A. Morsi et al., THE DEVELOPMENT OF SINOATRIAL DYSFUNCTION IN PACEMAKER PATIENTS WITH ISOLATED ATRIOVENTRICULAR-BLOCK, PACE, 21(7), 1998, pp. 1430-1434
The purpose of this paper is the assessment of sinus node competence o
ver time in patients with isolated atrioventricular block (AV block).
Patients implanted with AV synchronous pacemakers for isolated AV bloc
k between December 1993 and June 1995 were prospectively evaluated at
predischarge, 6 weeks, and subsequent 6 months follow-up with respect
to atrial rate monitors/24-hour Holter and modified exercise test. Pat
ients unable to maintain AV synchronous pacing or complete a modified
exercise test were excluded. Sinus node competency is interpreted as:
(1) absence of atrial brady- or tachyarrhythmia, (2) ability to achiev
e a minimum heart rate of 100 beats/min with modified exercise test or
during daily activities. There were 58 patients (22 women), mean age
71.0 +/- 13.8 with an average follow-up of 30.4 months (11-40). Three
patients did not complete a modified exercise test, 4 patients were lo
st to follow-up, and 2 patients were unable to maintain AV synchronous
pacing. Of the remaining 49 patients, 3 developed chronic or paroxysm
al atrial fibrillation. No patient developed significant bradyarrhythm
ias. All patients achieved a heart rate of greater than or equal to 10
0 beats/min modified exercise test. In our group of patients with isol
ated AV block within a moderate follow-up period, development of sinoa
trial dysfunction was rare (6%). A longer follow-up is required to del
ineate the natural history of sinoatrial dysfunction in patients with
isolated AV block.