Causes of Tachycardia at Rest

Introduction

Tachycardia is a condition in which the heart beats faster than normal, typically over 100 beats per minute (bpm) at rest. Understanding its causes is essential for proper diagnosis and treatment.

Common Causes of Tachycardia at Rest

1. Physiological Causes

• Stress and Anxiety – The body's natural response to stress or panic can trigger an increased heart rate.
• Physical Deconditioning – Lack of regular exercise can lead to an elevated heart rate even at rest.

2. Cardiac Causes

• Atrial Fibrillation (AFib) – A common arrhythmia where the heart's upper chambers (atria) beat irregularly and rapidly.
• Supraventricular Tachycardia (SVT) – An abnormal fast heart rhythm originating from the atria or AV node.
• Ventricular Tachycardia (VT) – A dangerous arrhythmia originating from the ventricles, often linked to serious heart conditions.
• Heart Failure – Weakening of the heart muscle can lead to compensatory tachycardia.
• Myocardial Infarction (Heart Attack) – Damage to heart tissues can induce tachycardia as a compensatory mechanism.

3. Endocrine and Metabolic Causes

• Hyperthyroidism – Excess thyroid hormones increase metabolism and heart rate.
• Hypoglycemia (Low Blood Sugar) – Can trigger adrenaline release, leading to tachycardia.
• Electrolyte Imbalances – Low potassium, magnesium, or calcium levels can cause abnormal heart rhythms.

4. Medication and Substance-Induced Causes

• Caffeine and Stimulants – Excessive consumption of caffeine, nicotine, or other stimulants (e.g., cocaine, amphetamines) can speed up the heart rate.
• Medications – Some drugs, such as bronchodilators (used for asthma), decongestants, and certain psychiatric medications, can elevate heart rate.

5. Infections and Systemic Conditions

• Fever and Infections – Conditions like sepsis or severe flu can increase heart rate as the body fights infection.
• Anemia – Reduced oxygen-carrying capacity of blood leads to compensatory tachycardia.

6. Autonomic Nervous System Disorders

• Postural Orthostatic Tachycardia Syndrome (POTS) – Causes an excessive rise in heart rate upon standing.
• Inappropriate Sinus Tachycardia (IST) – A condition where the sinus node fires abnormally fast without an underlying cause.

Conclusion

Tachycardia at rest can arise from many causes, ranging from benign to life-threatening conditions. Proper diagnosis through clinical evaluation, ECG, and blood tests is crucial. If you experience persistent fast heart rates, seek medical advice.

Source recommendations

1. American Heart Association Guidelines on Tachycardia

1. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate
2. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/algorithms
3. https://www.ahajournals.org/doi/10.1161/cir.0000000000000311
4. https://cpr.heart.org/-/media/cpr-files/cpr-guidelines-files/algorithms/algorithmacls_tachycardia_200612.pdf
5. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549

2. European Society of Cardiology Guidelines on Arrhythmias

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
2. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
4. https://pubmed.ncbi.nlm.nih.gov/36017572/
5. https://www.ahajournals.org/doi/10.1161/01.cir.0000091380.04100.84