What’s ventricular fibrillation? What can cause ventricular fibrillation?

MNT Knowledge Center

Ventricular fibrillation is definitely an abnormally irregular heart rhythm brought on by rapid, uncoordinated fluttering contractions from the ventricles – the low chambers from the heart. These fluttering replace normal contractions. Ventricular fibrillation puts the heartbeat and pulse outperform of synch.

The moving chambers within the ventricles quiver uselessly, rather than moving bloodstream, producing a serious stop by bloodstream pressure, and also the reducing of oxygen-wealthy bloodstream to body organs.

Ventricular fibrillation is really a existence-threatening medical emergency. It’s most generally associated with cardiac arrest or scarring from the heart muscle from previous cardiac arrest. Someone with ventricular fibrillation generally collapses within a few moments – also it will not be lengthy before his/her breathing or pulse stops.

What is the difference between ventricular fibrillation and atrial fibrillation?

A persons heart has two upper chambers and 2 lower chambers. Top of the chambers are known as the left atrium and also the right atrium – the plural of atrium is atria. The 2 lower chambers would be the left ventricle and also the right ventricle. Once the two upper chambers – the atria – contract in an exorbitant rate, as well as in an irregular way, the individual has atrial fibrillation. Once the two lower chambers beat irregularly and flutter, the individual has ventricular fibrillation.

Quite simply – atrial fibrillation refers back to the two upper heart chambers while ventricular fibrillation refers back to the two lower heart chambers either in situation there abnormally irregular rhythm.

Ventricular fibrillation is much more serious than atrial fibrillation. Ventricular fibrillation frequently leads to lack of awareness and dying, because ventricular arrhythmias are more inclined to interrupt the moving of bloodstream, or undermine the heart’s capability to give you the body with oxygen-wealthy bloodstream.

Sudden cardiac dying (SCD) makes up about about 300,000 deaths yearly in the united states, which 75% to 80% result from ventricular fibrillation, based on the NIH (National Institutes of Health). The NIH adds more deaths are due to ventricular fibrillation rather than breast, cancer, AIDS or cancer of the lung.

Ventricular fibrillation is usually the very first expression of coronary heart (CAD) and accounts for roughly 50% of deaths from CAD.

What are the signs and symptoms of ventricular fibrillation?

An indicator is one thing the individual senses and describes, while an indication is one thing others, like the physician notice. For instance, sleepiness can be a symptom while dilated pupils can be a sign.

The most typical manifestation of ventricular fibrillation is:

Sudden collapse, lack of awareness or fainting since the brain and muscles have stopped receiving bloodstream in the heart.

Early ventricular fibrillation signs and symptoms – approximately an hour before the heart goes into ventricular fibrillation and the patient faints, the following may be experienced:

  • Dizziness
  • Nausea
  • Pain in the chest
  • Tachycardia – accelerated heartbeat, palpitations

What are the risk factors for ventricular fibrillation?

A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2.

The following risk factors are linked to ventricular fibrillation:

  • Having had ventricular fibrillation before
  • A previous heart attack
  • Cardiomyopathy – disease of the heart muscle (myocardium)
  • Cocaine and/or methamphetamine use
  • Congenital heart disease – being born with a heart defect
  • Electrocution or other injuries that resulted in heart muscle damage

What are the causes of ventricular fibrillation?

Once the human heart beats, electrical impulses that trigger a contraction have to consume a specific route (path) towards the heart. If there’s a problem using the road to these impulses, i.e. if there’s a disruption to those impulses, arrhythmia (irregular heartbeat) can happen.

The center is split into four hollow chambers – top of the chambers are known as the atria (singular: atrium) and also the lower chambers are known as the ventricles. The walls from the atria and ventricles are created virtually of 100% pure muscle. A heartbeat is because the tightening of those muscles. Once the muscles tighten the chambers squeeze closed and push the bloodstream that is included.

Throughout a heartbeat the muscular atria (the smaller sized chambers) contract and fill the relaxed ventricles with bloodstream. The contraction starts once the sinus node (select few of cells within the right atrium) produces an electric impulse making the left and right atria contract.

