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Atrial resynchronization in patients after heart transplantation
Andrzej Kutarski1, Michał Zakliczyński, Krzysztof Oleszczak
1Dept. of Cardiology, University Medical Academy, Lublin, Poland. a_kutarski@yahoo.com
Annals of Transplantation
|November 6, 2002
Summary
Recipient sinus node pacing can help select heart transplant patients with sinus node dysfunction. However, donor atrium pacing is more effective due to frequent electrical changes in the recipient atrium.
Area of Science:
- Cardiology
- Transplantation Medicine
- Biomedical Engineering
Background:
- Orthotopic heart transplantation (OHT) frequently utilizes the Lower-Shumway technique, resulting in patients with two atria and two sinus nodes.
- Sinus node dysfunction (SND) is a common complication post-OHT, necessitating innovative pacing solutions.
Purpose of the Study:
- To assess the feasibility of using the recipient's sinus node as a biosensor for triggered pacing of the donor atrium in OHT patients with SND.
- To evaluate the pacing and sensing capabilities of the recipient atrium in these patients.
- To conduct a long-term observation of the efficacy of the atrioatrial (A2A2T(/D)) pacing mode.
Main Methods:
- 10 out of 37 OHT patients received A2A2T or A2A2T/D pacing systems.
- For patients with a normal sinus rhythm (NSR) in the recipient atrium, frequency acceleration was evaluated during exercise and with atropine administration.
Main Results:
- Only 15 of 37 patients exhibited NSR in the recipient atrium; 22 had various forms of dysfunction (bradycardia, flutter, AF, or no electrical activity).
- Of the 15 patients with NSR, 12 responded positively to exercise and atropine, with 8 subsequently receiving A2A2T or A2A2T/D pacing.
- Donor atrium demonstrated superior sensing (2.1 mV) and pacing (0.8 V) thresholds compared to the recipient atrium (1.1 mV and 1.4 V).
- Four patients experienced sensing issues with the recipient atrium, resolved by switching to AAI-R mode without compromising atrial resynchronization. Nine patients preferred AAT over AAI-R pacing. Lead dislodgement occurred in 1 patient (2%).
Conclusions:
- Atrial resynchronization using the recipient sinus node is feasible in only about 25% of SND patients post-OHT due to frequent electrophysiological abnormalities.
- Pacing and sensing are significantly more favorable in the donor atrium compared to the recipient atrium in heart transplant recipients.
- Atrial resynchronization is subjectively well-tolerated and remains a promising pacing strategy for selected OHT patients with SND.