The postpacing interval minus ventricular tachycardia cycle length difference did not significantly differ between effective (114 msec) and ineffective (177 msec) ablation sites (P=0.1).
Observational (n=24)
Does the postpacing interval (PPI) identify effective target sites for ablation of ventricular tachycardia at sites of concealed entrainment in patients with prior myocardial infarction?
The postpacing interval is not clinically useful for identifying effective sites for radiofrequency ablation of ventricular tachycardia in patients with prior myocardial infarction.
Absolute Event Rate: 114% vs 177%
p-value: p=0.1
INTRODUCTION: The postpacing interval (PPI) has been used to discriminate bystander sites from critical sites within a ventricular tachycardia (VT) reentry circuit, with a PPI that is similar to the VT cycle length (CL) being indicative of a site within the reentry circuit. The purpose of this study was to assess the clinical value of the PPI for identifying effective target sites for ablation of VT at sites of concealed entrainment in patients with prior myocardial infarction. METHODS AND RESULTS: In 24 patients with coronary artery disease and a past history of myocardial infarction, 36 VTs with a mean CL of 483+/-80 msec (+/- SD) were mapped and targeted for radiofrequency (RF) ablation. The only criterion used to select target sites for ablation was concealed entrainment. In a post hoc analysis, the PPI was measured at 47 ineffective and 26 effective ablation sites. The mean PPI-VTCL difference at the 26 effective sites (114+/-137 msec) did not differ significantly from the mean at the 47 ineffective sites (177+/-161 msec; P = 0.1). The sensitivity of a PPI-VTCL difference < or = 30 msec for identifying an effective ablation site was 46%, the specificity 64%, the positive predictive value 41%, and the negative predictive value 68%. CONCLUSION: The PPI-VTCL difference is not useful for discriminating between sites of concealed entrainment that are within or outside of a VT reentry circuit in patients with prior infarction. Therefore, in patients with prior infarction, the PPI is not clinically useful for identifying sites of concealed entrainment at which RF ablation should or should not be attempted.
Bogun et al. (Fri,) conducted a observational in Ventricular tachycardia in patients with prior myocardial infarction (n=24). Postpacing interval (PPI) measurement vs. Ineffective ablation sites was evaluated on Mean PPI-VTCL difference at effective versus ineffective ablation sites (p=0.1). The postpacing interval minus ventricular tachycardia cycle length difference did not significantly differ between effective (114 msec) and ineffective (177 msec) ablation sites (P=0.1).