Dynamic Left Ventricular Outflow Tract Obstruction in a Patient with Massive Pulmonary Embolism

Case Presentation:

A 63‐year‐old white man complained of shortness of breath with sharp chest pain radiating to his left arm. His medical history included hypertension and several distant orthopedic surgeries. He denied immobility, recent long trips, or a personal or family history of prior blood clots. On examination, he was in moderate distress and diaphoretic; his blood pressure was 93/65 mm Hg, heart rate and rhythm 118/min sinus, respiratory rate 24/minute, and 2/6 systolic ejection murmur loudest at the left sternal border. His chest radiograph was unremarkable, and an echocardiogram showed a right ventricular strain pattern of S1Q3T3 and a right bundle branch block. The chest CTA showed a saddle embolus extending to the segmental divisions of the right upper and lower lobes. Echocardiography demonstrated right atrial and ventricular dilatation, pulmonary hypertension at 48 mm Hg, and a dynamic left ventricular outflow tract (LVOT) obstruction with a peak gradient of 64 mm Hg. The patient responded to fluid resuscitation. Serial echocardiogram showed resolution of the dynamic LVOT obstruction with diminution of the peak gradient to 17 mm Hg. His systolic ejection murmur also resolved.

Discussion:

Increased pulmonary artery pressure as a consequence of a massive pulmonary embolism (PE) will lead to right ventricular dilatation and dysfunction resulting in impaired left ventricular filling, decreased cardiac output, and ultimately hemodynamic instability and death. Our case is unique in that the patient's hemodynamic instability resulted not only from right ventricular hypertension but also from a dynamic LVOT obstruction from ventricular septal transmigration into the left ventricle. This phenomenon physiologically can mimic hypertrophic cardiomyopathy and is reversible with adequate fluid resuscitation.

Conclusions:

PE is associated with increased pulmonary artery pressure, right ventricular dilatation, and right ventricular dysfunction. Untreated massive PE has a mortality rate up to 38%. Physicians treating PE should evaluate cardiac structure and function with echocardiography and have a high clinical suspicion for a dynamic LVOT obstruction, especially in those with hemodynamic instability, as fluid resuscitation can readily reverse the condition.

Author Disclosure:

S. H. Nguyen, none; C. Butcher, none; A. Levitov, none.