The Propensity for Inducing Atrial Fibrillation: A Comparative Study on Old versus Young Rabbits.
It is well established that atrial fibrillation (AF) is far more common in elderly humans. Autonomic activation is thought to be an operative mechanism for AF propensity. The aim of the study was to investigate the impact of age on atrial tachyarrhythmia induction in a rabbit model. Six old (aged 4-6 years) and 9 young (aged 3-4 months) New Zealand white rabbits were subjected to a catheter-based electrophysiological study. Atrial tachyarrhythmia susceptibility was tested by burst pacing before and after infusion of increasing concentrations of acetylcholine. Both young and old rabbits were in normal sinus rhythm at the beginning of the infusion/burst pacing protocol. The old rabbits had faster heart rates and a marked increase in atrial tachyarrhythmias compared to the young rabbits. Nonsustained and sustained AF events were more frequent in the old rabbits. No significant fibrosis was observed in the atria of either young or old rabbits. In conclusion, the old rabbits have a greater propensity for induction of AF. The significantly faster heart rates in the old rabbits suggest that dominant sympathetic activity may play an important role in the propensity for AF in this group.
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Hongliang
H
Li
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Benjamin J
BJ
Scherlag
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
David C
DC
Kem
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Caitlin
0000-0002-5782-8664
C
Zillner
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Shailesh
S
Male
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Sorkko
0000-0003-3046-1150
S
Thirunavukkarasu
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Xiaohua
X
Shen
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Alexandria
A
Benbrook
Department of Pathology, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Jan V
JV
Pitha
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Ralph
R
Lazzara
Heart Rhythm Institute, Department of Medicine, University of Oklahoma Health Sciences Center and Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA.
Xichun
0000-0001-6760-3410
X
Yu