Abstract 10327: Admittance Method to Monitor Stroke Volume With Bi-Ventricular Devices
Background: Implantable cardioverter defibrillators (ICDs) monitor intracardiac electrocardiograms (EGM) to discriminate between ventricular and supraventricular tachycardias. The incidence of inappropriate shocks remains high due to misclassification of the tachycardia in an otherwise hemodynamically stable individual. Coupling EGMs with an assessment of left ventricular (LV) stroke volume (SV) would be helpful in gauging hemodynamic status during an arrhythmia and reduce inappropriate shocks.
Methods: An ultrasonic flow-probe and two-dimensional LV endocardial crystals (Vol (ml)) were placed in canines (n=12) as the standard for LVSV. Biventricular pacing leads were inserted to attain admittance measurements. A tetrapolar, compleximpedance measurement was made between the Bi-V leads (figure A). The real and imaginary components of impedance were used to separate and discard the myocardial from the blood component to derive instantaneous blood conductance (Gb). The alterations in SV were measured during pacing, dopamine infusion, and inferior vena cava occlusion (IVCO).
Results: Gb tracks steady state changes in SV more accurately than traditional magnitude (i.e.
- Arrhythmias, treatment of
- Implantable cardioconvert defibrillator
- Stroke volume
- Supraventricular tachycardia
- © 2013 by American Heart Association, Inc.