Overview
Ventricular tachycardia is a heart rhythm disorder (arrhythmia) caused by abnormal electrical signals in the lower chambers of the heart (ventricles). Your heart rate is regulated by electrical signals sent across heart tissues. A healthy heart normally beats about 60 to 100 times a minute when at rest and is defined by signals that originate in the upper chambers of the heart (atria). In ventricular tachycardia (V-tach or VT), abnormal electrical signals in the ventricles cause the heart to beat faster than normal, usually 100 or more beats a minute, out of sync with the upper chambers.

What is Ventricular Tachycardia?
When Ventricular tachycardia happens, your heart may not be able to pump enough blood to your body and lungs because the chambers are beating so fast or out of sync with each other that they don't have time to fill properly. Ventricular tachycardia may be brief, lasting for only a few seconds, and perhaps not cause any symptoms. Or it can last for much longer and cause symptoms such as dizziness, lightheadedness, palpitations or even loss of consciousness.

In some cases, ventricular tachycardia can cause your heart to stop (sudden cardiac arrest), which is a life-threatening medical emergency. This condition usually occurs in people with other heart conditions, such as those who have had a previous heart attack or other structural heart disease (cardiomyopathy).


Ventricular fibrillation:
A dangerous condition related to ventricular tachycardia is ventricular fibrillation (V-fib). In V-fib, your lower heart chambers contract in a very rapid and uncoordinated manner. Sometimes this rhythm may occur as a result of ventricular tachycardia degenerating into ventricular fibrillation, or it may originate from single ventricular beats. This abnormal rhythm happens most often in people with established heart disease or a prior heart attack. It may also occur due to electrolyte abnormalities (such as high or low potassium levels) or, rarely, in otherwise normal hearts. Ventricular fibrillation may also cause sudden cardiac arrest and lead to death if not treated immediately.


What are the symptoms?
Brief episodes of ventricular tachycardia may not cause any symptoms in some people. Others may experience:
Dizziness
Shortness of breath
Lightheadedness
Feeling as if your heart is racing (palpitations)
Chest pain (angina)
Seizures

Sustained or more serious episodes of ventricular tachycardia may cause:
Loss of consciousness or fainting
Cardiac arrest (sudden death)

When to see a doctor?
A number of conditions can cause ventricular tachycardia. It's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if you or your child experiences any V-tach symptoms.

If you faint, have difficulty breathing or have chest pain lasting more than a few minutes, get emergency care, or call your local emergency number. Seek emergency care for anyone experiencing these symptoms.

What are the causes?
V-tach is caused by a disruption in the normal electrical impulses that control the rate of your ventricles' pumping action. Many things can cause or contribute to problems with the heart's electrical system. These include:
Lack of oxygen to the heart due to tissue damage from heart disease
Abnormal electrical pathways in the heart present at birth (congenital heart conditions, including long QT syndrome)
Structural heart disease (cardiomyopathy)
Medication side effects
An inflammatory disease affecting skin or other tissues (sarcoidosis)
Abuse of recreational drugs, such as cocaine
Imbalance of electrolytes, mineral-related substances necessary for conducting electrical impulses

In some cases, the exact cause of ventricular tachycardia can't be determined (idiopathic ventricular tachycardia).

The heart's electrical system:
To understand the causes of heart rate or rhythm problems such as ventricular tachycardia, it helps to understand how the heart's internal electrical system works.

Your heart is made up of four chambers — two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is normally controlled by a natural pacemaker called the sinus node, which is located in the right atrium. The sinus node produces electrical impulses that normally start each heartbeat.
From the sinus node, electrical impulses travel across the atria, causing the atria muscles to contract and pump blood into the ventricles.
The electrical impulses then arrive at a cluster of cells called the atrioventricular (AV) node — usually the only pathway for signals to travel from the atria to the ventricles.
The AV node slows down the electrical signal before sending it to the ventricles. This slight delay allows the ventricles to fill with blood. When electrical impulses reach the muscles of the ventricles, they contract, causing them to pump blood either to the lungs or to the rest of the body.

When anything disrupts this complex system, it can cause the heart to beat too fast (tachycardia), too slow (bradycardia) or with an irregular rhythm.

What are the risk factors?
Any condition that puts a strain on the heart or damages heart tissue can increase your risk of ventricular tachycardia. Lifestyle changes or medical treatment may decrease the risk associated with the following factors:

Heart disease (for example, prior heart attack, hypertrophic cardiomyopathy, inflammatory diseases of the heart or genetic conditions)
Use of recreational drugs
Severe electrolyte abnormalities
Medication side effects
Other risk factors
If you have a family history of ventricular tachycardia or other heart rhythm disorders, you may have an increased risk of ventricular tachycardia.

