ekg practice test Flashcards

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1. At standard paper speed, how fast does ECG paper move? A. 10 mm per second. B. 25 mm per second. C. 50 mm per second. D. 100 mm per second.
2. On standard ECG paper, how much time does one small box represent? A. 0.04 seconds. B. 0.02 seconds. C. 0.12 seconds. D. 0.20 seconds.
3. How many large boxes span one second on a standard-speed ECG strip? A. Three. B. Ten. C. Twenty-five. D. Five.
4. With standard calibration, how far should a 1 mV signal move the stylus? A. 1 mm (1 small box). B. 5 mm (1 large box). C. 1 cm (10 small boxes). D. 2 cm (4 large boxes).
5. A regular rhythm has 4 large boxes between consecutive R waves. What is the approximate heart rate? A. About 60 beats per minute. B. About 75 beats per minute. C. About 100 beats per minute. D. About 150 beats per minute.
6. A regular rhythm has 15 small boxes between consecutive R waves. What is the approximate heart rate? A. About 100 beats per minute. B. About 50 beats per minute. C. About 150 beats per minute. D. About 200 beats per minute.
7. What is the quickest way to estimate the rate of an irregular rhythm? A. Divide 300 by the number of large boxes between any two R waves. B. Count the P waves on a 3-second strip and multiply by 10. C. Divide 1500 by the shortest R-R interval in small boxes. D. Count the QRS complexes on a 10-second strip and multiply by 6.
8. Below what heart rate is a rhythm described as bradycardia? A. 50 beats per minute. B. 70 beats per minute. C. 60 beats per minute. D. 40 beats per minute.
9. What does the P wave represent? A. Ventricular repolarization. B. Atrial depolarization, right atrium first and then left. C. Depolarization of the interventricular septum. D. Conduction delay in the AV node.
10. In normal sinus rhythm, in which lead is the P wave consistently negative? A. aVR. B. Lead II. C. Lead I. D. aVF.
11. What is the normal range for the PR interval? A. 40 to 80 ms (1 to 2 small boxes). B. 200 to 280 ms (5 to 7 small boxes). C. 360 to 440 ms (9 to 11 small boxes). D. 120 to 200 ms (3 to 5 small boxes).
12. What is the normal duration of the QRS complex? A. 120 to 200 ms. B. Under 40 ms. C. Under 120 ms, usually 60 to 100 ms. D. 200 to 240 ms.
13. A widened QRS complex should raise concern for which pair of causes? A. Hypothermia or sinus arrhythmia. B. Hyperkalemia or a bundle branch block. C. Hypercalcemia or first-degree AV block. D. Pericarditis or atrial flutter.
14. How wide must a Q wave be to count as pathologic? A. Wider than 40 ms (one small box). B. Wider than 10 ms. C. Wider than 120 ms (three small boxes). D. Wider than 200 ms (one large box).
15. With normal R-wave progression across the chest leads, which lead shows the smallest R wave? A. V3. B. V5. C. V6. D. V1.
16. What electrical event does the T wave represent? A. Atrial depolarization. B. Atrial repolarization. C. Ventricular repolarization. D. Conduction through the bundle of His.
17. A small wave that follows the T wave is most often linked to which electrolyte problem? A. Hyperkalemia. B. Hypokalemia. C. Hypercalcemia. D. Hypernatremia.
18. Tall, peaked T waves should make you think of which electrolyte disorder? A. Hyperkalemia. B. Hypokalemia. C. Hypomagnesemia. D. Hyponatremia.
19. An Osborn (J) wave on the ECG is a clue to which condition? A. Hyperthyroidism. B. Digoxin toxicity. C. Acute pericarditis. D. Hypothermia.
20. How much ST elevation is considered significant? A. Any elevation in a single lead. B. At least 0.5 mm in any lead. C. At least 1 mm in a limb lead or 2 mm in a precordial lead. D. At least 5 mm in a limb lead.
