Echocardiographic Deformation Characteristics In Arrhythmogenic Right Ventricular Cardiomyopathy

Abstract

Thesis Outline This thesis is divided into three parts: Part I provides an overview of the current value of echocardiography in ARVC and a further elaboration on the possible clinical value of echocardiographic deformation imaging in ARVC is provided. Part II focuses on early detection of ARVC and shows the capability of echocardiographic RV deformation imaging to detect early pathological changes in absence of established disease criteria. While activation delay is one of the hallmarks of ARVC, we explored the value of measuring activation delay by RV deformation imaging. We defined a new deformation imaging derived parameter: time to onset of myocardial contraction (or electromechanical interval (EMI)), as a surrogate marker for activation delay. In Chapter 3, the hypothesis was tested whether this parameter could identify signs of activation delay in both ARVC patients and family members during early disease stages. Previously, several other deformation parameters were described with potential value for early detection of ARVC. In Chapter 4 we described a new patternbased approach that combines multiple deformation parameters into deformation patterns, including those described in chapter 3, and were correlated to disease severity. In the same chapter, we aimed to characterize the underlying substrate causing these patterns by a computer model to determine the underlying disease substrate. Based on current literature, we hypothesized that abnormal deformation patterns in the early stages of ARVC were caused by an underlying electrical substrate consisting of activation delay. In Chapter 5, we further explored the clinical value of RV deformation patterns, as proposed in chapter 4, in early ARVC. In this chapter we tested the hypothesis that the presence of abnormal RV deformation patterns predicts disease progression in early ARVC. Although ARVC preferentially affects the RV, early LV abnormalities are now more frequently recognized in ARVC.49-51 Chapter 6 explores the capability of echocardiographic deformation imaging to detect early subtle LV pathology in ARVC and tested the hypothesis that the presence of LV involvement has prognostic implications with respect to the occurrence of arrhythmic events, heart failure, and death. In Part III, we explored the role of both conventional echocardiography and RV deformation imaging for the optimal assessment of structural disease. In Chapter 7 we aimed to gain insight in the capability of conventional echocardiography to detect progressive RV dysfunction in advanced ARVC during long-term follow-up. Previous studies showed that structural disease progression detected by conventional imaging approaches is rare in early ARVC. In the last chapter of this part (chapter 8), we explored the value of echocardiographic deformation imaging to detect structural disease progression in early ARVC. Our hypothesis was that echocardiographic deformation imaging detects signs of structural disease progression in absence of disease progression by conventional imaging approaches. All parts are discussed further in Chapter 9 and Chapter 10. In these chapters we summarize our findings and look at the future perspective of echocardiographic deformation imaging and ARVC.