Introduction: continuous noninvasive hemodynamic monitoring by the method of electrical velocimetry (EV) is used mainly in intensive care setting for beat to beat monitoring of the cardiac output (CO) and systemic vascular resistance (SVR).
Methods: to asses the usefulness of the beat to beat noninvasive recording of CO, SVR and heart rate using 4 standard ECG electrodes and intermittent manual blood pressure measurements during head up tilt testing (HUTT) in syncope patients.
Results: 212 patients referred for syncope evaluation underwent HUTT with nitroglycerine challenge using non-invasive monitoring by EV method. HUTT was positive in 157 (74%). Positive responses were predicted by progressive decrease in SVR (dyne/cm5/m2) at symptom onset comparing with baseline: 2175±321 vs. 2090±431 (p=NS) and 1178±215 vs. 1701±382 in patients with negative response (p<0.1). Concomitant changes in CO and SV but blood pressure( BP)recording was available at a mean interval of 42±12 seconds.
Conclusions: the EV hemodynamic monitoring method can be used during HUTT but limitations on continuous BP measurement and carotid massage have to be considered.