New Onset of AV- Nodal Reentrant Tachycardia (AVNRT) in the elderly – an uncommon diagnosis?

Abstract

\n \n \n Arrhythmias in elderly patients (>70 years) are common in daily clinical practice. Most frequently, they are based on atrial fibrillation or other atrial tachycardia with an indication for oral anticoagulation and specific antiarrhythmic medications. The electrographic (ECG) documentation related to symptoms is essential before therapy initiation. In case of suspected AVNRT based on surface ECG, an electrophysiological study (EP) with ablation as curative strategy should be planned.\n \n \n \n We analysed all patients >70 years with AVNRT diagnosed by electrophysiologic (EP) studies between May 2018 and December 2020.\n \n \n \n An EP study for suspected AVNRT was performed in 27 patients >70 years. The diagnosis of AVNRT was confirmed in 20 patients (75%). From all EP- studies with the diagnosis of AVNRT (n=93) in this period, 20 patients (22%) were older than 70 years (mean age 77 years with a range of 70–85 years), 12 were women. In most of the patients, the duration of symptoms was short (3 month). Only 4 patients had symptoms of paroxysmal tachycardia longer than 10 years. Except for 2 patients, all patients had at least one ECG- documentation (12- lead- ECG, Holter- ECG, telemetric ECG and/or in the loop recorder). In 12 patients, a 12- lead- ECG- documentation was available, in 5 patients the tachycardia has been registered in the Holter-ECG and in 1 in a loop recorder. In the 12- lead- ECG before ablation in sinus rhythm the PQ interval was with 196 (120- 300) ms in the upper range. In 16/ 20 patients was during the EP- study a sustained AVNRT (CL 410, 314- 538 ms) inducible. In the others, up to 3 typical AV- nodal- echo beats were induced in the EP- study. A slow pathway ablation/ modification was performed in all patients in typical position. In 2 patients, the implantation of a dual- chamber- pacemaker was necessary due to intermittent high- degree AV-nodal-block during the same hospital stay. In both patients, a first degree AV-block with PQ- interval of 250 and 300 ms was pre-existing.\n \n \n \n Especially for the elderly patients with new onset of clinical symptoms of arrhythmia, clinical anamnesis including an ECG- documentation is required for planning the therapeutic strategy. A borderline long PQ- interval as sign of an age- dependent fibrosis in the AV- node and, therefore, altered conduction properties in the AV node can be a cause of AVNRT in these older patients. In patients with pre-existing long PQ- interval (>250 ms), the risk of pacemaker implantation after successful ablation is higher. In this group of patients, medical therapeutic options are limited and often associated with the need of pacemaker implantation.\n \n \n \n Type of funding sources: None.\n