21. Why do you look for ST elevation in two or more contiguous leads? A. A single lead is too fast to measure. B. Elevation in contiguous leads is highly specific for infarction. C. Contiguous leads cancel out artifact. D. Only contiguous leads can show PR depression.
22. Diffuse ST elevation with PR depression most suggests which diagnosis? A. Acute pericarditis. B. Inferior STEMI. C. Hypokalemia. D. Wolff-Parkinson-White pattern.
23. An inferior wall STEMI typically produces reciprocal ST depression in which leads? A. II and aVF. B. V1 and V2. C. V5 and V6 only. D. I and aVL.
24. Which coronary artery usually supplies the inferior wall of the heart? A. The left anterior descending artery. B. The circumflex artery. C. The right coronary artery. D. The left main coronary artery.
25. Hyperacute T waves early in a myocardial infarction appear where? A. Only in lead aVR. B. In the leads corresponding to the affected coronary artery. C. In every lead equally. D. Only in the limb leads.
26. Large, symmetric T-wave inversions in the anterior chest leads can signal which dangerous lesion? A. Severe narrowing of the proximal left anterior descending artery (Wellens syndrome). B. Right coronary artery spasm. C. An accessory pathway. D. Hypercalcemia.
27. Which non-ischemic causes can produce ST depression? A. Hypercalcemia only. B. First-degree AV block. C. Sinus arrhythmia. D. Digoxin toxicity, hypokalemia, hypothermia and tachycardia.
28. How does the QT interval change as the heart rate increases? A. It lengthens. B. It stays the same. C. It shortens. D. It becomes irregular.
29. A prolonged QT interval puts the patient at risk for which arrhythmia? A. Sinus arrhythmia. B. Torsades de pointes. C. First-degree AV block. D. Atrial flutter with 2:1 block.
30. Above what QTc value does the risk of torsades de pointes clearly rise? A. 500 ms. B. 350 ms. C. 400 ms. D. 300 ms.
31. Which formula is most commonly used to correct the QT interval for heart rate? A. The Cockcroft-Gault formula. B. The Parkland formula. C. The Friedewald formula. D. The Bazett formula (QT divided by the square root of RR).
32. When the QTc is prolonged, which blood levels should be checked? A. Sodium and chloride only. B. Glucose and lactate. C. Potassium, calcium and magnesium. D. Troponin only.
33. What is the first-line drug treatment for torsades de pointes? A. Adenosine. B. Magnesium sulfate. C. Digoxin. D. Verapamil.
34. A patient in torsades de pointes becomes hemodynamically unstable. What is indicated? A. Non-synchronized electrical defibrillation. B. Synchronized cardioversion at low energy. C. Adenosine rapid IV push. D. Vagal maneuvers.
35. A short QT interval (under 360 ms) may be associated with which electrolyte abnormality? A. Hypocalcemia. B. Hypokalemia. C. Hypomagnesemia. D. Hypercalcemia.
36. What PR interval defines first-degree AV block? A. A PR interval that lengthens until a beat drops. B. A PR interval shorter than 120 ms. C. A constant PR interval longer than 200 ms with every P wave conducted. D. P waves unrelated to the QRS complexes.
37. The PR interval gets longer with each beat until a P wave is not followed by a QRS. What rhythm is this? A. Second-degree AV block, Mobitz type II. B. Second-degree AV block, Mobitz type I (Wenckebach). C. Third-degree AV block. D. First-degree AV block.
38. In Mobitz type II block, how do the PR intervals of the conducted beats behave? A. They stay constant, with single P waves dropped at unpredictable intervals. B. They lengthen progressively before each dropped beat. C. They vary randomly because the atria and ventricles are dissociated. D. They are shorter than 120 ms with a delta wave.
39. Which type of AV block usually produces no symptoms? A. Mobitz type II block. B. Third-degree block with a slow ventricular escape. C. Complete heart block after a large infarction. D. First-degree and Mobitz type I second-degree block.
40. A rare symptomatic, unstable patient with Mobitz type I block may need which emergency treatment? A. Adenosine. B. Magnesium sulfate. C. Atropine or cardiac pacing. D. Synchronized cardioversion.