The electrical impulse is constantly on the the middle of the center, towards the atrioventricular node. This node is situated around the path between your atria and also the ventricles. In the atrioventricular node our desire travels with the ventricles, which makes them contract, leading to bloodstream being pumped from the heart and in to the body.

So how exactly does ventricular fibrillation start? In nearly all cases ventricular tachycardia happens. Ventricular tachycardia is definitely an abnormally rapid heart rhythm that arises from a ventricle. It is because abnormal electrical impulses that travel around a scar which developed from the previous cardiac arrest. Ventricular tachycardia happens in patients with a few type of heart defect.

Ventricular tachycardia can happen after which disappear about thirty seconds later and cause no signs and symptoms – this is whats called non-sustained ventricular tachycardia. Whether it continues in excess of about thirty seconds it’ll generally cause palpitations, lightheadedness and/or lack of awareness. If not treated, ventricular tachycardia can result in ventricular fibrillation.

Ventricular fibrillation happens when the ventricles quiver uselessly, moving without any bloodstream in to the body – this is because disordered electrical impulses. The center winds up with no effective heartbeat bloodstream stops flowing round the body and vital organs, such as the brain lose their necessary bloodstream supply.

Someone with ventricular fibrillation will typically lose awareness very rapidly and can require immediate, emergency medical attention, including CPR (cardiopulmonary resuscitation). If CPR is shipped before the heart could be shocked back to an ordinary rhythm having a defibrillator, a person’s possibility of survival tend to be better.

Diagnosing ventricular fibrillation

Diagnosis of ventricular fibrillation is usually done in emergency circumstances, because most likely the patient has lost consciousness. The following diagnostic checks can confirm ventricular fibrillation:

  • A heart monitor – this device reads the electrical impulses that cause the heart to beat and will detect either no heart beat or an erratic one.
  • Checking the pulse – the pulse will be difficult to detect, it may either be very weak or not there at all.

Diagnostic tests to find out what caused the ventricular fibrillation:

  • ECG (electrocardiogram) – a medical device that monitors the electrical activity of the heart muscles. Our hearts produce a small electric signal at every beat. A heart specialist (cardiologist) can use this device to see how well the heart is functioning, whether there is any damage to the heart muscle, or abnormalities with the heart rhythm. A doctor can tell, when checking the data coming from the ECG, whether the patient has had a heart attack recently, or even earlier. Heart attack is a common cause of ventricular fibrillation.
  • Cardiac enzyme test – when a person has a heart attack some enzymes make their way into the bloodstream. A blood test can detect these enzymes. Usually, enzyme blood levels are checked regularly over a few days.
  • Chest X-ray – this can be useful to see if the heart has any swelling, or if there is anything unusual with the heart’s blood vessels.
  • Nuclear scan – can detect blood flow problems to the heart. Thallium, or some other radioactive material is injected into the bloodstream. The radioactive material is detected by special cameras as it flows through the lungs and heart. This test can detect where areas of reduced blood flow to the muscles are.
  • Echocardiogram – This is a type of ultrasound test that utilizes high-pitched sound waves that are sent through a transducer – a wand-like device that is held on the chest. The transducer picks up echoes of the sound waves as they bounce off different parts of the patient’s heart. The data is presented on a video screen where the doctor can see the heart as it moves. This test can help a doctor identify underlying structural heart disease.
  • Angiogram (coronary catheterization) – a catheter (thin, flexible tube) is introduced into a blood vessel until it goes through the aorta into the patient’s coronary arteries. The catheter usually enters the body at the groin or arm. A dye is injected through the catheter into the arteries. This dye stands out on images created by an X-ray and helps doctors detect coronary artery disease (arteries to the heart that have narrowed).
  • Cardiac MRI (magnetic resonance imaging) or CT (computed tomography) scan – they can measure ejection fraction as well as the heart arteries and valves. They can also determine whether the patient had a heart attack. These scans are also useful in seeking out unusual heart failure causes.

