Implantable loop recorder for recurrent syncopes

Syncope is a common disorder which may recur and impair the survival and the quality of life of the patients. The objective of the investigation of syncope is to diagnose the cardiac etiology, as mortality rate is high. Implantable loop recorder or insertable cardiac monitor (ICM) is a useful tool to establish a correlation between syncope and heart rhythm. About half of implanted patients complain of a new syncope and about 50% of these patients had cardiac rhythm disturbances on ICM. The most frequent is a sinus bradycardia or sinus arrest, but these results depend on the age of patients, resting electrocardiography (ECG) abnormalities and structural cardiac disease. A classification of the mechanisms of recurrent syncopes has been defined with the results of the ISSUE study, separating the syncope due to primary cardiac arrhythmia from neurally-mediated syncope and from unknown syncope. The analysis of the presyncopal phase on the ICM restored ECG allows physicians to adapt the treatment (antiarrhytmic agents or pacemaker) and optimize the programming of the pacemaker when necessary. It is early recommended to implant the ICM in patients affected with syncope with normal physical examination, normal ECG and without structural heart disease and negative tilt testing. In the presence of cardiac disease, it is recommended to implant ICM after performing an electrophysiological study and tilt testing. In syncope patients with depressed left ventricular ejection fraction, the implantation of an automatic implantable cardiac defibrillator is preferable. The indications of the ICM tend to be extended to new syncope populations such as pediatric patients and epileptic population. Early application of ICM reduces the cost of the investigation of the patients suffering from syncope, especially when the electrophysiological study is avoided. In the future the implantation of the ICM should be early discussed in the Syncope Unit to shorten the duration and the cost of the hospitalizations of the patients with recurrent syncopes.