Anomalous papillary muscle producing dynamic left ventricular outflow tract obstruction.

A patient with a dynamic left ventricular outflow murmur was shown to have an anomalous anterolateral papillary muscle by transthoracic and transesophageal two-dimensional Doppler echocardiography. High late systolic outflow velocity and systolic anterior motion were demonstrated in the lateral outflow tract near the anomalous muscle, suggesting a role for the Venturi effect. This is the first confirmation by Doppler echocardiography of an anomalous papillary muscle contributing to abnormal left ventricular hemodynamics.