What is Ventricular Tachycardia?
Ventricular tachycardia (VT) refers to a heart condition where the heart beats too quickly. It is defined by at least three consecutive beats occurring at a speed of over 100 times per minute, originating from the lower part of the heart, known as the ventricle. This condition could be life-threatening and is a major reason for sudden heart deaths in the USA.
There are two main types of ventricular tachycardia: non-sustained and sustained. Non-sustained ventricular tachycardia means the fast heartbeat lasts for less than 30 seconds while sustained VT lasts more than 30 seconds or demands immediate medical intervention due to the heart’s inability to pump enough blood.
The type of VT can also be categorized by the shape of the heart’s electrical signals, known as QRS morphology. Monomorphic VT presents as a single, constant QRS shape with no beat-to-beat variation, whereas polymorphic VT shows different QRS shapes with each heartbeat. Torsades de Pointes and Bidirectional ventricular tachycardia are forms of polymorphic ventricular tachycardia with their unique patterns.
Ischemic heart disease which is a condition where the blood supply to the heart is reduced, often due to blockages, is typically the most common reason for ventricular tachycardia. It is not uncommon for 5-10% of patients with acute coronary syndrome, a term that includes heart attacks and unstable angina, to experience ventricular arrhythmias or abnormal heart rhythms.
Ventricular tachycardia can lead to sudden heart death particularly in patients with damaged heart muscles from ischemic and non-ischemic cardiomyopathy, a disease that makes it harder for your heart to pump blood to the rest of your body. The symptoms of VT may range from feeling heart palpitations to sudden cardiac death.
To manage VT and reduce the risk of sudden heart death, it’s important to understand the causes and how the disease develops within the heart, as well as the underlying structural heart disease. Evaluation and management for people showing symptoms or diagnosed with VT is crucial.
What Causes Ventricular Tachycardia?
Ventricular tachycardia, a type of heart rhythm disorder, accounts for about 8% of cases of a fast heart rate that starts in the lower chambers of your heart. The most common cause is an underlying heart disease. When this condition occurs during a heart attack, it often changes forms, but if it’s due to a scar on the heart muscle, it usually takes a single form. This type of fast heart rate can signal a higher risk of death after a heart attack.
Other potential causes include other types of heart muscle damage or heart disease, inherited conditions that affect the electrical activity of the heart, heart conditions caused by diseases like lupus and rheumatoid arthritis, electrolyte imbalances, drug use such as cocaine or methamphetamine, and side effects of certain heart medications. If the heart has a predisposition for this condition, triggers can include heart attacks, electrolyte imbalances, severe systemic infections, and metabolic acidosis (a condition that occurs when your body produces too much acid).
Certain inherited conditions that disrupt the heart’s normal rhythm are more common in younger people. “Long-QT syndrome” is the most common inherited condition, with a characteristic feature being Torsades de Pointes, a specific type of irregular heart rhythm. Other inherited conditions that can cause ventricular tachycardia include Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, short QT syndrome, and malignant early repolarization syndrome. Heart conditions such as hypertrophic cardiomyopathy (a disease in which the heart muscle becomes abnormally thick), arrhythmogenic right ventricular cardiomyopathy (an inherited heart condition that affects the heart muscle), and myocarditis (inflammation of the heart muscle) can lead to this fast heart rate and even cause sudden cardiac death.
A rare type of this condition, “idiopathic” ventricular tachycardia, usually occurs in younger individuals who don’t have heart disease. Most often, it originates from the outflow tracts (where blood leaves the heart), the annulus (ring of a heart valve), and fascicles of the left bundle branch (part of the system that sends electrical signals in the heart). This type usually responds well to calcium channel blockers, a type of heart medication, and can often be successfully treated with a procedure called catheter ablation.
Risk Factors and Frequency for Ventricular Tachycardia
Ventricular tachycardia and ventricular fibrillation, two types of irregular heart rhythms, cause many of the sudden heart-related deaths each year. These conditions contribute to about half of all heart-related deaths. A strong link exists between ventricular tachycardia and heart disease. In fact, about 15% of people with heart disease also have ventricular tachycardia.
This heart rhythm issue mostly affects men due to the higher prevalence of heart disease among them. However, as heart disease becomes more common in women, the incidence of ventricular tachycardia in women is also expected to rise.
