What is Inappropriate Sinus Tachycardia or IST?
IST is a complex heart condition that occurs in otherwise healthy younger people and causes rapid heart rates of over 100 bpm, even at rest.
Common symptoms of inappropriate sinus tachycardia include:
- Palpitations - fluttering or pounding sensations in your chest
- Chest discomfort
- Weakness or dizziness
- Lightheadedness or fainting
- Shortness of breath
- Fatigue
- Anxiety
- Exaggerated response to exercise or stress
These symptoms can affect day-to-day activities and can diminish one’s quality of life. There are currently no FDA-approved therapies to treat inappropriate sinus tachycardia. However, a hybrid sinus node sparing ablation is being studied as a potential new treatment option for patients who suffer from symptomatic, drug-resistant or intolerant IST.
How POTS Differs from IST
Postural Orthostatic Tachycardia Syndrome (POTS) is another type of heart condition. Although patients with POTS can experience similar symptoms to inappropriate sinus tachycardia like lightheadedness, shortness of breath, fatigue and anxiety, a key difference between POTS and IST is resting heart rate. Individuals with POTS typically have a resting heart rate of 90 bpm or less, whereas those with IST have a resting heart rate usually greater than 100 bpm.
Dr. Rani Kronenberger (University Hospital, Brussels, Belgium) describes key differences between IST and POTS and introduces the hybrid ablation procedure to treat IST.