Does an implantable loop recorder improve diagnostic yield in patients with unexplained syncope compared to conventional testing?
Implantable loop recorders provide a high diagnostic yield (up to 85%) for unexplained syncope, potentially outperforming conventional short-term monitoring and testing.
Syncope is a complex symptom with multiple potential etiologies that can be difficult to establish. The major obstacles to diagnosis are the periodic and unpredictable nature of events and the high spontaneous remission rate. Short-term ECG monitoring often is unproductive when initial noninvasive testing is negative due to the low probability of recurrence during the brief monitoring period. Implantable loop recorders extend the ability to monitor cardiac patients, enhancing the diagnostic yield to as high as 85% in difficult to diagnose syncope. Several recent studies suggest that prolonged monitoring with an implantable loop recorder has a role in patients with syncope and conduction disturbances, negative tilt testing, and unexplained seizures, and may be superior to conventional testing with tilt and electrophysiologic studies.
Krahn et al. (Mon,) studied this question.