In Reply We appreciate the insightful comments made by Drs Zhao and Wang on our Challenge in Clinical Electrocardiography.1 In this case report, we quoted the conclusions from a study by Shvilkin and colleagues2 to illustrate how right ventricular (RV) apical pacing-induced cardiac memory (CM) could be distinguished from myocardial ischemia-induced T-wave inversion (TWI). The combination of a positive TaVL, positive or isoelectric TI, and maximal precordial TWI greater than TWIIII was 92% sensitive and 100% specific for CM and could distinguish it from ischemia-induced TWI. However, as Drs Zhao and Wang noted, other pacing positions within the RV produce different QRS complex vectors that result in different TWI distributions. Suran and colleagues3 investigated the following 2 combinations: (1) a positive TaVF with a T-wave amplitude in the aVF lead greater than or equal to the absolute value of the most negative precordial T wave and (2) a positive TaVF with a positive TV5 and a positive or isoelectric TI. Both could distinguish postseptal pacing−induced CM from ischemia-induced TWI with a sensitivity and specificity of 91% and 92%, respectively.