Human Anatomy and Physiology : Help with Heart Injuries and Disorders
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Example Question #21 : Circulatory And Respiratory Systems
Hyperkalemia will most commonly cause what type of change to an ECG recording of the heart?
Flattened T-waves
Peaked T-waves
Short P-R interval
Peaked P-waves
Prolonged P-R interval
Peaked T-waves
The correct answer is peaked T-waves. The T-wave of an ECG reading corresponds to repolarization of the cardiac muscle after a ventricular contraction. Cardiomyocytes establish their repolarization through the influx of potassium during the T-wave. If potassium is elevated within the blood (i.e. hyperkalemia), this T-wave reading will be exaggerated due to the excessive influx of potassium into the cardiac cells.
Example Question #22 : Circulatory And Respiratory Systems
A 45 year old male with a history of hypertension (high blood pressure) and diabetes reports to the emergency room with three hours of chest pain. He is found to have a myocardial infarction as evidenced by EKG tracings. Which of the following laboratory tests is likely to be elevated in this patient?
Troponin
Blood urea nitrogen
Sodium
Calcium
Potassium
Troponin
Elevations in troponins are diagnostic for a myocardial infarction (heart attack). Troponin is a protein released into circulation from cardiac myocytes when they die from lack of oxygen. The other laboratory values are not affected by myocardial death.
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