Refining success of cardiac resynchronization therapy using a simple score predicting the amount of reverse ventricular remodelling: results from the MARC study – authors reply

We thank Stankovic and Voigt1 for their interest in our study2 and agree that the identification of apical rocking as an independent predictor of response to cardiac resynchronization therapy (CRT) in the MARC study is not a new finding.3 The main novelty of the MARC study, however, is not the identification of one novel marker for CRT response. Instead, we prospectively tried to evaluate multiple biomarkers from several domains, including echocardiographic, electrocardiographic, blood, and clinical biomarkers in order to predict response to CRT. Using this approach, we not only found apical rocking being a marker of intraventricular dyssynchrony, but in addition, another, also easy reliable echocardiographic marker of interventricular dyssynchrony (interventricular mechanical delay), as well as an electrocardiographic marker (vectorcardiographic QRSAREA) and a clinical marker (age), all independently predicting response to CRT and representing the CAVIAR response score. A novelty is, nevertheless, that this score not only predicts response to CRT but in addition the amount of reverse remodelling after CRT. As suggested by Stankovic and Voigt, the CAVIAR score in addition to other prospective analyses can aid in refining guideline-proposed criteria in identifying CRT candidates. The value of the CAVIAR score, however, still needs to be confirmed in an additional prospective CRT cohort. Conflict of interest: none declared.