41. P waves and QRS complexes march along with no relationship to each other. What is the rhythm? A. Mobitz type I block. B. Third-degree (complete) heart block. C. First-degree AV block. D. Sinus arrhythmia.
42. In complete heart block, what keeps the ventricles beating? A. A junctional or ventricular escape rhythm. B. Conducted sinus impulses. C. An accessory pathway. D. Retrograde atrial activation.
43. Which AV blocks tend to reflect severe damage to the conduction system? A. First-degree block only. B. Mobitz type I only. C. Sinus arrhythmia. D. Mobitz type II and third-degree block.
44. What is the mainstay of treatment for irreversible complete heart block? A. Long-term atropine. B. Catheter ablation of the AV node. C. A permanent pacemaker. D. Beta-blockers.
45. Which tick-borne infection can cause complete heart block that may reverse with antibiotics? A. Influenza. B. Lyme disease. C. Hepatitis A. D. Strep throat.
46. A QRS wider than 0.12 seconds with an RSR' pattern in V1 and V2 indicates what? A. Right bundle branch block. B. Left bundle branch block. C. Left ventricular hypertrophy. D. Wolff-Parkinson-White pattern.
47. In left bundle branch block, where are the broad or notched R waves found? A. Leads V1 and V2 only. B. Leads II, III and aVF. C. Lead aVR only. D. Leads I, aVL, V5 and V6.
48. How many lead wires does a conventional 12-lead ECG use? A. Twelve. B. Six. C. Ten. D. Four.
49. Where is the V4 electrode placed? A. Fourth intercostal space, right sternal border. B. Fifth intercostal space, midclavicular line. C. Fifth intercostal space, midaxillary line. D. Second intercostal space, midclavicular line.
50. Where is the V6 electrode placed? A. Fifth intercostal space, midaxillary line. B. Fifth intercostal space, midclavicular line. C. Fourth intercostal space, left sternal border. D. Sixth intercostal space, posterior axillary line.
51. Where are V1 and V2 placed relative to the sternum? A. Both on the left midclavicular line. B. V1 left of the sternum and V2 right of it. C. Both directly over the sternum. D. V1 just right of the sternal border and V2 just left of it.
52. Which leads are the augmented unipolar limb leads? A. I, II and III. B. V1, V2 and V3. C. aVR, aVL and aVF. D. V4, V5 and V6.
53. In which plane do the precordial (chest) leads record the heart's electrical activity? A. The vertical (frontal) plane. B. The horizontal plane. C. The sagittal plane only. D. They record no plane; they measure rate only.
54. The QRS is positive in both lead I and aVF. What is the axis? A. Normal axis. B. Left axis deviation. C. Right axis deviation. D. Extreme (northwest) axis.
55. The QRS is negative in lead I and positive in aVF. What does this suggest? A. Left axis deviation. B. Normal axis. C. Low voltage. D. Right axis deviation.
56. Are there absolute contraindications to recording a 12-lead ECG? A. Yes, a pacemaker. B. Yes, pregnancy. C. No, there are none. D. Yes, recent chest surgery.
57. What are the classic ECG features of atrial fibrillation? A. A regular narrow rhythm with sawtooth flutter waves. B. An irregularly irregular rhythm with no discrete P waves and a fibrillatory baseline. C. A short PR interval with a delta wave. D. Progressive PR lengthening with dropped beats.
58. What is the most common sustained cardiac arrhythmia? A. Atrial fibrillation. B. Ventricular tachycardia. C. Atrial flutter. D. Third-degree AV block.
59. In the CHA2DS2-VASc stroke-risk score for atrial fibrillation, how many points does a prior stroke or TIA add? A. 1 point. B. 3 points. C. 0 points. D. 2 points.
60. Can aspirin replace anticoagulation for stroke prevention in atrial fibrillation? A. Yes, aspirin is equivalent. B. Yes, if combined with clopidogrel. C. No; aspirin alone or with clopidogrel is not recommended as an alternative. D. Yes, for any patient over 65.
