Outcome of patients with syncope beyond the implantable loop recorder.
OBJECTIVE
The implantation of an implantable loop recorder (ILR) leads to the diagnosis in about 35% of patients with syncope of unknown origin. Information on outcome of patients in whom a diagnosis is not reached during the lifetime of the device is scarce. The aim of our study is to determine the outcome of these patients in terms of syncope recurrence and survival.


RESULTS
An ILR was implanted to 97 patients with syncope of unknown origin. Patients were classified in groups A and B depending on their high or low risk, respectively, of having arrhythmic syncope. Diagnosis had not been reached in 60 patients (62%) when the ILR battery reached end operational life. Five patients were lost to follow up. During a median follow-up of 48 months after ILR explantation (interquartile range 36-56), 22 patients (40%) had recurrence of syncope (32% in group A vs. 48% in group B, P = 0.3). Syncopes with no neurally mediated profile were more frequent in group A (18 vs. 0%, P = 0.05) and neurally mediated profile syncopes were more frequent in group B (44 vs. 11%, P = 0.007). Five patients died, four of them in group A and 1 in group B (P = 0.4). No sudden or cardiac deaths were detected during follow-up. All deaths were due to non-cardiac causes.


CONCLUSIONS
Recurrent syncope is common in patients in whom a diagnosis is not established after the full battery life of an ILR. The prognosis of these patients seems to be good, without observed sudden or cardiac death.
Cardiology Department, Hospital Clínico Universitario Valencia, Blasco Ibanez, 17, Valencia 46010, Spain. pilarmerlos@gmail.com
Pilar
P
Merlos
Eva
E
Rumiz
Ricardo
R
Ruiz-Granell
Ángel
Á
Martínez
Maria Teresa
MT
Izquierdo
Ángel
Á
Ferrero
Eloy
E
Dominguez
Juan Miguel
JM
Sánchez
Salvador
S
Morell
Roberto
R
García-Civera
D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D015716:Electrocardiography, Ambulatory / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012008:Recurrence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology; D016019:Survival Analysis; D015996:Survival Rate; D013575:Syncope / Q000175:diagnosis* / Q000401:mortality*