Methodological Considerations in the NODE‐303 Trial of Etripamil for PSVT

We read with interest the study by Ip et al. which reports results from NODE-303 and shows that self-administered etripamil nasal spray effectively terminates paroxysmal supraventricular tachycardia (PSVT) episodes without requiring prior test dosing [1]. While their study advances our understanding of etripamils clinical utility, we have observed methodological concerns which require discussion to contextualize these findings and to help guide future investigations. First, the single-arm open label approach prevents comparison with placebo or active controls thereby potentially restricting the assessment of true treatment efficacy against natural conversion rates. The PSVT episodes can spontaneously terminate and reported rates show 6%–23% within the first hour [2]. Without a concurrent control group the observed 70.5% conversion rate at 60 min may overestimate etripamil's therapeutic benefit. Future studies should incorporate historical controls or matched cohorts to better isolate drug specific effects. Second, the exclusion rate from the efficacy population raises concerns about selection bias. Of the 1,054 treated episodes only 552 (52.4%) met the criteria for confirmed AV-nodal-dependent PSVT with 31% not having sufficient ECG monitoring data. This high exclusion rate suggests potential systematic differences between analyzed and excluded patients. Which may have potentially inflated the apparent efficacy rates. More rigorous monitoring protocols and intention to treat analyses could strengthen the validity. Third, requiring ECG monitoring device application before treatment may have introduced a temporal bias favoring more sustained episodes. Patients must recognize symptoms, apply monitoring equipment, attempt vagal maneuvers and then self administer etripamil, which is a process likely requiring 5−10 min. Episodes terminating during this interval would be missed potentially selecting for more refractory cases that might respond differently to treatment [3]. Finally, safety assessment was limited by the absence of systematic cardiovascular monitoring beyond ECG rhythm analysis. Nasal adverse effects were well characterized but the comprehensive evaluation of blood pressure, heart rate variability and exercise tolerance could provide a more complete safety profiling given etripamil's calcium channel blocking properties [4]. Despite these limitations, NODE-303 gives valuable evidence supporting etripamils potential role in PSVT management. Addressing these methodological concerns in future studies can strengthen the evidence base for this therapeutic approach. The authors have nothing to report. The authors have nothing to report. The authors declare no conflicts of interest.