Introduction: Ventricular arrhythmia and sudden cardiac death risk are associated with prolonged electrocardiographic (ECG) QT and Tpeak-Tend intervals.
Objective: To evaluate the influence of blood pressure variables on ventricular repolarization parameters, especially QT and Tpeak-Tend intervals.
Method: Two groups of patients were enrolled in the study. The firs group included 77 patients, with essential hypertension, aged 62±12 years, 40% males. The control group included 56 patients, age and sex matched, with optimal, normal and high normal blood pressure. They underwent 12-lead ECG and ventricular repolarization parameters were assessed. QT intervals: QTmax (maximal QT interval duration), QTc (heart rate corrected QTmax), QTm (mean QT interval duration in all leads), QTIIc (heart rate corrected QT interval duration in lead DII), and T wave variables: T0e (maximal T wave duration), Tpe (maximal Tpeak-Tend interval) and Ta (maximal T wave amplitude) were manually measured. Arterial blood pressure variables: systolic (SBP), diastolic (DBP), mean arterial (MAP) and pulse pressure (PP), were recorded.
Result: SBP was 139±24 mmHg, DBP 86±13 mmHg, MAP 103±15 mmHg, PP 53±16 mmHg, QTmax 430±51 ms, QTc 474±48 ms and Tpe 100±26 ms in the hypertensive group. Multiple regression analysis revealed significant associations (multiple R=0.985, significance F<0.01) of DBP with QTIIc (p<0.01) and Tpe (p<0.01). MAP was significantly associated (multiple R=0.986, F<0.01) with QTc (p<0.001) and QTm (p=0.014). Multiple regression analysis also revealed significant associations between blood pressure variables and ECG parameters in the control group. Arterial blood pressure values and mean arterial blood pressure were sensitive and specific predictors of prolonged QT intervals in the hypertensive group.
Conclusion: Elevated systolic and diastolic blood pressures and mean arterial pressure are predictors of prolonged QT intervals. Blood pressure variables are associated with the ventricular repolarization parameters.