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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, RESULTS. Meshes: Animals, Arrhythmias, Cardiac, Cardiac Pacing, Artificial, Coronary Disease, Dogs, Female, Heart, Male, Physical Conditioning, Animal.
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Does transient ischaemia induced by rapid cardiac pacing result in myocardial preconditioning? Context: The aim was to determine whether rapid ventricular pacing can protect against the ventricular arrhythmias occurring during a subsequent coronary artery occlusion. 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. 25 anaesthetised mongrel dogs in a restricted body weight range were used. 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%).
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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. Final Decision: yes