Prediction of Head-Up Tilt Test outcomes through Heart Rate Variability Using Receiver Operating Characteristic Curve (ROC)

Abstract

Objective: To determine the cut-off values of heart rate variability (HRV) as a predictor of head-up tilt test (HUTT) outcomes using receiver operating characteristic (ROC) curve.

Study Design: Diagnostic accuracy study

Place and Duration of Study: This study was conducted at the Department of Cardiac Electrophysiology, Armed Forces Institute of Cardiology, Rawalpindi from January 2016 to October 2016.

Materials and Methods: Ninety- three adult patients both male and female with complaint of repeated unexplained syncope were registered. Head-up tilt test was performed, during the test patients were Holtered for getting ambulant ECG records using DMS 300-4L Holters. Cardio Scan premier 12 lux software was used to analyze frequency domain parameters of HRV. Heart Rate Variability cut-off values were determined by using Receiver operating characteristic (ROC) curve.

Results: Out of a total of 93 patients, 77 (82.8%) responded positively and 16 (17.2%) responded negatively to HUTT. The receiver operating characteristic (ROC) curve was utilized to find out the cut-off values of heart rate variability frequency domain parameters. ROC analysis of total power (TP) parameter measured during initial and terminal 5 minutes of stage -I of head-up tilt test was statistically significant.

Conclusion: Determination of cut-off values of total power (TP) parameters of heart rate variability by using the receiver operating characteristic (ROC) curve could predict the outcome of head-up tilt test results. This initial estimation can change the administration of nitroglycerine and shorten the duration of head-up tilt test.