Study population
We enrolled 13 patients, 10 males (76.9%), with a median age of 51 (42 - 63) years. Nine patients (69.2%) were symptomatic (syncope / pre-syncope related to bradyarrhythmia) and the remaining four patients were asymptomatic (#2, #6, #10 and #11) (table 1). The diagnosis was transient high-grade AV block in three patients (one had also sinus arrest), cardioinhibitory syncope in two patients and sinus arrest in eight patients. The mean ECG heart rate (HR) was 55 (45 - 61), beats per/minute (bpm) (table 2) and the PQ interval on 12 lead ECG among patients was 180 (170 - 220) ms. Four out of eight patients with sinus arrest had also sinus bradycardia and four had brady-tachy syndrome with paroxysmal atrial fibrillation (table 1).
The longest pause (either for sinus arrest or AV block) was 7000 (4000 - 10000) ms. Regarding assessment on 24-hour Holter monitoring, minimal HR was 34 (26 - 43) bpm and mean HR 65 (47 - 72) bpm.