（二）正常心电图波形 normal electrocardiographic complexes （三）心电图导联 leads of the ECG （一）心血管传导系统 cardiovascular intrinsic conduction sys【ppt】心电图学教学PPT(彩图完整版、免积分、完美奉献!tem .
Methods We comparedthe surface ECG in 12leadsduringsinus rhythm withtachycardia, and tried to findtherelation betweenthedifferentlocationsofretrogradeP' waveand QRS complex in all leads.