Abstract
Aims
Various mode-switching algorithms are available with different tachyarrhythmia detection criteria to be satisfied to initiate mode-switching. This study evaluated three different mode-switching algorithms in patients with paroxysmal atrial fibrillation.
Methods and Results
Seventeen patients completed the study. Three mode-switching algorithms were downloaded as software into the pacemaker, each for 1 month in a single-blind, randomized sequence. The criteria to initiate mode-switching were: mean atrial rate (‘standard’), ‘4-of-7’ or ‘1-of-1’ atrial intervals to exceed the atrial detection rate. Symptoms for each were measured using the Symptom Checklist–Frequency and Severity index.
The median number of mode-switch episodes increased from 20 for ‘standard’ to 39 for ‘4-of-7’ (P=0·029 vs ‘standard’) and 103 for ‘1-of-1’ (P=0·0012 vs ‘standard’) onset criteria. Median duration of episodes decreased from 2·5 min with ‘standard’ to 1·4 min with ‘4-of-7’ and 0·4 min with ‘1-of-1’ onset criteria. Frequency of symptoms was lower using ‘4-of-7’ (18·2±12·0 vs 23±12·0, P=0·08) or ‘1-of-1’ (20·4±12·4 vs 23±12·0, P=0·07) than ‘standard’ onset criteria. Severity of arrhythmia tended to be less with either ‘4-of-7’ (16±10·4 vs 19·1±19·4, P=0·12) or ‘1-of-1’ (17·5±10·3 vs 19·1±9·4, P=0·18) than with ‘standard’ onset criteria.
Conclusions
The more sensitive onset criteria for detection of atrial tachyarrhythmias were associated with lower frequency and severity of symptoms.
AV node ablation and implantation of mode switching dual chamber pacemakers: effective treatment for drug refractory PAF
