In hypertrophic obstructive cardiomyopathy, smaller aorto-mitral angle and increased coaptation height contribute to SAM and LVOT obstruction; MR severity associates with AML length and LVOT gradient.
In HOCM, a smaller aorto-mitral angle and increased mitral coaptation height contribute to SAM and LVOT obstruction, while MR severity is independently associated with anterior mitral leaflet length and mean LVOT gradient.
Absolute Event Rate: 0% vs 0%
Abstract Objective The mechanism underlying systolic anterior motion (SAM) of the mitral leaflets and the associated mitral regurgitation (MR) remains debatable in patients with hypertrophic cardiomyopathy (HCM) and left ventricular outflow tract obstruction. We hypothesize that both phenomena may originate from a shared pathophysiological mechanism related to mitral valve geometry. Materials and Methods This study included 177 consecutive patients diagnosed with hypertrophic cardiomyopathy (HCM). Mitral valve morphology, systolic anterior motion (SAM), and the severity of mitral regurgitation (MR) were comprehensively evaluated using transthoracic echocardiography. The aorto-mitral angle, mitral leaflet length, mitral coaptation height, and left ventricular outflow tract gradient (LVOTG) were measured at rest. MR severity was graded according to established guidelines, and patients were categorized into two groups: Group A (MR moderate) and Group B (MR ≥ moderate). A multivariable stepwise forward logistic regression analysis was conducted to identify the common determinants of LVOTG and MR severity in HCM. Results A total of 52 patients (mean age 51 ± 16 years, 36.54% female) were classified into Group A, while 125 patients (mean age 49 ± 14 years, 34.40% female) were in Group B. There were no significant differences between the groups in terms of age, sex, or body mass index (BMI). Compared to Group A, patients in Group B had significantly greater maximum interventricular septal thickness (IVSmax), anterior mitral leaflet (AML) length, posterior mitral leaflet (PML) length, mitral coaptation height (CoapH), peak left ventricular outflow tract gradient (LVOTG), and mean LVOTG (all p 0.001). In contrast, the aorto-mitral angle was significantly smaller in Group B (p 0.001). Peak LVOTG and systolic anterior motion (SAM) were independently associated with the aorto-mitral angle and CoapH; mean LVOTG was independently associated with the aorto-mitral angle and AML (all p 0.001). After adjusting for IVSmax, peak LVOTG, PML, CoapH, and aorto-mitral angle, MR grade was independently associated with AML (β = 0.29, p = 0.001) and mean LVOTG (β = 0.35, p 0.001). Conclusion In HOCM, a smaller aorto-mitral angle and increased mitral coaptation height contribute to SAM and LVOT obstruction, while MR severity is independently associated with anterior mitral leaflet length and mean LVOT gradient. These findings highlight a shared pathophysiological mechanism linking SAM and MR, underscoring the critical role of mitral geometry in disease progression and its importance in determining the need for mitral valve repair during septal myectomy.Figure 1.Mitral valve geometry Table1.
Wang et al. (Sat,) reported a other. In hypertrophic obstructive cardiomyopathy, smaller aorto-mitral angle and increased coaptation height contribute to SAM and LVOT obstruction; MR severity associates with AML length and LVOT gradient.
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