[Recording of ventricular pressure by conventional catheter manometer systems. I. Minimal requirements of blood pressure recording systems and estimation of frequency response characteristics].

Parallel recordings of pressure pulses by conventional catheter manometer systems and catheter tip manometer demonstrate severe errors in the peak velocity of pressure rise estimated by conventional systems. This fact is due to inadequate dynamic response characteristics of conventional systems in relation to the frequency content of pressure curves. During cardiac rest the error in dp/dt max is less than 10% if the frequency response of the recording system is uniform up to 10 Hz, the corresponding value under maximal cardiac stimulation is about 40 Hz. This is equal to the first 10 harmonics of heart rate. The examination of left and right ventricular pressure curves leads to similar results. The experimental determination of dynamic response characteristics of cathermanometer systems requires a test system producing suitable sinus or step functions, parallel high fidelity recording of pressure functions to be recommended. A simple test station is described. Examinations of temperature influence on catheter material and resulting changes in dynamic response characteristics were carried out. The incubation of catheters at the temperature of 37 degrees C is indispensable. A new diagram for simplifying the interpretation of results is described. Other publications are discussed in viewpoint of employed techniques and representation of results.