Tachycardia

Your heart beats to move blood. Sometimes, it beats very fast. This is called tachycardia. A fast heart rate can happen when you run. It can also happen when you feel fear.

When the heart beats too fast, it may not work well. It might not send enough blood to your body. This can make a person feel dizzy or faint.

There are many reasons for a fast heart. A fever can make it beat fast. Being thirsty can do it too. Stress or panic can also cause it.

Doctors use a special tool to check the heart. This tool shows how the heart beats. It helps them see if the fast beat is safe.

Some fast beats come from the top of the heart. Other fast beats come from the bottom. Doctors work to help the heart beat right.

Your heart beats to move blood through your body. Sometimes, it beats much faster than normal. This is called tachycardia. For adults, this means a resting rate over 100 beats per minute.

A fast heart rate can be normal. It happens when you exercise. It can also happen when you feel fear or stress. Other things can cause it, like fever or being thirsty. Some people have medical issues that make the heart beat too fast.

When the heart beats too fast, it may not work well. It might not pump enough blood to the rest of your body. This can lead to fainting. It can also make the heart work much harder.

Doctors use a tool called an electrocardiogram, or ECG. An ECG shows the heart's rhythm on a screen. Doctors use it to find the type of tachycardia. Some fast beats start in the top parts of the heart. These are called supraventricular tachycardias. Other fast beats start in the bottom parts. These are called ventricular tachycardias.

Doctors must decide if a person is stable or unstable. A stable person is not in immediate danger. An unstable person may have trouble with their organs. Doctors use different ways to help the heart slow down.

Your heart works hard to pump blood through your body. Sometimes, it beats much faster than it should while you are resting. This is called tachycardia. The word comes from Greek words meaning "quick" and "heart." For adults, a resting heart rate over 100 beats per minute is usually considered tachycardia.

A fast heart rate is not always a bad thing. It can be a normal response to exercise or feeling fear. However, it can also happen because of electrical problems inside the heart. When the heart beats too fast, it might not pump blood efficiently. This means the body and the heart itself might not get enough blood flow.

There are many different ways the heart can beat too fast. Doctors often group these into two main types. They look at a tool called an electrocardiogram, or ECG, to see the rhythm. They check the width of the QRS complex, which is a part of the heart signal. If the signal is narrow, it is called a narrow complex tachycardia. These often start in the upper parts of the heart, called the atria. If the signal is wide, it is a wide complex tachycardia. These usually start in the bottom parts of the heart, called the ventricles.

Many different things can cause the heart to speed up. Some causes are simple, like being thirsty or having a fever. Stress and panic attacks can also trigger a fast heart rate. Some people have medical conditions like hyperthyroidism or anemia. There are even special muscle issues, like McArdle's disease, that cause an unusual heart rate during exercise. In McArdle's, the heart tries to help by pumping extra fast to deliver fuel to the muscles. Other causes include using certain drugs or having a problem with the heart's natural pacemaker.

Doctors use specific numbers to know when a heart rate is too high. These numbers change depending on how old a person is. For a baby only 1 to 2 days old, a rate over 159 beats per minute is tachycardia. For a child aged 3 to 4 years, the cutoff is 137 beats per minute. For teenagers and adults, the number is usually 100 beats per minute. Doctors must also look at the whole clinical picture to understand the patient. They check if the person is stable or unstable. An unstable person might have organs that are not working correctly.

Treating tachycardia depends on the type of fast rhythm. If a person is stable, doctors might use physical moves called vagal maneuvers to slow the heart. They might also use medicine to help. If a person is unstable, they may need something called cardioversion. This is a way to help the heart return to a normal rhythm quickly. Some types of tachycardia, like ventricular tachycardia, can be very dangerous if they last a long time. Doctors work hard to find the right way to help the heart beat steadily again.

Tachycardia is a medical term for a heart rate that is faster than the normal resting rate. The word comes from Greek, combining "tachys," meaning quick, and "kardia," meaning heart. In adults, a resting heart rate exceeding 100 beats per minute (bpm) is generally accepted as tachycardia. While a fast heart rate can be a normal response to physical exercise, it can also indicate abnormal electrical problems within the heart. When the heart beats too rapidly, it may pump blood less efficiently. This can reduce blood flow to the rest of the body and even to the heart muscle itself. This increased demand for oxygen can lead to a condition called rate-related ischemia.

Doctors use a tool called an electrocardiogram, or ECG, to classify different types of tachycardia. They look specifically at the QRS complex, which is a part of the electrical signal recorded by the ECG. Tachycardias are divided into two main categories: narrow complex and wide complex. A narrow complex has a duration of 0.1 seconds or less. Narrow complex tachycardias, also called supraventricular tachycardias, usually originate in the atria, the upper chambers of the heart. Wide complex tachycardias typically originate in the ventricles, which are the lower chambers.

There are many specific types of narrow complex rhythms. Sinus tachycardia is one of the most common and starts in the sino-atrial (SA) node near the superior vena cava. Atrial fibrillation is another common type, often appearing as an irregular rhythm. Atrial flutter and atrial tachycardia are also distinct types. Other forms include AV nodal reentrant tachycardia (AVNRT), which is the most common reentrant tachycardia, and junctional tachycardia, which originates in the AV junction. Some types, like AV reentrant tachycardia (AVRT), require an accessory pathway to maintain the rhythm. This can involve orthodromic conduction, which results in a narrow complex, or antidromic conduction, which can appear as a wide complex.

Wide complex tachycardias include ventricular tachycardia (VT), which originates in the ventricles. VT is often a regular rhythm with a rate between 120 and 250 bpm. A serious subvariant of VT is called torsades de pointes, which means "twisting of the points" due to its appearance on an ECG. If VT persists, it can lead to ventricular fibrillation, which is extremely dangerous. Other wide complex rhythms might include supraventricular tachycardia with aberrancy, where a narrow complex rhythm is combined with a conduction system problem. Pacemaker-mediated tachycardia can also present in this way.

Many different factors can trigger tachycardia. Some are simple physiological responses, like fever, dehydration, or anxiety. The body uses feedback mechanisms to maintain blood pressure; for example, reflex tachycardia occurs when blood pressure drops. Physical or psychological stress can increase sympathetic nervous system stimulation. This triggers the release of hormones like epinephrine, also known as adrenaline. Certain medical conditions, such as hyperthyroidism, anemia, or pheochromocytoma, can also cause a rapid heart rate. Even metabolic issues, like McArdle's disease, can cause an "inappropriate" sinus tachycardia during exercise because the muscles cannot create energy efficiently.

Because heart rates vary by age, doctors use specific cutoff values to diagnose tachycardia. For a newborn only 1 to 2 days old, the threshold is over 159 bpm. For infants aged 3 to 5 months, it is over 186 bpm. Children aged 8 to 11 years have a cutoff of 130 bpm. For teenagers and adults, the standard cutoff is 100 bpm. Doctors must always consider these numbers within the patient's full clinical picture. They must also watch for complications like fainting or thrombosis. Thrombosis, or blood clots within vessels, can occur due to turbulence caused by rapid blood flow.

Managing tachycardia depends on whether a patient is stable or unstable. An unstable patient is one whose organ functions are affected or who is at risk of cardiac arrest. For unstable patients with narrow complex tachycardia, doctors may use intravenous adenosine. For other unstable types, immediate cardioversion is recommended. A stable patient is one where the fast heart rate is not an immediate threat. For stable patients, doctors might use vagal maneuvers, which are physical actions to slow the heart. If the cause is chronic, the tachycardia may return unless the underlying problem is corrected.