Unexplained hypotension: the spectrum of dynamic left ventricular outflow tract obstruction in critical care settings

To illustrate the clinical and hemodynamic abnormalities caused by dynamic left ventricular outflow tract obstruction (LVOTO) in critical care setting.

We reviewed cases referred to Cardiology with echocardiographic evidence of LVOTO and their clinical presentations. We present those cases where LVOTO can transiently occur without hypertrophic cardiomyopathy when inotropic agents are used for hypotension.

Five women in the 50-70 age range and prior history of hypertension presented with various symptoms like chest discomfort, fatigue, dizziness, atrial fibrillation, and hypotension. An ejection systolic murmur was noted most often in the left third intercostal space and ECG revealed ST-T wave abnormalities. LVOTO caused by mitral systolic anterior motion was detected by echocardiography and catheterization excluded acute coronary disease. In critical care setting, LVOTO can occur due to apical ballooning syndrome, coronary disease, medications, volume depletion, and valvular abnormalities. Because this condition mimics acute coronary syndrome or other etiologies of hypotension in medical and surgical intensive care units, appropriate treatment can be delayed. Nonhypertrophic cardiomyopathy LVOTO usually responds well to fluid replacement, beta blockers, and medication changes.

LVOTO should be suspected especially in women presenting with hypotension and systolic murmur in critical care settings. Clinical acumen and timely echocardiography are required to effectively counter this transient but potentially lethal problem.