Atrial gradient as a potential predictor of atrial fibrillation.
OBJECTIVE
We tested the utility and comparability of the atrial gradient and atrial ERP as early markers of electrical remodeling and a propensity to atrial fibrillation (AF).


BACKGROUND
Pacing at physiologic rates from the left atrium alters the atrial gradient and is associated with atrial tachyarrhythmias. At these physiologic rates, there is no change in the atrial effective refractory period (ERP).


METHODS
Sixty-one chronically instrumented mongrel dogs in complete heart block were paced from the left or right atrium at 400 to 900 bpm for 46 +/- 3 days. Dogs were monitored weekly and electrophysiologic studies conducted to determine changes in the atrial gradient, ERP, and rhythm.


RESULTS
Rapid atrial pacing was associated with concordant decreases in atrial gradient, ERP, and occurrence of AF. Incidence of AF increased with increasing pacing rate. Although there ultimately was an equal incidence of AF with left atrial and right atrial pacing, the onset of AF occurred earlier with left atrial pacing. As expected, ERP decreased in both atria. Animals with long control ERP did not fibrillate.


CONCLUSIONS
Rapid pacing induces changes in atrial gradient, which can be used as a noninvasive marker of electrical remodeling. AF is accompanied by decreases in atrial gradient and ERP, and the incidence is highest in dogs with short control ERP.
Chandra
Parag
P
Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
Rosen
Tove S
TS
Herweg
Bengt
B
Plotnikov
Alexei N
AN
Danilo
Peter
P
Rosen
Michael R
MR
D000818:Animals; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D004195:Disease Models, Animal; D004285:Dogs; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005557:Formaldehyde; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*
D005557:Formaldehyde