[Permanent atrial resynchronization by synchronous bi-atrial pacing in the preventive treatment of atrial flutter associated with high degree interatrial block].

UNLABELLED: Interatrial conduction block results in a very delayed and retrograde activation of the left atrium and is associated with a high incidence of atrial tachyarrhythmias, especially a particular (and specific) form of atypical atrial flutter. Electrophysiologic studies have suggested that these arrhythmias were usually due to reentry and could be directly related to the conduction disturbances in the atrium. If so, we can expect reasonably that permanent atrial resynchronization resulting from simultaneous pacing in different target sites in the atria, may not only correct for interatrial dysynchrony, but also may significantly contribute to prevent arrhythmia recurrences. Twenty-eight patients, mean age 68 years, were included. The mean P wave duration in spontaneous sinus rhythm was 181 +/- 28 ms. In all patients, many recurrences of atrial tachyarrhythmia were documented, especially a specific form of atypical atrial flutter. Medical therapy was constantly ineffective. Three different pacing modes were used: 6 patients, with normal A-V conduction were implanted with a SSI device, programmed in AAT mode and connected, using a Y bifurcated connector, to two atrial leads, one positioned in the right atrium, the second one into the coronary sinus-in 14 patients, with A-V conduction defects, a conventional DDDR unit was implanted and connected to a composite biatrial electrode and a ventricular lead. In that configuration atrial resynchronization was only effective on paced atrial cycles -a specific DDD Chorus ELA Medical device with a special algorithm loaded into the RAM memory was implanted in 14 patients (8 new indications, and 6 patients first implanted with a DDDR unit).
RESULTS: during sinus rhythm atrial resynchronization induced a reduction of the P wave duration from 181 +/- 28 ms to 116 +/- 12 ms. During permanent pacing the mean value decreased from 209 +/- 38 ms to 108 +/- 13 ms. During follow-up (34 +/- 15 months) arrhythmia prevention was assessed by history, by monthly surface ECG's and by bimonthly 24 hours Holters recordings and telemetric interrogation of the pacemaker statistics. Twenty-one patients did not experienced any recurrence of arrhythmia. One to three recurrences occurred in the other seven patients, including six patients implanted with a conventional DDDR unit. These preliminary results seem validate the new concept of atrial resynchronization for prevention of atrial arrhythmia associated with interatrial conduction block.