A Dynamic Cause of Cardiogenic Shock Identified on Point-of-Care Ultrasound: A Case Report.

Abstract

Dynamic left ventricular outflow tract obstruction (dLVOTO) is an important cause of cardiogenic shock to consider as its management differs from garden-variety cardiogenic shock from systolic dysfunction. It is best suited for serial evaluation by point-of-care ultrasound (POCUS) as its dynamic nature may cause it to be missed on routine echocardiograms. We present a case of a 95-year-old male who presented for constipation and went into cardiac arrest after manual disimpaction. After intubation and advanced cardiovascular life support with eventual return of spontaneous circulation, the patient developed cardiogenic shock. He developed persistent lactic acidosis, increasing ventilator requirements, and worsening renal function despite diuresis and escalating epinephrine and norepinephrine requirements. POCUS revealed left ventricular systolic dysfunction with apical hypokinesis and basal hyperkinesis suspicious for stress-induced cardiomyopathy. Moreover, systolic anterior motion of the mitral valve on M-mode ultrasound and a left ventricular outflow tract pressure gradient of 46 mm Hg on spectral Doppler were noted, consistent with dLVOTO. On recognition of dLVOTO, epinephrine and norepinephrine were weaned after adding vasopressin and phenylephrine. The patient's clinical status drastically improved thereafter and he was weaned off vasopressors and the ventilator within 48 hours. POCUS techniques that are often excluded from basic critical care ultrasound exams are required to identify the characteristic features of hemodynamically significant dLVOTO. These features are important to recognize in cardiogenic shock as inotropes and diuresis can lead to paradoxical worsening of the dLVOTO. Instead, these patients should be managed with pure vasopressors and measures to increase left ventricular preload (beta blockers and intravenous fluids).