ones include:
If you are experiencing heart attack symptoms, call 911 or seek medical care immediately.
Most heart attacks occur due tocoronary artery disease, in which fatty deposits (plaque) build up within thecoronary arteries, whose job is to transport oxygenated blood to the heart.
These plaques can break open, and a blood clot can form. This can entirely or partially block off a coronary artery, depriving the heart muscle of blood and causing a heart attack.
Certain factors elevate a person’s chances of developing coronary artery disease, such as:
What Is Coronary Artery Disease?
In addition to heart attacks, other possible causes of or contributors to ventricular fibrillation include:
Since VFib causes cardiac arrest within seconds, there is no time for a diagnostic evaluation.
Instead, if a person is experiencing symptoms of sudden cardiac arrest, call 911, get an automatic external defibrillator (AED) immediately, and performcardiopulmonary resuscitation(CPR).
What Is an AED?An AED is a sophisticated yet easy-to-operate portable device that analyzes the heart’s rhythm and delivers an electrical shock if an arrhythmia like VFib is detected.
What Is an AED?
An AED is a sophisticated yet easy-to-operate portable device that analyzes the heart’s rhythm and delivers an electrical shock if an arrhythmia like VFib is detected.
Once a person has been resuscitated from cardiac arrest, anelectrocardiogram(ECG or EKG), among other tests, will be performed to discern the cause of the ventricular fibrillation.
VFib resembles chaotic, patternless waves or a thin, bumpy line on an ECG. The grossly irregular electrical activity on the ECG usually has a ventricular rate (a measure of how fast impulses move through the AV node) greater than 300 beats per minute.
Moreover, the height of the waves distinguishes the two types of ventricular fibrillation—coarse and fine VFib.
Coarse VFib iswhere the ECG waves measure 3 millimeters (mm) or more. It tends to occur early after the onset of cardiac arrest and is more likely to be shocked into a normal heart rhythm thanfine VFib.
Emergency Treatment
The first response to VFib and cardiac arrest is calling 911, performing CPR, and using electrical defibrillation.
More specifically, take the following steps:
Hospital Treatment
If a person survives a cardiac arrest, they will be admitted to a critical-care facility with a comprehensive post–cardiac arrest treatment system.
Another primary goal is promptly treating the cause of the VFib. For example, if underlying coronary artery disease is the culprit, various procedures or surgeries may be performed, such as:
While in the hospital, animplantable cardioverter defibrillator(ICD)may also be placed.
There is no surefire way to reverse or cure VFib once it has occurred.
However, some therapies, like taking certain medications, such as abeta-blockerorantiarrhythmic, having animplantable cardioverter defibrillator(ICD)placed,or undergoingcatheter ablation, may help prevent future VFib episodes.
AnICDis a small, battery-operated device surgically placed under the skin in a person’s chest or abdomen. It’s connected to the heart with wires (leads) and can deliver an electric shock to the heart if a dangerous arrhythmia is detected.
Catheter ablationis a procedure that destroys parts of the heart that are generating abnormal electrical signals and may help prevent future VFib episodes.
These behaviors include:
If you see someone with a known or possible heart problem suddenly lose consciousness, call 911, get an AED, and start CPR immediately.
Also, seek emergency care if you are experiencing early symptoms of VFib, such as those associated with ventricular tachycardia:
Summary
Ventricular fibrillation, or VFib or VF, is a dangerous arrhythmia that causes the heart’s lower chambers (ventricles) to erratically quiver instead of pumping blood as they should. VFib results in sudden cardiac arrest and requires emergent defibrillation (electric shock) to restore the heart’s normal rhythm.
Once the heart’s rhythm is restored, specializedpost–cardiac arrest care within a hospital is required to help prevent organ damage. This care often involves oxygen therapy and cooling devices to lower the body’s temperature.
Determining the cause of the VFib is also done, including procedures to address that cause—for example, opening up a blocked coronary artery with a stent.
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