Ventricular burst pacing

A "slow" VT (approx. 130 b.p.m.) is clearly seen on the left side of the strip. Ventricular burst pacing from the ICD is initiated, and terminates the VT. 

Ventricular burst pacing may be extremely effective for termination of slower varieties of VT, and should thus be considered for initial therapy when a VT zone is programmed. 

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. 

Cook JR, Kirchhoffer JB, Fitzgerald TF, Lajzer DA. Comparison of decremental and burst overdrive pacing as treatment for ventricular tachycardia associated with coronary artery disease. Am J Cardiol 1992 70 311-5. 

Fig. 12.2 An example of atrial fibrillation (AF) organizing into atrial flutter. A. The upper strip in the top panel demonstrates the atrial electrogram (EGM) and the lower strip demonstrates the annotated markers indicating how the pacemaker classifies each atrial and ventricular event as well as the cycle length (in ms) between each interval. The atrial electrogram shows the rapid irregular atrial rhythm which subsequently transitions into an organized atrial tachycardia. B. Atrial antitachycardia pacing (ATP) therapy - a burst train followed by two premature extrastimuli is delivered restoring atrial paced rhythm. The marker channel notations indicate how the device classifies each beat. Inter-beat intervals are also shown (in ms). AP - atrial paced event VP - ventricular paced event AR - atrial event sensed in atrial refractory period FS - AF sensed event TD - tachycardia detected TS - tachycardia sensed event. Courtesy AM Gillis.

The single EGM is measured between the atrial and ventricular lead tips. This displays both an atrial and ventricular EGM component, and allows one to see an atrial tachycardia conducting 2 1 to the ventricles. The EGM recording ceases (normal device function per the manufacturer), but the marker channels show a single round of atrial burst overdrive pacing that fails to terminate the arrhythmia (in fact it temporarily speeds it up). 

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