Clinical features of the systolic anterior motion of the mitral valve among patients without hypertrophic cardiomyopathy.

BACKGROUND

The prevalence and clinical features of the systolic anterior motion of the mitral valve (SAM) without hypertrophic cardiomyopathy (HCM) have not been studied well.

METHODS

Records of 9180 sequential patients who underwent echocardiography at Tokyo Women's Medical University Hospital were reviewed. SAM patients were divided into those with HCM (HCM; n=60, 68%) and those without HCM (non-HCM; n=28, 32%). To assess SAM morphology, non-HCM patients were divided into the valvular and chordal groups.

RESULTS

The prevalence of non-HCM SAM was 0.3%. Non-HCM patients showed older age (65.7±15.0 years vs. 56.9±16.8 years, p=0.02), higher prevalence of sigmoid septum (75% vs. 50%, p=0.03), and lower left ventricular outflow tract pressure gradient (LVOT-PG) (27±31mmHg vs. 43±41mmHg, p=0.03) than HCM patients. However, 8 of 28 non-HCM patients showed a LVOT-PG >30mmHg. Valvular SAM showed higher dyspnea prevalence (29% vs. 0%, p=0.04), higher LVOT-PG (39±36mmHg vs. 6±2mmHg, p<0.001), longer anterior mitral leaflet (28±2mm vs. 26±3mm, p=0.04) and more pronounced mitral regurgitation than chordal SAM.

CONCLUSION

Non-HCM SAM prevalence was 0.3% in the Japanese population. Non-HCM SAM correlated with older age, sigmoid septum, and a lower LVOT-PG compared with HCM SAM. Among non-HCM SAM, valvular SAM showed a significant symptom, higher LVOT-PG, and more pronounced mitral regurgitation than chordal SAM.