Objective Best treatment outcomes in Fabry disease (FD) associated cardiomyopathy can be obtained when treatment is started as early as possible. The rationale of this study was to assess the role of ECG changes for identification of cardiac involvement and patients at an earlier stage of the disease more likely deriving a benefit from enzyme replacement therapy (ERT).

Methods A retrospective analysis of patient data was performed from an observational, longitudinal, prospective cohort. Treatment response was defined as absence or presence of disease progression, defined as new onset or increase in left ventricular (LV) mass >10%. Demographic, clinical, ECG and echocardiographic parameters at baseline were tested for their value in determining absence or presence of disease progression under ERT at 5-year follow-up.

Results The study population consisted of a total of 38 patients (25 men, mean age 36±13 years, overall median follow-up duration 6.4±1.2 years). Patients in the progression group (14 men, 4 women) had a longer QRS duration (99±11 ms vs 84±13 ms, p<0.05 for men, 93±9 years vs 81±5 years, p<0.05 for women) and QTc interval (401±15 ms vs 372±10 ms, p<0.005 for men) and a higher amount of ECG abnormalities (86% vs 18%, p<0.005 for men and 100% vs 0%, p<0.005 for women) at the time of ERT initiation. An abnormal baseline ECG was significantly associated with disease progression (sensitivity 94.1%, specificity 88.9%, positive likelihood ratio of 8.47, p<0.005).

Conclusions An abnormal ECG at the time of treatment initiation is significantly associated with cardiac disease progression in FD. This effect seems to be independent of age, gender or LV mass at baseline and suggests maximal treatment benefit when ERT is initiated before ECG abnormalities develop.