Key Points about inappropriate sinus tachycardia
- Inappropriate sinus tachycardia (IST) is characterized by an abnormally fast heart rate (over 100 bpm) without a clear cause.
- The condition can cause symptoms like palpitations, dizziness and shortness of breath, especially with normal activities.
- IST is often triggered by autonomic nervous system dysfunction or hormonal imbalances, like hyperthyroidism.
- Diagnosis involves an ECG, Holter monitor and blood tests to rule out other causes.
- Treatment may include medications like beta-blockers, stress management and in some cases, catheter ablation.
Common related conditions
Inappropriate sinus tachycardia causes
Inappropriate sinus tachycardia may be caused by:
- Overactivity of the sinus node (the heart’s natural pacemaker).
- Dysfunction in the autonomic nervous system, which controls the heart rate.
- Hormonal imbalances, such as those found in hyperthyroidism.
- Chronic stress or anxiety, which can exacerbate symptoms.
- Certain medications or stimulants that elevate the heart rate.
Inappropriate sinus tachycardia risk factors
Risk factors for IST include:
- Female gender, as the condition is more common in women, particularly young adults.
- A history of stress, anxiety, or panic disorders.
- Thyroid conditions, particularly hyperthyroidism.
- A family history of arrhythmias or related heart conditions.
- Use of stimulant medications or recreational drugs.
Inappropriate sinus tachycardia symptoms
Common symptoms of IST include:
- A consistently high heart rate, typically over 100 beats per minute, even when at rest.
- Palpitations or the feeling of your heart racing.
- Dizziness or lightheadedness, especially with physical activity.
- Shortness of breath, fatigue, or reduced exercise tolerance.
- Chest discomfort or tightness in some cases.
Inappropriate sinus tachycardia diagnosis
To diagnose IST, doctors will often use:
- An electrocardiogram (ECG or EKG) to detect an elevated heart rate and rule out other arrhythmias.
- A Holter monitor to track the heart's activity over a 24-hour period and capture episodes of tachycardia.
- Blood tests to check for thyroid issues or other potential contributing factors.
- Sometimes autonomic function testing to evaluate the nervous system's role in heart rate regulation.
Inappropriate sinus tachycardia treatment
Treatment for IST can include:
- Medications like beta-blockers or calcium channel blockers to help control heart rate.
- Treatment of underlying conditions, such as hyperthyroidism, if applicable.
- Stress reduction techniques, such as relaxation exercises, yoga, or meditation.
- In severe cases, catheter ablation may be considered to modify the activity of the sinus node.
When to Seek Care
Seek medical care if you experience:
- A persistently fast heart rate, especially if it's causing palpitations, dizziness, or shortness of breath.
- New or worsening symptoms that interfere with daily activities.
- Any discomfort or chest pain associated with a rapid heart rate.
- Difficulty exercising or increased fatigue that you haven't experienced before.