Key result
Ivabradine lowers heart rate and improves physical and social functioning vs placebo in hyperadrenergic POTS.
Why the study?
Postural orthostatic tachycardia syndrome impairs functional status and quality of life, but current pharmacological treatments are limited.
Does ivabradine reduce heart rate and improve quality of life in patients with hyperadrenergic POTS?
RCT (n=22)
Double-blind
Crossover
Does ivabradine reduce heart rate and improve quality of life in patients with hyperadrenergic POTS?
p-value: p=<0.001
Ivabradine safely and effectively reduces heart rate and improves quality of life in patients with hyperadrenergic POTS.
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Among patients with hyperadrenergic POTS, ivabradine was associated with an improvement in heart rate and some quality of life measures (physical functioning and social functioning). Standing norepinephrine levels were also marginally improved with ivabradine. Although this was a small trial, the use of ivabradine for this challenging condition seems reasonable.”
“It is not clear why the authors studied only the hyperadrenergic population, and this unfortunately limits the evidence-based use of ivabradine. As well, the apparent effects of ivabradine on the sympathetic response to orthostatic stress may simply be a sampling error, and unquestionably deserves further study.”
“The editorialists also pointed out that standing heart rate in the placebo phase was only 94 beats/min, suggestive of only mild POTS. Most study participants technically did not experience POTS during the study, which raises the question of whether ivabradine was actually tested in people with active POTS, they said.”
Offers viable option for hyperadrenergic POTS; extends ivabradine evidence beyond heart failure.
BACKGROUND Postural orthostatic tachycardia syndrome (POTS) is a complex, multifaceted disorder that impairs functional status and quality of life. Current pharmacological treatments are limited. OBJECTIVES This study investigated the effect of ivabradine (selective blocker of the Ifunny channel in the sinoatrial node) on heart rate, quality of life (QOL), and plasma norepinephrine (NE) levels in patients with hyperadrenergic POTS defined by plasma NE >600 pg/ml and abnormal tilt table test. METHODS In total, 22 patients with hyperadrenergic POTS as the predominant subtype completed a randomized, double-blinded, placebo-controlled, crossover trial with ivabradine. Patients were randomized to start either ivabradine or placebo for 1 month, and then were crossed over to the other treatment for 1 month. Heart rate, QOL, and plasma NE levels were measured at baseline and at the end of each treatment month. RESULTS The average age was 33.9 ± 11.7 years, 95.5% were women (n = 21), and 86.4% were White (n = 23). There was a significant reduction in heart rate between placebo and ivabradine (p < 0.001). Patients reported significant improvements in QOL with RAND 36-Item Health Survey 1.0 for physical functioning (p = 0.008) and social functioning (p = 0.021). There was a strong trend in reduction of NE levels upon standing with ivabradine (p = 0.056). Patients did not experience any significant side-effects, such as bradycardia or hypotension, with ivabradine. CONCLUSION Ivabradine is safe and effective in significantly improving heart rate and QOL in patients with hyperadrenergic POTS as the predominant subtype.
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Taub et al. (2021) conducted an RCT in Hyperadrenergic postural orthostatic tachycardia syndrome (POTS) (n=22). Ivabradine vs. Placebo was evaluated on Heart rate (p=<0.001). Ivabradine significantly reduced heart rate (P<0.001) and improved physical (P=0.008) and social functioning (P=0.021) compared to placebo in patients with hyperadrenergic POTS.
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