Complications:
Complications of ventricular tachycardia vary in severity depending on such factors as the rate, and duration of a rapid heart rate, the frequency with which it happens, and the existence of other heart conditions. Possible complications include:
Inability of the heart to pump enough blood (heart failure)
Frequent fainting spells or unconsciousness
Sudden death caused by cardiac arrest

Prevention:
The most effective way to prevent ventricular tachycardia is to reduce your risk of developing heart disease. If you already have heart disease, monitor it and follow your treatment plan to lower your ventricular tachycardia risk. In some cases, ventricular tachycardia may occur in the absence of heart disease (idiopathic ventricular tachycardia).


How to prevent heart disease?
Treat or eliminate risk factors that may lead to heart disease. Take the following steps:

Exercise and eat a healthy diet. Live a heart-healthy lifestyle by exercising regularly and eating a healthy, low-fat diet that's rich in fruits, vegetables and whole grains.

Maintain a healthy weight. Being overweight increases your risk of developing heart disease.

Keep blood pressure and cholesterol levels under control. Make lifestyle changes and take medications as prescribed to correct high blood pressure (hypertension) or high cholesterol.

Stop smoking. If you smoke and can't quit on your own, talk to your doctor about strategies or programs to help you break a smoking habit.

Drink in moderation. If you choose to drink alcohol, do so in moderation.

For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger. For some conditions it's recommended that you completely avoid alcohol. Ask your doctor for advice specific to your condition. If you can't control your alcohol consumption, talk to your doctor about a program to quit drinking and manage other behaviors related to alcohol abuse.

Don't use recreational drugs. Don't use stimulants, such as cocaine. Talk to your doctor about an appropriate program for you if you need help ending recreational drug use.

Use over-the-counter medications with caution. Some cold and cough medications contain stimulants that may trigger a rapid heartbeat. Ask your doctor which medications you need to avoid.

Limit caffeine. If you drink caffeinated beverages, do so in moderation (no more than one to two beverages daily).

Control stress. Avoid unnecessary stress and learn coping techniques to handle normal stress in a healthy way.

Go to scheduled checkups. Have regular physical exams and report any signs or symptoms to your doctor.


How to monitor and treat existing heart disease?
If you already have heart disease, you can take steps to lower your risk of developing ventricular tachycardia or another arrhythmia:
Follow the plan. Be sure you understand your treatment plan, and take all medications as prescribed.
Report changes immediately. If your symptoms change or get worse or you develop new symptoms, tell your doctor immediately.

Tachycardia is a common type of heart rhythm disorder (arrhythmia) in which the heart beats faster than normal while at rest.

It's normal for your heart rate to rise during exercise or as a physiological response to stress, trauma or illness (sinus tachycardia). But in tachycardia (tak-ih-KAHR-dee-uh), the heart beats faster than normal in the upper or lower chambers of the heart or both while at rest.

Your heart rate is controlled by electrical signals sent across heart tissues. Tachycardia occurs when an abnormality in the heart produces rapid electrical signals that quicken the heart rate, which is normally about 60 to 100 beats a minute at rest.

In some cases, tachycardia may cause no symptoms or complications. But if left untreated, tachycardia can disrupt normal heart function and lead to serious complications, including:

Heart failure
Stroke
Sudden cardiac arrest or death
Treatments, such as drugs, medical procedures or surgery, may help control a rapid heartbeat or manage other conditions contributing to tachycardia.

Types of tachycardia
There are many different types of abnormal tachycardia. They're classified according to the origin and cause of the abnormally fast heartbeat. Common types of tachycardia include:

Atrial fibrillation. Atrial fibrillation is a rapid heart rate caused by chaotic, irregular electrical impulses in the upper chambers of the heart (atria). These signals result in rapid, uncoordinated, weak contractions of the atria.

Atrial fibrillation may be temporary, but some episodes won't end unless treated.

Atrial fibrillation is the most common type of tachycardia. Most people with atrial fibrillation have some structural abnormalities of the heart related to underlying conditions such as heart disease or high blood pressure. Other factors that may contribute to atrial fibrillation include a heart valve disorder, hyperthyroidism or heavy alcohol use.

Atrial flutter. In atrial flutter, the heart's atria beat very fast but at a regular rate. The fast rate results in weak contractions of the atria.

Atrial flutter is caused by irregular circuitry within the atria. Episodes of atrial flutter may resolve themselves or may require treatment.

People who experience atrial flutter also often experience atrial fibrillation at other times.

