Waveform abnormalities

Horan LG, Hand C, Johnson JC, Sridharan MR, Rankin TB, Flowers NC (1978) A theoretical examination of ventricular repolarization and the secondary T wave. Circ Res 42 750-757 Mandel WJ, Burgess MJ, Neville J, Abildskov JA (1968) Analysis of T waveform abnormalities associated with myocardial infarction using a theoretical model. Circulation 38 178-188 Moe GK, Abildskov JA, Han J (1964) Factors responsible for initiation and maintenance of ventricular fibrillation. In Sudden Cardiac Death , NY Grune Stratton 56-63 Nielsen BL (1973) ST-segment elevation in acute myocardial infarction. Prognostic importance. Circulation 48 338-345... 

Figure 9-3 Scope Setup and Abnormal Waveforms for a Buck and a Boost...

Electroencephalography (EEG) records the electrical activity of the brain. The record is interpreted by observing the basic rhythms and waveforms, the symmetry of the recording, and abnormal electrical discharges. It also may be used to assess the response to photic stimulation or hyperventilation. It is used primarily in the diagnosis of seizures and may be helpful in the evaluation of patients with altered mental status. EEG also may be used to measure evoked potentials (EPs). The EPs are the EEG response to repetitive stimuli (visual, auditory, or tactile) and provide information about the presence of abnormalities and disturbances (but not the cause) in the specific pathways tested. 

During the concentric needle examination, the investigator searches for abnormal insertional activity, spontaneous activity in relaxed muscles, and motor unit potentials with abnormal appearance. The waveshape of motor unit potentials is assessed on the basis of the quantitative waveform features defined in Figure 25.7 ... 

Nervous system Abnormal, asymptomatic electroencephalographic (EEG) waveforms were observed in almost 20% of 197 patients... 

Continuous-wave (CW) Doppler waveforms are commonly used in conjunction with segmental pressures or ABIs. Waveforms can help in identifying the location of arterial disease in the lower extremity. Waveforms are usually taken from the common femoral, superficial femoral, popliteal, dorsalis pedis, and posterior tibial arteries and recorded on a strip chart recorder. Qualitative analysis of the waveforms is performed to identify abnormalities in the arterial circulation. The presence of triphasic waveforms at any level indicates absence of a hemodynamically significant arterial lesion proximal to that level. Attenuated waveforms that have lost their triphasic appearance indicate an arterial stenosis proximally. 

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