Assessment of QT interval in ventricular paced rhythm: Derivation of a novel formula

We proposed a new, simple formula for QT estimation in RV pacing. JT interval in paced complexes is highly HR dependent and is not accurate for QT assessment. The new spline approach for HR correction for the QT, once incorporated into some previously proposed formulae, blunts HR dependency and improves prediction of QT before pacing. QTcRBK*0.86 and QTcRBK - (QRS*0.5) demonstrated the best balance of relatively strong correlation to QTc before pacing and accurate QTc prolongation identification. Abnormal QT for QTcRBK*0.86 as defined by the 97.5th and 99th percentile are 469 and 479 ms respectively.