Supraventricular tachycardia (SVT). Supraventricular tachycardia is an abnormally fast heartbeat that originates somewhere above the ventricles. It's caused by abnormal circuitry in the heart that is usually present at birth and creates a loop of overlapping signals.
Ventricular tachycardia. Ventricular tachycardia is a rapid heart rate that originates with abnormal electrical signals in the lower chambers of the heart (ventricles). The rapid heart rate doesn't allow the ventricles to fill and contract efficiently to pump enough blood to the body.

Ventricular tachycardia episodes may be brief and last only a couple of seconds without causing harm. But episodes lasting more than a few seconds can become a life-threatening medical emergency.

Ventricular fibrillation. Ventricular fibrillation occurs when rapid, chaotic electrical impulses cause the ventricles to quiver ineffectively instead of pumping necessary blood to the body. This can be fatal if the heart isn't restored to a normal rhythm within minutes with an electric shock to the heart (defibrillation).

Ventricular fibrillation may occur during or after a heart attack. Most people who experience ventricular fibrillation have an underlying heart disease or have experienced serious trauma, such as being struck by lightning.

Symptoms
When your heart is beating too fast, it may not pump blood effectively to the rest of your body. This can deprive your organs and tissues of oxygen and can cause the following tachycardia-related signs and symptoms:

Shortness of breath
Lightheadedness
Rapid pulse rate
Heart palpitations — a racing, uncomfortable or irregular heartbeat or a sensation of "flopping" in the chest
Chest pain
Fainting (syncope)
Some people with tachycardia have no symptoms, and the condition is only discovered during a physical examination or with a heart-monitoring test called an electrocardiogram.

When to see a doctor
A number of conditions can cause a rapid heart rate and tachycardia symptoms. It's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if you or your child experiences any tachycardia symptoms.

If you faint, have difficulty breathing or have chest pain lasting more than a few minutes, get emergency care, or call 911 or your local emergency number. Seek emergency care for anyone experiencing these symptoms.

Causes
Tachycardia is caused by something that disrupts the normal electrical impulses that control the rate of your heart's pumping action. Many things can cause or contribute to problems with the heart's electrical system. These include:

Damage to heart tissues from heart disease
Abnormal electrical pathways in the heart present at birth (congenital heart conditions, including long QT syndrome)
Disease or congenital abnormality of the heart
Anemia
Exercise
Sudden stress, such as fright
High or low blood pressure
Smoking
Fever
Drinking too much alcohol
Drinking too many caffeinated beverages
Medication side effects
Abuse of recreational drugs, such as cocaine
Imbalance of electrolytes, mineral-related substances necessary for conducting electrical impulses
Overactive thyroid (hyperthyroidism)
In some cases, the exact cause of tachycardia can't be determined.

The heart's electrical system
To understand the causes of heart rate or rhythm problems such as tachycardia, it helps to understand how the heart's internal electrical system works.

Your heart is made up of four chambers — two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is normally controlled by a natural pacemaker called the sinus node, which is located in the right atrium. The sinus node produces electrical impulses that normally start each heartbeat.

From the sinus node, electrical impulses travel across the atria, causing the atrial muscles to contract and pump blood into the ventricles.

The electrical impulses then arrive at a cluster of cells called the atrioventricular (AV) node — usually the only pathway for signals to travel from the atria to the ventricles.

The AV node slows down the electrical signal before sending it to the ventricles. This slight delay allows the ventricles to fill with blood. When electrical impulses reach the muscles of the ventricles, they contract, causing them to pump blood either to the lungs or to the rest of the body.

When anything disrupts this complex system, it can cause the heart to beat too fast (tachycardia), too slow (bradycardia) or with an irregular rhythm.

Risk factors
Any condition that puts a strain on the heart or damages heart tissue can increase your risk of tachycardia. Lifestyle changes or medical treatment may decrease the risk associated with the following factors:

Heart disease
High blood pressure
Sleep apnea
Overactive or underactive thyroid
Smoking
Diabetes
Heavy alcohol use
Heavy caffeine use
Use of recreational drugs
Psychological stress or anxiety
Anemia
Other risk factors
Other factors that may increase the risk of tachycardia include:

Older age. Aging-related wear on the heart makes you more likely to develop tachycardia.
Family. If you have a family history of tachycardia or other heart rhythm disorders, you may have an increased risk of tachycardia.
Complications
Complications of tachycardia vary in severity depending on factors such as the type of tachycardia, the rate and duration of rapid heart rate, and the existence of other heart conditions. Possible complications include:

Blood clots that can cause a stroke or heart attack
Inability of the heart to pump enough blood (heart failure)
Frequent fainting spells or unconsciousness
Sudden death, usually only associated with ventricular tachycardia or ventricular fibrillation
Prevention
The most effective way to prevent tachycardia is to maintain a healthy heart and reduce your risk of developing heart disease. If you already have heart disease, monitor it and follow your treatment plan to lower your tachycardia risk.

