ABSTRACT
Cardiac remodeling is a compensatory physiologic response to an event or condition that compromises cardiac function. Triggers for remodeling include infarction, hypertension, wall stress, inflammation, pressure overload, and volume overload. Rapid ventricular pacing causes cardiac enlargement and failure within a matter of weeks, and is one of the most widely used methods to induce myocardial remodeling. The severity of cardiac dysfunction directly correlates with the rate of pacing. Rapid pacing can be extremely detrimental and in some cases results in death in less than six weeks. Rapid ventricular pacing is primarily employed in dogs paced at 210–260 beats per minute, through the left or right ventricle, for three to six weeks. This technique produces chamber dilation within two weeks, and causes a decrease in the ejection fraction and cardiac output within three weeks. Chronic rapid pacing in dogs elicits augmented sympathetic tone and decreased parasympathetic activity.
