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Figure 5 Change in Left Atrial Pressure and Myocardial Relaxation According to the Severity of LVOT Gradient and Baseline MR

Only 2 patients had LVOT gradient <50 mm Hg and grade III or IV mitral regurgitation. However, as shown in (A), septal ablation led to decreases in left atrial pressure in patients with gradient 50 mm Hg independently of the severity of MR, whereas those patients with LVOT gradient <50 mm Hg more commonly had increases in left atrial pressure. *p = 0.002 and **p = 0.03 for comparison versus LVOT gradient <50 mm Hg and grade I or II mitral regurgitation. Furthermore, as shown in (B), improvement in tau (the time constant of myocardial relaxation) was observed in patients with gradients 50 mm Hg independently of the severity of MR. However, prolongation of tau more frequently occurred in those patients with gradients <50 mm Hg. *p = 0.006 and **p = 0.03 for comparisons versus LVOT gradient <50 mm Hg and grade I or II mitral regurgitation. All other comparisons were not statistically significant. LVOT = left ventricular outflow tract; MR = myocardial relaxation.