Correlation of lipid profile and QT interval, T-wave changes as a risk factor for cardiovascular disease

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. Dyslipidemia is an important risk factor for the initiation and progression of atherosclerosis and is strongly associated with cardiovascular events. Many studies in the past have established the value of lipid profile abnormalities and the ECG changes- QT interval prolongation and T wave inversion as markers of future adverse cardiovascular events. This study will try to establish if these two individual risk factors are associated with each other or not. It was a prospective, observational study conducted on 40 subjects of abnormal lipid profile compared to 40 control subjects both of whom were otherwise healthy. In the ECG, parameters like RR interval and heart rate, QT interval (QTi), Corrected QT interval (QTC), T wave changes (inversion) was calculated and noted, then compared with both the groups. By the independent sample‘t’ test, when compared to the control group, the group with abnormal lipid profile showed a significant QTi prolongation (by P<0.02) and a highly significant QTc prolongation (by P<0.001). However, T wave inversion did not show any significant presence in the test group as compared to the controls. Abnormal lipid profile has shown a consistent positive association with QT interval prolongation while no such association exists with T wave changes. Thus patients with an abnormal lipid profile are likely to be associated with an additional CVD risk of prolonged QTc. This compounds the risk of CVD in patients with any one of these individual factors and therefore the threshold for preventive therapy like lifestyle modification and/or preventive drug therapy like low dose aspirin must be lowered.