By Olivia Trani 

A new study led by researchers at Virginia Commonwealth University and UVA Health has shown that a medication used to treat heart problems may also help patients with Postural Orthostatic Tachycardia Syndrome (POTS), a condition that causes an abnormal heart rate increase when standing up.  

The drug, ivabradine, is typically used to treat chronic heart failure by slowing the heart rate without impacting blood pressure. In an analysis of patients with POTS, the research team found that the drug reduced their heart from racing while improving other symptoms, such as chest pain, fatigue and lightheadedness. The results from the study, published in the Journal of Cardiovascular Pharmacology, also shed new light on the underlying causes of the syndrome.  

“Our findings suggest that, for some patients with POTS, the high heart rate could potentially be a key driver of the disease rather than just a symptom,” said Justin M. Canada, Ph.D., an associate professor in the VCU School of Medicine’s Department of Internal Medicine and the VCU Health Pauley Heart Center and one of the study co-authors. “While more research is needed, these results provide promising insights into how we may be able to better help patients with this condition.”  

Other co-authors of the study from VCU include Georgia Thomas, M.D., Ph.D., an assistant professor in the School of Medicine’s Department of Internal Medicine and hospitalist at VCU Health, and Roshanak Markley, M.D., a noninvasive cardiologist at the Pauley Heart Center.  

Canada spoke with VCU Health News about what these new results tell us about the future of treatment for this condition.  

What is POTS, and how does it typically develop?

POTS is a syndrome with a constellation of symptoms that occur when a patient changes body positions, typically when they stand up after lying down or sitting. When the patient stands, they often experience an exaggerated increase in heart rate, which can lead to dizziness, lightheadedness, shortness of breath, chest pain and fatigue. This condition often makes people more reluctant to participate in their usual daily activities or exercise.  

People with POTS – who are predominantly young women – often develop the condition after experiencing a viral infection or other acute illness or injury. Following the COVID-19 pandemic, there has been an increase in people diagnosed with this syndrome.  

How is POTS treated? 

Currently there isn’t a well-defined pathway for treating this condition. Patients with POTS are not always impacted in the same way, which is why it’s important to have different treatment options available.  

Patients are often treated with medications to help control their heart rate, like beta blockers, however these medications also lower their blood pressure, which can exacerbate POTS symptoms. Sometimes patients are given medicines to maintain or increase blood pressure if they’re at risk of blood pressure decreasing.  

Patients are also encouraged to be vigilant about their hydration, as well as have adequate salt intake to maintain blood volume.  

How does the medication ivabradine work? What did this new study reveal about ivabradine’s effect on POTS symptoms? 

Unlike other drugs used for heart conditions, ivabradine can lower a patient’s heart rate without directly impacting blood pressure, which makes it a promising drug candidate for helping patients with POTS.  

In this study, we analyzed clinical data from 10 patients diagnosed with POTS and treated with ivabradine. Before treatment, the patients’ heart rate would increase by 40 beats per minute (bpm) on average when standing. After taking the medication, their heart rate increased by only 15 bpm on average, without significant changes in blood pressure. The patients also experienced improvements in other symptoms, such as less instances of chest pain, lightheadedness, dizziness and shortness of breath.  

What else does this study tell us about POTS? 

The underlying causes of these symptoms are still debated by the medical community, with some believing that the increased heart rate associated with POTS may be a biological response to compensate for low blood pressure.  The improvements patients experienced after taking ivabradine without any changes in their blood pressure suggest that, in some forms of POTS, the high heart rate may potentially be a component of the disease rather than just a symptom. This high heart rate could potentially occur as a result of dysregulation of the central nervous system.  

This research is still in its early stages, and our team is looking to conduct more clinicals studies to better understand POTS and assess ivabradine’s impact on patients.

The researchers involved in this study were supported by funding from the National Heart, Lung, and Blood Institute of the National Institutes of Health. 

What is POTS? VCU Health experts who study the complex disorder explain its causes and how they care for patients living with it.

Read more heart health stories on the Pauley Heart Center Blog