Press Releases

MONTREAL and CHARLOTTE, N.C., Aug. 27, 2026 (GLOBE NEWSWIRE) -- Milestone^® Pharmaceuticals Inc. (Nasdaq: MIST), a biopharmaceutical company focused on the development and commercialization of innovative cardiovascular medicines, today announced findings from a longitudinal study describing how paroxysmal supraventricular tachycardia (PSVT) affects patients’ daily lives and quality of life in the periods between episodes. The findings are being presented in a moderated ePoster session titled “The Impact of PSVT on Patients’ Daily Life and QoL in Between Episodes” at the European Society of Cardiology (ESC) Congress 2026 on August 30, 2026, 15:15-16:00 CET, Station 6, Research Gateway, Hall A1.

“This study’s findings broaden our understanding of the patient experience with PSVT and show that its impact can extend well beyond the acute episode,” said Sean D. Pokorney, M.D., MBA, Assistant Professor of Medicine, Duke University Medical Center and the Duke Clinical Research Institute, and study presenter. “The changes patients reported in activities such as driving, travel and exercise, together with persistent anxiety between episodes, illustrate a burden that is not captured by looking at episode frequency or duration alone.”

PSVT is a common heart rhythm disorder in which the heart suddenly beats very fast affecting an estimated two million people in the United States. The acute symptoms of a PSVT episode are well recognized. However, the impact of living with the condition between episodes has not been well established. This study assessed patient-reported outcomes over nearly a year, capturing how PSVT shaped participants’ activities, emotions, and quality of life outside of a healthcare setting. The results show that many people living with PSVT change their behavior, avoid everyday activities, and carry anxiety with them even when they are not having an episode.

Key Findings

• Approximately two in three patients adjusted their lifestyle between episodes to avoid stress, and nearly 40% reduced their activity or exercise routine because of PSVT.
• 73% of patients reported daytime activity interruption between PSVT episodes.
• Automobile driving (53%) and travel (43%) were the everyday activities for which avoidance between PSVT episodes was most frequently rated as bothersome or extremely bothersome (score of 6 or 7 on a 7-point scale).
• Anxiety persisted between PSVT episodes. Patients reported an average anxiety level of 3.1 on a 7-point scale; 26% of patients reported feeling extremely anxious at some point during the study, and 16% reported the maximum anxiety score at least once.
• Side effects of medications taken chronically (e.g., daily) for PSVT were frequently reported as burdens. Fatigue and weakness were each rated as bothersome or extremely bothersome (6 or 7 on a 7-point scale) by 65% of patients.
• Sleep (30%) and capacity for work (22%) were the most commonly reported areas of lifestyle dissatisfaction (score of 1 or 2 on a 5-point scale).

Conclusions

• PSVT imposes a substantial quality-of-life burden between episodes, affecting anxiety, daily activities, sleep, and work. Medication side effects and activity avoidance further contribute to this burden, underscoring that the impact of PSVT extends beyond acute symptomatic episodes and highlighting an unmet treatment need.
• The authors call for future research to evaluate the quality-of-life impact of at-home, self-administered treatments to terminate PSVT episodes.

The prospective, longitudinal, web-based survey study enrolled 247 adults in the United States and United Kingdom with a self-reported diagnosis of PSVT and no history of catheter ablation at enrollment. Participants completed a baseline survey in February 2019, weekly tracking surveys through December 2019, and a closing survey. During weeks without a PSVT episode, participants completed quality-of-life assessments, including the World Health Organization Quality of Life–Brief Version (WHOQOL-BREF), and answered questions about lifestyle changes, avoidance behaviors, emotional symptoms, and anxiety. Participants had a mean age of 52 years, 72% were female, and the population carried a substantial comorbidity burden. The study was funded by Milestone Pharmaceuticals.

“Better understanding the impact of PSVT on the patients’ daily lives – including between acute events – is important as we consider the management and treatment options which can more fully address the needs of people living with this condition,” said David Bharucha, M.D., PhD, FACC, Chief Medical Officer of Milestone Pharmaceuticals.

About Paroxysmal Supraventricular Tachycardia (PSVT)

An estimated two million people in the United States are currently diagnosed with PSVT, which is a type of arrhythmia or abnormal heart rhythm. PSVT is characterized by episodes of sudden onset rapid heartbeats often exceeding 150 to 200 beats per minute. The heart rate spike is unpredictable and may last several hours. The rapid heart rate often causes disabling severe palpitations, shortness of breath, chest discomfort, dizziness or lightheadedness, and distress, forcing patients to limit their daily activities. The uncertainty of when an episode of PSVT will strike or how long it will persist can provoke anxiety in patients and negatively impact their day-to-day life between episodes. The impact and morbidity from an attack can be especially detrimental in patients with underlying cardiovascular or medical conditions, such as heart failure, obstructive coronary disease, or dehydration. Many healthcare providers are dissatisfied with the lack of effective treatment options, with patients often electing to pursue prolonged, burdensome, and costly trips to the emergency department or even undergo invasive cardiac ablation procedures.

About Milestone Pharmaceuticals

Milestone Pharmaceuticals Inc. (Nasdaq: MIST) is an emerging commercial-stage biopharmaceutical company advancing innovative cardiovascular medicines to benefit people living with certain heart conditions. Milestone’s lead product is CARDAMYST^® (etripamil) nasal spray, a novel calcium channel blocker, which is FDA-approved for the conversion of acute symptomatic episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm in adults. Etripamil is also in Phase 3 development for the control of symptomatic episodic attacks associated with AFib-RVR. https://milestonepharma.com/

Contact:

Investor Relations
Kevin Gardner, kgardner@lifesciadvisors.com

Media Relations
Rebecca Novak, rnovak@milestonepharma.com