What are the causes of sinus tachycardia (increased heart rate)?

From the Guidelines

Sinus tachycardia is primarily caused by physiological responses, medical conditions, and substances that increase heart rate, and addressing the underlying cause is crucial for management, as stated in the 2016 guideline by the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society 1.

Causes of Sinus Tachycardia

The causes of sinus tachycardia can be categorized into:

• Physiological responses: exercise, anxiety, pain, fever, and dehydration
• Medical conditions: anemia, hyperthyroidism, heart failure, pulmonary embolism, and myocardial infarction
• Substances and medications: stimulants (caffeine, nicotine), certain medications (beta-agonists, anticholinergics), recreational drugs (cocaine, amphetamines), and alcohol withdrawal

Management of Sinus Tachycardia

According to the 2016 guideline 1, treating the underlying cause of sinus tachycardia is essential, rather than the tachycardia itself. For example:

• Fever reduction for infection
• Fluid replacement for dehydration
• Discontinuation of stimulants In cases of chronic inappropriate sinus tachycardia without clear cause, beta-blockers like metoprolol or ivabradine may be prescribed to slow the heart rate, as supported by the 2003 guidelines from the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines 1.

Key Considerations

It is essential to note that sinus tachycardia may signal severe underlying pathologies and often requires comprehensive evaluation, as highlighted in the 2003 guidelines 1. Additionally, the body increases heart rate through sympathetic nervous system activation and catecholamine release, which act on cardiac beta-receptors to increase the firing rate of the sinoatrial node. The 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care also emphasize the importance of identifying and treating the underlying cause of sinus tachycardia 1.

From the Research

Causes of Sinus Tachycardia

The causes of sinus tachycardia can be classified into two main categories: secondary to a specific medical condition and related to incompletely defined conditions.

• Secondary causes include:
  • Pulmonary embolism 2
  • Anemia 3, 4
  • Infection 3, 4
  • Hyperthyroidism 3, 4, 5
  • Hypovolemia 4
  • Pain 4
• Incompletely defined conditions include:
  • Inappropriate sinus tachycardia (IST) 4, 6
  • Postural tachycardia syndrome 3
  • Mast cell disorder 3
  • Post-COVID syndrome 3

Extrinsic and Intrinsic Causes

Inappropriate sinus tachycardia (IST) can be caused by either an intrinsic increase in sinus node automaticity or an extrinsic cause.

• Extrinsic causes include:
  • IgG anti-β receptor antibodies 4
  • Medications/substances (such as anti-cholinergic, beta-blocker withdrawal, caffeine, and alcohol) 4
• Intrinsic causes are not well understood, but autonomic dysfunction is considered a central abnormality in IST 6

Other Causes

Other causes of sinus tachycardia include:

• Somatoform disorders 2
• Oral contraceptives 2
• Panic attacks 4
• Fever 4
• Drug abuse 5
• Structural heart disease 5