Tachycardia control with cardiac pacemakers

Techniques used to treat tachyarrhythmias with brief electrical impulses are described. The disease process is described, identifying the prevention of one of the three conditions required for reentry (which provides the mechanism for most electrically convertible rhythms) as the basis for therapy. The risk of inducing fibrillation is discussed. The four major pacing techniques used to treat tachycardia are described. The first technique involves using additional pacemaker pulses to establish the appropriate conditions permitting interruption of the tachycardia. The second technique, which permits adaptation to the variations in tachycardia characteristics, is scanning. Scanning changes the intervals on successive bursts in an interactive process, allowing a series of paced intervals to be tested. The third technique is usually called an adaptive or automatic technique. The final technique is ramp pacing, which allows extrastimuli to be introduced at progressively premature intervals within a burst of stimuli.