The Electrocardiogram as a Risk Predictor in Asymptomatic Aortic Stenosis

Abstract

Calcific aortic stenosis (AS) shares several etiological factors and histopathological changes with vascular atherosclerosis and the two diseases often coincide (Otto et al. 1994). Observed cardiovascular event rates might therefore differ substantially despite equal AS severity in the presence of additional vascular disease, such as atherosclerosis or hypertension (Otto et al. 1999; Briand et al. 2005). Moreover, cardiac response to the same pressure load may not be uniform in otherwise comparable patients (Awtry and Davidoff 2011). As such, is the development of left ventricular (LV) hypertrophy in response to increased afterload, the result of a complex dynamic process which involves mechanical, genes, molecular and biochemical factors (Devereux and Roman 1999). Thus, sole reliance on echocardiographic AS severity and symptoms might prove insufficient to identify all AS patients whose prognosis could be improved by earlier aortic valve replacement or other available therapy. A simple and reproducible score, which encapsulates the sum of AS and coexisting risk factors is therefore needed for reliable prognostication in these patients. In turn, this may allow for improved prediction of the safety of continued watchful waiting prior to the occurrence of potentially irreversible or fatal cardiac damage. The electrocardiogram a low-cost and easily repeatable examination is appealing in this context, as it is feasible for mass examination and sensitive to changes in cardiac structure and function induced by valvular- as well as vascular disease (Greve et al. 2011a; Wachtell et al. 2000; Nesto and Kowalchuk 1987). The purpose of this chapter is therefore to review the potential role of classic electrocardiography as a widely available tool for risk stratification in a growing population of patients with calcific aortic valve disease.