Left Ventricular Outflow Tract Obstruction
LVOTO is caused by systolic anterior motion (SAM) of the mitral valve. The anterior mitral valve leaflet moves into the LVOT and during systole comes into contact (severe cases) with the hypertrophied basal septum and affects blood flow through the LVOT, thus creating haemodynamic instability (figure 1). The degree of obstruction can vary and is dependent on several factors. LVOTO is dynamic and can worsen in the context of reduced preload (e.g. Valsalva), reduced afterload (vasodilators) and positive inotropes. [4]. Based on the severity of obstruction patients can experience a reduction in cardiac output, worsening of mitral regurgitation, diastolic dysfunction leading to increase in LV end diastolic pressure and affect coronary blood flow and some degree of arrhythmia (figure 2).[5]