| Objective To study the variations of QT interval, QT dispersion (QTd), and Tpeak-Tend (TpTe) interval through surface electrocardiogram (ECG) in patients undergoing primary percutaneous coronary intervention for ST segment elevation myocardial infarction and the their relationships with malignant ventricular arrhythmia.Methods All of the102subjects were selected from the admission patients of the CCU, Cardiology department of Tianjin medical university general hospital since January2007to July2001. All of the subjects underwent primary percutaneous coronary intervention for ST segment elevation myocardial infarction. They all received ECG monitoring for at least1week. According to the results of the ECG monitoring,46patients who experienced ventricular tachycardia and/or ventricular fibrillation, aged69.28±11.97were included as case group, while the other56patients who did not experience ventricular arrhythmia were included as control group. Divided the patients into anterior myocardial infarction group and inferior and/or lateral wall myocardial infarction group according to the results of ECG and Coronary angiography (CAG). The case group was consisted of21patients with anterior myocardial infarction and25patients with inferior and/or lateral wall myocardial infarction, while the control group was27and29patients respectly. All of the patients met ST segment elevation myocardial infarction criteria according to2010Chinese expert consensus and2009AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram. Patients who had Valvular heart disease, congenial heart disease, hypertrophic cardiomyoopathy, chronic pulmonary disease, ventricular conduction block, pre-excitation syndrome, atrial fibrillation, electrolyte disturbance or who took pharmaceuticals which could effect QT interval or T wave morphology, such as amiodarone and sotalol, or who diagnosised myocardial hypertrophy in echocardiography (UCG) were excluded. QT and Tpeak-Tend intervals of each lead were measured from12-lead ECG before PCI, and were measured repeatly in the3day and7day respectly. QT dispersion, Rate corrected QT (QTc) and TpTe (TpTec) intervals, QTd were calculated according to Bazett’s formulation. The average values of the QT, QTc and TpTe, TpTec from all of the12, limb and precardial leads were also calculated respectly. The differences of the indexes above before and after PCI were compared and the relationship with malignant ventricular arrhythmia as well as the different locations of the infarction was aslo be evaluated.Results Compared to control group, the average values of TpTe and TpTec intervals from all of the12, limb and precardial leads were obvious longer in case group before PCI and in3rd,7th day(P<0.05). However, the average values of QT, and QTc intervals and from all of the12, limb and precardial leads had no differences between groups as well as QTd and QTcd(P>0.05). the average values of TpTe and TpTec intervals from all of the12, limb and precardial leads and malignant ventricular arrhythmia were obvious correlated. The upper limit of the average values of TpTe and TpTec intervals from all of the12leads of every segment and ventricular arrhythmia were linear correlated (r=0.677, P<0.05; r=0.698, P<0.05; respectly). There were no differences of the average values of QT, QTc and TpTe, TpTec intervals from all of the12, limb and precardial leads between anterior myocardial infarction group and inferior and/or lateral wall myocardial infarction group (P>0.05).Conclusion Among the patients who undergoing primary percutaneous coronary intervention for ST segment elevation myocardial infarction, TpTe and TpTec intervals were obvious longer in patients who experienced malignant ventricular arrhythmia, and these differences would exist for7days. Reperfusion could decrease the TDR in AMI patients. Both TpTe and TpTec intervals were associated with malignant ventricular arrhythmia and could be used to predictive the appearance of the malignant ventricular arrhythmia in AMI patientes. Both TpTe and TpTec intervals were independent of infarct-related artery. |
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