Ventricular Fibrillation vs Ventricular Tachycardia ECG

Understanding the key differences between ventricular fibrillation and ventricular tachycardia, recognizing the symptoms, and seeking appropriate medical care are important. Ventricular fibrillation (VF) and ventricular tachycardia (VT) are cardiac emergencies. Both conditions require immediate treatment. These are heart rhythm irregularities that can lead to life-threatening situations.

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They are distinct arrhythmias, and recognizing the differences can be life-saving. Ventricular arrhythmias can occur in structurally normal and abnormal hearts. What it means is that some patients have no underlying heart disease except an abnormality in the electrical system of the ventricles or lower heart chambers that can make the heart go out of rhythm.

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In this blog post, we will explore the differences between VF and VT. Their causes, diagnosis, risk, and treatment options aim to shed light on the differences between cardiac rhythm disorders and emergency heart care. Before we proceed to understand abnormal cardiac rhythms, let us know how the heart beats.

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How Does the Heartbeat?

To understand Ventricular tachycardia and ventricular fibrillation. We must know how the heart works.

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The heart has four chambers

• 2 upper chambers called atria.

• 2 lower chambers called ventricles.

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The heart's electrical system controls the heartbeat. The electrical signals originate from the sinus node or SA node. The signals pass from the upper to the lower heart’s lower chambers through the atrioventricular (AV) node. The movement of the signal causes the heart to contract and pump blood. In a healthy heart, these signals pass smoothly, resulting in a resting heart rate of 60 to 100 beats per minute.

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Often, changes occur in pathways that transmit electrical signals through the heart in ventricles, causing faulty cardiac electrical signals in the lower heart chambers. It causes the heart to beat 100 or more times a minute.

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Ventricular Fibrillation

A chaotic and unorganized rhythm originating in the ventricles is called ventricular fibrillation. It prevents the heart from pumping blood. The ventricles do not contract; instead, they quiver rapidly and do not cause a pulse or circulation. It can be fatal if untreated and requires immediate attention.

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Ventricular arrhythmias interrupt the pumping of blood and undermine the heart’s ability to supply oxygenated blood. It causes ventricular fibrillation, which results in loss of consciousness and even death.

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Symptoms

People with this condition often collapse with no warning and respond or react upon waking up. They also gasp for breath. They experience irregularly fast and erratic heartbeats.

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Other symptoms are

• Chest pain.

• Dizziness or lightheadedness.

• Nausea.

• Racing or erratic pulse.

• Palpitation.

• Shortness of breath.

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Causes

The cause of ventricular fibrillation is often unknown, yet it may be caused by:

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• Problems in the heart's electrical properties.

• Disruption of blood supply to heart muscles.

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Risk factors

• A previous episode of ventricular fibrillation.

• Congenital heart defect.

• Heart muscle disease (cardiomyopathy).

• Injuries causing damage to heart muscles, such as being struck by lightning and in sports.

• Cocaine and methamphetamine misuse.

• Severe electrolyte imbalance of potassium or magnesium.

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Complications

It requires immediate attention. Rapid heartbeats cause the heart to stop pumping blood to the body, and the blood pressure drops suddenly. A delay in resuming the blood supply causes damage to the brain and other organs. Ventricular fibrillation is a frequent cause of sudden death. Other complications depend on how fast the treatment is provided to the patient.

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The complications caused by ventricular fibrillation are.

• Sudden cardiac arrest.

• Coma.

• Heart muscle damage.

• Brain damage.

• Kidney failure.

• Liver failure.

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However, it is rare to make a complete recovery after ventricular fibrillation.

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Ventricular fibrillation on ECG

On an ECG, VF presents the following characteristic features.

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• Ventricular fibrillation shows no P waves, T waves, or QRS complexes on the ECG.

• The heart rate may be as high as 600 beats per minute.

• The heartbeat is erratic, and the heart struggles to pump blood. The deflections vary in amplitude, and amplitude usually decreases as time passes.

• VF looks like a thin line without organized complexes. 

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Ventricular Tachycardia

Ventricular tachycardia is a type of irregular heartbeat or arrhythmia. It starts in the lower chamber of the heart, the ventricles. A healthy heart beats 60-100 times a minute at rest. In ventricular tachycardia, the heartbeat is faster and accounts for 100 beats a minute. A rapid heartbeat prevents the chambers of the heart from pumping enough blood to the body.

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If this happens, the person feels short of breath or light-headed and loses consciousness. Episodes of Ventricular tachycardia last for a short duration and do not cause harm. If they last longer than a few seconds, they can be life-threatening. It may even cause all activity to stop and cause cardiac arrest.

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Symptoms

A rapidly beating heart is not able to pump enough blood to the rest of the body, so the organs and tissues do not get enough oxygen. Symptoms of ventricular tachycardia are due to lack of oxygen and are similar to those in ventricular fibrillation.

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 VT is grouped according to how long an episode lasts

• Non-sustained VT lasts not more than 30 seconds. Episodes do not cause any major symptoms.

• Sustained VT lasts for more than 30 seconds. And can cause serious health problems.

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Symptoms of sustained VT are

• Fainting.

