The Relationship Between The Slope And Angle Of QRS With Left Ventricular Hypertrophy

Objective: The purpose of this study is to explore the relationship between the slope and angle of QRS and left ventricular hypertrophy, and observe the effects of pericardial effusion on QRS slope and angle.Methods: The 117 normal subjects constituted group A. There are 188 subjects who exhibited an echocardiographically demonstrable increase in thickness of interventricular septum(group B, 66 patients), interventricular septum and left ventricular posterior wall(group C, 24 patients), and isolated left ventricular internal dimension(group D, 98 patients). Group B is divided into groups B1(mild hypertrophy, 61 patients) and B2(severe hypertrophy, 5 patients) based on the measurements of interventricular septum.Group D is divided into groups D1(mild enlargement, 65 patients) and D2(severe enlargement, 33 patients) based on measurements of left Ventricular internal dimension.The patients who have pericardial effusion are divided into groups E1(trace or small amounts of fluid, 54 patients) and E2(or a large amount of fluid, 33 patients) based on the amount of pericardial effusion. All of the above patients have ECG examination within two months before or after ECG examination. The electrocardiograms(ECG) of the above cases are reviewed in order to explore the relationship between the slope and angle of QRS and left ventricular hypertrophy and the effects of pericardial effusion on QRS slope and angle.Results:(1) Compared with normal subjects, all kinds of LVH have smaller angle R(?R), larger upward slope(S U) and / or smaller downward slope(S D) in leads I, V4 and V5. But there was no significant difference between the various types of LVH in the lead I(P> 0.05).D has greater S D than C in lead V4.Compared with B, C and D respectively have smaller S D and larger S U in lead V5.Compared with A, B has greater ?R and smaller S U, while C and D have smaller S D in lead a VF. Compared with B, C and D have smaller S D.(2) compared with A, B1 has smaller ?R, smaller S D and greater S U in leads I, V4 and V5. However, B1 has larger ?R and smaller S U in lead a VF. Compared with A or B1, B2 has not significantly different about all indicators.(3) D1 has smaller ?R, larger S U or smaller S D in leads I, a VF, V4 and V5. Compared with A, D2 has smaller ?R, larger S U or smaller S D, in leads a VF, V4 and V5. S D inverse relationship with LVEDD in leads a VF and V5.(4) Compared with A, E1 has not significant different on all indicators(P> 0.05). E2 has greater ?R and S D, as well as smaller S U than E1 or A in leads I, a VF, V4 and V5.(5)The Sensitivity of standard 12-lead ECG diagnosis of LVH is 28.79%, 45.83% and 54.08% on B, C and D.Their specificity is 67.91%, 68.68% and 77.78%.Conclusion:(1) Left ventricular hypertrophy resulting in smaller ?R, larger upward slope(S U) or smaller downward slope(S D) in leads I, V4 and V5. S D is inversely proportional with LVEDD in leads a VF and V5.(2) The increase in thickness of IVS and LVPW and the enlargement of LVEDD lead to smaller ?R, larger S U or smaller S D. But the increase in thickness of isolated IVS causes larger ?R and smaller S U in a VF.(3) The increase in thickness of IVS and LVPW or isolated IVS has no effect on R-wave voltage of lead a VF. While the changes of ?R, S U and S D in a VF have significant differences.(4) Micro small amount of pericardial effusion have no effect on QRS slopes and angles.Large pericardial effusion resulting in larger R ?R, smaller S U or larger S D in leads I, V4 and V5.