Ann Thorac Surg 2005;80:1564
© 2005 The Society of Thoracic Surgeons
Correspondence
Did the Global Myocardial Ischemia Produce an Influence On High-Frequency QRS Potentials: Reply
Shonosuke Matsushita, MD,
Yuzuru Sakakibara, MD
Department of Surgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575 Japan
(Email: shomatsu{at}md.tsukuba.ac.jp).
To the Editor:
Dr Terada [1] has raised several questions about our article regarding the relationship between the high-frequency QRS potentials and the cardiac index (CI) immediately after cardiac surgery [2].
In response to the first point, it is generally agreed that aortic cross-clamping time (AoCCT) is an important factor for myocardial damage in cardiac surgery. In fact, we have already reported the relationship between the recovery time from reduced high frequency potentials of QRS complex and AoCCT in pediatric cardiac surgery [3]. We found that the coefficient of correlation between the recovery time and AoCCT was high (r = 0.80; p = 0.0009). The correlation of the root-mean-square voltage (RMST) of the total QRS duration (ie, the value of high frequency potentials of QRS complex) and the CI were reevaluated according to a different AoCCT period every 10 minutes. The coefficients of correlation between the RMST and the CI were statistically significant regardless of the length of AoCCT. It was suspected that AoCCT was not the only factor reducing the postoperative RMST in adult cardiac surgery.
Regarding the second point, there were no significant differences between coronary artery bypass grafting and valve surgery in the RMST and the CI at 1 to 2 hours after aortic declamping (RMST: CABG, 71% vs valve, 64%; CI: CABG, 3.35 L/min/m2 vs valve, 3.32 L/min/m2).
Finally, the measurement of high-frequency potentials in off-pump coronary artery bypass grafting (OPCAB) was preliminarily performed. There was no significant reduction of high frequency RMST in the OPCAB group. However, further study is necessary for obtaining conclusions in association with various cardiac positionings in OPCAB.
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References
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- Terada Y. Did the global myocardial ischemia produce an influence on high-frequency QRS potentials?(letter) Ann Thorac Surg 2005;80:1563-1564.[Free Full Text]
- Matsushita S, Sakakibara Y, Imazuru T, et al. High-frequency QRS potentials as a marker of myocardial dysfunction after cardiac surgery Ann Thorac Surg 2004;77:1293-1297.[Abstract/Free Full Text]
- Abe M, Atsumi N, Matsushita S, et al. Recovery of high-frequency QRS potentials following cardioplegic arrest in pediatric cardiac surgery Pediatr Cardiol 2001;22:315-320.[Medline]
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