Tachycardia refers to a fast resting heart rate, usually over 100 beats per minute. Depending on its underlying cause and how hard the heart has to work, it can be dangerous.
Some people with tachycardia have no symptoms, and complications never develop. However, it can increase the risk of stroke, heart failure, sudden cardiac arrest, and death.
There are different types of tachycardia, depending on which part of the heart has the problem.
In this article, learn more about the symptoms, causes, and treatment options associated with tachycardia.
Tachycardia refers to a high resting heart rate. In adults, the heart usually beats between 60 and 100 times per minute.
Doctors usually consider a heart rate of over 100 beats per minute to be too fast, though this varies among individuals. Factors such as age and fitness levels can affect it.
When tachycardia is present, either the upper or lower chambers of the heart beat significantly faster.
When the heart beats too rapidly, it pumps less efficiently. Blood flow to the rest of the body, including the heart, reduces.
Also, when the heart beats faster, the heart muscles need more oxygen. In time, oxygen-starved cells can die, leading to heart attack.
Atria, ventricles, and the electrical circuitry of the heart
The human heart consists of four chambers: the atria, which are the two upper chambers, and the ventricles, which are the two lower chambers. (There are left and right atria and ventricles.)
The heart has a natural pacemaker, called the sinoatrial node, in the right atrium. This produces electrical impulses. Each one triggers an individual heartbeat.
As the electrical impulses leave the sinoatrial node, they cross the atria, making the atrial muscles contract. This contraction pushes blood into the ventricles.
The electrical impulses continue to the atrioventricular (AV) node, which is a cluster of cells. The AV node slows down the electrical signals, then sends them on to the ventricles.
In doing so, it allows time for the ventricles to fill with blood. When the ventricular muscles receive the electrical signals, they contract, pumping blood either to the lungs or to the rest of the body.
A problem with the electrical signals can result in a faster-than-normal heartbeat. This is tachycardia.
Tachycardia usually stems from a disruption in the normal electrical impulses that control the heart’s pumping action, or the rate at which the heart pumps.
Depending on the type and cause of tachycardia, the following factors may trigger it:
- a reaction to certain medications
- congenital irregularities of the heart
- consuming excessive amounts of alcohol or caffeine
- using cocaine or other recreational drugs
- electrolyte imbalance
- poor blood supply and damage to heart tissues due to heart disease, coronary artery disease, heart valve disease, heart failure, heart muscle disease, tumors, or infections
- hypertension, or high blood pressure
- certain lung conditions, thyroid problems, anemia, and other health concerns
- severe bleeding
- physical and mental stress, including illness and anxiety
- previous heart surgery
Sometimes, however, the exact cause may not be clear.
The treatment options for tachycardia will depend on various factors, including:
- the cause
- the age of the person
- their overall health
Treatment aims to address the cause, but a doctor may also try to:
- slow the heart rate
- prevent further episodes
- reduce the risk of complications
If there is no clear underlying cause, it may take some time to find a suitable treatment option.
There are several ways to slow a rapid heartbeat during an episode. The following sections will look at these in more detail.
The vagus nerve helps regulate the heartbeat.
Some techniques, or maneuvers, can affect this nerve and help slow the heartbeat. Such techniques include:
- stimulating the gag reflex
- applying abdominal pressure
- applying cold water to the person’s face
- applying gentle pressure to the area of the neck where the carotid artery is
- holding the nostrils closed while the person blows out through the nose
These may be helpful in an emergency.
A healthcare professional may also apply gentle pressure to the eyeballs while the person has their eyes closed.
A doctor can administer antiarrhythmic drugs either orally or intravenously. These drugs aim to restore a normal heart rhythm and control the heart rate.
Some examples of antiarrhythmic drugs include amiodarone (Cordarone), sotalol (Betapace), and mexiletine (Mexitil).
Cardioversion and defibrillators
A healthcare provider can attach patches, or electrodes, to the person’s body and have a machine deliver an electric shock to their heart. This affects the electrical impulses in the heart and may restore a normal rhythm.
There are different ways of performing cardioversion. These are as follows:
- In an emergency setting: While waiting for medical help to arrive, a first responder or bystander may use an automatic external defibrillator if the person’s heart goes into a rhythm that prevents it from beating properly.
- In the hospital: A cardiologist may use cardioversion as part of a scheduled treatment.
- Ongoing treatment: An implantable cardioverter defibrillator can continuously monitor the person’s heartbeat. A cardiologist can implant the small device into the chest, where it detects abnormal heartbeats and delivers a shock to restore a normal rhythm when needed.
Some measures can help prevent and manage tachycardia. The following sections will discuss these measures in more detail.
