I commend the work of Gowda et al. , looking at left ventricular (LV) mechanical synchrony values in pediatric patients with heart failure (HF). The most important issue regarding this work is that comparing LV mechanical synchrony values in pediatric patients with HF with those in the normal pediatric population, though intellectually interesting, may not be of much help in developing LV cardiac resynchronization therapy (CRT) options in future efforts to treat LV failure in pediatric patients. This was a concept my group was made aware of in postpublication critiques of work we reported on synchrony values in normal pediatric patients.

Readers may be tempted to use such normative data to try to predict which patients with LV dysfunction might respond to CRT. There needs to be a strong cautionary note that this is a long way from predicting which patients with LV dysfunction may respond to CRT. In addition to the known limitations in adult LV CRT studies of trying to use mechanical dyssynchrony (vs electrical dyssynchrony) to predict CRT response that Gowda et al. do point out, developing echocardiographic predictors for LV CRT response will require dyssynchrony studies on pediatric HF responders and nonresponders to CRT therapy, much like previous LV adult CRT studies. The mechanical synchrony (or dyssynchrony) characteristics of pediatric HF CRT responders versus nonresponders are what need to be studied, with normative data of likely little consequence in such an endeavor. Although the authors do state, “The echocardiographic method with the best indicator of ventricular dyssynchrony and predictive ability of ventricular reverse remodeling after CRT in pediatric patients with HF remains to be determined,” this one-line cautionary note may not be enough to discourage readers from using such normative data to come up with ill-designed pediatric HF CRT treatment plans.