Inappropriate sinus tachycardia is a condition where the heart beats faster than normal with no obvious cause. Treatments include lifestyle changes, medication, and possibly catheter ablation.
Your heart has an electrical system that controls the rhythm and rate your heart beats, and it’s set by electrical impulses from what’s known as the sinus node.
There are many reasons people may experience tachycardia, from stress to anemia to hyperthyroidism. When tachycardia has no obvious explanation, it’s called inappropriate sinus tachycardia or IST.
IST is rare. Researchers believe that just
What’s happening: The sinus node in the heart sends electrical signals that make the heart beat faster than normal. This is called an arrhythmia, which is a disorder of the heart that affects its rhythm.
Again, tachycardia can be caused by things like stress, exercise, or different health conditions. When your resting heart rate is high without an obvious underlying cause, it’s considered IST.
Not everyone experiences IST the same way. Your heart rate may be high at rest and during exercise. It may increase with or without any changes in position. Your heart rate may even be normal at times.
It’s the average heart rate that doctors use to make a diagnosis.
When the heart beats faster than it should, it may have trouble pumping enough blood through the body, leading to symptoms. You may feel a bit off. Your heart may beat fast or hard inside your chest even if you’re just sitting in a chair watching TV.
That said, not all people have symptoms with IST.
Typical symptoms include:
Still, symptoms can significantly affect a person’s daily activities.
But IST is not generally a sign of a more serious condition. If it occurs after a virus, it may only last a short period of time. In young, otherwise healthy people, IST may persist for 5 years or longer with no long-term health effects.
Yes, some people may develop IST after having COVID-19 or another virus.
Both postural orthostatic tachycardia syndrome (POTS) and IST may impact
Diagnosing inappropriate sinus tachycardia is made by exclusion. This means that your doctor will only diagnose IST after ruling out (or excluding) other conditions that also cause abnormal heart rhythms.
At your appointment, your doctor will ask about your symptoms and health history, as well as give you a physical exam.
Additional tests may include:
IST is treated through lifestyle changes, medications, and certain medical procedures. If you are not experiencing symptoms, however, treatment may not be necessary.
Avoiding potential triggers is the first approach doctors use to treat IST.
You may try:
- consuming less caffeine or alcohol
- quitting smoking or using other nicotine products
- engaging in regular physical activity
- drinking plenty of fluids with appropriate levels of salt and electrolytes
Your doctor may suggest ivabradine. This drug works by slowing electrical currents that increase heart rate. For example, ivabradine can slow a mean heart rate of 100 BPM down to 75 BPM.
Ivabradine is taken by mouth, typically 5 milligrams (mg), twice a day. Your dose may be adjusted up to 7.5 mg or decreased as needed.
Other potential options may include:
- Beta-blockers: These medications block the effects of adrenaline on the heart.
- Calcium channel blockers: These drugs treat high blood pressure.
Still, these medications are not effective for all people.
In cases where anxiety may be contributing to symptoms, your doctor may prescribe:
If IST does not respond to lifestyle measures or medications, your doctor may suggest catheter ablation.
While you are under sedation, your cardiologist will thread a catheter through a blood vessel and into your heart. Electrodes on the catheter’s tip apply energy (heat) to the areas of the heart that are causing the tachycardia, reducing the heart rate.
Ablation can be
Speak with your doctor to create an exercise plan that works best for you.
In general, you’ll want to start gradually and increase the intensity and duration of your workouts slowly. The key is to engage in movement — both cardio and strength training — that you can tolerate without becoming symptomatic. Then, build from there.
Make an appointment with your doctor if you experience an elevated heart rate at rest, particularly if you have other symptoms of IST. Early identification and treatment can help ease symptoms and improve your quality of life.
If you are not experiencing symptoms, it’s still important to note your tachycardia. IST may go away on its own with time but should be monitored closely by your doctor.