Author + information
- Received May 31, 1983
- Revision received October 17, 1983
- Accepted November 28, 1983
- Published online May 1, 1984.
- Paul Walinsky, MD, FACC*,1,
- Allan M. Lefer, PhD, FACC1,
- Peter Frasca, MD1 and
- William Santamore, PhD1
- ↵*Address for reprints: Paul Walinsky, MD, Department of Medicine, Jefferson Medical College, 11th and Chestnut Streets, Philadelphia, Pennsylvania 19107.
The effect of atrial pacing on coronary hemodynamics and platelet adhesion was evaluated in 13 dogs. In all 13 dogs, a snare was placed around the circumflex artery and tightened so that distal coronary artery pressure decreased to 60 to 70 mm Hg. In 10 dogs, atrial pacing was instituted at twice the heart rate at rest for 10 minutes. In three dogs, observation was continued for 10 minutes without pacing. In the 10 dogs undergoing pacing, heart rate increased from 90.5 ± 32.6 to 173.5 ± 45.8 beats/min. Aortic pressure was unchanged. Distal coronary artery pressure decreased from 70.8 ± 7.8 to 53.2 ± 10.0 mm Hg (p < 0.05) and the pressure gradient across the stenosis increased from 47.6 ± 12.7 to 61.2 ±9.1 mm Hg (p < 0.05). Stenotic resistance increased from 2.5 ± 0.8 to 3.6 ± 2.4 mm Hg/ml min−1, but coronary flow was unchanged. In all three control dogs, there was no change in coronary dynamics for the 10 minute period.
In 8 of the 10 dogs that underwent pacing, platelet deposition was observed at the site of coronary stenosis. In contrast, in the three control dogs there was no platelet deposition. Atrial pacing in the presence of coronary stenosis appears to alter coronary hemodynamics such that there are activation and deposition of platelets at the site of stenosis. This platelet deposition may be transient or could become the nidus for subsequent platelet-related events in the coronary vessel.
- Received May 31, 1983.
- Revision received October 17, 1983.
- Accepted November 28, 1983.
- American College of Cardiology Foundation