Pathophysiology of dynamic left ventricular outflow tract obstruction in a critically ill patient.

Left ventricular outflow tract obstruction is not a rare problem in the intensive care units and can precipitate hemodynamic shock unresponsive to catecholamine therapy. The use of echocardiographic examination is extremely important in recognizing this phenomenon and its underlying conditions, finally identifying the most appropriate therapeutic strategy. The simple correction of one or more of these factors can dramatically change patients clinical outcome. We report the clinical case of a 72-year-old man who developed hemodynamic shock in the intensive care unit. Hypovolemia, catecholamine infusion, and mechanical ventilation induced geometric modification of the left ventricle causing a systolic anterior motion of the mitral anterior leaflet and a severe subaortic gradient. Simple restoration of fluids and discontinuation of medical therapy dramatically changed the outcome of the patient. A review of the medical literature has been carried out to deeply investigate pathophysiology of left ventricular outflow tract obstruction in critically ill patients.