Pacing anti-tachycardia

Abstract Two thirds of the nearly half a million deaths per year in the United States due to sudden cardiac death (SCD) is attributed to coronary artery disease (CAD) and most commonly results from untreated ventricular tachyarrhythmias. Patients with ischemic cardiomyopathy and left ventricular dysfunction are at highest risk for SCD, but this still defines only a small subset of patients who will suffer SCD. Multiple lines of evidence now support the superiority of implantable cardioverter defibrillator (ICD) therapy over antiarrhythmic therapy for both primary and secondary prevention of SCD in advanced ischemic heart disease. Optimization of ICD therapy in advanced ischemic cardiomyopathy includes preventing right ventricular pacing as well as the use of highly effective anti-tachycardia pacing to reduce the number of shocks. While expensive, ICD therapy has been shown to compare favorably to the accepted standard of hemodialysis in cost effectiveness analyses. 

As opposed to a pacemaker, whereby placement of a magnet causes it to pace asynchronously, this has no effect on pacing in the current generation of ICD. As such it has no "magnet rate" and needs to be interrogated at regular intervals in order to determine how much battery life there is. Placement of a magnet over an ICD, however, may actually turn off the delivery of anti-tachycardia therapies, and should only be performed by individuals experienced with this action. 

The ICD circuitry determines how and when both bradycardia pacing and anti-tachycardia therapies are delivered. The sophisticated circuitry... 

Addendum About 3 months later she presented to the office for followup without having any complaints. The logbook from her device showed multiple episodes of ATP (anti-tachycardia ventricular burst pacing) therapy, with each one successfully converting apparent typical AVNRT. 

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