“Ghost” Tachycardias: Electrophysiologic Study Diagnostic Approach

Aims: The etiology of palpitations cannot be established from patient‘s history, physical examination and 12-lead electrocardiogram in up to 16% of patients. The value of electrophysiologic study (EPS) in the identification of arrhythmic mechanism in patients with non-documented palpitations remains controversial. We evaluated the diagnostic yield of EPS in this population.
Methods: From January 2000 to December 2014, 76 patients (30 males, mean age 40.8 years old) with history of non-documented palpitations, normal resting ECG and 24h Holter recordings, underwent complete EPS. The clinical and electrophysiologic feautures were evaluated.
Results: The duration of palpitations was 1 hour) in 15.4%. Regarding the frequency of episodes, 13% of patients reported symptoms less often than once at six months, 22.2% had > 1 episodes at six months but less ofetn than 1 at month, 14.8% had >1 episode/month but less than 1/week and 50% had >1 episode/week. A total of 51 patients (67.1%) had inducible tachycardia. Tachycardias were induced with a typical study protocol in 53.9% of patients, after isoproterenol infusion in 9.2% and due to mechanical stimulation in 3.9%. The mean tachycardia’s cycle length was 320±64msec. Atrioventricular nodal reentrant tachycardia (AVNRT) was provoked in 32 patients (42.1%). Atrial tachycardia (AT) as the cause of palpitation was established in 9 patients (11.8%), atrial fibrillation (AF) in 2 patients (2.6%), atrioventricular reentry tachycardia (AVRT) in 2 patients (2,6%), ventricular tachycardia in 2 patients (2.6%) and sinus reentry tachycardia in other 2 patients (2.6%) and 2 patients with both AT and AVNRT. Among the 25 patients without inducible tachycardias, dual pathways at atrioventricular node ± echo beats were identified in 13 patients (17.1% of the total population). No complications related to the procedure were observed in our population study.
Conclusions: EPS constitutes a safe and feasible tool in the diagnostic approach of non-documented palpitations. Of utmost importance, 67% of patients with non-documented palpitations had some form of inducible tachycardias with AVNRT being the most frequent underlying arrhythmic mechanism.