What are the treatment options for ventricular fibrillation?

In emergency treatment, focus is on restoring blood flow to organs throughout the body, including the brain – in other words, restoring blood flow as soon as possible. When this is done, the patient may receive treatment to prevent or minimize a recurrence.

Emergency treatments may, and will probably include:

  • CPR (cardiopulmonary resuscitation) – can restore blood flow through the body. CPR can be done by anybody with some basic life support training.

    Manual chest compressions and mouth-to-mouth

      • 30 chest compressions to the heart

    and then

  • Two mouth-to-mouth resuscitation breaths (mouth-to-mouth)

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Mouth-to-mouth not necessary

Most health care professionals these days say that breathing into the person’s mouth is not necessary. The patient should receive about two compressions per second, or between 100 and 120 per minute – the chest should be allowed to rise back between compressions. This should be continued until either emergency personnel arrive or somebody comes with a portable defibrillator.

  • Defibrillator – This is a CPS medical device. It sends electric shocks across the patient’s chest – the aim is to use electricity to shock the heart back into proper activity. Initially, the electric shock stops the heart momentarily – but it also stops the chaotic heart rhythm, which usually restores normal heart rhythm.

    A public-use defibrillator can be used by a lay person. These devices often have voice instructions on their use. A public-use defibrillator is programmed to detect ventricular fibrillation and emit a shock at the right moment. In most countries, especially industrialized nations, public-use (portable) defibrillators will be available in public places, such as airports, major train and bus stations, shopping malls, community centers, places where elderly people gather, casinos, etc.

 

Preventing ventricular fibrillation from occurring again

If a physician determines that the ventricular was cause by scarred tissue from a heart attack, or some structural defect in the heart, medications and medical procedures may be recommended to minimize the risk of recurrence. The following may be recommended:

  • Medications:
    • Beta blockers are commonly used to prevent sudden cardiac arrest or ventricular fibrillation. These drugs make the heart beat more slowly and with less force, thus easing the heart’s workload. They also stabilize the heart’s electrical activity. Examples include metoprolol, propranolol, timolol, and atenolol.
    • ACE (angiotensin-converting enzyme) inhibitors – these drugs help ease the workload on the heart by opening up blood vessels and lowering blood pressure. Experts say ACE inhibitors also protect the heart from further damage. Patient will have a blood test to make sure their kidneys are working properly before starting on this type of medication. Then, about ten days after starting treatment, the patient will undergo further tests to make sure his/her kidneys are still working fine. Over a period of about 3 weeks the patient’s dose is gradually increased. Examples of ACE inhibitors include lisinopril, perindopril and ramipril.
    • Amiodarone (Cordarone) or calcium channel blockers may also be prescribed.

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  • ICD (implantable cardioverter-defibrillator) – this device is placed inside the body. It is designed to recognize certain types of arrhythmias (abnormal heart rhythms) and correct them by emitting electric shocks to reset the heart to a normal rhythm.
  • Coronary angioplasty – this surgical procedure is sometimes necessary in severe cases of coronary artery disease. Angioplasty opens up the coronary artery. A small wire goes up the artery from the patient’s groin or arm and is pushed until it reaches where the clot is in the coronary artery. There is a small balloon, shaped like a sausage, at the end of the wire. The balloon is placed at the narrowest part of the artery and is then inflated, squashing the clot away. A flexible metal mesh, called a stent, is then placed there to keep that part of the artery open.
  • CABG (Coronary artery bypass graft) – the damaged blood vessel is by-passed with grafts taken from blood vessels elsewhere in the body. The bypass effectively goes around the blocked area of the artery, allowing blood to pass through into the heart muscle. If blood supply to the heart is improved, the risk of ventricular fibrillation goes down.
  • Ventricular tachycardia ablation – catheters are inserted through a vein, usually in the groin and threaded to the heart, to correct structural heart problems that cause an arrhythmia. The aim is to clear the signal pathway (of electrical impulses) so that the heart may beat normally again. Put simply, tissue that blocks the electrical signal is either destroyed or scarred.