CASE PRESENTATION: A 73-year-old Asian woman on
escitalopram and
lorazepam was transported to our hospital for chest and
back pain with altered consciousness. On arrival, she was in
shock and developed pulseless electrical activity. After initiation of conventional
cardiopulmonary resuscitation according to adult advanced cardiovascular life support guidelines, she could not regain spontaneous circulation. She was ultimately resuscitated via
venoarterial extracorporeal membrane oxygenation initiation. The only abnormal laboratory result at admission was
anemia. Her hemodynamic status stabilized after
red blood cell transfusion, and
venoarterial extracorporeal membrane oxygenation was subsequently terminated. Transthoracic echocardiography showed a sigmoid septum;
dobutamine-infused Doppler echocardiography revealed a significant outflow gradient, and continuous monitoring showed Brockenbrough-Braunwald sign, which confirmed a diagnosis of latent
left ventricular outflow tract obstruction due to a sigmoid septum. As a result,
carvedilol and
verapamil were initiated. A follow-up
dobutamine-infused Doppler echocardiography showed a reduction of outflow gradient, and she was discharged without any sequelae. Latent
left ventricular outflow tract obstruction worsened due to increasing cardiac contraction and the depletion of preload and afterload. Depleted preload occurred due to
dehydration and
anemia, whereas depleted afterload occurred due to the prescribed drugs, which subsequently caused pulseless electrical activity. Moreover, β-stimulation from the
adrenaline probably enhanced the hypercontractile state and caused refractory pulseless electrical activity in our case.
CONCLUSIONS: