BACKGROUND: Since left ventricular reverse remodeling (LVRR) and sphericity index (SI) are correlated with DCM patients' survival, we attempted to establish the relationship between LVRR, SI and left ventricle (I,V) dimensions. METHODS: In 70 DCM patients, we measured EF, LV transverse (sLVd) and longitudinal (ILVd) diameters at hospital admission, then after 3 and 12 months. SI was assessed thus: SI=sLVd/ILVd. RESULTS: LVRR was present in 32 patients (52%). SI measurements were similar in LVRR-present and -absent groups at baseline (0.71 vs. 0.70) and differed after 3 and 12 months (0.61 vs. 0.72, P<0.005; 0.59 vs. 0.73, P<0.001; respectively). During 12 months. SI and sLVd decreased in the LVRR-present (0.71 vs. 0.61 vs. 0.59, P<0.05; 5.75 vs. 5.00 vs. 4.82 cm, P<0.001: respectively) and increased in the LVRR-absent cohort (0.70 vs. 0.72 vs. 0.73, P<0.001; 6.01 vs. 6.15 vs. 6.67, P<0.001; respectively). ILVd remained stable (8.23 vs. 8.16 vs. 8.38cm; 8.66 vs. 8.85 vs. 9.13 cm; respectively). SI was significantly correlated with sLVd but not with ILVd. At 3-month follow-up, SI (P<0.005, OR=14000 [95% CI: 5 - 3.9*10(7)]) was found to be a significant LVRR predictor via univariate logistic regression. CONCLUSIONS: To summarize, changes in sLVd arc crucial for changes in LV geometry, whereas ILVd has a negligible effect on this process. The presence of LVRR was not always associated with an improvement in SI and its absence with increase in SI. Since the assessment of SI is less complex than LVRR, SI as a significant LVRR predictor can be useful part of a regular echocardiography examination.