Feddo Kirkels

26 | Chapter 2 INTRODUCTION Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is an inherited cardiomyopathy diagnosed by a complex set of tests defined in the 2010 Task Force Criteria (TFC).1 This includes echocardiography, which combines measures of right ventricular (RV) dilatation and function with subjective visual wall motion assessment to obtain diagnostic criteria. However, a recent clinical validation study of the TFC demonstrated that these echocardiographic criteria lack sensitivity for ARVC diagnosis.2 Subtle wall motion abnormalities can be missed by visual assessment, hampering diagnosis. In contrast, echocardiographic deformation imaging is known for its high sensitivity for detection of wall motion abnormalities. The performance of deformation imaging within the TFC for ARVC diagnosis remains however unknown. We performed a head-to-head comparison of the diagnostic value of TFC visual wall motion assessment versus deformation imaging in a real-world cohort of consecutive patients evaluated for ARVC. METHODS The study population was derived from a recently published study on TFC performance, which included 160 consecutive patients who were referred for ARVC evaluation at the UMC Utrecht, the Netherlands, between 2009-2011.2 Of those, we included 59 patients who underwent an echocardiogram according to our current protocol3 on a single vendor, allowing deformation analysis. The study was approved by the local ethics board. In absence of a gold standard test for diagnosis of ARVC, the reference standard was diagnosis by consensus of 3 independent ARVC experts (JvdH/RH/AtR) who re-evaluated all available patient data, beyond the scope of the TFC, including a median follow-up of 5.9 years IQR[2.7-7.6 years] after the echocardiographic examination.2 All echocardiograms were performed with a Vivid 7 or E9 scanner and post-processed with EchoPac v.202 (GE Healthcare, Horten, Norway). The original clinical assessment of RV outflow tract dimensions, fractional area change and wall motion was used to determine conventional echocardiographic TFC.1 In addition, RV deformation patterns of the subtricuspid area3 were obtained by two experienced operators (FK/KT) blinded for clinical data. Deformation patterns were scored as either normal or abnormal, according to the presence of regional mechanical dysfunction (type II/III, as previously described in detail).3 We evaluated the effect of replacing visual wall motion assessment with deformation imaging on the sensitivity, specificity and C-statistic of the echocardiographic TFC for ARVC diagnosis. (Figure 1A)

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