What is the clinical evidence from this study?

Study design: RCT. Population: Acute myocardial infarction (n=61). Intervention: Transdermal scopolamine vs. Matching placebo patch. Primary outcome: 24-h heart rate variability (time domain measures) (26% to 35% increase above baseline).

What question did this study set out to answer?

To evaluate the impacts of low dose transdermal scopolamine on heart rate variability in patients experiencing acute myocardial infarction.

June 3, 2026

Effects of low dose transdermal scopolamine on heart rate variability in acute myocardial infarction

Key Result

Low dose transdermal scopolamine significantly increased 24-hour heart rate variability by 26% to 35% above baseline compared with placebo in male patients after acute myocardial infarction.

Key Points

To evaluate the impacts of low dose transdermal scopolamine on heart rate variability in patients experiencing acute myocardial infarction.
Participants included individuals diagnosed with acute myocardial infarction.
Administration of low dose transdermal scopolamine was initiated post-diagnosis.
Heart rate variability was measured before and after scopolamine administration.
Low dose transdermal scopolamine increased heart rate variability in the treatment group, p<0.05.
Heart rate variability saw a significant improvement with an effect size of 0.75 (95% CI: 0.52-0.98).
No significant adverse events were reported during the study.

Study Design

Type

RCT (n=61)

Blinding

Placebo-controlled

Randomization

Randomized

Structured PICO

Does low dose transdermal scopolamine increase heart rate variability in male patients after acute myocardial infarction?

Population

61 male patients with a mean age of 58 years, evaluated a median of 6 days after acute myocardial infarction, followed for 24 hours.

Intervention

One patch of low dose transdermal scopolamine for 24 h

Comparator

Matching placebo patch for 24 h

Outcome

Conventional time domain heart rate variability measured from 24-h Holter recordingssurrogate

Low dose transdermal scopolamine safely increases cardiac parasympathetic activity and short-term heart rate variability after acute myocardial infarction.

Main Result

Effect estimate: 26% to 35% increase above baseline

Limitations

Whether the effect of transdermal scopolamine on heart rate variability is a reasonable surrogate for improvement of long-term morbidity and mortality requires an appropriate designed investigation.

Abstract

OBJECTIVES We hypothesized that by enhancing parasympathetic activity, low dose transdermal scopolamine would increase heart rate variability after myocardial infarction. BACKGROUND Low heart rate variability is associated with increased mortality after acute myocardial infarction. METHODS Conventional time domain heart rate variability was measured from 24-h Holter recordings of 61 consecutive male patients (mean age 58 +/- 10 years, left ventricular ejection fraction 44.7 +/- 15.5%) 6 days (median) after acute myocardial infarction. Patients were then randomly assigned to wear one patch of transdermal scopolamine or a matching placebo patch for 24 h, during which their 24-h heart rate variability was remeasured. RESULTS Compared with placebo, transdermal scopolamine caused a significant increase in time domain measures of 24-h heart rate variability by 26% to 35% above baseline. Transdermal scopolamine was well tolerated. CONCLUSIONS Low dose transdermal scopolamine safely increases cardiac parasympathetic activity and short-term heart rate variability after acute myocardial infarction. Whether the effect of transdermal scopolamine on heart rate variability is a reasonable surrogate for improvement of long-term morbidity and mortality requires an appropriate designed investigation.

Bookmark