Sinus Tachycardia

What Is Sinus Tachycardia?

The normal adult resting heartrate ranges from 60 to 100 beats per minute. Tachycardia is the medical term for any heart rate over 100 beats a minute. Sinus tachycardia is when the electrical signals in the heart’s natural pacemaker – the sinoatrial node – cause the heart to beat faster than normal. A common condition, sinus tachycardia is usually caused by stressors such as fear, exercise and dehydration.

If the cause of sinus tachycardia is unknown, the condition is called inappropriate sinus tachycardia. People with inappropriate sinus tachycardia have an increased heart rate without known triggers, even when they are at rest.

Sinus Tachycardia Symptoms

Sinus tachycardia doesn’t always cause noticeable symptoms. When symptoms do occur, they typically don’t last long. Symptoms may include:

• Fast heartbeat
• Palpitations
• Fainting
• Chest pain
• Lightheadedness
• Difficulty breathing.
• Dizziness

Common symptoms of inappropriate sinus tachycardia include:

• Palpitations
• Shortness of breath
• Fatigue
• Low endurance for exercise

What Causes Sinus Tachycardia?

Sinus tachycardia is usually a normal reaction to something stressful, including:

• Intense exercise
• Fear
• Nervousness
• Fever
• Dehydration
• Certain drugs

Other less common causes include:

• Damaged heart muscle
• Anemia
• Heavy bleeding
• Overactive thyroid (hyperthyroidism)

If your doctor rules out these causes, they may diagnose you with inappropriate sinus tachycardia.

Sinus Tachycardia Diagnosis

If you have signs or symptoms of sinus tachycardia, your doctor may order tests to evaluate how your heart is working. These tests may include:

• Electrocardiogram (ECG or EKG): A diagnostic tool that records your heart’s electrical activity on a graph. An ECG detects fast, slow or otherwise abnormal heart rhythms.
• Echocardiogram (or echo): This test uses sound waves to create a moving picture of your heart. In addition to showing the structure of your heart and its valves, the test can reveal areas of poor blood flow through the heart.
• Patch recorder: A patch attached to the chest to capture two weeks of continuous monitoring of the heart’s electrical activity.
• Blood tests: Can check for an overactive thyroid, an electrolyte imbalance or other issues that may cause sinus tachycardia.
• Pulse oximetry: A test that checks how much oxygen is in your blood.
• Chest x-ray: An imaging test that uses X-rays to look at the structures and organs in the chest, including the heart and lungs.

Sinus Tachycardia Treatment

Your doctor will first seek to treat the cause of your sinus tachycardia. Occasional, short-term sinus tachycardia caused by exercise and other known triggers generally doesn’t require treatment. However, your doctor may consider treatment if you have inappropriate sinus tachycardia.

Treatment for inappropriate sinus tachycardia may include:

• Beta blockers
• Calcium channel blockers
• Ivabradine
• Cognitive behavioral therapy (CBT)

In more severe cases that don’t respond to medication or lifestyle changes, your doctor may recommend a cardiac catheter ablation procedure, which involves using small bursts of heat (radiofrequency ablation) or extreme cold (cryoablation) to destroy a tiny part of the heart tissue that causes the sinus tachycardia.