Author + information
- Received September 7, 1999
- Revision received December 3, 1999
- Accepted January 17, 2000
- Published online May 1, 2000.
- Jens Cosedis Nielsen, MDa,
- Morten Bøttcher, MDa,
- Torsten Toftegaard Nielsen, MD, DMSca,
- Anders Kirstein Pedersen, MD, DMSca and
- Henning Rud Andersen, MD, DMSca,* ()
- ↵*Reprint requests and correspondence: Dr. Henning Rud Andersen, Department of Cardiology, Skejby Sygehus, Aarhus University Hospital, Brendstrupgaardsvej, 8200-DK, Aarhus N, Denmark
This study aimed to evaluate regional myocardial blood flow (MBF) and global left ventricular ejection fraction (LVEF) during chronic pacing in patients with sick sinus syndrome (SSS) randomized to either single chamber atrial (AAI) or dual chamber (DDD) pacing.
Experimental studies indicate that chronic pacing in the right ventricular apex changes regional MBF, thereby compromising left ventricular function.
Thirty patients (age 74 ± 10 years) were randomized to AAI (n = 15) or DDD (n = 15) pacemakers. After 22 ± 7 months of pacing, MBF was quantified with 13N-labeled ammonia positron emission tomography scanning at 60 beats per min and 90 beats per min. Patients in the DDD group furthermore underwent MBF measurement at temporary AAI pacing, 60 beats per min. Myocardial blood flow was assessed in the anterior, lateral, inferior and septal regions, and the global mean MBF was calculated. Left ventricular ejection fraction was determined by echocardiography at pacemaker implantation and at the time of MBF measurements.
Myocardial blood flow at rates 60 and 90 beats per min did not differ between the AAI and DDD groups. During temporary AAI pacing in the DDD group, MBF was significantly higher than during DDD pacing in both the inferior (p = 0.001) and septal (p = 0.004) regions and also globally (0.61 ± 0.15 vs. 0.53 ± 0.13 mL·g−1·min−1, p = 0.005). In the DDD group, LVEF decreased from pacemaker implantation to time of MBF measurements (0.61 ± 0.09 vs. 0.56 ± 0.07, p = 0.013). Left ventricular ejection fraction during temporary AAI pacing at time of MBF measurements was not different from LVEF at pacemaker implantation.
In patients with SSS, chronic DDD pacing reduced inferior, septal and global mean MBF as well as LVEF, as compared with temporary AAI pacing. The LVEF reversed to baseline level during temporary AAI pacing despite 22 months of permanent ventricular pacing preceding it. Augmenting pace rate to 90 beats per min increased MBF equally in the two treatment groups.
☆ Dr. Jens Cosedis Nielsen is the recipient of a grant from the Faculty of Health Sciences, University of Aarhus, Denmark. Morten Bøttcher is the recipient of a fellowship from the Danish Heart Foundation. The study was financially supported by the Danish Heart Foundation (grants 96-1-3-56-22367 and 98-2-5-74-22661), by ‘Hjerteforeningens Pacemakerklubs Jubilæumsfond’ and by The Danish Health Science Research Council (grant no. 9600822, Aarhus University-Novo Nordic Center for Research in Growth and Regeneration).
- Received September 7, 1999.
- Revision received December 3, 1999.
- Accepted January 17, 2000.
- American College of Cardiology