Chapter 185 - Electrocardiogram evaluation

Question 1

When reading an ECG, does the patient position affect the orientation and amplitude of the waveforms? The duration and intervals of the waveform?

Answer 1

• Orientation and amplitude of the waveforms can vary markedly
• Durations of the intervals and waveforms seldom are affected

Question 2

What is the most notable change on the ECG due to hypercalcemia?

Answer 2

QT-interval shortening => this finding can be an important signal to the clinician to measure both total and ionized calcium levels

Question 3

How does myocardial hypoxia affect T-waves?

Answer 3

• Sudden appearance of large T waves can be a sign of hypoxemia;
  => any abrupt change in T-wave appearance warrants an evaluation of the patient’s blood gases