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Low Dose Disopyramide Often Fails to Prevent Neurogenic Syncope During Head‐Up Tilt Testing
Author(s) -
KELLY PATRICIA A.,
MANN DAVID E.,
ADLER STUART W.,
FUENZALIDA CHARLES E.,
REITER MICHAEL J.
Publication year - 1994
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1994.tb02392.x
Subject(s) - disopyramide , medicine , syncope (phonology) , anesthesia , tilt (camera) , cardiology , mechanical engineering , engineering
Low dose disopyramide has been used to prevent neurally‐mediated syncope during head‐up tilt testing but a correlation between blood levels and efficacy has not been described. We measured disopyramide levels in 15 patients with recurrent syncope and positive 70° head‐up tilt tests who underwent one or more repeat tests on the drug. There were 9 males and 6 females, age range 15–78 years. Fourteen of the 15 patients had structurally normal hearts. The daily disopyramide dose was 645 ± 165 mg (mean ± SD). Patients developed syncope during 9 tests and had no syncope during 12 tests. The mean disopyramide level in patients with positive tests was significantly lower than the level in patients with negative tests (2.4 ± 0.15 μ/mL vs 3.2 ± 0.22 μ/mL, P = 0.018). Six patients were tested twice on different disopyramide doses. Five of these six patients had syncope during head‐up tilt testing on the lower dose and negative tests on the higher dose (disopyramide levels 2.2 μ 0.17 μ/mL vs 3.2 μ0.17 fi/mL, P = 0.004). Thus, disopyramide is effective in preventing neurogenic syncope during head‐up tilt testing, but higher blood levels are often necessary for efficacy. In a given patient, failure to respond to low dose disopyramide does not preclude success on higher doses.