Long-term hemodynamic benefit of atrial synchronization with A2A2D or A2A2T pacing in sinus node syndrome after orthotopic heart transplantation.

BACKGROUND

Exercise capacity after heart transplantation (HTx) may be limited by sinus node disease of the donor heart and atrioatrial dissociation. The role of pacemaker therapy in this setting is not well defined. The purpose of this study was to compare clinical and hemodynamic data of heart transplant recipients with acquired sinus node disease treated with atrial synchronized pacing and patients with other pacing modes or without pacemakers 1 year after operation.

METHODS

Our cohort comprises a total of 112 HTx recipients from the years 1984 to 1996. Atrial synchronized pacing was performed in 21 patients with donor sinus node disease and recipient sinus rhythm. There was no associated morbidity or death for the pacemaker implantation. Fourteen patients received a dual-chamber pacemaker programmed with a short atrioventricular-Delay in A2A2D mode (donor atrial pacing triggered by recipient atrial sensing or both atria stimulated on demand); in the last 6 consecutive patients a single-chamber pacemaker was implanted with two unipolar leads to the atria connected with a Y adapter programmed in A2A2T mode (both atria were sensed and stimulated by triggering each other).

RESULTS

Signals and thresholds remain stable over time. When clinical and hemodynamic data of 12 A2A2D/T patients with complete 1 year follow-up were compared to age- and sex-matched control HTx recipients with other pacing modes or without pacemakers, a significant benefit of atrial synchronization could be shown regarding rise in heart rate response to exercise (+38% vs 30% vs 16% at 50 watt), New York Heart Association classification (1.6 vs 1.8 vs 2.2), Roskamm staging (1.3 vs 2.5 vs 1.5), cardiac index at rest (3.2 vs 2.78 vs 3.1 L/min x m2), cardiac index at 50 watt (5.5 vs 4.5 vs 5.2 L/min x m2), stroke work at rest (51 vs 38 vs 42 pondmeter [PM]), stroke work at 50 watt (66 vs 48 vs 51 PM), pulmonary wedge pressure at rest (7 vs 13 vs 8 mm Hg) and pulmonary wedge pressure at 50 watt (14 vs 24 vs 18 mm Hg).

CONCLUSION

It is concluded that electromechanical synchronization of the atria was of long-term benefit in heart transplant recipients with recipient sinus rhythm and donor sinus node disease.