These different patterns of ICG waveform are relatively easy to recognise and can be cost-effectively and quickly obtained to reliably distinguish between normal and abnormal cardiac function. The goal of fluid resuscitation in shock is to improve organ perfusion while avoiding the harms of excess fluid administration.
The O wave is associated with mitral valve opening and is abnormally enlarged in heart failure. Impedance cardiography was incorporated into routine exercise testing on a bicycle ergometer for a group of 15 patients (mean age 53.2 +/- 3.0 yrs, SEM) who had sustained a major myocardial infarct 6 to 12 months previously, (EF 38.1 +/- 3.5, SEM). The S wave reflects ventricular contractility and is deformed by ventricular dyssynchrony. Reproducibility for CO over one week was highly significant (r 0.94 P less than 0.001). It can, therefore, be abnormal in both atrial and ventricular arrhythmias and is abnormally increased when there is diastolic dysfunction. Normally, the A wave follows atrial contraction and occurs in late diastole.
The first derivative velocity waveform shows a smooth S wave that corresponds with systole, while the second derivative acceleration waveform (dZ/dt) contains several reference points that outline the A, S and O waves.
FUJIFILM IMPEDANCE CARDIOGRAPH SOFTWARE
Modern pattern recognition software can now produce a composite signal-averaged ICG that considerably simplifies interpretation. Breathing, arrhythmia, movements and posture interfere with the ICG. Date Posted: August 29, 2011: Recall Number: Z-3043-2011: Product: Medtronic SynchroMed II, Model 8637, (The SynchroMed® II Pump is supplied in 20 ml or 40 ml reservoir size. Impedance cardiography (ICG) charts the rises and falls of thoracic impedance as the fluid content of the chest changes with each heartbeat.
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