In a new study from the San Diego School of Medicine of the University of California, researchers found that a remedy used for heart failure improves the symptoms associated with postural orthostatic tachycardia syndrome, otherwise known as POTS. This complicated, debilitating disorder affects the autonomic nervous system of the body and causes a high heart rate, usually when standing.
Subscribe to the online issue of February 15, 2021 Journal of the American College of Cardiology, study authors investigated the drug ivabradine and its effects on heart rate, quality of life and plasma norepinephrine levels in people living with POTS. Norepinephrine is a stress hormone and neurotransmitter. In blood plasma, it is used as a measure of sympathetic nervous system activity. Participants in the trial experienced a decrease in heart rate, improvement in their symptoms and overall quality of life a month after using the drug.
“Ivabradine is a new drug approved by the FDA for heart failure, but based on its mechanism, we thought it might be helpful for patients with POTS, as it lowers the heart rate without affecting blood pressure,” Pam said. Taub, managing director, cardiologist of the Cardiovascular said. Institute at UC San Diego Health and Associate Professor of Medicine at the UC San Diego School of Medicine. “If we can lower the heart rate, we offer these patients the opportunity to stand up, something they previously could not do without problems due to their POTS diagnosis.”
The study involved 22 individuals whose mean age was 32 years. Each participant was screened and recruited from cardiology clinics at UC San Diego Health from 2018 to 2020.
The study used a randomized, double-blind, placebo-controlled crossover design in which patients started on ivabradine or placebo for one month. At the end of the month, all participants underwent a washout period where no drug or placebo was taken for one week. After flushing time, participants who had previously received ivabradine switched to placebo for one month and vice versa.
During the two months, patients also met with researchers for seven different clinic visits in which plasma norepinephrine levels were measured and a side-by-side test was done to observe the patient’s heartbeat when sitting, lying down or getting up.
“Before the study, these patients with an increased heart rate would live between 100 and 115 beats per minute when standing,” Taub said. ‘After taking ivabradine twice daily for a month, the standing heart rate decreased significantly to about 77 beats per minute compared to the placebo group. Participants also showed an improvement in quality of life while using the drug. ‘
The researchers also noted that ivabradine is well tolerated without significant side effects, while other drugs used to lower heart rate, such as beta blockers, can cause fatigue and blood pressure.
Taub said the study was the first randomized clinical trial using ivabradine to treat POTS.
POTS is usually caused by a viral infection, trauma, surgery or forced bed rest, and is most common in young women who are either athletes or very active. Currently, there is no FDA-approved treatment for POTS, and the condition can seriously affect quality of life. Other symptoms of POTS include ‘brain fog’, lightheadedness, palpitations, tremor, weakness, dull face and fatigue.
POTS has recently been identified as a potential ‘long-term’ symptom of COVID-19.
“In our current practice, we see that patients previously infected with COVID-19 have symptoms similar to POTS,” said Jonathan Hsu, MD, cardiologist at UC San Diego Health. “Given the similarities, this study raises the question of whether treatment with ivabradine could help patients experiencing similar symptoms after a COVID-19 infection and also provide an important area for future study.”
The authors said they hope ivabradine will be considered as a possible treatment option for those with a confirmed diagnosis of POTS. Currently, the drug has not been approved by the FDA for the disease, and if used clinically, it has been used as a ‘non-label’.
“Similar to patients with COVID-19, patients with POTS should be closely monitored,” Taub said. “The treatment of POTS should be personalized for each individual and with this drug, coupled with lifestyle therapy, including exercises specific to POTS, we hope that more individuals will overcome this unfortunate condition.”
Reference: February 15, 2021, Journal of the American College of Cardiology.
DOI: 10.1016 / j.jacc.2020.12.029
Co-authors include: Adena Zadourian, Hannah C. Lo, Cameron K. Ormiston and Shahrokh Golshan, all at UC San Diego.
Disclosure: Pam Taub has served as a consultant for Amgen, Bayer, Esperion, Boehringer Ingelheim, Novo Nordisk and Sanofi and is co-founder of Empirium Bio. Jonathan Hsu serves as a consultant for Medtronic, Abbott, Boston Scientific, Biotronik, Biosense Webster, Zoll Medical, Pfizer, Bristol Myers Squibb and Janssen Pharmaceuticals.