Following an exhaustive aetiological investigation, 10 to 26% of syncopal attacks remain unexplained. In these cases the correlation between symptoms and rhythm is a deciding step for the aetiological diagnosis. We report our initial experience using an implantable electrocardiographic monitor, a new diagnostic tool in patients suffering from syncope and recurrent unexplained syncopal attacks.
Results: The study included 32 patients (average age 55 +/- 22 years; 23 males) suffering from syncope and/or recurrent syncopal attacks remaining unexplained following an exhaustive aetiological investigation. The average follow up was 10.2 +/- 2.5 months. No case of sudden death was registered, and the device was removed in only one patient due to poor tolerance. During follow up, 21 recordings were memorized and analysed in 15 patients (45%), giving an average of 1.4 recordings per patient. The average interval for recurrence of symptoms after implantation was from 84 +/- 104 days, 75% of the episodes coming in the first 2 months following implantation. An arrhythmia was detected on 10 occasions: a malignant ventricular arrhythmia in 2 patients, a non-sustained ventricular tachycardia in 1 patient, a junctional tachycardia in 1 patient, entry into paroxysmal atrial fibrillation in 4 patients, a sinus bradycardia in 1 patient, and a sinus pause for 19 seconds in 1 patient. In one patient ST segment depression was documented following anterior chest pain. The tracing was normal with sinus rhythm recorded on 10 occasions, representing the only documented information in 4 patients. In total, an aetiology was found in 11 of the 32 patients evaluated (34%). Once the aetiological diagnosis was established and a specific treatment initiated, all the patients became asymptomatic.
Conclusions: Our preliminary results underline the significance of the implantable ECG monitor in the diagnostic approach to recurrent unexplained syncopal attacks. The exact place of this tool in the decisional algorithm for syncope remains to be defined with further studies.