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Pacemaker dependence in transient high-grade atrioventricular block
Insights
Pacemaker dependence can persist even after recovery from high-grade atrioventricular block. Patients with recovered conduction often remain pacemaker-dependent, highlighting the need for continued pacing.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- High-grade atrioventricular block necessitates pacemaker implantation.
- Assessing pacemaker dependence after conduction recovery is clinically important.
Observation:
- Prospective study of 16 patients with recovered atrioventricular conduction after pacemaker implantation.
- Six patients developed recurrent high-grade atrioventricular block during long-term follow-up (median 62 months).
- Five additional patients with bradycardia pacemakers showed dependence despite recovered conduction (median 7 months).
Findings:
- Pacemaker dependence was observed in patients even after recovery of atrioventricular conduction.
- Recurrence of atrioventricular block was not linked to specific patient characteristics or follow-up duration.
- Conventional methods may underestimate pacemaker dependence in these patients.
Implications:
- Clinical assessment of conduction defect prognosis is limited in patients with recovered spontaneous rhythm.
- Discontinuation of pacing is not advised, even with sustained conducted heart rhythm.
- Bradycardia-indicating pacemakers frequently demonstrate dependence in patients with recovered conduction.
Abstract:
In a prospective study 16 patients who had been given a pacemaker because of symptomatic high-grade atrioventricular block and whose conduction had been recovered were checked for their dependence on the pacemaker. During a follow-up time ranging from 32 to 158 months (median 62 months) six patients proved to be dependent on the device owing to the development of recurrent stable high-grade atrioventricular block. The subsequent return of atrioventricular block was evidently not associated with etiology, age, sex, ECG-pattern or length of follow-up period. Five additional patients equipped with a bradycardia-indicating pacemaker all proved to be pacemaker-dependent after a follow-up time ranging from 1-20 months (median 7 months), even though atrioventricular conduction had recovered and its presence had been confirmed at regular outpatient checks. It is thus evident that the conventional clinical methods are of limited value for examining the course of conduction defect and assessing the prognosis for patients whose spontaneous cardiac activity has returned after periods of symptomatic high-grade atrioventricular block. When a bradycardia-indicating pacemaker was furnished, pacemaker dependence was demonstrated in most of the patients whose atrioventricular conduction had recovered. This confirms that pacing introduced because of symptomatic high-grade atrioventricular block should not be discontinued even if a conducted heart rhythm has been established and maintained for long periods.