Affiliations: [a] Department of Electrical & Computer Engineering, College of Engineering, Sultan Qaboos University, Oman | [b] Department of Physiology, College of Medicine, Sultan Qaboos University, Oman | [c] Division of Cardio-Thoracic Surgery, Sultan Qaboos University Hospital, Oman
Correspondence:
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Corresponding author: A. Hossen, Department of Electrical & Computer Engineering, College of Engineering, Sultan Qaboos University, Oman, P.O. Box 33, Al-Khoud, 123 Muscat, Oman. E-mail:[email protected]
Abstract: BACKGROUND: Myocardial revascularization by coronary artery bypass
grafting (CABG) is an effective measure for reducing symptoms and mortality
in patients with unstable or severe coronary artery disease (CAD). Autonomic
function can be estimated non-invasively using heart rate variability (HRV).
HRV of patients undergoing CABG is investigated before and after CABG using
a soft-decision wavelet based spectral analysis.
OBJECTIVE: The main purpose of this work is to evaluate
non-invasively HRV in patients undergoing CABG before operation; and to
monitor the status of patients through HRV investigation on day 6 and day 30
after the CABG operation.
The study intends to contribute scientific value to understanding the effect
of CABG on the cardiovascular autonomic function and surgical outcome. METHODS: The soft-decision wavelet-based technique is used in this
work in order to measure the power spectral density of the three main bands
(VLF, LF, and HF) of HRV in 24 patients undergoing CABG operation, before
the operation (Group 1: G1), and 6 days after operation (Group 2: G2) and 30
days after operation (Group 3: G3). The data is obtained from Sultan Qaboos
University hospital in Oman. RESULTS: The HF power increases in 22 out of 24 patients in G2
compared to G1. While the LF power decreases in 21 out of 24 patients in G2
compared to G1. Comparing G3 to G1 the LF power decreases in 20 patients.
The sum of the VLF and LF power is reduced in G2 in all 24 subjects compared
to G1, and in 19 subjects in G3 compared to G1. CONCLUSIONS: The power spectral density of the HF shows increase in
patients recorded on day 6 after operation compared to patients before the
operation. The LF shows a decrease in G2 compared to G1. The results of G3
after 30 days of operation still show an increase of the HF power and a
decrease in the LF power in most of the patients compared to their values
before operation.