Prevent heart disease
Treat or eliminate risk factors that may lead to heart disease. Take the following steps:

Exercise and eat a healthy diet. Live a heart-healthy lifestyle by exercising regularly and eating a healthy, low-fat diet that's rich in fruits, vegetables and whole grains.
Maintain a healthy weight. Being overweight increases your risk of developing heart disease.
Keep blood pressure and cholesterol levels under control. Make lifestyle changes and take medications as prescribed to correct high blood pressure (hypertension) or high cholesterol.
Stop smoking. If you smoke and can't quit on your own, talk to your doctor about strategies or programs to help you break a smoking habit.
Drink in moderation. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger. For some conditions it's recommended that you completely avoid alcohol. Ask your doctor for advice specific to your condition.
Don't use recreational drugs. Don't use stimulants, such as cocaine. Talk to your doctor about an appropriate program for you if you need help ending recreational drug use.
Use over-the-counter medications with caution. Some cold and cough medications contain stimulants that may trigger a rapid heartbeat. Ask your doctor which medications you need to avoid.
Limit caffeine. If you drink caffeinated beverages, do so in moderation (no more than one to two beverages daily).
Control stress. Avoid unnecessary stress and learn coping techniques to handle normal stress in a healthy way.
Go to scheduled checkups. Have regular physical exams and report any signs or symptoms to your doctor.
Monitor and treat existing heart disease
If you already have heart disease, you can take steps to lower your risk of developing tachycardia or another arrhythmia:

Follow the plan. Be sure you understand your treatment plan, and take all medications as prescribed.
Report changes immediately. If your symptoms change or get worse or you develop new symptoms, tell your doctor immediately.

काही लोकांना हृदयाचे ठोके एकदम वाढण्याचा त्रास होत असतो. तसे साधारणतः आपण पळत सुटलो, एखादे संकट समोर उभे राहिले किंवा अनपेक्षितपणे आपल्या भावना भडकवणारी घटना घडली, खूप राग आला किंवा उत्तेजीत करणारा अनुभव आला की छातीची धडधड वाढते. परंतु काही लोकांमध्ये अशी धडधड उगाचच होते. शरीराच्या कसल्याही असाधारण हालचाली न होता ते हृदयाचे ठोके वाढतात.

अशा लोकांमध्ये प्रसंगा प्रसंगाने किंवा काही प्रसंग नसतानाही छातीची धडधड वाढली की काही वेळाने ती कमी होते. परंतु या प्रक्रियेचे काहीतरी कायमचे अंश त्यांच्या शरीरात राहून जातात म्हणजे काहीतरी कायमस्वरूपी नुकसान होऊन गेलेले असते. हा विकार प्रामुख्याने मानसिक असतो. त्याची कारणे प्रामुख्याने मानसिक असली तरी आपल्या नकळतपणे आपल्या शरीरात निर्माण झालेले काही दोष किंवा विविध अवयवातल्या काही गोष्टींचे अभाव हेही त्यास कारणीभूत असतात. शरीरामध्ये पोटॅशियमची पातळी कमी झाली किंवा डीहायड्रेशन झाले तरीसुध्दा हृदयाचे ठोके अनियमित होतात.

रक्तातील शर्करा कमी झाल्यामुळेसुध्दा धडधड होते. अधिक कॉङ्गी पिणे, चॉकलेटचे प्राशन करणे किंवा मर्यादेच्या बाहेर दारू पिणे यामुळेही हृदयाचे ठोके अनियमित होऊ शकतात. मादक द्रव्य आणि निकोटीन हे सुध्दा छातीतल्या धडधडीस कारणीभूत ठरतात. गरोदर अवस्था, रजो निवृत्तीची अवस्था, रक्त कमी होणे, हृदयविकार, हृदयाच्या झडपांमधले दोष यामुळे सुध्दा छातीत धडधड करू शकते. यागोष्टी टाळण्यासाठी संतुलित आहार तर आवश्यक आहेच पण शक्य तो मनाचा प्रक्षोभ होणार नाही याची दक्षता घेणे, ध्यान आणि प्राणायाम करणे, वाटेल ती अनुचित पेय प्राशन करण्याचे टाळणे, भरपूर पाणी पिणे या गोष्टी सांभाळल्या की हा विकार मर्यादेत राहतो.

