Peak Deflection Index (PDI) for Identifying a Patient with Outflow Tract Ventricular Tachycardia Who Is Likely to Fail Radiofrequency Catheter Ablation
Hachiya et al used the Peak Deflection Index (PDI) to identify a patient with outflow tract ventricular tachycardia who is unlikely to respond to radiofrequency catheter ablation (RFCA). These patients may have the origin of the tachycardia at a point not affected by the catheter ablation, either deep within the ventricular septum or at an epicardial site. The authors are from Tokyo Medical and Dental University.
Patient selection: with outflow tract ventricular tachycardia
ECG lead: inferior lead with with the tallest R wave (II, III, aVF)
Parameter:
(1) QRS duration in milliseconds
(2) time from QRS onset to peak of the R wave (earliest peak deflection)
peak deflection index =
= (time from QRS onset to R wave peak in milliseconds) / (QRS duration in ms)
Interpretation:
• A PDI > 0.6 is associated with a high rate of RFCA failure.
Performance:
• The sensitivity was 80% and specificity 90%.
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