Researchers at University of Virginia Health have identified a potential new treatment for postural orthostatic tachycardia syndrome (POTS) using ivabradine, an established heart failure medication. The pilot study, published in the Journal of Cardiovascular Pharmacology, suggests that controlling heart rate may be key to managing this debilitating condition that affects primarily young women.
Study Demonstrates Significant Symptom Improvement
The research team treated 10 POTS patients with ivabradine, with participants averaging 28 years of age and 8 of 10 being women. Results showed dramatic improvements in the condition's hallmark symptom: excessive heart rate increases upon standing.
Prior to treatment, patients' heart rates jumped by an average of 40 beats per minute when standing. After taking ivabradine, this increase was reduced to only 15 beats per minute. Additionally, participants reported a 69% decrease in feeling faint and a 66% decrease in chest pain.
"These data suggest that the inappropriate increase in heart rate is exactly why patients feel sick, and that reducing the heart rate with a medication that does not affect blood pressure can make a difference in the quality of life," said senior researcher Dr. Antonio Abbate, a cardiologist at University of Virginia Health.
Mechanism Reveals New Understanding of POTS
The study findings support a new understanding of how POTS symptoms develop. Researchers suspect that standing triggers an excessive release of norepinephrine, the "fight or flight" hormone, in POTS patients, causing the heart to race.
"The mechanisms controlling heart rate with standing appear to be dysfunctional, leading to an excessive increase in heart rate, which is in turn sensed by the brain as a 'danger' signal leading to further release of stress hormone, norepinephrine, and to symptoms that resemble anxiety and panic attacks," Abbate explained. "When the heart rate is controlled with ivabradine, the loop is inhibited and patients feel better."
This mechanism challenges previous assumptions about POTS. "Once considered to be purely a compensatory mechanism secondary to low blood pressure, the high heart rate may itself be responsible for the symptoms," Abbate noted.
Addressing Diagnostic Challenges
POTS affects 1% or less of the general population but has gained attention on social media platforms like TikTok. Many patients struggle to obtain proper diagnosis due to the condition's unclear etiology and complex presentation.
"Patients go doctor to doctor because the primary care may not be familiar or know what to do. The cardiologist thinks it is not a heart problem – and it indeed it is not," Abbate said. "The neurologist says there is no issue with the brain – and indeed there isn't. It's really a 'software' problem rather than a 'hardware' issue."
Treatment Implications and Future Research
Ivabradine (Corlanor) works by affecting the heart's electrical activity to slow heart rate without impacting blood pressure. The drug is already approved for preventing heart failure progression, which could facilitate faster implementation for POTS treatment.
"Being that this medication is already available, and we know a lot about the safety, we may just continue to treat some patients with this medication," Abbate noted.
However, researchers emphasize that larger studies are needed to confirm these preliminary findings. The next step involves conducting a randomized, double-blind, controlled clinical trial with some patients receiving ivabradine while others receive placebo to determine broader efficacy.
The study was conducted collaboratively between researchers at UVA Health and Virginia Commonwealth University, representing a significant step forward in understanding and treating a condition that has long challenged both patients and healthcare providers.