• Loss of consciousness.

• Cardiac arrest and sudden death.

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Risk factors

A condition that puts a strain on the heart or damages heart tissue increases the risk of ventricular tachycardia. Lifestyle changes. Healthy eating and not smoking Lower the risk of tachycardia Conditions.

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Which can cause tachycardia are

• Heart disease.

• Side effects of medicines.

• Electrolyte imbalances.

• Use of stimulant drugs such as cocaine.

• Family history.

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Complications

They depend upon

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• How fast is the heartbeat?

• How long does the rapid heart rate last?

• Other associated heart conditions.

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A life-threatening complication of VT is Ventricular Fibrillation, VF. It causes the heart to stop suddenly and can even lead to death. VF happens to most people who have heart disease or a history of heart attack. It may even occur in those with low potassium in the blood.

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Other complications of VT are

• Frequent spells of unconsciousness.

• Heart failure.

• Sudden death due to cardiac arrest.

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Prevention

To prevent VT, keep the heart healthy. In case of heart disease, regular health checkups and following the treatment plan advised are essential. We should.

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• Eat a balanced, nutritious diet.

• Do regular exercises.

• Maintain healthy weight.

• Control blood pressure and cholesterol.

• Manage stress.

• Limit alcohol, caffeine, and smoking.

• Have regular sleep.

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Some other lifestyle changes that go a long way in preventing VT are.

• Avoiding the use of illegal drugs, which are stimulants, for example, cocaine.

• Certain cough and cold prescriptions increase heart rate.

• Regular physical examination.

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Ventricular tachycardia on ECG

Ventricular tachycardia is a rhythm that originates from an abnormal single focus in the ventricles and does not follow the normal conduction pathway.  The QRS complex is not thin but wide and bizarre-looking. Usually, they are greater than 120 ms.

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It refers to heart rates over 100 beats per minute. VT has a wide QRS complex and a heart rate between 100 and 250 beats per minute. ECG characteristics indicate that the beats come from the ventricle instead of the normal conduction pathway.

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They are

• All the complexes are upright, or all the complexes are downwards.

• QRS complexes > 0.14 seconds wide.

• There is AV dissociation.

• fusion and capture beats present.

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Ventricular Storm: How Medical Emergency (Cardiac Arrest) Occurs

VT and VF arise from underlying structural heart conditions- coronary artery disease or heart failure.

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Coronary artery disease

The coronary arteries supply oxygen to the heart. When plaque deposits narrow or clog the arteries, blood cannot flow properly. It causes symptoms like chest pain (angina) and difficulty in breathing. If the blood flow is completely blocked, a heart attack occurs.

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Muscles are weakened after a heart attack, and scar tissues are formed. It contributes to abnormal electrical circuits and disruption of the heart's es between VT and VF

Both VT and VF are a medical emergency

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1. Origin and nature: Both originate in ventricles and our caused as a result of rapid firing of ventricular impulses.

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2. Life-threatening arrhythmias: Both can lead to sudden cardiac arrest. Both appear as palpitations, dizziness, chest pain, shortness of breath or syncope. They are caused by the heart’s inability to pump blood.

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3. Emergency Management: Both require defibrillation in advanced stages.

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4. Diagnosis and monitoring: They have distinct patterns, but both show abnormal ventricular rhythms

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5. Risk factors and triggers: Both share the same causes and triggers.

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6. Prevention: Diet, exercise, avoiding smoking, alcohol, caffeine, and managing hypertension are important lifestyle factors that help to prevent VT and VF.

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Differences Between Ventricular Fibrillation and Ventricular Tachycardia 

VT and VF are serious conditions that can have grave consequences. Let us tabulate the difference between the two conditions.

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ECG results: Ventricular tachycardia vs Ventricular fibrillation

VT and VF can be diagnosed on ECG, which represents the electrical signals of the heart. They are also visible in hospitals on automatic external defibrillators used for cardiac telemetry monitoring. VT shows wide QRS complexes on ECG.

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VF shows chaotic waves and no proper QRS complexes. The patterns of waves can be characterized as

• Coarse VF: The waves measure 3 mm or greater.

• Find VF: When the waves measure less than 3 mm.

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Pulseless Ventricular tachycardia or Ventricular fibrillation

When the ventricles beat rapidly and inefficiently, pulseless ventricular tachycardia occurs. The heart contracts so quickly that it doesn't have time to refill with blood between the beats. This results in no pulse and inadequate blood flow to the organs.

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Its characteristics are

• Fast, regular rhythm with wide QRS complexes.

• No pulse due to rapid contraction.

• Increased heart rate but regular.

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If VT progresses into cardiac arrest or VF, Cardiopulmonary resuscitation (CPR) and electrical defibrillation are required.

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Conclusion

Ventricular tachycardia and ventricular fibrillation are two cardiac emergencies that originate in the ventricles. Ventricular fibrillation is more dangerous and requires immediate attention. They share similarities and have distinct differences in rhythms and how they affect the heart.

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At Gauze, we help you learn and interpret ECGs and identify the differences between VT and VF. It recognizes the distinctive features and improves outcomes in patients experiencing arrhythmias.