A Cautionary Tale on Atrial Capture Management, Biventricular Pacing, and Recurrent Asystole

Capture management algorithms in current cardiac implantable electronic devices (CIEDs) can enhance device performance and battery longevity. Although generally safe, these algorithms have on rare occasions been implicated in the onset of significant complications, especially in pacemaker-dependent patients. CIEDs implanted in patients with postoperative congenital heart disease (CHD) often require epicardial pacing leads rather than transvenous leads; unfortunately, epicardial leads can experience higher rates of malfunction. We herein report on a young adult with a status of postoperative CHD and complete atrioventricular block following implantation of a epicardial dual-chamber cardiac resynchronization therapy pacemaker (CRT-P; Consulta^®; Medtronic, Minneapolis, MN, USA) who developed frequent periods of asystole after malfunction of one of the ventricular leads. The underlying cause of asystole was found to be due to the atrial capture management (ACM) algorithm of the CRT-P device, temporarily converting biventricular to right ventricular–only pacing as part of the algorithm. This case highlights implications of the ACM algorithm in devices with a similar platform for pacemaker-dependent patients.

Long-term outcome of transvenous bipolar atrial leads implanted in children and young adults with congenital heart disease

AIMS

Atrial leads are often implanted in paediatric patients needing a pacemaker (PM). The aim of this study is the evaluation of their outcome in young patients.

METHODS AND RESULTS

We evaluated transvenous atrial leads outcome in children and young adults from a single centre, with a retrospective analysis. A P< 0.05 was considered significant. Between 1992 and 2008, 110 patients, 75 with congenital heart defects (d-transposition of great arteries status/post, s/p, Mustard 41%, atrioventricular septal defect 11%, tetralogy 9%, ventricular septal defect 8%), aged 13.3 ± 5.3 years, underwent PM implantation with bipolar atrial transvenous leads for sinus node dysfunction (50%), atrioventricular block (38%), cardiomyopathies, and primary ventricular arrhythmias (12%). Leads are steroid-eluting (98%), tined (59%), screw-in (41%), polyurethane-insulated (72%), silicone-insulated (28%), and have been positioned by transcutaneous puncture of subclavian vein into right atrial appendage/remnant (RAA, 50%), right atrial free wall/septum (25%), left atrium (s/p Mustard, 25%). Follow-up duration is 6.4 ± 4.8 (range 0.1-18) years. At multivariate analysis, younger age at implant was a risk factor for lead failure (4 leads, 3.5%) (P= 0.03); 16 leads (14%) dislodged post-implantation and 12 were successfully repositioned, the others extracted or abandoned. Dislocation occurred more frequently with screw-in leads (P= 0.03) positioned outside RAA (P= 0.02). Atrial threshold showed a small but significant increase, 0.002 V/month (P< 0.001), impedance showed a decrease (0.6 Ω/month, P< 0.001), P-wave showed no significant difference.

CONCLUSIONS

Transvenous bipolar atrial leads have good long-term results in young patients, with a very low rate of lead failure. Older age at implant can further reduce this rate. Lead dislodgement is frequent in the post-operative period.