Optimal echocardiographic assessment of myocardial dysfunction for arrhythmic risk stratification in phospholamban mutation carriers

Figure 1. Distribution of LVEF and LVMD values in PLN p. Arg14del mutation carriers. The vertical black line represents the cut-off value for LVEF (45%), whereas the horizontal black line represents the cut-off value for LVMD (45 ms). According to these cut-off values, mutation carriers were classified into three subgroups: normal LV function (preserved LVEF and normal LVMD, in green), mechanical LV dysfunction (preserved LVEF and abnormal LVMD, in yellow) and overt LV dysfunction (reduced LVEF, in red). Mutation carriers who experienced sustained VA during follow-up are marked with a black dot. LV, left ventricular; LVEF, LV ejection fraction; LVMD, LV mechanical dispersion; VA, ventricular arrhythmia.

Figure 2. VA-free survival of PLN p.Arg14del mutation carriers in different LV function classes. VA-free survival differed significantly between the three LV function classes. Mutation carriers with a normal function had the most favourable survival, whereas mutation carriers with mechanical dysfunction and overt dysfunction had worse survival. LV, left ventricular; VA, ventricular arrhythmia.

Take home figure. Optimal echocardiographic assessment of myocardial dysfunction for arrhythmic risk stratification in PLN p.Arg14del mutation carriers. The ‘45/45’ rule can be used to stratify PLN p.Arg14del mutation carriers into three echocardiographic risk categories. Subjects with LVEF < 45% are classified as having overt LV dysfunction, and are considered to be at high risk to develop sustained VA. In subjects with LVEF ≥45%, LVMD should be additionally measured. In case of normal LVMD (i.e. normal LV function), the risk of developing sustained VA is low. However, in case of LVMD >45 ms (i.e. mechanical LV dysfunction), the risk of developing sustained VA is higher, despite normal LVEF. When LVMD is added on top of the current VA risk prediction model, it provides a high NPV, particularly in the lower risk categories. LVEF, left ventricular ejection fraction; LVMD, left ventricular mechanical dispersion; NPV, negative predictive value; PLN, phospholamban; PPV, positive predictive value; (s)VA, (sustained) ventricular arrhythmia.