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Midodrine for Prevention of Vasovagal Syncope
Quick Takes
- Oral midodrine significantly decreased the proportion of recurrent syncope, in young healthy individuals with vasovagal syncope, when it was administered in conjunction with guideline-directed teaching about lifestyle risk reduction.
- Those most likely to benefit are younger patients with a high syncope burden who do not have hypertension or contraindications to midodrine.
- The study was limited by its small size, an observation period that was brief relative to the condition's long duration, the restriction of the study to young and otherwise healthy participants, and the high proportion of patients from one center.
Study Questions:
Can midodrine prevent the recurrence of vasovagal syncope?
Methods:
This was a randomized, double-blind, placebo-controlled clinical trial, which included patients aged ≥18 years, had a Calgary Syncope Symptom Score of ≥2, and had fainted at least twice in the year before enrollment. Patients were randomly assigned 1:1 to placebo or midodrine and followed for 12 months. The primary outcome measure was the proportion of patients with ≥1 syncope episode during follow-up. Secondary analyses included the frequency of syncope and time to first syncope recurrence, using time-to-event analysis, censoring patients if they were lost to follow-up for any reason before a first syncope.
Results:
The study cohort comprised 133 patients who had a median of six syncope episodes in the prior year (median age, 32 years; 73% female). Compared with patients receiving placebo, fewer patients receiving midodrine had ≥1 syncope episode (28 of 66 [42%] vs. 41 of 67 [61%]). The relative risk was 0.69 (95% confidence interval [CI], 0.49-0.97; p = 0.035). The actuarial syncope event rates over 1 year were 46.0% in the midodrine group and 67.3% in the placebo group (log-rank p = 0.031). The absolute risk reduction was 19 percentage points (CI, 2-36 percentage points), and the number needed to treat to prevent one patient from having syncope was 5.3 (CI, 2.8-47.6). The time to first syncope was longer with midodrine (hazard ratio, 0.59; CI, 0.37-0.96; p = 0.035; log-rank p = 0.031). Adverse effects were similar in both groups.
Conclusions:
The authors concluded that midodrine can reduce the recurrence of syncope in healthy, younger patients with a high syncope burden.
Perspective:
Although this study comprises a small sample size and the follow-up period was about 12 months, the findings are important because midodrine may be helpful in one out of five patients with recurrent syncope. Also important to note, the side effect profile of midodrine appears to be similar to placebo. Until more data are available, the findings of this study suggest that midodrine will be an important therapeutic option in the management of recurrent syncope.
Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Congenital Heart Disease and Pediatric Cardiology, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, CHD and Pediatrics and Arrhythmias, CHD and Pediatrics and Prevention, CHD and Pediatrics and Quality Improvement, Hypertension
Keywords: Arrhythmias, Cardiac, Hypertension, Life Style, Midodrine, Outcome Assessment, Health Care, Recurrence, Risk Reduction Behavior, Secondary Prevention, Syncope, Syncope, Vasovagal, Young Adult
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