13th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 1998

January 24-31, 1998
Marilleva, Trento, Italy

RT-35

Role of serial head-up tilt testing for assessing therapy in patients with neurally mediated syncope

Maria Stella Fera, Alessandro Carunchio, Andrea Mazza, Maurizio Burattini, Maria Margherita Martinelli, Vincenzo Ceci.
Division of Cardiology, S. Spirito Hospital, Rome, Italy

Abstract

Objectives. This study sought to evaluate in patients with unexplained syncope: 1. the diagnostic value of basal and potentiated with nitrates head-up tilt test (HUTT); 2. the efficacy of the prophylactic treatment guided by serial HUTT.

Methods. Ninety-four patients with history of syncope (S) and 43 asymptomatic control subjects underwent HUTT at 60° for 45 min without medication, if S did not develop, the patients received sublingual nitroglycerin and continued to be tilted for further 20 min. The patients with positive HUTT were randomized in 2 groups: Group A - chronic oral treatment with metoprolol (M) or ethylephrine (E) based on a HUTT performed 10 days after the start of the treatment: the patients were followed-up with the drug effective in preventing S or with the last drug tested; Group B - the patients were followed up with placebo. During the follow-up were considered the recurrences of S.

Results. Out of a hundred and thirty-seven patients fifty-five had positive HUTT [51/94 (54%) and 4/43 (9%) of control subjects]. During the drug-free phase 31/51 patients (61%) and 1/43 control subjects had positive HUTT; after nitroglycerin administration S occurred in further 20 patients and 3 control subjects. Sensitivity and specificity of drug free phase HUTT were, respectively, 33% and 98%, after nitroglycerin was 54% and 91%. Twenty-eight patients were randomized to guided therapy (Group A): 15/28 patients treated with M, HUTT remained positive in 3 patients; 13/28 treated with E, HUTT remained positive in 5 patients. In total, the HUTT remained positive in 8 patients (29%) and negative in 20 patients (71%). Gr. B (placebo) consisted of 27 patients. During the follow-up (20 ± 6 months) S recurred in 6/28 patients in Group A (21%) and in 7/27 patients in Group B (26%) p = ns. Out of 8 patients in Group A with positive HUTT, S recurred in 4 patients (50%) vs 2/20 patients (10%) with negative HUTT p < 0.05. The positive and negative predictive values of the serial HUTT were 50% and 90%.

Conclusions. Nitroglycerin significantly increases the sensitivity of the HUTT. During a long-term follow-up we have observed low incidence of S in pts treated with therapy evaluated by serial HUTT as well as placebo group, likely because pts are instructed to recognize prodromal symptoms before the episode with subsequent measures to prevent S.

Key Words

Syncope
head-up tilt testing, nitroglycerin, OA