Tachycardia refers to a fast resting heart rate, usually over 100 beats per minute. Tachycardia can be dangerous, depending on its underlying cause and on how hard the heart has to work.
Some people with tachycardia may have no symptoms or complications. However, tachycardia significantly increases the risk of stroke, sudden cardiac arrest, and death.
What is tachycardia?
The heart consists of two ventricles and two atria. Tachycardia occurs when these beat too fast.
Tachycardia refers to a high resting heart rate.
In general, a resting adult heart beats between 60 and 100 times per minute. When an individual has tachycardia, the upper or lower chambers of the heart beat significantly faster.
When the heart beats too rapidly, it pumps less efficiently and blood flow to the rest of the body, including the heart itself, is reduced.
Because the heart is beating quicker, the muscles of the heart, or myocardium, need more oxygen. If this persists, oxygen-starved myocardial cells can die, leading to a heart attack.
Atria, ventricles, and the electrical circuitry of the heart
The human heart consists of four chambers:
Atria: These are the two upper chambers.
Ventricles: These are the two lower chambers
There are left and right atria and ventricles.
The heart has a natural pacemaker called the sinus node. It is located in the right atrium. The sinus node produces electrical impulses. Each one triggers an individual heartbeat.
The electrical impulses leave the sinus node and go across the atria, making the atria muscles contract. This atria muscle contraction pushes blood into the ventricles.
The electrical impulses continue to the atrioventricular (AV) node, a cluster of cells. The AV node slows down the electrical signals, and then sends them on to the ventricles.
By delaying the electrical signals, the AV node is able to give the ventricles time to fill with blood first. When the ventricle muscles receive the electrical signals, they contract, pumping blood either to the lungs or the rest of the body.
When there is a problem with the electrical signals resulting in a faster-than-normal heartbeat, an individual has tachycardia.
Tachycardia is generally caused by a disruption in the normal electrical impulses that control our heart’s pumping action – the rate at which our heart pumps. The following situations, conditions, and illnesses are possible causes:
a reaction to certain medications
congenital abnormalities of the heart
consuming too much alcohol
consumption of cocaine and some other recreational drugs
heart disease which has resulted in poor blood supply and damage to heart tissues, including coronary artery disease, heart valve disease, heart failure, heart muscle disease, tumors, or infections
an overactive thyroid gland
certain lung diseases
Sometimes, the medical team may not be able to identify the exact cause of the tachycardia.
Treatment options vary, depending on the cause of the condition, the age and general health of the person with tachycardia, and other factors.
The aim of treatment is to address the cause of the tachycardia. When clinically applicable, the doctor may try to slow the rate, prevent subsequent episodes of tachycardia, and reduce risk complications.
In some cases, all that is required is to treat the cause. In other cases, no underlying cause is found, and the doctor may have to try out different therapies.
Ways to slow down a fast heartbeat
There are a variety of ways to treat tachycardia.
The vagal nerve helps regulate our heartbeat. Maneuvers that affect this nerve include coughing, heaving (as if you were having a bowel movement), and placing an ice pack on the person’s face.
Antiarrhythmic drugs can be administered orally or by injection. They restore a normal heartbeat. This is done in a hospital.
Available drugs restore normal heart rhythm, control the heart rate, or both. Sometimes an individual will need to take more than one antiarrhythmic drug.
Paddles or patches are used to deliver an electric shock to the heart. This affects the electrical impulses in the heart and restores normal rhythm. This is carried out in a hospital.
There are certain measures that can prevent a heartbeat becoming too fast or escalating into a health problem.
Radiofrequency catheter ablation
Catheters enter the heart via blood vessels. Electrodes at the ends of the catheter are heated to ablate, or damage. the small sections of the heart responsible for the abnormal heartbeat.
When taken regularly, anti-arrhythmic medications can prevent tachycardia. A doctor may prescribe other medications to be taken in combination with antiarrhythmics, for example, channel blockers, such as diltiazem (Cardizem) and verapamil (Calan), or beta-blockers, such as propranolol (Inderal) and esmolol (Brevibloc).
Implantable cardioverter defibrillator (ICD)
A device that continuously monitors the heartbeat is surgically implanted into the chest. The ICD detects any heartbeat abnormality and delivers electric shocks to restore normal heart rhythm.
Sometimes, surgery is needed to remove a section of tissue. The surgeon may create a pattern of scar tissue. Scar tissue is a bad conductor of electricity. This procedure is generally only used when other therapies have not been effective, or if the person has another heart disorder.
Warfarin makes it harder for the blood to clot and is given to individuals with a high or moderate risk of developing stroke or heart attack. Although Warfarin increases the risk of bleeding, it is prescribed for people whose risk of stroke or heart attack is greater than their risk of bleeding.
The following signs and symptoms of tachycardia are possible:
a fast pulse
low blood pressure
shortness of breath
It is not unusual for some cases with tachycardia to cause no symptoms at all. In such cases, the condition is typically discovered when the individual has a physical examination.