Determination of delay time in individual transfer function for central aortic pressure reconstruction

In previous research, time-delay （△t） was a more important parameter than the reflection coefficient in the individual transfer function of central aortic pressure reconstruction. The At can be obtained by electrocardiography （ECG） or phonocardiography （PCG）. Because the pre-ejection period remains an uncertain factor, the present study used ECG and PCG to define the delay time and analyzed the accuracy of the reconstruction results. The △tpre is the actual delay time derived from the aorta to the carotid pressure wave, △tpco is the time delay between the aortic valve component of the second heart sound and the dicrotic incisura of the carotid pressure wave, and AtEcc represents the delay from the interval of the ECG R-peak to the foot of the carotid pressure wave. Compared with the measured aortic pressure, the reconstruction result obtained by △t=△tpcslightly differed from the best result estimated by △t=△tpre. However, the differences between the result obtained by △t=△tEco and the best result were significant in terms of the diastolic blood pressure, and pulse pressure, and especially in terms of the augmentation index and root-mean-square-error. Thus, the At should be determined by PCG for central aortic pressure reconstruction in practice.

Central aortic systolic blood pressure can better predict prolonged QRS duration than brachial artery systolic blood pressure in rural community residents

Background Central aortic systolic blood pressure（CASP） has been shown to be a stronger predictor of target-organ damage and cardiovascular events than brachial systolic blood pressure（BSBP）, but there was no data about whether CASP can predict prolonged QRS duration more than BSBP. We examined the association of CASP and BSBP with QRS duration in rural community residents. Methods We retrospectively analyzed 490 rural community residents. Standard resting 12-lead ECG and central aortic blood pressure（CABP） were measured noninvasively in all subjects at baseline. The QRS duration was equal to or more than 120 ms being defined as prolonged QRS duration. Results The prolonged QRS duration group showed higher CASP（139.38 ± 11.67 vs. 135.36 ± 16.22, P = 0.031） and BSBP（136.03 ± 6.74 vs. 124.44 ± 13.01, P 〈 0.001） as compared with controls. Multivariate linear regression analysis showed that CASP, BSBP and heart rate were independently affecting QRS duration. Logistic regression analyses showed that CASP（OR 1.057, 95%CI： 1.027, 1.088, P 〈 0.001）and BSBP（OR 1.056, 95%CI： 1.027, 1.086, P = 0.032） were independent predictors of prolonged QRS duration after adjustment for age, sex, body mass index, heart rate. CASP had a better predictive value for prolonged QRS duration than（AUC： 0.793 vs. 0.601, P 〈 0.001） BSBP. Conclusions Our findings demonstrate that both CASP and BSBP are risks for prolonged QRS duration, but CASP can predict prolonged QRS duration better than BSBP.