Transient ischaemia induced by rapid cardiac pacing results in myocardial preconditioning.
OBJECTIVE
The aim was to determine whether rapid ventricular pacing can protect against the ventricular arrhythmias occurring during a subsequent coronary artery occlusion.


METHODS
The effect was examined of two 2 min periods of pacing (300 beats.min-1) in chloralose-urethane anaesthetised dogs on a subsequent 25 min coronary artery occlusion. Ventricular arrhythmias, ST segment elevation, and inhomogeneity of conduction were analysed.


METHODS
25 anaesthetised mongrel dogs in a restricted body weight range were used.


RESULTS
Preocclusion pacing reduced the severity of occlusion induced ST segment elevation, degree of inhomogeneity, and arrhythmias: ventricular premature beats were reduced from 528(SEM 40) to 136(45), and there were lower incidences of ventricular fibrillation (0% v 47%) and ventricular tachycardia (30% v 80%).


CONCLUSIONS
Rapid ventricular pacing "preconditions" the myocardium in a manner similar to that following short coronary artery occlusions. Short periods of ischaemia no matter how induced protect the heart against the arrhythmogenic effect of a prolonged coronary artery occlusion.
Vegh
A
A
Institute of Pharmacology, Albert Szent-Gyorgyi Medical University, Szeged, Hungary.
Szekeres
L
L
Parratt
J R
JR
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D003327:Coronary Disease / Q000209:etiology* / Q000503:physiopathology; D004285:Dogs; D005260:Female; D006321:Heart / Q000503:physiopathology*; D008297:Male; D010805:Physical Conditioning, Animal / Q000379:methods*