COMPARISON OF ARTERIAL STIFFNESS INDEX AND TPE/QT RATIO IN NORMOTENSIVE, PREHYPERTENSIVE AND HYPERTENSIVE SUBJECTS
Background: When the blood pressure rises, there is decrease in coronary blood flow to the endocardium and mid-myocardial cells, thereby slowing repolarization in these areas. The major underlying pathophysiology in essential hypertension is arterial stiffness. In this study we compared arterial stiffness index (ASI), T wave peak to end interval (Tpe) and Q to T wave (QT) interval on ECG tracings. Methods: It was a cross-sectional study. Written informed consent was obtained from all subjects. Using non-probability convenience sampling a total of ninety (90) male subjects aged 35â€“55 years were selected and divided into 3 equal groups, i.e., normotensive, prehypertensive and hypertensive. Blood pressure was measured with mercury sphygmomanometer according to the standard protocols. The ASI was calculated from digital volume pulse recorded by photoplethysmography via iWorx-214; physiological interface system. The 12-lead surface EGG was recorded with Delta-1 Plus digital ECG machine. The ECG tracings were scanned and saved in the computer. QTc, cQTp and cTpe/QTc ratio was calculated in normotensive, prehypertensive and hypertensive middle-aged men. These intervals were corrected by Bazzetâ€™s formulae. Results: The ASI was significantly different (p<0.0001) amongst the groups along with QTc and cQTp. However, cTpe intervals and cTpe/QTc were comparable amongst the groups. Conclusion: ASI is major culprit in pathophysiology of hypertension. QTc and cQTp interval are more robust parameter than other ECG markers in detecting trans-mural dispersion of repolarization in prehypertensive and hypertensive subjects.
Pak J Physiol 2018;14(2):34â€“7
2. Lee HY, Oh BH. Aging and arterial stiffness. Circ J 2010;74(11):2257â€“62.
3. Lee SH, Choi S, Jung JH, Lee N. Effects of atrial fibrillation on arterial stiffness in patients with hypertension. Angiology 2008;59(4):459â€“63.
4. Gupta P, Patel C, Patel H, Narayanaswamy S, Malhotra B, Green JT, et al. T(p-e)/QT ratio as an index of arrhythmogenesis. J Electrocardiol 2008;41(6):567â€“74.
5. Arima H, Murakami Y, Lam TH, Kim HC, Ueshima H, Woo J, et al. Effects of prehypertension and hypertension subtype on cardiovascular disease in the Asia-Pacific Region. Hypertens 2012;59(6):1118â€“23.
6. Yan GX, Antzelevitch C. Cellular basis for the normal T wave and the electrocardiographic manifestations of the long-QT syndrome. Circulation 1998;98(18):1928â€“36.
7. Kurbel S. A vector-free ECG interpretation with P, QRS & T waves as unbalanced transitions between stable configurations of the heart electric field during P-R, S-T & T-P segments. Theor Biol Med Model 2014;11(1):10.
8. Clarenbach CF, Stoewhas A-C, van Gestel AJR, Latshang TD, Lo Cascio CM, Bloch KE, et al. Comparison of photo-plethysmographic and arterial tonometry-derived indices of arterial stiffness. Hypertens Res 2012;35(2):228â€“33.
9. Millasseau SC, Ritter JM, Takazawa K, Chowienczyk PJ. Contour analysis of the photoplethysmographic pulse measured at the finger. J Hypertens 2006;24(8):1449â€“56.
10. Usman S, Reaz MBI, Ali MAM. Determining the arterial stiffness through contour analysis of a PPG and its association with HbA1c among diabetic patients in Malaysia. Acta Sci Technol 2013;36(1):123â€“8.
11. Mozos, I, Serban, C, Mihaescu, R. The relation between arterial blood pressure variables and ventricular repolarization parameters. Int J Collab Res Intern Med Public Health 2012;4:860â€“75.
12. Zhao Z, Yuan Z, Ji Y, Wu Y, Qi Y. Left ventricular hypertrophy amplifies the QT, and Tp-e intervals and the Tp-e/ QT ratio of left chest ECG. J Biomed Res 2010;24(1):69â€“72.
13. Porthan K, Virolainen J, Hiltunen TP, Viitasalo M, VÃ¤Ã¤nÃ¤nen H, Dabek J, et al. Relationship of electrocardiographic repolarization measures to echocardiographic left ventricular mass in men with hypertension. J Hypertens 2007;25:1951â€“7.
14. Hall JE. Guyton and Hall Textbook of Medical Physiology: Enhanced E-book: Elsevier Health Sciences; 2010;11:10â€“19s.
15. Passino C, Franzoni F, Gabutti A, Poletti R, Galetta F, Emdin M. Abnormal ventricular repolarization in hypertensive patients: role of sympatho-vagal imbalance and left ventricular hypertrophy. Int J Cardiol 2004;97(1):57â€“62.
16. Salles GF, Cardoso CRL, Muxfeldt ES. Prognostic value of ventricular repolarization prolongation in resistant hypertension: a prospective cohort study. J Hypertens 2009;27(5):1094â€“101.
17. Dekker JM, Schouten EG, Klootwijk P, Pool J, Kromhout D. Association between QT interval and coronary heart disease in middle-aged and elderly men. The Zutphen Study. Circulation 1994;90(2):779â€“85.
18. Schillaci G, Pirro M, Ronti T, Gemelli F, Pucci G, Innocente S, et al. Prognostic impact of prolonged ventricular repolarization in hypertension. Arch Intern Med 2006;166:909â€“13.
Pakistan Journal of Physiology, Pak J Physiol, PJP is FREE for research and academic purposes. It can be downloaded and stored, printed, cited and quoted with full reference of, and acknowledgement to the PJP.