Ventricular tachycardia is especially common in people facing acute coronary syndrome, which includes conditions like a heart attack. Around 5-10% of patients who come to the hospital with a heart attack can experience ventricular tachycardia within the initial few days of their hospital stay. If they develop this heart rhythm issue after the first two days, their risk of death increases. Ventricular tachycardia is rare in kids, but it may happen in cases of inherited conditions affecting the heart’s electrical function or structural heart diseases.
Sometimes, ventricular tachycardia can occur without any known cause, and this is known as idiopathic ventricular tachycardia. This condition is quite rare, only affecting around 15 in every 100,100 people. There’s no gender difference in who gets it, and it has become slightly more common in recent years because of better diagnostic methods and increased awareness. The age of diagnosis can range widely, but typically the average age someone gets diagnosed is around 52.
- Ventricular tachycardia and ventricular fibrillation cause a lot of sudden heart-related deaths.
- About half of heart-related deaths are due to these heart rhythm conditions.
- 15% of people with heart disease also have ventricular tachycardia.
- Because heart disease is more common in men, so is ventricular tachycardia.
- With the climbing rate of heart disease in women, their rate of ventricular tachycardia is also expected to increase.
- 5-10% of people hospitalized for a heart attack have ventricular tachycardia in the first few days.
- Ventricular tachycardia is unusual in children but can occur with inherited or structural heart conditions.
- Idiopathic ventricular tachycardia, which happens without a known cause, affects about 15 out of every 100,100 people.
- Men and women are equally likely to experience idiopathic ventricular tachycardia.
- The average age of diagnosis for idiopathic ventricular tachycardia is 52.
Signs and Symptoms of Ventricular Tachycardia
Ventricular tachycardia is a heart condition that can present differently based on the patient’s age, overall health, the presence of other heart conditions, and the specific type of ventricular tachycardia. Common symptoms often include heart palpitations, breathlessness, chest pain, and fainting. However, in severe cases, it can lead to cardiac arrest or even sudden death. Some people only notice symptoms during physical activity or emotional stress, and others may first experience breathlessness due to heart failure.
- Palpitations
- Shortness of breath
- Chest pain
- Fainting (syncope)
- Cardiac arrest or sudden cardiac death in severe cases
In cases where ventricular tachycardia is caused by coronary artery disease or left ventricular systolic dysfunction, the symptoms might be more severe, leading to significant decrease in blood flow (hemodynamic compromise). It might lead to fainting, severe shortness of breath due to fluid buildup in the lungs (pulmonary edema), cardiac arrest or even sudden death. Meanwhile, people who have an implanted device to correct heart rhythm (ICD) may experience shocks from the device.
Ventricular tachycardia due to heart rhythm disorders (channelopathies) may cause fainting, cardiac arrest, and sudden death as the first signs. Therefore, if a young person is diagnosed with ventricular tachycardia, it is crucial to get a detailed family history going back three generations.
Physical examination of patients with ventricular tachycardia may reveal low blood pressure and signs of heart failure. Even stable patients might present with high jugular venous pressure and cannon waves (a visible and palpable wave in the neck veins). Also, detailed examination might show signs of underlying structural heart disease and side effects of antiarrhythmic drugs like amiodarone.
Testing for Ventricular Tachycardia
A thorough examination and medical history are critical when dealing with a patient with ventricular tachycardia, a rapid heart rate that arises from improper electrical activity in the lower chambers of the heart. Patients should be questioned about potential risk factors for heart disease, prior experiences of heart flutters or fainting, and a family history of heart conditions. Guidelines suggest taking a detailed family history spanning three generations for patients who may have inherited heart rhythm disorders. A physical examination can not only help identify any pre-existing heart problems, but it is also crucial for managing patients with ventricular tachycardia.
An electrocardiogram (ECG), a test that checks the heart’s electrical activity, is the first step when evaluating a suspected case of ventricular tachycardia. An ECG done during the rapid heart rhythm and when the heart is beating normally can help determine the cause of the ventricular tachycardia. In some cases, further testing might be needed such as a treadmill stress test or an ambulatory ECG monitoring, which records heart rhythms over time while the patient is at home. Patients whose symptoms suggest ventricular tachycardia but are not frequent, might need a device known as an implantable loop recorder to keep track of heart rhythms.
