Midodrine: a role in the management of neurocardiogenic syncope.
OBJECTIVE
To determine the benefit of midodrine, an alpha agonist, on symptom frequency and haemodynamic responses during head up tilt in patients with neurocardiogenic syncope.


METHODS
Cardiovascular investigation unit (a secondary and tertiary referral centre for the investigation and management of syncope).


METHODS
16 outpatients (mean (SD) age 56 (18) years; five men) with frequent hypotensive symptoms (more than two syncopal episodes and fewer than 20 symptom free days per month), and reproducible syncope with glyceryl trinitrate (GTN) during head up tilt.


METHODS
Randomised double blind placebo controlled study. Patients were randomised to receive either placebo or midodrine for one month. Symptom events were recorded during each study month. At the end of each study month patients completed a quality of life scoring scale (Short Form 36) and a global assessment of therapeutic response. They received GTN with head up tilt for measurement of heart rate (electrocardiography), phasic blood pressure (digital photoplethysmography), and thoracic fluid index (transthoracic impedance plethysmography) during symptom provocation.


RESULTS
Patients administered midodrine had an average of 7.3 more symptom free days than those who received placebo (95% confidence interval (CI) 4.6 to 9; p < 0.0001). Eleven patients reported a positive therapeutic response with midodrine (p = 0.002). All domains of quality of life showed improvement with midodrine, in particular physical function (8.1; 95% CI 3.7 to 12.2), energy and vitality (14.6; 95% CI 7.3 to 22.1), and change in health status (22.2; 95% CI 11 to 33.4). Fourteen patients who were given placebo had tilt induced syncope compared with six given midodrine (p = 0.01). Baseline supine systolic blood pressure was higher and heart rate lower in patients who received midodrine than in those who were given placebo (p < 0.05). A lower thoracic fluid index in patients administered midodrine indicates increased venous return when supine and during head up tilt. There were no serious adverse effects.


CONCLUSIONS
Midodrine had a conspicuous beneficial effect on symptom frequency, symptoms during head up tilt, and quality of life. Midodrine is recommended for the treatment of neurocardiogenic syncope in patients with frequent symptoms.
Ward
C R
CR
Cardiovascular Investigation Unit, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
Gray
J C
JC
Gilroy
J J
JJ
Kenny
R A
RA
D000316:Adrenergic alpha-Agonists / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002307:Cardiography, Impedance; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D008879:Midodrine / Q000627:therapeutic use*; D019462:Syncope, Vasovagal / Q000188:drug therapy*; D018667:Tilt-Table Test
D000316:Adrenergic alpha-Agonists; D008879:Midodrine