167 Cinical impact of the implantable loop recorder on patients with isolated syncope, bundle branch block and a negative work-up including an electrophysiological study. A prospective randomized study

Abstract

Little is known in patients with isolated syncope, bundle branch block[BBB], and a negative work-up including an electrophysiological study [EPS]. Norandomized study exists in this subset of patients comparing a strategy of waiting and the implantable loop recorder (ILR). The aim of this multicenterprospective study was to evaluate in a population with BBB and a negative EPS: [1] the prognosis impact of an ILR [group I] compared with the waiting clinical follow-up approach [group II]; [2] the incidence of relevant electrical events. From January 2005 to December 2009, 78 pts were included. The mean follow-up was 19 ± 12 months. Population characteristics were: mean age of 76 ± 8 years old; 30 female [38.5%]; 18 cardiomyopathy [23%]; previous AFib [15.4%]; LVEF [56.5 ± 11%]; ECG abnormalities [34 left BBB;11 right BB and 33 bifascicular block] and a negative EPS [mean HV interval of 55 ± 6 ms]. Seventeen pts [22%] developed a significant arrhythmic event: 1 ventricular tachycardia [1.3%], 1 sudden death [1.3%], 2 AV block II [2.6%], 8 AV block III [10.25%] and 5 sick sinus syndrome [6.4%]. The number of events detected was significantly different between ILR group [n = 13; 16.6%] and clinical follow-up [n = 4; 5.1%]; (p = 0.02). The Kaplan-Meier estimates of the probability of remaining free of arrhythmia events and the Logrank test [Figure]. In accordance with the final diagnosis, 15 patients received a pacemaker therapy. This randomized prospective study found that in patients with isolated syncope, BBB and a negative EPS, the % of arrhythmic events is close to 22% at 2 years. A strategy with an ILR is superior to the clinical follow-up for detecting recurrent events and may influence the prognosis of these patients.