The two main diagnostic tests used to confirm right ventricular hypertrophy are electrocardiography and echocardiography. Polysomnography often includes electroencephalography, electromyography, electrocardiography, muscle activity and respiratory function. The Holter's most common use is for monitoring ECG heart activity (electrocardiography or ECG). EDF+ has applications in PSG, electroencephalography (EEG), electrocardiography (ECG), electromyography (EMG), and Sleep scoring. DCT can be used in electrocardiography for the compression of ECG signals. Services include general x-ray, mammography, ultrasound, electrocardiography, spirometry and laboratory services. Sleep researchers also use simplified electrocardiography (EKG) for cardiac activity and actigraphy for motor movements. Blood tests, electrocardiography, and chest radiography may be useful to determine the underlying cause. In electrocardiography, the T wave represents the repolarization of the ventricles. This is determined usually either by palpation or electrocardiography. Patients receiving emetine should be monitored for changes in pulse, blood pressure and electrocardiography. The first use of electrocardiography in clinical medicine was in 1908. Numerous diagnoses and findings can be made based upon electrocardiography, and many are discussed above. It has an appearance on electrocardiography of irregular electrical activity with no discernable pattern. "Electrocardiography" (ECG/EKG in German vernacular.