If a patient has ventricular tachycardia and there might be structural heart disease involved as well, an echocardiogram is recommended. This imaging test gives pictures of the heart’s structures and helps diagnose conditions such as hypertrophic cardiomyopathy (thickened heart muscle), dilated cardiomyopathy (enlarged and weakened heart chambers) and arrhythmogenic right ventricular cardiomyopathy (a rare type of heart muscle disease). In selected patients, cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) may also be considered. These imaging techniques can help understand the condition of the heart muscle and diagnose various heart conditions.
In some situations, invasive methods like a coronary angiogram, a test that uses a special dye and X-rays to see how blood flows through the heart, may be necessary. For example, this could be the case for patients who had a cardiac arrest caused by ventricular tachycardia that’s believed to stem from heart muscle disease. In a select few cases, an endomyocardial biopsy, a procedure where a small amount of heart tissue is removed for examination, may be required.
Genetic testing generally isn’t recommended routine practice for patients with ventricular tachycardia. However, in certain patients, this might be necessary if an inherited heart rhythm disorder is suspected. Family members who don’t have symptoms but are related to someone with certain heart conditions might also be recommended to undertake genetic testing.
Other important tests include checking blood levels of certain substances like potassium, magnesium, and calcium. A test known as high-sensitivity cardiac troponin is needed to diagnose a heart attack. On the other hand, the levels of a substance called natriuretic peptide can give an idea about the prognosis of patients with structural heart disease and ventricular tachycardia who have a risk of sudden cardiac death.
Treatment Options for Ventricular Tachycardia
Cardiac arrest is a life-threatening emergency that can be caused by a condition known as ventricular tachycardia, where the heart beats too quickly. If this happens, medical professionals have to closely follow a set of procedures, known as advanced life support methods, to revive the patient. If a patient shows signs of ventricular tachycardia but hasn’t experienced cardiac arrest, a reset technique called direct current cardioversion might be done. This is used to bring the heart’s rhythm back to normal. In cases where this approach isn’t effective or the condition repeats, a drug named amiodarone is used.
If ventricular tachycardia is triggered by other heart diseases and happens more than three times in 24 hours, it is called ‘VT storm’. This condition usually needs control using antiarrhythmic drugs, anti-tachycardia pacing (a method that uses electrical impulses to regulate the heart rhythm) or direct current cardioversion. In severe cases, it may necessitate the insertion of a tube into the patient’s airway or the use of a machine to assist circulatory function or proceed with a procedure to stop the abnormal heart rhythm.
Medications like procainamide, amiodarone, and sotalol can be used in patients with other heart diseases whose heart rhythm can be adequately maintained despite the fast pace of ventricular tachycardia. Another drug named lidocaine can also be used if the mentioned drugs are unavailable.
People with ventricular tachycardia caused by ‘cardiac channelopathies’ – a condition that affects the electrical activity of the heart – will also undergo similar treatment, which includes beta-blockade and correction of mineral levels in the body.
In the long run, anyone with ventricular tachycardia should consider placing a device known as an ‘implantable cardiac defibrillator’ if their heart performance is weak. This device monitors the heartbeat and gives electric shocks to restore the heart’s normal rhythm if necessary. Other medicines like beta-blockers can help with prevention and reduction of the risk of sudden cardiac death. If they experience recurrent episodes of ventricular tachycardia despite medication, catheter ablation might be considered as a treatment.
In cases of non-ischemic cardiomyopathy – a type of heart disease – if medicines fail to prevent recurrence of VT, a procedure called catheter ablation, which treats select parts of the heart’s muscle, may be recommended. This approach has been shown to reduce the recurrence of abnormal heart rhythm and improve survival.
For other heart conditions such as arrhythmogenic right ventricular cardiomyopathy and catecholaminergic polymorphic ventricular tachycardia – conditions that cause abnormal heart rhythms, beta-blockers are an effective treatment. If the cause is because of a genetic condition that affects the heart’s electrical system, you may need to have an implantable cardioverter-defibrillator inserted. This device can constantly monitor and correct abnormal heart rhythms and potentially save your life.
So, it is crucial to remember that while immediate treatment is needed to control ventricular tachycardia, long-term management, including appropriate medications and procedures, plays a key part in reducing your risk of the condition recurring.
What else can Ventricular Tachycardia be?
