| (Abstract)Objective:To compare different methods of QRS wave duration measurement on surface ECG, to explore the methodology to improve the accuracy.Methods:Randomly selected patients with a total of 172 cases who need radiofrequency catheter ablation or Pacemaker implantation in the First Affiliated Hospital of Kunming Medical College of Cardiology Catheter Room from April 2009 to February 2010, including 85 male and 87 female cases, the average age is 58.08±12.78 years old. Including 91 cases of paroxysmal supraventricular tachycardia,33 cases of sick sinus syndrome,24 cases of atrioventricular block,16 cases of intraventricular conduction block and 8 cases of Dilated Cardiomyopathy. Each patient simultaneously recorded surface 12-lead ECG of standards gain and paper speed on 12-lead ECG machine before entered the operating room and obtained four different reading groups,they are:automaticly measurement of the QRS wave duration (group 1), measured QRS wave on any leads with sub-rules (in this study I ECG) (group 2), the most abnormal wide QRS duration between 12 leads (group 3), QRS wave measured from the starting point of the earliest lead to the ending point of the latest lead (Group 4). Then use 32 channels digital signal analysis system to repeat show/describe synchronous 12-lead surface electrocardiogram. Recorded QRS duration when gain is 20mm/mv, set different record/display speeds, freezed clear images without interference, move the cursor on the screen carefully to find 12-lead QRS wave in the latest first starting point and ending point, record the time measured on the multi-channel system by the cursor automatically recorded and displayed, which screen speed 25mm/s for the group of 5,50 mm/s for the group of 6,100 mm /s for the Section 7. Analysis and comparison the value of the relevance and the extent of seven groups QRS wave duration, which P＜0.05 as statistically significant sentence.Results:1.7 groups QRS wave durations of 172 cases are:group 1 (111.4±18.34) ms,2 groups (90.0±12.03) ms,3 groups (111.16±16.64) ms,4 group (117.76±19.43) ms; 5 groups (125.63±29.3) ms; 6 group (125.7±32.73) ms; 7 group (127.76±32.54) ms. The order of QRS wave duration from small to large is:group 2＜group 3＜group 1＜4 group＜5 group＜6 group＜7 groups. The relevance descending order each group with the most wide-Group (Group 7) by correlation analysis were:6 group (r= 0.934)＞5 group (r= 0.873)＞4 group (r= 0.777)＞Group 1 (r= 0.667)＞3 group (r= 0.626)＞2 groups (r= 0.547).The LSD pairwise comparison method was: group1 was significantly different from group 2,5,6,7 (P＜0.05); group 2and the other six groups were statistically different (P＜0.05); group3 was significantly different from group 2,5,6,7 (P＜0.05); group4 was significantly different from group2 (P＜0.05); group5 andwas significantly different from group 1,2,3 (P＜0.05); group6 and was significantly different from group 1,2,3 (P＜0.05); group 7 was significantly different from group 1,2,3 (P＜0.05). The narrowest group (group2) underestimated the wave limits 29.56%(37.76 ms) than the most wide-QRS group (group7).2. The first sub-group is 36 patients whose computer QRS wave value≥120ms. Analyzed severe deformity QRS wave duration, QRS wave duration in each group were:group 1 (142.70±13.736) ms; 2 group (113.80±16.49) ms,3 groups (135.60±17.23) ms,4 group (146.50±16.37) ms. Group 5 (166.60±26.85) ms; Section 6 (167.80±27.16) ms; 7 group (168.90±27.17) ms. The order is the same with an overall analysis of 172 cases. The narrowest group (group2) underestimated the wave limits 32.62%(55.1 ms) (P＜0.05) than the most wide-QRS group (group7), compared to the 136 patients whose QRS＜120 ms (The narrowest group (group2 (84.82±22.67) ms) underestimated the wave limits 26.53%(30.64 ms) than the most wide-QRS group (group7(115.46±13.27)ms),the difference is even more pronounced.3. The second sub-group is 131 patients whose computer QRS wave value≥100ms. Analyzed QRS wave duration greater than normal reading, QRS wave duration in each group were:group 1 (117.52±16.45) ms; 2 group (93.04±11.85) ms,3 groups (116.74±14.82) ms,4 group (124.04±17.55) ms. Group 5 (131.91±30.79) ms; Section 6 (135.00±33.87) ms; 7 group (136.57±34.87) ms. The order is the same with an overall analysis of 172 cases. The narrowest group (group2) underestimated the wave limits 31.87%(43.53ms) (P＜0.05)than the most wide-QRS group (group7), compared to the 41 patients whose QRS＜100 ms (The narrowest group (group2(81.97±32.01)ms) underestimated the wave limits 22.58%%(23.92 ms) than the most wide-QRS group (group7 (105.89±11.21) ms),the difference is even more pronounced. But compared with 36 cases whose QRS wave≥120 ms, the extent of QRS wave duration underestimate has no significant difference (32.62%(55.1 ms) and 31.87%(43.53ms), P＞0.05).4.7 Detection of QRS wave duration are non-invasive operation and can be completed finished by one people, group 1 took an average of 6min, group 2 took 7min, group 3 to 7 took 8min. Cost of common ECG groups of about 20 yuan/time, less than the multi-channel digital signal analysis system groups.Conclusion:1. At present, varies methods that measure QRS wave on 12-lead simultaneous surface ECG are highly relevant are different.2. To compared with digital multichannel signal analysis system with high-gain, high-speed, high signal to noise ratio,other measurement methods exist QRS wave duration underestimate.The underestimate extent of visual ECG QRS wave with conventional paper-speed and gain is most obvious.3. The cases with intraventricular conduction delay, QRS wave duration underestimate degree measured by different methods is more significant different. It prompts that the ventricular wave is more significant broad, the more careful ventricular wave width measurement is need for patients. 4. In determining the indications for CRT and analysis of the severity of ventricular conduction disturbances and other special circumstances, the use of special methods of improving the QRS wave duration measurement accuracy is necessary.5. To improve QRS wave duration measurement accuracy,the method by cursor locking the synchronous display QRS wave group's first starting point to the latest ending point of surface 12-lead ECG on digital multi-channel physiological recording system with high signal to noise ratio, high gain, high-speed, seems the efficient, safe, simple, the first choice easy to repeat.
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