Tachycardia Overview
Tachycardia is a condition that makes the heart beat more than 100 beats per minute. This can either start in the heart’s lower chambers (ventricles) or upper chambers (atria). At these elevated rates, the heart is not able to efficiently pump oxygen-rich blood to the body.
In most of the human adult individuals the heart usually beats between 60 to 100 beats per minute (bpm) which is considered a normal heart rate.
The human heart consists of four chambers, which are the atria, which are the two upper chambers, and the ventricles, which are the two lower chambers.
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 condition is known as tachycardia.
Types of Tachycardia
- Sinus Tachycardia: Sinus tachycardia occurs when the heart’s natural pacemaker sends out electrical signals faster than normal. Your ticker beats fast, but it beats the way it should.Sinus tachycardia is usually caused by anxiety, stress, strenuous exercise, a fever, fear, certain medications, and illegal drugs. It can also be triggered by anemia, an overactive thyroid, or damage from a heart attack or heart failure.
- Supraventricular: Supraventricular is a condition that occurs when the electrical signals in the organ’s upper chambers misfire and cause the heart rate to speed up. It beats so fast that it can’t fill with blood before it contracts. That reduces blood flow to the rest of your body.Supraventricular tachycardia is most likely to affect patients who smoke, drink too much alcohol, or have a lot of caffeine. In some cases it’s linked to heart attacks. It’s more common in women and children.
- Ventricular: In Ventricular condition is a rapid heart rate that starts in the heart’s lower chambers. It occurs when the electrical signals in these chambers fire the wrong way. The heart beats so fast that it is unable to fill with blood and pump it through the rest of your body.The ventricular type is associated with abnormal electrical pathways which are present at birth (long QT), structural problems of the heart such as a cardiomyopathy or coronary disease, medications, or electrolyte imbalance.
Signs and Symptoms of Tachycardia
Following are the common signs and symptoms of tachycardia:
- Chest Pain
- Confusion
- Dizziness
- Fast Pulse
- Heart Palpitations
- Lightheadedness
- Loss of Consciousness
- Shortness of breath
- Weakness
In some tachycardia, a super-fast heart rate causes no symptoms at all. In some extreme cases, it is possible that a patient with tachycardia could become unconscious or go into cardiac arrest.
Causes of Tachycardia
Exact causes of tachycardia are sometimes unknown. However several factors and conditions can cause tachycardia.
- Anemia
- Alcohol and caffeine consumption in large amounts
- Certain lung diseases
- Congenital irregularities of the heart
- Coronary heart and artery disease
- Drug abuse (cocaine)
- Electrolyte imbalance
- Fatigue
- Infections
- Heart valve problems
- Hypertension or high blood pressure
- Poor blood supply and damage to heart tissues
- Reaction to certain medications
- Smoking
- Tumors
- Physical and mental stress, including illness and anxiety
- Previous heart surgery
- Severe bleeding
- Thyroid problems
Diagnosis of Tachycardia
Following are some of the tests performed to diagnose tachycardia:
- Electrocardiogram (ECG or EKG): This records the electrical activity in your heart and helps your doctor search for things that don’t look normal.
- Echocardiogram: An ultrasound that looks at the structure of the heart valves, walls and chambers.
- Exercise Stress Test: Stress test is performed by making the patient walk on a treadmill while the doctor monitors the heart activity.
- Magnetic Source Imaging: This measures the heart muscle’s magnetic fields and looks for weaknesses.
- Holter monitor — a monitor of the heart beat rhythm that is worn for 24 hours.
Treatment of Tachycardia
Tachycardia can be ventricular (in the lower chambers of the heart) or atrial (in the upper chambers of the heart), and the treatment strategy may vary depending on what type of tachycardia someone may have.
The treatment of tachycardia will be decided by the doctor after patients complete evaluation and getting the patients diagnostics test results.
Patients with sinus tachycardia, they’ll help you pinpoint the cause and suggest things to lower your heart rate. These might include lifestyle changes like easing stress or taking medicine to lower a fever.
If the patient have supraventricular tachycardia, your doctor may recommend that you drink less alcohol and caffeine, quit smoking and get more sleep.
Treatments for ventricular tachycardia may include medication to reset the heart’s electrical signals or ablation, a procedure that destroys the abnormal heart tissue that is leading to the condition. Your doctor might also use a defibrillator to disrupt rapid heart rhythms.
Vagal maneuvers
Several ways can help to slow a rapid heartbeat during an episode. Vagal maneuvers are one of those techniques, the vagus nerve helps regulate the heartbeat.
Following are some of the techniques, or maneuvers can affect this nerve and help slow the heartbeat.
- Applying gentle pressure o the area of the neck where the carotid artery is located
- Applying abdominal pressure
- Applying cold water to the person’s face
- Holding the nostrils closed while the person blows out through the nose
- Stimulating the gag reflex
Medications
Antiarrhythmic dugs are used to restore a normal heart rhythm and control the heart rate. These can be given either orally or intravenously. Some examples of antiarrhythmic drugs include amiodarone (Cordarone), sotalol (Betapace), and mexiletine (Mexitil).
Cardioversion and Defibrillators
A doctor 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.
Complications of Tachycardia
The risk of complications depends on several factors, including:
- Severity and duration of the tachycardia
- Type of tachycardia
- Overall health of the patient
- Other heart conditions patients might 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.
Complications of Tachycardia
The risk of tachycardia complications depends on some of the following factors:
- 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.
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