Open AccessDeterminants of Efficacy of Beta‐Blocker Therapy in Patients with Asystole Induced During Head‐up Tilt Testing
Author(s) -
Kouakam Claude,
Lacroix Dominique,
Vaksmann Guy,
Klug Didier,
Jarwe Moustapha,
Mairesse Georges,
Key Christian,
Kacet Salem
Publication year - 1999
Publication title -
annals of noninvasive electrocardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.494
H-Index - 48
eISSN - 1542-474X
pISSN - 1082-720X
DOI - 10.1111/j.1542-474x.1999.tb00226.x
Subject(s) - asystole , medicine , beta blocker , cardiology , anesthesia , bradycardia , heart rate , heart failure , blood pressure
Background: The prognosis and treatment of patients with prolonged asystole during head‐up tilt test (HUT) remain controversial. The aim of this study was to identify factors predicting a favorable outcome in patients with unexplained syncope who have an asystolic response during HUT. Methods: Passive HUT was performed at 60° for up to 45 minutes in 329 patients (162 women and 167 men, mean age 38 ± 22 years). Isoproterenol was given in escalating doses when passive HUT was negative. Asystole was defined as a ventricular pause 5 seconds. Results: Among the 173 patients with positive HUT, 21 developed syncope related to asystole (mean duration 13 ± 7.5 seconds). According to our initial experience, beta‐blocker therapy was used as a first line treatment. At repeat HUT on beta blockers, 16 patients (group I) were partially (n=5) or totally (n=11) controlled by beta blockers, as opposed to 5 patients (group II) in whom asystole remained inducible. Three of them required implantation of a pacemaker and the two others refused. When compared to group I patients, group II patients were older (50 ± 9 vs 24 ± 10 years, P < 0.001) and had a longer asystole duration (22 ± 7 vs 10 ± 5 seconds, P < 0.005) during initial HUT, while spontaneous clinical manifestations were identical. The diagnostic accuracy to predict failure of beta blockers was 83% for age > 40 years, 80% for asystole > 15 seconds and 100% for both. After a follow‐up of 35 ± 11 months, the two patients of group II who refused pacemaker, experienced recurrence of syncope, while the three others remained free of symptoms. Concerning group I, patients successfully managed were asymptomatic, and few episodes of recurrent presyncope were observed in only four of those partially controlled by beta blockers. Conclusions: Prolonged asystole (> 15 seconds) and an older age (> 40 years) both predict a poor response to beta‐blocker therapy in patients with vasovagal syncope referred to as malignant. Satisfactory HUT under beta blockers predict a favorable clinical outcome. A.N.E. 1999;4(4):377–384