The Relation Between Left Ventricular Wall Stress and QT Dispersion in Hypertensive Urgency Patients

Polat Durukan; Murat Pekdemir; Yılmaz Özbay; Ilgın Karaca; Mustafa Yıldız; Mehmet Akbulut; Cemil Kavalcı; Ali Rahman

Polat Durukan¹, Murat Pekdemir², Yılmaz Özbay³, Ilgın Karaca³, Mustafa Yıldız⁴, Mehmet Akbulut³, Cemil Kavalcı⁵, Ali Rahman⁶

¹Department Of Emergency Medicine, Medicine Faculty Of Erciyes University, Kayseri
²Department Of Emergency Medicine, Medicine Faculty Of Kocaeli University, Kocaeli
³Departments Of Cardiology,medicine Faculty Of Fırat University, Elazığ
⁴Departments Of Emergency Medicine, Medicine Faculty Of Fırat University, Elazığ
⁵Ankara Atatürk State Hospital, Emergency Department, Ankara
⁶Departments Of Cardiovascular Surgery, Medicine Faculty Of Fırat University, Elazığ

Abstract

Objectives: Mortality of hypertensive patients is due to systolic and diastolic dysfunction and hypertrophy of left ventricle, coronary artery disease, arrhythmias and sudden death. Measurement of QT dispersion (QTD) is a noninvasive method for evaluation of heterogenity of myocardial repolarization and it is thought to accompany arrhythmogenic events. Left ventricular hypertrophy is accepted to be the major factor affecting QTD in hypertensive patients. Aim of this study is to investigate the relation between QTD and left ventricular wall stress caused by an increase in afterload independant from left ventricular hypertrophy in hypertensive urgency patients.
Materials and Methods: Standart 12-lead surface electrocardiographic records of 76 patients matching inclusion criteria were taken in hypertensive period and period in which mean blood pressure lowered 10% by Na-nitroprussid and then QTD and corrected QT dispersion (QTcD) were calculated. Left ventricular geometric patterns were determined by echocardiographic measurements.
Results: Mean age of the patients was 57.29±11.3 and 68.4% of them were women. In the hypertensive period mean systolic blood pressure (SBP), QTD and QTcD were 192.11±20.2 mmHg, 45.79±14.90 msec and 54.78±17.96 msec and in lowered blood pressure (LBP) period they are 149.08±11.9 mmHg, 29.47±13.65 msec and 34.06±15.73 msec respectively (p<0.001). In 50% of patients concentric hypertrophy and in 11.8% of patients normal ventricular geometry were detected. According to left ventricular geometry mean QTD and QTcD were similar between the groups in hypertensive and LBP periods. Although mean QTDs were similar (p=0.058) in normal left ventricular geometry group in both hypertensive and LBP periods, mean QTcDs were different (p=0.036). In patient groups having other left ventricular geometric patterns mean QTD and QTcD were different in hypertensive and LBP periods (for each p<0.05). In hypertensive patients when blood pressure is high, due to an increase in afterload ventricular wall stress increases and due to myocardial ischemia QTD and QTcD lengthen, when the blood pressure comes to normal QTD and QTcD shorten.
Conclusion: As a result it is thought that when blood pressure changes acutely, QTD and QTcD change due to left ventricular wall stress.