61. How is ventricular tachycardia defined? A. Any single premature ventricular beat. B. Three or more consecutive wide-complex beats at a rate over 100 per minute. C. A narrow-complex rhythm over 150 per minute. D. Two wide beats in a row at any rate.
62. Ventricular tachycardia is sorted into monomorphic and polymorphic types based on what? A. QRS morphology. B. The PR interval. C. P-wave shape. D. The patient's age.
63. What is "VT storm"? A. VT lasting longer than 30 seconds. B. VT that converts to atrial fibrillation. C. VT that occurs during exercise. D. Three or more episodes of sustained VT within 24 hours.
64. Is adenosine reliable for terminating ventricular tachycardia? A. Yes; it is first line for VT. B. Yes, but only for polymorphic VT. C. No; it is typically ineffective in VT. D. Yes, if given intramuscularly.
65. What QRS width and heart rate characterize supraventricular tachycardia (SVT)? A. Wide QRS with a rate of 60 to 100. B. Narrow QRS (under 120 ms) with a rate over 100, typically 150 to 220. C. Narrow QRS with a rate under 60. D. Wide QRS with a rate over 250 only.
66. Which medication is first line for acute SVT, especially when the AV node is involved? A. Adenosine. B. Amiodarone. C. Magnesium sulfate. D. Atropine.
67. How should adenosine be given? A. As a slow IV infusion over 30 minutes. B. Intramuscularly. C. By mouth. D. As a rapid IV push, preferably through a large peripheral vein.
68. A patient in SVT is hypotensive with altered mental status. What should be considered? A. Oral beta-blocker and recheck in an hour. B. Non-synchronized defibrillation at the lowest energy. C. Immediate synchronized cardioversion. D. Observation only.
69. What is a delta wave? A. A notch at the end of the T wave. B. A slurred upstroke at the start of the QRS complex. C. An extra P wave before each QRS. D. A deep Q wave in lead III.
70. Which PR interval is typical of the Wolff-Parkinson-White pattern? A. Short, under 120 ms. B. Normal, 120 to 200 ms. C. Long, over 200 ms. D. Progressively lengthening.
71. Why are AV nodal blocking drugs such as adenosine dangerous in WPW with atrial fibrillation? A. They cause severe hypokalemia. B. They convert the rhythm to sinus bradycardia. C. They lengthen the QT interval. D. They allow unopposed conduction down the accessory pathway, which can lead to ventricular fibrillation.
72. What R-R variation defines sinus arrhythmia? A. Absent P waves with an irregular rhythm. B. R-R variation under 0.04 seconds. C. R-R variation greater than 0.12 seconds with normal sinus P waves. D. Dropped QRS complexes.
73. What usually causes the rate to vary in respiratory sinus arrhythmia? A. An accessory pathway. B. Vagal stimulation that changes with breathing. C. Degeneration of the AV node. D. Low potassium.
74. What is the main goal of a prehospital 12-lead ECG? A. Identify STEMI sooner so reperfusion happens faster. B. Measure the QT interval for billing. C. Replace the hospital ECG. D. Diagnose sinus arrhythmia.
75. For a STEMI patient taken to a PCI-capable center, what is the goal first-medical-contact-to-device time? A. 3 hours or less. B. 6 hours or less. C. 12 hours or less. D. 90 minutes or less.
76. How should a new-onset left bundle branch block be treated in a patient with a fitting clinical picture of acute coronary syndrome? A. As a benign incidental finding. B. As proof of hyperkalemia. C. As an ST-segment elevation equivalent. D. As a reason to give adenosine.
77. What QRS duration fits an incomplete right bundle branch block? A. 60 to 80 milliseconds. B. 100 to 119 milliseconds. C. 120 to 160 milliseconds. D. Over 200 milliseconds.
78. An isolated right bundle branch block is found in an asymptomatic patient. How is it generally regarded? A. As benign. B. As a STEMI equivalent. C. As an indication for immediate pacing. D. As diagnostic of pulmonary embolism.

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