Recovery time dispersion measured from 87-lead body surface potential mapping as a predictor of sustained ventricular tachycardia in patients with idiopathic dilated cardiomyopathy

Recovery Time Dispersion in DCM, Introduction: The clinical usefulness of Q T dispersion in 12-lead ECG has been controversial in identifying subjects at risk for sustained ventricular tachycardia (VT) in patients with idiopat hic dilated cardiomyopathy (DCM). We hypothesized that increasing the spati al resolution of the ECG improves the accuracy of risk stratification. The purpose of this study was to test the ability of recovery time dispersion m easured from 87-lead body surface potential mapping (BSPM) to identify pati ents at risk for sustained VT in idiopathic DCM. Methods and Results: We obtained 87-lead BSPM and 12-lead ECG in 33 patient s with idiopathic DCM (15 patients with a history of sustained VT [VT(+) gr oup] and 18 patients without a history of sustained VT [VT(-) group]) and i n 20 normal control subjects. We measured the corrected QT dispersion and c orrected recovery time dispersion from 12-lead ECG (QTc-12 dispersion and R Tc-12 dispersion, respectively) and 87-lead BSPM (QTc-87 dispersion and RTc -87 dispersion, respectively). Signal-averaged ECG also was recorded in 25 patients. Neither the QTc-12 nor QTc-87 dispersion discriminated between th e VT(+) and VT(-) groups patients, The VT(+) group patients had a larger bu t insignificant RTc-12 dispersion than the VT(-) group patients. In contras t, the RTc-87 dispersion was significantly larger in the VT(+) group patien ts than in the VT(-) group patients (236 +/- 39 msec vs 184 +/- 28 msec, P < 0.001). Receiver operating curve analysis indicated that the RTc-87 dispe rsion was as good as late potentials in predicting susceptibility to sustai ned VT; its sensitivity, specificity, and negative predictive value were 73 %, 76%, and 76%, respectively (cutoff value 200 msec), RTc-87 dispersion >2 00 msec combined with positive late potentials provide high sensitivity (92 %) and high negative predictive value (88%) for sustained VT. Conclusion: The RTc-87 dispersion is a useful tool to identify subjects at risk for sustained VT in patients with idiopathic DCM.