What are the other Names for this Condition? (Also known as/Synonyms)

• Inappropriate Sinus Node Tachycardia
• IST (Inappropriate Sinus Tachycardia)
• Non-Physiological Sinus Tachycardia

What is Inappropriate Sinus Tachycardia? (Definition/Background Information)

• Inappropriate Sinus Tachycardia (IST) is a condition characterized by an abnormally fast heart rate at rest or with minimal exertion despite the absence of any underlying medical conditions or identifiable triggers. It is a type of sinus tachycardia that is deemed excessive and disproportionate to the body's requirements
• Inappropriate Sinus Tachycardia is a type of dysautonomia that occurs without any identifiable underlying cause, often resulting from dysfunction in the autonomic nervous system's regulation of heart rate
• The associated signs and symptoms include palpitations, fatigue, shortness of breath, and exercise intolerance. A diagnosis of Inappropriate Sinus Tachycardia involves ruling out other potential causes of tachycardia and assessing autonomic function
• The treatment may include medications, lifestyle modifications, and exercise programs. The prognosis of Inappropriate Sinus Tachycardia varies, with some individuals experiencing improvement in symptoms with treatment, while others may require ongoing management

Who gets Inappropriate Sinus Tachycardia? (Age and Sex Distribution)

• Inappropriate Sinus Tachycardia can affect individuals of any age, including both males and females
• However, it is most commonly seen in young to middle-aged women
• The condition may occur worldwide, affecting individuals of all racial and ethnic groups

What are the Risk Factors for Inappropriate Sinus Tachycardia? (Predisposing Factors)

The exact risk factors for Inappropriate Sinus Tachycardia are not well-established. However, certain factors may contribute to its development, such as:

• Female gender
• History of anxiety or panic disorder
• Previous viral illness or infection

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Inappropriate Sinus Tachycardia? (Etiology)

The precise causes of Inappropriate Sinus Tachycardia are still not fully understood.

• However, it is believed to result from abnormal functioning of the sinus node, which is responsible for initiating the electrical signals that regulate the heart's rhythm
• The dysfunction may be related to disturbances in the autonomic nervous system or abnormalities in the heart's electrical conduction pathways

What are the Signs and Symptoms of Inappropriate Sinus Tachycardia?

The signs and symptoms of Inappropriate Sinus Tachycardia may be mild or severe and can vary from one individual to another. These may include:

• Rapid heart rate (typically exceeding 100 beats per minute at rest)
• Palpitations or awareness of a racing heart
• Fatigue or weakness
• Shortness of breath
• Dizziness or lightheadedness
• Chest discomfort or chest pain (in rare cases)

How is Inappropriate Sinus Tachycardia Diagnosed?

A diagnosis of Inappropriate Sinus Tachycardia may involve the following tests and exams:

• Medical history and symptom assessment: The doctor will inquire about the individual's symptoms, medical history, and potential triggers
• Electrocardiogram (ECG): This test measures the heart's electrical activity and can help identify sinus tachycardia
• Holter monitoring: A portable device is worn to record the heart's activity continuously over 24 to 48 hours, providing more extended monitoring of heart rate patterns
• Exercise stress testing: This test measures the heart's response to physical exertion to evaluate if the heart rate increases excessively
• Laboratory tests and radiological imaging studies, as needed

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Inappropriate Sinus Tachycardia?

The complications of Inappropriate Sinus Tachycardia may include:

• Reduced quality of life: Symptoms of rapid heart rate and associated discomfort can significantly impact an individual's daily activities, leading to decreased quality of life
• Emotional distress: Living with chronic symptoms and uncertainty can cause anxiety and emotional distress

How is Inappropriate Sinus Tachycardia Treated?

The treatment of Inappropriate Sinus Tachycardia may involve the following measures:

• Medications: Beta-blockers, calcium channel blockers, or ivabradine may be prescribed to help control the heart rate and reduce symptoms
• Lifestyle modifications: Stress management techniques, regular exercise, and avoiding triggers, such as caffeine or alcohol, may help manage symptoms

How can Inappropriate Sinus Tachycardia be Prevented?

There are no specific preventive measures known for Inappropriate Sinus Tachycardia. However, managing underlying conditions, maintaining a healthy lifestyle, and adhering to prescribed treatment plans can help minimize symptoms and prevent exacerbations.

What is the Prognosis of Inappropriate Sinus Tachycardia? (Outcomes/Resolutions)

The prognosis of Inappropriate Sinus Tachycardia is generally favorable with appropriate treatment.

• Most individuals can achieve symptom relief and lead normal lives with a combination of medications and lifestyle modifications
• However, the condition can be chronic and may require long-term management

Additional and Relevant Useful Information for Inappropriate Sinus Tachycardia:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/