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The 3-phase model of sudden cardiac arrest

…is in. The three phases following a sudden cardiac arrest were described by Weisfeldt and Becker (2002). Drawing on physiology, observational and experimental studies, they…

Technical aspects of the ultrasound image

…because the vibrations in the piezoelectric crystals, and thus the electric current they send back to the machine, vary with the amplitude of the reflected…

QT duration & corrected QT (QTc) duration: ECG features & implications

…incorporated in modern ECG machines) are to be preferred. QTc duration is calculated automatically in all modern ECG machines. Most machines present the longest QTc…

The electrical axis of the heart (ECG axis)

…is referred to as left axis deviation. The axis is calculated (to the nearest degree) by the ECG machine. The axis can also be approximated…

The electrical axis of the heart (heart axis): ECG & physiology

…is referred to as left axis deviation. The axis is calculated (to the nearest degree) by the ECG machine. The axis can also be approximated…

Assessment of Pacemaker Malfunction

…metabolic disorders, hypoxemia, antiarrhythmic drugs, or electromagnetic disturbance caused by other machines/devices. Below follows ECG tracings demonstrating each type of failure. Figure 1. Failure…

Cardiac electrophysiology: Action potential, automaticity and vectors

…by a repolarization (recovery). The action potential occurs in all cardiac cells but its appearance varies depending on cell type. During de and repolarization ions…

ECG in left ventricular hypertrophy (LVH): criteria and implications

…more complicated, indexes that are utilized in modern ECG machines but the sensitivity and specificity are only negligibly better than the old indexes. Figure 2…

Hemodynamic principles and calculations

…the investigator performs simple measurements and Doppler recordings, which the ultrasound machine uses to calculate various hemodynamic parameters. The Doppler effect The central principle to…

Pulsed Wave Doppler

…pulsed wave Doppler sends and analyses sound waves sequentially. The ultrasound machine is programmed to ignore all signals, except those reflected from a certain depth…

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