Empirical slow pathway modulation: clinical and procedural characteristics as well as long term follow-up

Abstract

Introduction: Atrioventricular nodal reentrant tachycardia (ANVRT) is the most common supraventricular tachycardia (SVT). First line treatment is the radiofrequency (RF) modulation of the slow pathway (SPM). For patients with a typical history in whom AVNRT is non inducible, the current guidelines give a Class 2 recommendation for empirical SPM (ESPM) under the precondition that both, dual nodal pathway physiology (DNP) and a surface ECG compatible with AVNRT exist. This recommendation is based on small series of patients. Patient population and outcome: Out of 2927 patients who underwent SPM at our institution between 1994 and 2012, we included 223 patients who clinically suffered from SVT but had no inducible SVT. We here present data on 63 of these patients who received a long term follow-up. Follow up of the remaining 160 patients is under way and will be completed by the end of 2012. 73% of the 63 patients (27 male; 36 female; mean age 51±2 yrs) had an ECG documentation of SVT. Programmed atrial stimulation during electrophysiological study revealed DNP in 91% of patients by occurrence of either an AH jump (n=33) or 1 or 2 echo beats (1 echo beat: n=37; 2 echo beats: n=13). Presence of an accessory pathway was excluded in all cases. In 97% of all patients either ECG documentation existed or DNP was present. ESPM was performed in all patients. No severe complications occurred in any of the patients. A telephone questionnaire was conducted for long term follow up (mean follow up interval 29±3 months). 44% of all patients reported to be free of symptoms. 48% of the patients reported an improvement of symptoms in at least one of the following criteria; duration, intensity or frequency of arrhythmia events. 8% had experienced no improvement. Out of those patients with ECG documentation only, but absence of DNP (n=9), 6 were free of symptoms and 3 reported improvement of symptoms. Out of those patients with DNP but absence of ECG documentation (n=15), 6 reported freedom from symptoms, 8 reported improvement of symptoms and 1 did not benefit at all. Conclusion: Our data show that empiric slow pathway modulation is a safe procedure that improves clinical symptoms in the majority of patients during long term follow up. This also seems to apply for cases where there is no DNP but a characteristic ECG documentation, and vice versa.