Doppler Diagnosis

The diagnosis, guided by ECG, was typical of a “lobster claw” pattern. This is found in apical hypertrophic cardiomyopathy especially in association with mid-ventricular obstruction.^[1] The late systolic intraventricular gradient is a result of the opposing hypertrophied left ventricular (LV) walls, creating a narrow, hourglass-shaped ventricular cavity.^[2] The intracavitary diastolic gradient as seen in the Doppler figure is due to two factors: (a) blood may become entrapped under pressure in the apical cavity during ventricular systole and is able to empty out during relaxation, creating a small early diastolic gradient and (b) an impaired and delayed apical diastole, resulting in transiently higher pressures in the apex during diastole.^[3] The paradoxical jet flow in this patient, during diastole, was directed toward the base away from the apex, hence a negative Doppler shift. The timing of apical gradients is earlier than that of LV outflow tract (LVOT) diastolic gradients that occur when the anterior mitral leaflet contacts the septum, creating flow restriction into the LVOT.

These gradients can be quite high and need to be differentiated from LVOT gradients related to residual systolic anterior motion (SAM) postmyectomy. Failure to distinguish an intracavitary gradient from the one generated by SAM-septal contact might prompt the surgeon toward a more extensive septal resection, risking an iatrogenic ventricular septal defect.

The upright diagrammatic representation of the lobster claw pattern is shown in [Figure 3], which resembles the Doppler signal of this patient.

Figure 3: The upright diagrammatic representation of the lobster claw pattern, which resembles the Doppler signal of this patient Click here to view

The corresponding echo pictures are shown in [Figure 4] and [Figure 5].

Figure 4: Parasternal long-axis and apical three-chamber views showing significant left ventricular hypertrophy Click here to view

Figure 5: Due to technical limitations, a classical apical two-chamber view was difficult to obtain (as a portion of right ventricular is seen in the image). However, significant apical hypertophy with a classical “spade-” like pattern of left ventricular can be appreciated Click here to view