Ventricular tachycardia is often the main reason for a condition known as ‘broad complex tachycardia’. But, other causes can lead to this condition as well. Here are possible causes other than ventricular tachycardia:
- Supraventricular tachycardia with bundle branch aberration
- Supraventricular tachycardia with pre-excitation
- Antidromic atrioventricular tachycardia (AVRT)
- Pacemaker-mediated tachycardia
- Metabolic issues
Doctors will take a detailed health history, perform a clinical exam, and use an EKG (electrocardiogram) to tell ventricular tachycardia apart from the other causes of broad complex tachycardia. Special algorithms created for EKGs can be used to distinguish ventricular tachycardia from supraventricular tachycardia with aberrancy. Close examination of the EKG may also help pinpoint the source of ventricular tachycardia, and figure out if it’s idiopathic (of unknown cause) or caused by something else.
What to expect with Ventricular Tachycardia
The success of treating ventricular tachycardia, a fast heartbeat that starts in the lower part of the heart, vastly depends on what caused it and whether the patient has a structural heart disease. The most common cause of this condition is coronary artery disease, a form of heart disease that develops over time due to clogged arteries. Hence, patients suffering from ventricular tachycardia due to ischemic cardiomyopathy (damaged heart muscle tissue due to insufficient blood flow to the heart) often have the worst outcomes. If they don’t receive treatment, the two-year mortality rate can be as high as 30%.
Thankfully, implanting a defibrillator (a device that can monitor the heart rhythm and deliver electric shocks if it detects a life-threatening abnormal rhythm) significantly lessens the chance of sudden death from a heart condition and improves survival rates in these patients.
Patients diagnosed with idiopathic ventricular tachycardia, which is a rapid heart rate with no apparent cause, have excellent outcomes if they don’t have other existing illnesses. They are expected to live almost as long as the average individual.
However, patients with hypertrophic cardiomyopathy (a disease where heart muscle becomes abnormally thick), long QT syndrome (a heart rhythm disorder that can cause fast, chaotic heartbeats), and arrhythmogenic right ventricular cardiomyopathy (a rare type of cardiomyopathy where the heart muscle of the right ventricle is replaced by fat and fibrosis) have a higher risk of sudden cardiac death, even if the left ventricle’s function, an important chamber of the heart, remains normal.
Medications like beta-blockers can lessen the occurrence of ventricular tachycardia in these patients, while implantable cardioverter defibrillators can prevent sudden cardiac death.
Possible Complications When Diagnosed with Ventricular Tachycardia
The complications of ventricular tachycardia, a heart rhythm problem, can vary depending on the specific cause. The most common issues connected with idiopathic ventricular tachycardia, a condition with no known cause, include tachycardia-induced cardiomyopathy and heart failure. Tachycardia-induced cardiomyopathy, a disease that makes the heart muscles weak, is more common in patients who routinely experience VT episodes. Other factors can also increase its risk, for example, alcohol consumption.
Major complications for inherited ventricular tachycardia, a type that runs in families, and scar-related ventricular tachycardia, caused by scars on the heart, include cardiac arrest and sudden heart death. But, these complications can likely be minimized with early recognition of the condition and the installation of an implantable cardioverter-defibrillator, a device that manages heart rhythm. Use of beta-blockers, a type of heart medication, has been shown to decrease the occurrence of sudden heart death in patients with specific heart conditions.
Common Complications:
- Tachycardia-induced cardiomyopathy
- Heart failure
- Cardiac arrest
- Sudden heart death
Management Methods:
- Early recognition of the condition
- Implantable cardioverter-defibrillator
- Use of beta-blockers
Preventing Ventricular Tachycardia
Ventricular tachycardia is a heart condition that can be very serious and even life-threatening. The most common symptom is a fast heartbeat that you can feel, often called palpitations. However, some people may faint (known as syncope), suffer from a heart attack, or even die suddenly. Anyone who experiences these symptoms should get checked out thoroughly. This can involve discussing their family’s medical history over three generations, having an ultrasound scan of the heart (transthoracic echocardiogram), and sometimes having a special type of heart scan known as cardiac magnetic resonance imaging. If someone in your family died suddenly at a young age, it’s recommended to talk to a heart doctor (a cardiologist) to find out if you might have inherited heart problems. If you have family members who don’t have symptoms, but are related to someone who had inherited heart problems, it could be a good idea to get them to see a specialist in heart rhythms (a cardiac electrophysiologist) or a genetics expert. This may help identify potential issues and provide advice on genetic risks.