The Diagnosis Value Of The Back-lead Electrocardiogram On Arrhythmia

Objective: To investigate the recording methods of back-lead electrocardiogram and its diagnostic value for arrhythmia combined with conventional 12-lead electrocardiogram.Methods: This study enrolled 102 cases, including out-patients, in-patients and healthy volunteers. There were 58 cases of male and 44 cases of female with a mean age of (41.9±19.2)years old. They were subdivided into two groups: one group with sinus rhythm (n=82) and the other group with arrhythmia (n=20). The Conventional 12-lead electrocardiogram and six back-lead (B1-6) electrocardiograms were recorded in the sitting position, the right lateral position and the prone position respectively. The ratios of the amplitude of P wave and QRS waves (P/R ratio) in all leads were calculated, and the back lead and position with the maximum P/R ratio were defined as the best electrode placement and record position. Because all of the P waves in the group with arrhythmia were difficult to identify in the Conventional ECG, we analyzed the P waves in the best back lead and position to diagnose the arrhythmia compared with their esophageal ECG or intracardiac ECG.Results: (1) The best back-lead and position: In the Sitting position, there were 11 cases (10.8%) in B1, 14 cases(13.7%) in B2, 45 cases(44.1%) in B3, 20 cases(19.6%) in B4, 6 cases(5.9%) in B5 and 6 cases (5.9%) in B6 with the maximum P/R ratio respectively; in the right lateral position, there were 19 cases(8.8%) in B1,11 cases(10.8%)in B2,51 cases(50.0%)in B3,19 cases(18.6%)in B4,6 cases(5.9%)in B5 and 6 cases(5.9%) in B6 with the maximum P/R ratio respectively; in the prone position, there were 9 cases (8.8%) in both B1and B2, 58 cases (56.9%) in B3, 14 cases (13.7%) in B4, 6 patients (5.9%) in B5 and 6 patients (5.9%) in B6 with the maximum P/R ratio respectively. The P/R value in B3 lead in the three different positions was 0.1556±0.0788,0.1331±0.0700,0.1210±0.0784 respectively. The P/R value in B3 lead in the sitting position was maximum .There was statistically significance in the differences. (2) P wave in the group with sinus rhythm can be recognized clearly in both the back-lead and Conventional ECG. The P/R value of B3 was significantly larger than the lead II (0.1576±0.0814 vs. 0.1056±0.0644). There was statistically significance in the difference. (3) The diagnostic value of Back-lead ECG for arrhythmia was similar to the esophageal or intracardiac electrocardiogram.Conclusion: (1) The B3 lead in the sitting position was the best back-lead placement and recording position. (2)The back-lead electrocardiogram could be helpful for recognizing abnormal P wave more easily in some patients with arrhythmia, and elevating the diagnostic value for arrhythmia combining with conventional 12-lead ECG.