Abstract 11585: Determination of Aortic and Mitral Valve Opening and Closing Times Using Only LV Pressure Data

Abstract

Background: Identification of aortic and mitral valve opening and closure timing is crucial for assessment of left ventricle (LV) function, e.g. pressure-volume loops. This is particularly problematic when simultaneous imaging (e.g. echocardiography) is not available. We hypothesize that LV pressure and its time derivatives can detect valve opening and closure times. Our aim was to determine the aortic and mitral valve opening and closures using properties of the LV pressure waveform. Methods: For this pilot study, in 3 human participants in sinus rhythm, LV pressures were recorded with a high-fidelity catheter. Echocardiographic 2D-guided M-mode images were obtained across the aortic and mitral valves in the parasternal long axis view. The timing of aortic and mitral valve events was linked to the ECG tracing, using the peak of the ECG R wave as the reference point. For each participant, two consecutive heartbeats were selected and the first (dP/dt), second (d 2 P/dt 2 ), and third derivatives (d 3 P/dt 3 ) of LV pressure calculated. Local maxima and minima from these were compared with the valve timing from M-mode. Results: The maximum of dP/dt at the beginning of the systolic phase occurred consistently with the opening of the aortic valve. Local minimum and maximum d 2 P/dt 2 occurred at the closure of the aortic valve and pre-atrial contraction timing, respectively. The early diastolic minimum of d 3 P/dt 3 and early systolic maximum of d 3 P/dt 3 coincided with M-mode mitral valve opening and closure timing, respectively. There was a strong correlation between the valve events timing that was measured using these two methods (R 2 =0.98, p<0.001). Conclusion: Aortic and mitral valve timing defined using LV pressure waveform agrees with valve opening/closure timing determined using echo M-mode as the gold standard. Determination of these valve timings is helpful for advanced analysis of LV mechanics when simultaneous echocardiography is not available.