THE VALIDITY OF ELECTROCARDIOGRAPHIC QTC INTERVAL IN PREDICTING LEFT VENTRICULAR DIASTOLIC DYSFUNCTION IN HYPERTENSIVE PATIENTS

Hemn Hadi Kareem a and Amar Talib Al-Hamdi b


a Sulaimani Cardiac Hospital, Sulaimani, Kurdistan Region, Iraq. 
b Consultant Cardiologists and Electrophysiologist, Sulaimani, Kurdistan Region, Iraq.
  

Submitted: 25/7/2019; Accepted: 27/7/2020; Published: 21/9/2020

ABSTRACT


Background 

The QT interval extends from the onset of the QRS complex to the end of the T wave. Thus, it includes the total duration of ventricular activation and recovery and, in a general sense, reflects the duration of the ventricular action potential. The QT interval on electrocardiography is temporally aligned with diastolic dysfunction. 


Objectives 

To determine the significance of corrected QT (QTc) interval prolongation in predicting left ventricular diastolic dysfunction in hypertensive patients.


Patients and Methods

A cross-sectional study was conducted in the echocardiography department of SHAR teaching hospital from December 2018 to May 2019, on subjects diagnosed as hypertension; twelve lead electrocardiography was done to obtain QTc using Bazett formula. Echocardiography was performed using M mode, two-dimensional image, pulse wave, and tissue Doppler to calculate left ventricular diastolic dysfunction according to the published guideline.


Results

In this study, 64 patients who have met the inclusion and exclusion criteria were enrolled, 45.3 %( n=29) were male and 54.7 %( n=35) were female. 25 subjects (39.1%) met the criteria of diastolic dysfunction, and 39 subjects (60.9%) had a normal diastolic function. The mean QTc value of the diastolic dysfunction group was 459.2 ± 14.7 ms, while the mean QTc of normal diastolic function group was 402.8 ± 26.4 ms (P-value <0.001). The diagnostic value of the prolonged QTc interval (QTc >450 ms in male and > 460 ms in female) in determining diastolic dysfunction is 68 % sensitivity, 97.4% specificity, 94.4% positive predictive value, 82% negative predictive value and 85.9% accuracy. Among all variables; only ejection fraction (EF)%, echocardiographic LVH, tricuspid regurgitation (TR) velocity, E/e’ and left atrial volume index (LAVI) had statistically significant relation to QTc.


Conclusion

Electrocardiographic QTc interval is a simple but useful and accurate measurement for predicting diastolic dysfunction in hypertensive patients providing its high sensitivity and specificity.


KEYWORDS

Diastolic dysfunction; QTc interval; Hypertension.

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