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Is atrial activation beneficial in heart transplant recipients?
M G Midei1, K L Baughman, S C Achuff
1Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Insights
Heart transplant recipients benefit from atrial pacing. Atrial activation significantly improves arterial pressures and cardiac output compared to ventricular pacing, highlighting the atrium's crucial role in cardiac performance.
Area of Science:
- Cardiology
- Transplantation Medicine
- Cardiac Electrophysiology
Background:
- Atrial morphology is distorted after cardiac allograft transplantation.
- The impact of atrial and ventricular activation sequencing is unclear in these patients.
Purpose of the Study:
- To evaluate the atrial contribution to ventricular pump performance in heart transplant recipients.
Main Methods:
- Measured arterial pressure and cardiac output in nine heart transplant recipients.
- Pacing was performed from either the atrium or the ventricle.
Main Results:
- Systolic, diastolic, and mean systemic arterial pressures were significantly higher during atrial pacing versus ventricular pacing (p < 0.05).
- Cardiac output decreased significantly during atrial pacing compared to ventricular pacing (p < 0.005).
Conclusions:
- A significant atrial contribution to cardiac performance exists in heart transplant recipients.
- Findings have clinical implications for heart transplant patients requiring permanent pacemakers.
Abstract:
Because of the distortion of atrial morphology that occurs during cardiac allograft transplantation in humans, the beneficial effects of properly sequenced atrial and ventricular activation are unclear in these patients. To evaluate the atrial contribution to ventricular pump performance in heart transplant recipients, arterial pressure and cardiac output during pacing from either chamber were measured in nine patients 10 +/- 1 days after transplantation. Systolic, diastolic and mean systemic arterial pressures were significantly higher during atrial pacing compared with ventricular pacing: 143 +/- 23 versus 125 +/- 20 mm Hg, 73 +/- 15 versus 66 +/- 14 mm Hg and 94 +/- 17 versus 84 +/- 16 mm Hg, respectively (p less than 0.05 for all). In addition, cardiac output decreased from 5.5 +/- 1.4 to 4.6 +/- 1.5 liters/min (p less than 0.005) for atrial versus ventricular pacing. Thus, there is a significant atrial contribution to cardiac performance in patients after heart transplantation. This may have clinical implications in those patients who later require a permanent pacemaker.