The Timed Vectorcardiogram: A Useful Tool To Measure QT Interval

Objective The present study was designed to determine the clinical practical value of timed-vectorcardiogram for QT duration and parameters correlated. Methods QT interval QTd,QTc,QTcd is compued and measured in 110 healthy person and 45 atrial fibrillation patients in the First Affiliated Hospital of Xin jiang Medical University from March 2007 to March 2008 in this study,using 12-lead synchronous ECG and directedly from timed-vectorcardiographic frontal , horizontal, and right sagittal plane; and prospective method was performed when ECG and T-VCG materials were analyzed.Results In control group 63 cases were male and another 41 are female (accounts for 60.6% and 39.4% respectively ), aged between 4～83 years (mean 43.14±18.63). In Atrial Fibrillation group, 34 cases were male and another 11 are female (accounts for 75.6% and 24.4% respectively ), aged between 60.6～13.83 years (mean 43.14±18.63). 113 cases were Han, 34 were Uyger and 8 were another minorities (accounts for72.9%, 21.9% and 5.2% respectively ). 1) There are no significantly statistical differences of QT,QTc,QTd,QTcd beween using ECG and T-VCG in control group. 2) There are no significantly statistical differences of QT ,QTc between ECG and T-VCG in AF group . There are no significantly statistical difference of QTd,QTcd between group. 3) There are no significantly statistical differences of QT intervl between control group and AF group. There are significantly statistical difference of QTc; QTd, QTcd between two group. 4) There are no significantly statistical differences between the femail and mail. 5) There are no significantly statistical differences between the Han and Uygur. 6) There is a positive relationship between age and QTc,QTcd of ECG and QT,QTcd of T-VCG. There is a no relationship between age and QT,QTd of ECG and QTc,QTd of T-VCG.. 7) There is a positive relationship between heart rate and QT of ECG and T-VCG. There is a negative relationship between heart rate and QTc of ECG and T-VCG .There is a no relationship between heart rate and QTcd,QTd of ECG and QTd,QTcd of T-VCG.8)The lead which the biggest and smallest QT in is avF,? respectively in EVG(account for 53.5% and 46.5% respectively).The plane which the biggest and smallest QT in is right sagittal and horizontal plane(account for 16.67% and 18.06% respectively).Conclusion Our data suggest that the timed-vectorcardiogram appears to combine the advantages of the time relationships as best shown in the electrocardiogram ,and the graphic portray of vector forces as best seen in the spatial vectorcardiogram into a single simplified graphic method.It can be a used clinical tool to measure QT interval.