प्रत्यक्षात छातीचे ठोके वाढण्यावर कसलाही औषधोपचार नाही. कारण छातीचे ठोके वाढणे हे काही विकारांचे लक्षण आहे. तेव्हा ते विकार आटोक्यात ठेवले की हृदयाचे ठोके अनियमित होण्याचे प्रसंगच येत नाहीत. कसलीही व्यसने न करणे, भरपूर विश्रांती घेणे आणि दिनचर्या नियमाने पाळणे या गोष्टी सांभाळल्या तरीसुध्दा या त्रासापासून दिलासा मिळू शकतो.

सामान्य स्थितीमध्ये हृद्याचे दर मिनिटाला 60-90 ठोके पडतात. मात्र जेव्हा हृद्याचे डोके पडण्याचे प्रमाण 100 पेक्षा अधिक होते. तेव्हा हे धोकादायक ठरू शकते. या समस्येला टाकीकार्डिया म्हणतात. त्यामुळे जेव्हा हृद्यविकार किंवा हृद्याच्या कार्यामध्ये काही अडथळा निर्माण होतो तेव्हा हृद्याची धडधड वाढते.
टाकीकार्डिया च्या समस्येमध्ये हृद्याच्या व्हॉल्व्हमध्ये, हृद्याच्या स्नायूंमध्ये, रक्तवाहिन्यांमध्ये काही दोष निर्माण होत नाहीत.म्हणूनच हृद्यविकारांशिवाय
टाकीकार्डिया चा त्रास जाणवत असल्यास त्यामागील नेमके कारण काय असू शकते या बाबतचा खास सल्ला आशियाई हार्ट इन्स्टिटयूट मुंबई चे कंसल्टंट कार्डिओलॉजि आणि इलेकट्रोफसीओलॉजि , डॉ. देतात.

1. ऑटोमॅटीसिटी (Automaticity)

हृद्याची आकुंचन पावून पुन्हा प्रसरण पावण्याची क्षमता म्हणजेच पंपिंग हे ‘ हार्ट रेट’ मध्ये मोजले जाते. सामान्य स्थितीमध्ये हे प्रमाण दर मिनिटाला 60-90 ठोके इतके असते. मात्र एखादा जड व्यायाम केल्यास हे प्रमाण 120/130 ठोके दर मिनिटाला इतके होते. यामुळे काळजी करण्याची गरज नाही. मात्र काही वेळेस कोणतेही ठोस कारण नसताना हृद्याच्या अप्पर आणि लोअर चेम्बरमधील स्नायू हायपरअ‍ॅक्टीव्ह होतात. त्यामुळे जेव्हा अप्पर चेम्बरमधील स्नायू हायपरअ‍ॅक्टीव्ह होतात तेव्हा स्ट्रीअल टाकीकार्डिया चा त्रास जाणवतो. तर लोअर चेम्बरमधील स्नायू जेव्हा हायपरअ‍ॅक्टीव्ह होतात तेव्हा व्हेंट्रीकलर टाकीकार्डिया चा त्रास जाणवतो. मात्र यापैकी कोणत्याही त्रासामध्ये हार्ट रेट प्रतिमिनिट 140 पेक्षा अधिक गेल्यास धोका वाढतो.

2. अ‍ॅबनॉर्मल कंडक्शन (Abnormal conductions)

काहीमध्ये जन्मजात हृद्याचे ठोके पडण्याचे प्रमाण अधिक असते. तर काहींना वाढत्या वयानुसार हा त्रास जाणवतो. अ‍ॅबनॉर्मल कंडक्शनमध्ये हृद्याचा ठोका पाडताना इलेक्ट्रिकल इम्पल्सेस लोअर चेम्बरमधून एका विशिष्ट मार्गाने जाते मात्र अप्पर चेम्बरमध्ये ते वेगळ्याच मार्गाने बाहेर पडते.

3. ट्रिगर अ‍ॅक्टिव्हिटी (Triggered activity)

ऑटोमॅटीसिटी प्रमाणेच ट्रिगर अ‍ॅक्टिव्हिटीचाही त्रास असतो. मात्र यामध्ये हार्ट वाढण्यामागे कारण वेगळे असते. व्हायरल इंफेक्शन, काही औषधांमुळे हृद्याचे ठोके पडण्याचा वेग वाढतो. यासोबत अ‍ॅनिमिया, रक्तप्रवाह होणे, ताप, एखादी इजा/ अ‍पघात किंवा त्यामधून होणार्‍या वेदना यामुळे हार्ट रेट वाढतो. या कारणांमुळे हार्ट रेट 130-140 प्रतिमिनिट इतका होतो.