Tachycardia

Definition

Tachycardia is a condition characterized by a heart rate that exceeds the normal resting rate. Generally, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. It is a type of cardiac arrhythmia.

Causes

Tachycardia can be caused by several factors, including:

Cardiac diseases: Conditions such as high blood pressure and poor blood supply to the heart muscle due to coronary artery disease, heart valve disease, heart failure, heart muscle disease (cardiomyopathy), tumors, or infections can lead to tachycardia.
Lung diseases: Certain conditions such as pulmonary embolism or chronic obstructive pulmonary disease (COPD) can also cause tachycardia.
Electrolyte imbalances: Certain substances, mainly potassium, sodium, calcium, and magnesium, are needed for proper electrical signaling in the heart. Imbalances in these substances can increase the risk of tachycardia.
Overactive thyroid (Hyperthyroidism): An excess of thyroid hormone can also increase the heart rate.

A close-up image of a heart with a focus on the rhythmic contractions and expansions.

Symptoms

The symptoms of tachycardia can vary depending on the severity of the condition. Some people may have no symptoms or signs, while others may experience:

Shortness of breath
Rapid pulse rate
Heart palpitations — a racing, uncomfortable or irregular heartbeat or a sensation of "flopping" in the chest
Chest pain (angina)
Lightheadedness or fainting (syncope)
Sudden weakness
Fatigue

Diagnosis

The diagnosis of tachycardia can be done using various methods:

Electrocardiography (ECG): This is the most common test for diagnosing tachycardia. It involves the use of electrodes that are attached to the skin to measure the electrical impulses given off by the heart.
Holter monitoring: This test involves wearing a portable device that records all of the heart's activity for a full 24-48 hour period.
Echocardiography: This test uses sound waves to create a moving picture of the heart, allowing doctors to see if it's pumping properly.

Treatment

Treatment for tachycardia depends on the cause, the severity of symptoms and complications, and the overall health of the patient. It may include:

Vagal techniques: These simple maneuvers stimulate the vagus nerve, which can slow transmission of electrical signals through the atrioventricular (AV) node of the heart.
Medication: Certain medications can help regulate the heartbeat. These include beta-blockers, calcium channel blockers, and antiarrhythmics.
Cardioversion: In this procedure, a shock is delivered to the heart through paddles or patches on the chest to reset the heart's rhythm.
Catheter ablation: This procedure involves inserting a tube into an artery through the groin and threading it to the heart to deliver energy that can destroy the area of heart tissue causing the rapid heartbeat.

Prevention

Prevention of tachycardia primarily involves the reduction of risk factors, such as:

Maintaining a healthy weight
Regular exercise
Quitting smoking
Limiting caffeine and alcohol
Eating a healthy diet
Reducing stress and anxiety