abnormal impulse conducting system conduction abnormal heart electrocardiography waveform feature 2010-09-30T04:16:30Z MP:0010508 MPheno.ontology abnormal ECG abnormal EKG abnormal cardiac electrocardiography abnormal heart ECG waveform features any anomaly in the pattern of the graphic record of the integrated action currents of the cardiac cycle represented as changes in voltage; the prominent waves in the ECG correspond to specific conduction activity in areas of the heart and the timing and amplitude of ECG waveforms provide valuable information about heart rate and rhythm csmith