1. Figure 4 Doppler echocardiographic assessment
of left ventricular outflow tract obstruction (LVOTO)
Figure 4 | Doppler echocardiographic assessment of left ventricular outflow tract obstruction (LVOTO)93,94,95,96. a | The dynamic nature of LVOTO in hypertrophic cardiomyopathy gives rise to a continuous-wave Doppler (CWD) waveform often described as 'dagger-shaped'. The arrowheads indicate the concave-to-the-left pattern. b | In the presence of a gradient >60 mmHg, the pulsed-wave Doppler (PWD) trace at the entrance to the left ventricular outflow tract (LVOT), apical to the mitral valve, might show the 'lobster claw' abnormality. c | By contrast, the waveform of mitral regurgitation is usually symmetrical and bell-shaped. d | Complete systolic emptying of a hyperdynamic ventricle results in an asymmetric CWD profile; when the peak velocity has been reached, the left ventricular (LV) cavity is empty, so the trace returns to zero in late systole.
Sen-Chowdhry, S. et al. (2016) Update on hypertrophic cardiomyopathy and a guide to the guidelines
Nat. Rev. Cardiol. doi: /nrcardio