Accuracy of Impedance Cardiography in Acute Myocardial Infarction: A Literature Review

measures the electrical resistance at high frequencies with low steady current amplitude (1.5 mA, 86 KHZ) generated by external sensors and electrodes (in the thoracic and cervical regions) that capture instantaneous voltage changes. e device behaves according to Ohm's law: when a steady current is applied to the thorax, the voltage changes are directly proportional to the impedance changes. The total thoracic impedance, named baseline impedance (Z), is the sum of the impedance of all thoracic components (adipose tissue, heart, lung, skeletal muscle, vascular tissue, bones and air). e electrodes sense the Z change resulting from the pulsatile blood flow through the descending aorta during systole and diastole. Over time, this alteration has a direct impact on the left ventricular contractility. The alteration of Z is converted to stroke volume and cardiac output values using mathematical algorithms. The other hemodynamic variables are measured or calculated from the ICG data and provided on a continuous and real-time basis. jor studies demonstrate the efficacy of this method, making possible an early evaluation of heart failure, treatment guidelines in hypertension and monitoring of hemodynamic performance in acute myocardial infarction and in the postoperative of cardiac surgery. Normally, these hemodynamic measurements would be obtained for only the most critically-ill patients, such as Swan-Ganz catheter monitoring. However, due to the risk, discomfort, and cost of invasive procedures, bioimpedance is considered safer and more economical. pedance cardiography has been an attractive alternative for determining body composition, since