Detection of preclinical left ventricular dysfunction in Fabry disease: the contribution of tissue Doppler.

Introduction: Fabry disease is a rare X-linked lysosomal storage disorder caused by a deficiency of alpha-galactosidase, which results in progressive intracellular accumulation of glycosphingolipids in various tissues. Cardiac involvement is frequent, with left ventricular (LV) hypertrophy (concentric, apical or asymmetric septal) as the most common finding. Evaluating LV systolic dysfunction with conventional echocardiography is not sufficiently sensitive to detect impaired myocardial function early in the course of the disease. Doppler myocardial imaging can quantify changes in global and regional longitudinal myocardial function with great precision.

Aim: To identify parameters of cardiac dysfunction in patients with Fabry disease with no cardiac symptoms using conventional or Doppler echocardiography and tissue Doppler (including tissue tracking, strain and strain rate).

Methods: Four patients with Fabry disease (3 female; mean age 47 +/- 17 years) and 29 healthy controls (19 female and 10 male; mean age 38 +/- 14 years) were studied with conventional echocardiography and tissue Doppler imaging using a Vivid 7 scanner. The following parameters were measured: LV dimensions, ejection fraction (using Simpson's rule), systolic and diastolic velocities and tissue tracking of the mitral annulus at six sites (apical views). LV peak systolic strain and strain rate were obtained in 12 segments from apical views.

Results: Two patients had LV hypertrophy (one concentric and one apical). Diastolic impairment was detected in three patients by reduced flow propagation velocity of early transmitral flow (Vp) and E/Vp ratio. Mitral annulus systolic velocities were lower in Fabry disease than in the controls. Peak systolic strain and strain rate were diminished in all segments in three patients, showing impaired myocardial systolic function. The results are presented for each of the four patients.

Conclusions: In patients with Fabry disease, with no cardiac symptoms and normal LV systolic function on conventional echocardiography, diastolic dysfunction was detected by Vp and E/Vp ratio regardless of LV hypertrophy. However, tissue Doppler imaging was able to detect impaired myocardial systolic function, particularly in patients with LV hypertrophy.