Week 3 Cardiovascular Questions
Chapter 13 Test Bank Questions
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A patient with heart failure may be at risk for hypomagnesemia as a result of which factor? a. Pump failure b. Diuretic use c. Fluid overload d. Hemodilution
ANS: B Hypomagnesemia can be caused by diuresis. Diuretic use with heart failure often contributes to low serum magnesium levels.
A patient with a serum potassium level of 6.8 mEq/L may exhibit what type of electrocardiographic changes? a. A prominent U wave b. Tall, peaked T waves. c. A narrowed QRS d. Sudden ventricular dysrhythmias
ANS: B Normal serum potassium levels are 3.5 to 4.5 mEq/L. Tall, narrow peaked T waves are usually, although not uniquely, associated with early hyperkalemia and are followed by prolongation of the PR interval, loss of the P wave, widening of the QRS complex, heart block, and asystole. Severely elevated serum potassium (greater than 8 mEq/L) causes a wide QRS tachycardia.
Which criteria are representative of the patient in normal sinus rhythm? a. Heart rate, 64 beats/min; rhythm regular; PR interval, 0.10 second; QRS, 0.04 second b. Heart rate, 88 beats/min; rhythm regular; PR interval, 0.18 second; QRS, 0.06 second c. Heart rate, 54 beats/min; rhythm regular; PR interval, 0.16 second; QRS, 0.08 second d. Heart rate, 92 beats/min; rhythm irregular; PR interval, 0.16 second; QRS, 0.04 second
ANS: B The parameters for normal sinus rhythm are heart rate, 60 to 100 beats/min; rhythm, regular; PR interval, 0.12 to 0.20 second; and QRS, 0.06 to 0.10 second.
Which diagnostic test is most effective for measuring overall heart size? a. 12-lead electrocardiography b. Echocardiography c. Chest radiography d. Vectorcardiography
ANS: C Chest radiography is the oldest noninvasive method for visualizing images of the heart, and it remains a frequently used and valuable diagnostic tool. Information about cardiac anatomy and physiology can be obtained with ease and safety at a relatively low cost. Radiographs of the chest are used to estimate the cardiothoracic ratio and measure overall heart size.
ST segment monitoring for ischemia has gained increasing importance with the advent of thrombolytic therapy. What is the most accurate method for monitoring the existence of true ischemic changes? a. Biomarkers b. Echocardiogram c. 5-lead ECG d. 12-lead ECG
ANS: D Cardiac biomarkers are proteins that are released from damaged myocardial cells. The initial elevation of cTnI, cTnT, and CK-MB occurs 3 to 6 hours after the acute myocardial damage. This means that if an individual comes to the emergency department as soon as chest pain is experienced, the biomarkers will not have risen. For this reason, it is clinical practice to diagnose an acute myocardial infarction by 12-lead electrocardiography and clinical symptoms without waiting for elevation of cardiac biomarkers.
