Tachycardia, often defined as a resting heart rate of above 100 beats per minute, is an abnormally fast heart rate. Resting tachycardia is where the resting heartbeat remains too high, whereas, during exercise, the heartbeat can be normal or might go up temporarily with stress and anxiety. This could occur either in a healthy individual or in a person with existing heart conditions or other general medical problems.

Tachycardia is the heart's reaction to inappropriate electrical impulses. The sinoatrial (SA) node is essentially the heart's natural pacemaker that determines its rhythm. When, however, the electrical impulses in the heart start working out of rhythm or erratically, the heart can begin to pump too quickly. This may compromise the heart's efficiency and prevent it from delivering enough oxygen-rich blood to the body's organs and tissues.

Several kinds of tachycardia prevail and include:

• Atrial tachycardia: It arises from the atria, which is the upper chamber of the heart.
• Ventricular Tachycardia: This comes from the ventricles, which are the lower chambers of the heart. This could be a more dangerous condition because the complications of instant cardiac arrest happen.
• Supraventricular tachycardia (SVT): This condition affects the upper chambers but sometimes leads to fast heartbeats spreading to the ventricles.
• Sinus tachycardia: The heart pumps at a faster rate than normal but with a regular rhythm.

Causes of tachycardia

There are many causes of tachycardia. Some causes are benign or lifestyle- or short-term physiological state-related, while others signal an underlying medical condition. Major causes include:

• Heart disease: Structural anomalies in the heart, coronary artery disease, high blood pressure (hypertension), heart failure, or a history of heart attack all contribute to tachycardia.
• Electrolyte imbalance: The heart usually requires a fine balance of electrolytes such as potassium, calcium, and magnesium to maintain a normal rhythm. An imbalance in these electrolytes may result in abnormal rhythms.
• Overactive thyroid /hyperthyroidism
• Fever and infection
• Substances: Caffeine, nicotine, and others like cocaine stimulate heart rate. Medication, including decongestants and beta-agonists, in asthma treatment also stimulates tachycardia.
• Emotional stress or anxiety
• Physical activity.

Tachycardia symptoms

Tachycardia symptoms vary depending on the severity, type and duration of a tachycardia episode. Some will feel no discomfort, while others may experience all forms of discomfort. Some of the most common symptoms include:

• Palpitations
• Dizziness or lightheadedness
• Chest pain
• Fainting (syncope)

Diagnosis of Tachycardia

A cardiologist should diagnose tachycardia. The diagnosis involves the following:

• Electrocardiogram (ECG)
• Holter monitor
• Event monitor
• Echocardiogram
• Blood tests such as thyroid disturbances, electrolyte disturbances, or infection might suggest the underlying symptoms of tachycardia.

Management of tachycardia

Treatment of tachycardia varies according to the cause, severity, and overall health of the patient. Lifestyle modifications may be enough for causes such as stress, caffeine, or stimulants, but more often than not, beta-blockers, calcium channel blockers, or antiarrhythmic drugs are required to regulate heart rate and restore a normal cardiac rhythm.

Surgical procedures

• Ablation with a catheter: This is a minimally invasive procedure, which means it does not require surgical incision. The catheter is inserted into the body through blood vessels and guided until it reaches the heart, where it destroys small patches of tissue causing the abnormal rhythm.
• ICDs/Implantable devices: For patients with serious conditions, especially ventricular tachycardia, ICDs can be inserted to monitor your heart and correct life-threatening arrhythmias.
• Surgery: Scars can be surgically induced on the heart tissue, again with a maze procedure, but this time making a pattern that will prevent abnormal electrical signals.