Background: Phospholamban (PLN) R14del mutation carriers may develop arrhythmogenic cardiomyopathy due to disturbed intracellular calcium handling. Echocardiographic deformation imaging allows quantification of regional ventricular mechanical dysfunction, which may reflect disturbed calcium handling and early fibrosis in mutation carriers.
Objective: To investigate the predictive value of echocardiographic deformation imaging for sustained ventricular arrhythmias (VA) in PLN R14del mutation carriers.
Methods: We included 138 PLN R14del mutation of which 73 were pre-symptomatic (no history of VA, LVEF≥45%). All subjects underwent echocardiography at baseline, including deformation imaging. Sustained VA during follow-up was defined as sudden cardiac arrest, appropriate ICD intervention or recorded sustained VA by ECG or Holter-monitoring.
Results: During a median follow-up period of 2.5 [IQR 4.2] years, sustained VA occurred in 20 subjects (15%). Of all echocardiographic measurements, left ventricular mechanical dispersion (LVMD) had the highest area under the curve to predict sustained VA with an optimal cut-off value of 47msec. From the patients with LVMD<47msec (n=90), only one had sustained VA during follow-up (NPV=99% [95% CI 93%-100%]). From the patients with LVMD≥47msec (n=45), 19 had sustained VA during follow-up (PPV=42% [95% CI 34%-51%]). LVMD≥47msec was seen in 7 pre-symptomatic mutation carriers.
Conclusion: Measurement of echocardiographic LVMD may be helpful for early arrhythmic risk stratification in PLN R14del mutation carriers. We will further investigate this parameter in a multivariate model to determine its independent predictive value.