What are the non-cardiac causes of tachycardia (rapid heart rate)?

From the Guidelines

Non-cardiac causes of tachycardia include numerous physiological and pathological conditions that increase heart rate without primary cardiac disease, such as fever, anemia, hypoxemia, hypovolemia, pain, anxiety, and stress, as well as endocrine disorders like hyperthyroidism and pheochromocytoma, which can cause persistent tachycardia, as noted in the 2016 guideline for the management of adult patients with supraventricular tachycardia 1.

Common Causes of Non-Cardiac Tachycardia

• Fever: heart rate typically increases by 10 beats per minute for each degree Celsius elevation in body temperature
• Anemia: due to decreased oxygen-carrying capacity requiring increased cardiac output
• Hypoxemia: low oxygen levels in the blood
• Hypovolemia: dehydration or blood loss
• Pain, anxiety, and stress: trigger sympathetic nervous system activation
• Endocrine disorders: hyperthyroidism, pheochromocytoma, and hypoglycemia

Medications and Substances

• Caffeine, nicotine, alcohol withdrawal, sympathomimetics (like albuterol or pseudoephedrine), anticholinergics, and illicit drugs (cocaine, amphetamines) frequently cause heart rate elevation, as mentioned in the context of physiological sinus tachycardia 1

Systemic Conditions

• Sepsis, pulmonary embolism, and anaphylaxis produce tachycardia as part of the body's compensatory response
• Autonomic dysregulation as seen in postural orthostatic tachycardia syndrome (POTS) causes heart rate increases upon standing, characterized by an increase in heart rate of ≥30 bpm during a positional change from supine to standing, as defined in the 2017 guideline for the evaluation and management of patients with syncope 1

Other Considerations

• Pregnancy normally increases resting heart rate by 10-20 beats per minute due to increased metabolic demands
• When evaluating tachycardia, these non-cardiac causes should be considered before attributing the increased heart rate to primary cardiac pathology, emphasizing the importance of a thorough history, physical examination, and eyewitness observation, if available, as highlighted in the guidelines 1

From the Research

Non-Cardiac Causes of Tachycardia

The following are non-cardiac causes of tachycardia:

• Medications/substances such as anti-cholinergic, beta-blocker withdrawal, caffeine, and alcohol 2
• Medical conditions like panic attacks, pulmonary embolism, fever, hyperthyroidism, hypovolemia, anemia, and pain 2
• Non-cardiac drugs that impair cardiac repolarization (electrocardiographic QT prolongation) or depolarization and excitability (electrocardiographic QRS prolongation) 3
• Certain antidepressants like tricyclic antidepressants 4
• Antipsychotic drugs such as clozapine 4
• Antiparkinsonian drugs like pergolide and cabergoline 4
• Glucocorticoids 4
• Antifungal drugs such as itraconazole and amphotericin B 4
• NSAIDs, including selective cyclo-oxygenase (COX)-2 inhibitors 4

Extrinsic Causes of Inappropriate Sinus Tachycardia

Extrinsic causes of inappropriate sinus tachycardia include:

• IgG anti-β receptor antibodies 2
• Certain medications or substances 2

Other Non-Cardiac Conditions Associated with Tachycardia

Other non-cardiac conditions associated with tachycardia include:

• Anxiety disorders 2
• Thyroid disorders such as hyperthyroidism 2
• Dehydration or hypovolemia 2
• Anemia 2
• Pain 2
• Fever 2
• Pulmonary embolism 2