Values and limitations of programmed stimulation and ambulatory monitoring in the management of ventricular tachycardia.

Programmed stimulation (PES) and ambulatory electrocardiographic (Holter) monitoring are both widely used to evaluate the efficacy of antiarrhythmic drugs in patients with recurrent ventricular tachycardia (VT). PES is sensitive but nonspecific, and Holter is specific but insensitive. A failure to suppress ventricular premature complexes (VPCs) on Holter during drug therapy predicts a poor outcome. A suppression of VPCs by drug therapy, however, does not preclude a poor outcome. If VT is no longer induced by PES during drug therapy, the patients will have a good outcome. A persistent induction of VT during drug therapy, however, does not preclude good outcomes. Therefore some investigators have suggested alternative PES efficacy criteria such as the changes in the rate of induced VT during therapy. Further studies should be conducted to confirm this. Because both methods have values and limitations, a combined use of the 2 methods is recommended to improve the clinician's ability to predict the outcome of antiarrhythmic therapy. Studies designed to prove that 1 method is better than the other may prove futile.