Rhythm-based heartbeat duration normalization for atrial fibrillation detection

Md Saiful Islam; Nassim Ammour; Naif Alajlan; Hatim Aboalsamh

doi:10.1016/j.compbiomed.2016.03.015

Rhythm-based heartbeat duration normalization for atrial fibrillation detection

Comput Biol Med. 2016 May 1:72:160-9. doi: 10.1016/j.compbiomed.2016.03.015. Epub 2016 Mar 24.

Authors

Md Saiful Islam¹, Nassim Ammour², Naif Alajlan³, Hatim Aboalsamh⁴

Affiliations

¹ Department of Computer Science, College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia. Electronic address: saislam@ksu.edu.sa.
² Department of Computer Engineering, College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia. Electronic address: nammour@ksu.edu.sa.
³ Department of Computer Engineering, College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia. Electronic address: najlan@ksu.edu.sa.
⁴ Department of Computer Science, College of Computer and Information Sciences, King Saud University, Riyadh 11543, Saudi Arabia. Electronic address: hatim@ksu.edu.sa.

PMID: 27043858
DOI: 10.1016/j.compbiomed.2016.03.015

Abstract

Background: Screening of atrial fibrillation (AF) for high-risk patients including all patients aged 65 years and older is important for prevention of risk of stroke. Different technologies such as modified blood pressure monitor, single lead ECG-based finger-probe, and smart phone using plethysmogram signal have been emerging for this purpose. All these technologies use irregularity of heartbeat duration as a feature for AF detection. We have investigated a normalization method of heartbeat duration for improved AF detection.

Method: AF is an arrhythmia in which heartbeat duration generally becomes irregularly irregular. From a window of heartbeat duration, we estimate the possible rhythm of the majority of heartbeats and normalize duration of all heartbeats in the window based on the rhythm so that we can measure the irregularity of heartbeats for both AF and non-AF rhythms in the same scale. Irregularity is measured by the entropy of distribution of the normalized duration. Then we classify a window of heartbeats as AF or non-AF by thresholding the measured irregularity. The effect of this normalization is evaluated by comparing AF detection performances using duration with the normalization, without normalization, and with other existing normalizations.

Results: Sensitivity and specificity of AF detection using normalized heartbeat duration were tested on two landmark databases available online and compared with results of other methods (with/without normalization) by receiver operating characteristic (ROC) curves. ROC analysis showed that the normalization was able to improve the performance of AF detection and it was consistent for a wide range of sensitivity and specificity for use of different thresholds. Detection accuracy was also computed for equal rates of sensitivity and specificity for different methods. Using normalized heartbeat duration, we obtained 96.38% accuracy which is more than 4% improvement compared to AF detection without normalization.

Conclusions: The proposed normalization method was found useful for improving performance and robustness of AF detection. Incorporation of this method in a screening device could be crucial to reduce the risk of AF-related stroke. In general, the incorporation of the rhythm-based normalization in an AF detection method seems important for developing a robust AF screening device.

Keywords: Atrial fibrillation; Electrocardiographic monitoring; Entropy; Heartbeat normalization; Heartbeat rhythm; Screening.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Atrial Fibrillation / diagnosis*
Atrial Fibrillation / physiopathology
Heart Rate*
Humans