Background and Aims

Echocardiographic diagnosis of left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) often requires extensive provocative maneuvers. The aim of this analysis was to investigate whether echocardiography-derived parameters obtained at rest are helpful in excluding or identifying LVOTO.

Methods

Consecutive HCM patients of a single-center HCM referral center underwent standardized transthoracic echocardiographic examination with provocative maneuvers. In post-processing analyses, length of mitral leaflets, and distances between mitral valve coordinates and ventricular walls at resting conditions were measured in parasternal long axis and apical three-chamber (3ch) views, both at early and late systole. The investigator was blinded to individual patient data.

Results

Among 142 patients (mean age 59±13 years, 42% women), 68 (42%) had resting or provocable LVOTO with a maximal LVOT gradient ≥ 30 mmHg. Late-systolic distance between mitral leaflet tip and ventricular septum in 3ch view (TIS) correlated with peak LVOT gradient at rest and during Valsalva maneuver (Spearman’s r=-0.79 and -0.80, P<0.001, each). The area under the ROC curve of TIS for identification of LVOTO was 0.91 (95% CI 0.87–0.96). TIS ≤14 mm had a sensitivity of LVOTO of 97%, with TIS >14 mm yielding a negative predictive value regarding LVOTO of 95%. TIS ≤9 mm had a specificity and positive predictive value of LVOTO of 95% and 92%, respectively (Figure 1).

Conclusions