People with IST also experienceheart palpitations, fatigue, lightheadedness, or exercise intolerance.
IST symptoms can be debilitating and mimic conditions likeanemia,hyperthyroidism, and side effects of medication.
It is diagnosed after ruling out other causes.
Verywell / Lara Antal
This article discusses inappropriate sinus tachycardia.
What Is Inappropriate Sinus Tachycardia?
Tachycardia is a medical term for a fast heartbeat.
Inappropriate means it occurs outside of situations that would normally cause a rapid heart rate.
Sinus refers to the sinus node, the cardiac structure that controls thenormal heart rhythm.
An elevated heart rate is just one aspect of inappropriate sinus tachycardia, however.
Additional uncomfortable and sometimes debilitating symptoms are what differentiates IST from regular tachycardia.
An estimated 90% of people with IST experience heart palpitations.
See Your Healthcare Provider
Symptoms of inappropriate sinus tachycardia warrant medical attention.
Causes of Sinus Tachycardia
The main cause of IST is not yet known.
Studies show IST often first occurs after a precipitating event.
Still, some physicians are unfamiliar with it and may misdiagnose it as anxiety.
Get our printable guide for your next doctor’s appointment to help you ask the right questions.
Additionally, controlling the heart rate does not necessarily improve symptoms.
Treatments for IST may include drug therapy, non-drug therapy, or both.
Sometimes, no treatment is needed.
Drug Therapy
In some patients with IST, drug therapy can be helpful.
However, achieving optimal results often requires trial-and-error attempts with several medications, singly or in combination.
Ivabradine directly affects the firing rate of the sinus node, thereby reducing the heart rate.
Beta-Blockers
Beta-blockersare another category of drugs used to treat IST.
Calcium Channel Blockers
Calcium channel blockers(CCB) can directly slow the action of the sinus node.
They work by preventing calcium from entering the muscle cells of the heart and arteries.
This helps to relax and open up narrowed blood vessels, thereby reducing heart rate.
These drugs may include:
Sometimes, more than one medication is needed to treat IST symptoms.
Non-Drug Therapy
The following drug-free treatments may be used alongside medications or on their own.
Lifestyle Factors
Your healthcare provider may recommend making lifestyle changes to avoid things that may trigger episodes of tachycardia.
Drink water or electrolyte drinks to maintain adequate fluid and salt intake.
Dehydration can worsen IST symptoms.
Wearing compression socks, stockings, tights, and other pressure garments is also recommended for symptom relief.
Exercise Training
Another non-drug way to treat IST is exercise training.
CBT will not cure IST, nor does it aim to.
Sinus node ablation has so far achieved only limited success.
Waiting
One reasonable non-pharmacologic approach to managing IST is to do nothing.
Doing nothing may not be an option in people who are severely symptomatic.
Summary
Inappropriate sinus tachycardia causes uncomfortable symptoms associated with an increased heart rate.
It is four times more common among those assigned female at birth and often affects younger adults.
Heart palpitations, dizziness, chest pain, and fatigue that accompany IST can be debilitating.
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