MIDODRINE - A ROLE IN THE MANAGEMENT OF NEUROCARDIOGENIC SYNCOPE

Objective-To determine the benefit of midodrine, an a agonist, on symp tom frequency and haemodynamic responses during head up tilt in patien ts with neurocardiogenic syncope. Setting-Cardiovascular investigation unit (a secondary and tertiary referral centre for the investigation and management of syncope). Patients-16 outpatients (mean (SD) age 56 (18) years; five men) with frequent hypotensive symptoms (more than tw o syncopal episodes and fewer than 20 symptom free days per month), an d reproducible syncope with glyceryl trinitrate (GTN) during head up t ilt. Design and intervention-Randomised double blind placebo controlle d study. Patients were randomised to receive either placebo or midodri ne 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 r esponse. They received GTN with head up tilt for measurement of heart rate (electrocardiography), phasic blood pressure (digital photoplethy smography), and thoracic fluid index (transthoracic impedance plethysm ography) during symptom provocation. Results-Patients administered mid odrine had an average of 7.3 more symptom free days than those who rec eived placebo (95% confidence interval (CI) 4.6 to 9; p < 0.0001). Ele ven patients reported a positive therapeutic response with midodrine ( p = 0.002). All domains of quality of life showed improvement with mid odrine, in particular physical function (8.1; 95% CI 3.7 to 12.2), ene rgy and vitality (14.6; 95% CI 7.3 to 22.1), and change in health stat us (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 lo wer in patients who received midodrine than in those who were given pl acebo (p < 0.05). A lower thoracic fluid index in patients administere d midodrine indicates increased venous return when supine and during h ead up tilt. There were no serious adverse effects. Conclusions-Midodr ine had a conspicuous beneficial effect on symptom frequency, symptoms during head up tilt, and quality of life. Midodrine is recommended fo r the treatment of neurocardiogenic syncope in patients with frequent symptoms.