Use of Catheter-tip. Velocity-Pressure Transducer

A catheter-tip velocity transducer with two high-fidelity pressure manometers was used to evaluate the left ventricular (LV) hemodynamic effects of intravenous propranolol (10 mg). Nine patients without clinical evidence of heart failure were studied. Pulsatile ascending aortic blood flow velocity and pressure and LV pressure were measured continuously during drug administration. Beat-to-beat changes in stroke volume index, stroke work index, LV end-diastolic pressure, maximum blood flow velocity and acceleration, and maximum LV dP/dt were determined. Propranolol produced a decrease in maximum blood flow velocity (from 58 ± 4.7 to 42 ± 5.1 cm/sec, p < 0.002), and acceleration (from 1181 ± 130 to 847 ± 117 cm/sec2, p < 0.002), max dP/dt (from 1361 ± 70 to 1146 ± 63 mm Hg/sec, p < 0.002), stroke volume index (from 47 ± 3.0 to 38 ± 3.2 mI/m2, p < 0.002) and total stroke work index (from 702 ± 33 to 603 ± 44 mJ/m2 p < 0.04), with little change in mean aortic pressure, peak systolic pressure and LV enddiastolic pressure. Depression in myocardial function was detectable within 1 minute after initiation of propranolol and persisted when negative chronotropic effects were eliminated by atrial pacing. The multisensor catheter technique allows rapid and safe detection of changes in cardiovascular function during propranolol administration in conscious man.