Although classic Fabry's disease results in multiple causes of death, the cardiac variant of Fabry's disease affects only the cardiac system and results in initial symmetric left ventricular (LV) hypertrophy and later LV dysfunction, asymmetric basal posterior LV wall thinning, restrictive mitral flow, and functional mitral regurgitation with end-stage chronic heart failure (CHF), leading to death. The purpose of this study was to investigate whether these findings predict prognoses in patients with cardiac Fabry's disease. In 13 consecutive men with cardiac Fabry's disease, LV wall thickness, the ejection fraction, mitral E-wave deceleration time, the LV Tei index, and functional mitral regurgitation were measured by echocardiography. Patients were followed for 5 to 96 months (mean 41 +/- 9). Eight patients developed New York Heart Association class III CHF, and 6 experienced cardiac death. A LV Tei index >0.60 and basal posterior LV wall thinning with a ratio of ventricular septal to posterior wall thickness >1.3 significantly preceded CHF and death (Tei index: 4.4 and 5.1 years; posterior wall thinning: 4.0 and 4.7 years), respectively (p <0.05). In conclusion, an increased LV Tei index and asymmetric basal posterior LV wall thinning are important echocardiographic findings that precede CHF and cardiac death in patients with cardiac Fabry's disease.