Some ways to prevent tachycardia and other heart issues at home include:
- avoiding the use of tobacco and recreational drugs
- limiting the consumption of alcohol and caffeine
- reducing stress, if possible
- getting enough sleep
- following a healthful diet and getting regular exercise
Medications that can help people manage tachycardia include:
- antiarrhythmic drugs
- calcium channel blockers, such as diltiazem (Cardizem) or verapamil (Calan)
- beta-blockers, such as propranolol (Inderal) or metoprolol (Lopressor)
- blood thinners, such as warfarin (Coumadin) or apixaban (Eliquis)
Radiofrequency catheter ablation
An electrophysiologist can insert catheters into the heart through the blood vessels.
Electrodes at the ends of the catheter can ablate, or damage, small sections of the heart that are responsible for the abnormal heartbeat.
Sometimes, a doctor will recommend surgery to make repairs or changes that can help reduce the risk of tachycardia.
They will only do this if other therapies have not worked or if the person has another heart condition.
Depending on the type and cause of tachycardia, the following symptoms may occur:
- a fast pulse
- chest pain
- low blood pressure
- heart palpitations
- shortness of breath
- sudden weakness
- a loss of consciousness
- cardiac arrest, in some cases
However, many people have no symptoms and only find out that they have tachycardia during a routine examination.
The risk of complications depends on several factors, including:
- the severity and duration of the tachycardia
- the type
- the overall health of the person
- any other heart conditions they may have
The most common complications include:
- Blood clots: These can significantly increase the risk of heart attack or stroke.
- Heart failure: Without treatment, the heart can become weaker, increasing the risk of heart failure.
- Fainting: A person with a rapid heartbeat may lose consciousness, increasing their risk of a fall or other accident.
- Sudden death: This usually only occurs with ventricular tachycardia or ventricular fibrillation.
The following sections will outline some common types of tachycardia.
In this type, the heart beats faster than usual, but the rhythm is regular, and the impulse comes from the sinoatrial node.
- mental and physical stress
- the use of certain drugs
- some health conditions
Atrial or supraventricular tachycardia
Atrial or supraventricular tachycardia is an accelerated heart rhythm that starts in the upper chambers of the heart.
It is the most common heart rhythm problem in children and young people. Many people first experience it between the ages of 25 and 40 years.
An episode may last from a few minutes to several hours. It is not usually serious, but, in extreme cases, it can lead to unconsciousness and cardiac arrest.
Sometimes, electrical activity in the atria can override the heart’s natural pacemaker. This causes the chambers to contract rapidly and irregularly. This is known as atrial fibrillation (A-fib).
Most people with A-fib also have another heart condition. It is more likely to affect those over the age of 65 years. Consuming alcohol and smoking tobacco may contribute, as might hypertension and sleep apnea.
This is similar to A-fib, but the rhythms are more organized. Many people have both A-fib and atrial flutter.
Abnormal electrical signals in the lower chambers result in a rapid heart rate. This can result from cardiovascular problems, such as a previous heart attack, and the use of certain drugs.
The speed of the heartbeat does not allow the ventricles to fill and contract properly, thereby reducing blood supply to the body.
The cause and severity of the symptoms will determine how serious it is.
Ventricular fibrillation (V-fib) is a serious cardiac disturbance. The ventricles quiver instead of beating, resulting in poor blood supply to the body.
V-fib is a medical emergency. If a normal heart rhythm does not return quickly, blood circulation can cease, which can lead to death.
The following factors can increase the risk of tachycardia:
- age, as some kinds affect different age groups
- genetic factors
- a personal or family history of heart disease
- a high consumption of caffeine and alcohol
- high blood pressure
- mental stress
- the use of recreational drugs
- thyroid disease
If a person seeks medical advice for a suspected heart rhythm problem, the doctor will:
- ask about their symptoms
- carry out a physical exam
- order some tests
These tests may include:
- Electrocardiogram: Electrodes attached to the skin can measure electrical impulses that the heart produces.
- Echocardiogram: This is a type of ultrasound test that produces a moving image of the heart.
- Wearable devices: The person can carry a Holter monitor or event recorder. These devices can monitor heart rhythms or electrical impulses.
- Blood tests: These help determine whether thyroid or other problems are contributing to tachycardia.
- Graded exercise test: This can help identify how physical activity impacts heart rhythms.
Some of the complications of tachycardia can include:
- fainting and dizziness
- tiredness and fatigue
- shortness of breath
- chest pain and tightness, or angina
- low blood pressure and shock
- heart failure
Tachycardia refers to rapid heart rhythms. Some causes include heart disease and various lifestyle factors.
It is possible to have tachycardia without symptoms, but it can lead to complications, such as heart attack or stroke.
Anyone who has concerns about their heart health should seek medical advice, as early treatment can help prevent long-term and possibly life threatening complications.