Predicting the termination of paroxysmal atrial fibrillation (AF) may provide a signal to decide whether there is a need to intervene the AF timely. We proposed a novel RdR RR intervals scatter plot in our study. The abscissa of the RdR scatter plot was set to RR intervals and the ordinate was set as the difference between successive RR intervals. The RdR scatter plot includes information of RR intervals and difference between successive RR intervals, which captures more heart rate variability (HRV) information. By RdR scatter plot analysis of one minute RR intervals for 50 segments with non-terminating AF and immediately terminating AF, it was found that the points in RdR scatter plot of non-terminating AF were more decentralized than the ones of immediately terminating AF. By dividing the RdR scatter plot into uniform grids and counting the number of non-empty grids, non-terminating AF and immediately terminating AF segments were differentiated. By utilizing 49 RR intervals, for 20 segments of learning set, 17 segments were correctly detected, and for 30 segments of test set, 20 segments were detected. While utilizing 66 RR intervals, for 18 segments of learning set, 16 segments were correctly detected, and for 28 segments of test set, 20 segments were detected. The results demonstrated that during the last one minute before the termination of paroxysmal AF, the variance of the RR intervals and the difference of the neighboring two RR intervals became smaller. The termination of paroxysmal AF could be successfully predicted by utilizing the RdR scatter plot, while the predicting accuracy should be further improved.
This study aims to explore the intraventricular pressure difference (IVPD) within left ventricle in patients with paroxysmal atrial fibrillation (PAF) by using the relative pressure imaging (RPI) of vector flow mapping (VFM). Twenty patients with paroxysmal atrial fibrillation (PAF) and thirty control subjects were enrolled in the study. Systolic and diastolic IVPD derived from VFM within left ventricle and conventional echocardiographic parameters were analyzed. It was found that the B-A IVPD of left ventricle in PAF patients showed the same pattern as controls—single peak and single valley during systole and double peaks and double valleys during diastole. Basal IVPD was the main component of base to apex IVPD (B-A IVPD). The isovolumetric systolic IVPD was associated with early systolic IVPD, early systolic IVPD was associated with late systolic IVPD, and late systolic IVPD was associated with isovolumic diastolic IVPD (all P < 0.05). The B-A IVPD and basal IVPD during isovolumetric systole, early systole, late systole and isovolumetric diastole in PAF patients significantly decreased (all P < 0.05). The study shows that the B-A IVPD pattern of the PAF group is the same as controls, but systolic B-A IVPD and basal IVPD are significantly reduced in PAF patients. VFM-derived RPI can evaluate left ventricular IVPD in PAF patients, providing a visually quantitative method for evaluating left ventricular hemodynamic mechanics in the patients with PAF.