Results:

Baseline characteristics were similar between groups. All patients had increased left ventricular (LV) wall thickness, but normal LV cavity size and volume. LV wall thickness was decreased and the overall proportion of those with LV hypertrophy (LVH) declined in the GBS group (64% with LVH at baseline vs. 56% at 2 years). Left atrial volume decreased nonsignificantly in the GBS group, but was increased in the non-GBS cohort at 2 years. Right ventricular (RV) size decreased significantly in the GBS group at 2 years and correlated with body mass index (BMI) (p = 0.006). RV functional assessments were also improved. LV ejection fraction was normal in the majority of patients and not different between groups at baseline or 2 years. However, mid-wall fractional shortening was decreased at baseline, improved post-GBS, and correlated with exercise capacity (r = 0.12, p = 0.013). Similarly, LV filling pressures assessed by medial annulus E/E’ trended down in the GBS group and had a strong correlation with exercise duration (r = -0.16, p = 0.002). On multivariate analysis, factors independently associated with LV mass were change in BMI, age, and diastolic blood pressure. Findings on multivariate analysis were not different if surgical status was excluded from the model, suggesting that weight loss itself was the driving factor in improvement in chamber size and function.