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Effect of percutaneous transluminal coronary angioplasty on QT dispersion and heart rate variability parameters
Ali Aydinlar1, Tunay Sentürk, Bülent Ozdemïr
1Department of Cardiology, Uludağ University School of Medicine, Görükle, Bursa, Turkey.
Insights
Percutaneous transluminal coronary angioplasty (PTCA) significantly reduced QT interval dispersion (QTcd) and sympathetic activity in patients with coronary artery disease. Heart rate variability (HRV) parameters also improved post-PTCA, with QTcd negatively correlating with sympathetic indicators.
Area of Science:
- Cardiology
- Autonomic Nervous System Function
- Cardiac Electrophysiology
Background:
- Assessing sympathovagal control in coronary artery disease (CAD) patients undergoing percutaneous transluminal coronary angioplasty (PTCA) is crucial.
- Heart rate variability (HRV) and QT interval dispersion (QTd) are key indicators of cardiac autonomic function and ventricular repolarization.
- Understanding the relationship between HRV and QTd post-PTCA can offer insights into procedural effects on cardiac control.
Purpose of the Study:
- To analyze HRV and QTd parameters in patients undergoing elective PTCA.
- To determine the correlation between HRV and QT dispersion parameters after PTCA.
- To evaluate the impact of PTCA on sympathovagal balance and ventricular repolarization.
Main Methods:
- 26 patients with single-vessel CAD undergoing elective PTCA were studied.
- Time- and frequency-domain HRV analyses (SDNN, rMSSD, LF, HF, LF:HF ratio) were performed.
- Corrected QT interval dispersion (QTcd) was calculated before and immediately after PTCA.
Main Results:
- QTcd significantly decreased post-PTCA (52.2 to 42 ms).
- HRV parameters (SDNN, rMSSD, HF) increased significantly post-PTCA.
- Significant negative correlations were observed between QTcd and LF (r=-0.87) and QTcd and LF:HF ratio (r=-0.56) post-PTCA.
Conclusions:
- PTCA leads to a significant reduction in QTcd in CAD patients.
- Post-PTCA, there is a decrease in sympathetic activity, indicated by reduced LF and LF:HF ratio.
- QTcd negatively correlates with sympathetic parameters (LF and LF:HF ratio) after PTCA, suggesting improved cardiac autonomic regulation.
Background:
The aim of the study was to analyse parameters reflecting the sympathovagal control of ventricular depolarisation and repolarisation [heart rate variability (HRV) and QT interval dispersion (QTd)] in patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA), and determine whether HRV correlates with QT dispersion parameters.
Methods:
The study consisted of 26 consecutive patients (16 men, 10 women) with single-vessel coronary artery disease (CAD) who underwent elective coronary angioplasty. HRV analyses of all subjects were obtained with the time- and frequency-domain methods. For frequency-domain analysis, low-frequency HRV (LF), high-frequency HRV (HF) and the LF:HF ratio were measured. For time-domain analysis, standard deviations of the normal-to-normal QRS intervals (SDNN) and square roots of the mean squared differences of successive N-N intervals (rMSSD) were obtained. QT intervals were also corrected for heart rate using the Bazett's formula, and the corrected QT interval dispersion (QTcd) was then calculated. All measurements (HRV parameters and QTcd) were made before and immediately after PTCA.
Results:
QTcd was significantly decreased after PTCA (52.2 +/- 3.5 vs 42 +/- 3.9 ms). SDNN (94.1 +/- 22 vs 123.9 +/- 35.2 ms), rMSSD (43.7 +/- 20.1 vs 73.4 +/- 14.5 ms) and HF (51.1 +/- 48.8 vs 64.2 +/- 28.6 ms(2)) were significantly higher after PTCA, whereas LF (142 +/- 41.5 vs 157.2 +/- 25.9 ms(2)) and the ratio of LF:HF (3.3 +/- 1.9 vs 2.1 +/- 1.2) were significantly decreased after PTCA. We observed a significant negative correlation after PTCA between QTcd and LF (r = -0.87, p = 0.01) and between QTcd and the ratio of LF:HF (r = -056, p < 0.05).
Conclusion:
Among the patients with CAD undergoing PTCA, QTcd significantly decreased after PTCA, and negatively correlated with LF, the parameter reflecting the sympathetic system.
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