Chapter 5 Rhythm Strip Interpretation and Sinus Rhythms

10) What is the rate of a normal sinus rhythm? A) 60 to 100 bpm B) 40 to 60 bpm C) 100 to 150 bpm D) Greater than 150 bpm

Answer: A Explanation: Both the atrial and ventricular rates are between 60 and 100 bpm in normal sinus rhythm.

27) What must occur if sinus arrest exceeds 6 seconds? A) Medical emergency procedures must be initiated. B) Repeat ECGs must be done. C) Oxygen must be given. D) A licensed practitioner must be notified.

Answer: A Explanation: If sinus arrest reaches 6 seconds, this is considered a medical emergency.

33) In determining the type of ECG rhythm the patient has, the ECG technician evaluates the components of the ECG rhythm strip, including all of the following except: A) regularity. B) U wave. C) rate. D) PR interval.

Answer: B Explanation: ECG analysis consists of a five-step process of gathering data about each rhythm strip. These steps include evaluating the rhythm, rate, P wave configuration, PR interval, and QRS duration and configuration.

24) In which dysrhythmia do the P-P and R-R intervals progressively widen, and then narrow, following the patient's breathing pattern? A) Sinus tachycardia B) Sinus dysrhythmia C) Sinus bradycardia D) Normal sinus rhythm

Answer: B Explanation: In sinus dysrhythmia, the P-P and R-R intervals progressively widen, then narrow, following the patient's breathing pattern.

34) If a QRS complex measures 0.12 second or wider, it most likely indicates: A) normal ventricular conduction. B) delayed ventricular conduction. C) increased delay at the AV node. D) myocardial infarction.

Answer: B Explanation: When the QRS complex is wide, 0.12 second or greater, the current is taking longer than normal to cause the ventricles to contract.

16) A patient with sinus bradycardia may require what type of treatment? A) Medication or a pacemaker B) Physical therapy and a stress test C) IV fluids and oxygen D) Open-heart surgery

Answer: A Explanation: If you observe signs of low cardiac output with sinus bradycardia, report your findings to a licensed practitioner immediately. This rhythm may require medication administration or application of a pacemaker.

4) Which of the following questions is necessary to analyze a P wave on an ECG tracing? A) Does each P wave have a QRS complex following it? B) Is the interval between the P wave and the QRS complex constant? C) Are the atrial and ventricular rates the same? D) Is the ST segment at the isoelectric line?

Answer: A Explanation: In normal conduction pathways, a QRS complex always follows the P wave.

13) Identify the following rhythm: A) Sinus bradycardia B) Sinus tachycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: A Explanation: In sinus bradycardia, the heart rate is less than 60 beats per minute, and all other measurements are within normal limits.

7) The QRS complex represents the time it takes for: A) the ventricles to depolarize or contract. B) repolarization to take place. C) the electrical current to be initiated at the SA node. D) the current to move through the atria.

Answer: A Explanation: Measuring the QRS complex is essential in determining the time it takes for the ventricles to depolarize or contract.

35) Signs and symptoms of adequate cardiac output include: A) an alert and oriented patient. B) difficulty breathing. C) chest pain or pressure. D) hypotension.

Answer: A Explanation: Normal cardiac output means the heart is beating adequately, pumping blood to the body's organs to maintain normal function. Indications of normal cardiac output include an alert and oriented patient with no difficulty breathing, no chest pain or pressure, and a stable blood pressure.

9) If you can't identify an R wave on the ECG tracing, which of the following wave(s) can you use to determine the regularity of the ventricles? A) Q and S wave junction B) P and R wave junction C) T wave D) P wave

Answer: A Explanation: Occasionally, the QRS complex does not exhibit an R wave, in which case you can use the point of the Q and S wave junction as an easy point of evaluation.

36) What should you do if the patient you are monitoring is very pale and breathing very fast, yet his monitor indicates he is in normal sinus rhythm? A) Report his condition to a licensed practitioner immediately. B) Perform another ECG tracing to see if the rhythm changes. C) Call a Code Blue medical emergency. D) Tell the patient to take deep breaths.

Answer: A Explanation: Report the situation to a licensed practitioner or your supervisor immediately. The patient is showing signs of decreased cardiac output, which include pale skin and respiratory difficulty.

54) Which of the following conditions may result in sinus exit block? A) Acute myocardial infarction B) Congestive heart failure C) Sinus tachycardia D) Chronic bronchitis

Answer: A Explanation: Sinus exit block may occur as a result of acute myocardial infarction, ischemia, or drugs such as digitalis or quinidine.

50) Which of the following is a characteristic of sinus arrest? A) The cardiac complexes before and after the sinus pause are usually regular. B) The PR interval is affected by the pause during a sinus arrest episode. C) The atrial and ventricular rates are different. D) The QRS morphology varies during periods of sinus arrest.

Answer: A Explanation: The cardiac complexes before and after a sinus pause are usually regular, although the arrest period may end with a junctional or ventricular escape beat before regular electrical activity resumes. However, the rhythm is considered irregular because of the period of inactivity during the sinus pause.

40) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus bradycardia B) Sinus tachycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: A Explanation: The tracing shows a regular rhythm at 35 beats per minute. All of the other measurements are within normal limits, so you would classify this rhythm as sinus bradycardia.

23) The condition in which stimulation of the vagus nerve causes changes in heart rate is known as: A) vagal tone. B) ventricular tone. C) vascular tone. D) valvular tone.

Answer: A Explanation: Vagal tone is a condition in which inhalation increases the pressure or tension inside the chest cavity, which puts pressure on the heart. The heart sends information through the vagus nerve to the brain, causing an increase in heart rate. As the patient exhales, the tension in the chest cavity decreases, and the heart rate slows.

31) On the ECG tracing, what precedes and follows the sinus arrest period? A) Complete cardiac complexes B) Junctional escape beats C) Premature atrial contractions D) Changing P waves

Answer: A Explanation: You will usually observe regularly occurring PQRSTs both before and after the sinus arrest period.

53) What treatment may be needed for patients who have frequent episodes of sinus exit block with bradycardia? A) Physical therapy B) Temporary or permanent pacemaker C) Medication such as digitalis or quinidine D) Coronary bypass

Answer: B Explanation: For frequent episodes of SA block, temporary pacing or insertion of a permanent pacemaker may be needed.

19) Sinus tachycardia may be a normal finding in people as a result of: A) cardiac arrest. B) exercise. C) low cardiac output. D) hypertension.

Answer: B Explanation: If the patient has a heart rate of 108 beats per minute after walking the hallway, the tachycardia would be expected and is viewed as the patient's normal response to exercise.

12) Which sinus rhythm has a rate of less than 60 beats per minute? A) Sinus tachycardia B) Sinus bradycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: B Explanation: In sinus bradycardia, the heart rate is less than 60 beats per minute, and all other measurements are within normal limits.

47) Which of the following is a characteristic of sinus bradycardia? A) The QRS duration is between 0.10 and 0.16 second. B) The heart rate is less than 60 beats per minute. C) The shape of the P waves varies from one beat to the next. D) The PR interval is between 0.06 and 0.10 second.

Answer: B Explanation: In sinus bradycardia, the heart rate is less than 60 beats per minute. All of the other characteristics are within normal limits.

17) Which sinus rhythm has a rate of more than 100 beats per minute? A) Sinus bradycardia B) Sinus tachycardia C) Normal sinus rhythm D) Sinus dysrhythmia

Answer: B Explanation: In sinus tachycardia, the heart rate is greater than 100 beats per minute, and all other measurements are within normal limits.

2) QRS duration measurement is essential to determine the time it takes for: A) atrial depolarization. B) ventricular depolarization. C) ventricular relaxation. D) atrial relaxation.

Answer: B Explanation: Measuring the QRS complex is essential in determining the duration of time it takes for the ventricles to depolarize.

21) What symptom do patients with sinus tachycardia often complain of? A) Hypotension B) Palpitations C) Decreased urinary output D) Headache

Answer: B Explanation: Often the patient will complain of palpitations or heart fluttering with heart rates that are faster than normal.

29) A condition in which the patient loses consciousness or faints is known as: A) seizure. B) syncope. C) asystole. D) apnea.

Answer: B Explanation: Syncope is a condition in which the patient loses consciousness. The pauses caused by sinus arrest can cause syncope.

45) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus bradycardia B) Sinus dysrhythmia C) Sinus tachycardia D) Normal sinus rhythm

Answer: B Explanation: The tracing is within the specifications for normal sinus rhythm, except that the heart rate is irregular. This is sinus dysrhythmia.

42) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus arrest B) Sinus tachycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: B Explanation: The tracing shows a regular rhythm at 136 beats per minute. All other measurements are within normal limits, so this is sinus tachycardia.

37) To determine the actual rhythm on an ECG tracing, the ECG technician: A) views the computerized interpretation from the ECG machine. B) analyzes the characteristics of the rhythm and matches them to specific rhythm criteria. C) asks the physician to interpret the ECG tracing. D) estimates the distance between QRS complexes.

Answer: B Explanation: To determine the actual rhythm on an ECG tracing, the ECG technician gathers data about the characteristics of the tracing and then matches the information to the specific ECG rhythm criteria to classify the various cardiac dysrhythmias. Although some ECG machines provide an interpretation, only the physician can view this interpretation and determine whether it is correct.

3) The shape of the P wave is analyzed to determine whether: A) the atrial impulses caused the ventricular contraction. B) atrial depolarization occurred. C) all of the atrial current is moving in the same pathway. D) the atria and ventricles are contracting together.

Answer: C Explanation: If the shapes of the P waves appear different, the current is moving through the atria along more than one pathway.

32) Sinus bradycardia has almost the same criteria as normal sinus rhythm; the only difference is that the: A) P-P intervals are irregular. B) PR interval measurement is greater than 0.12 second. C) heart rate is slower. D) QRS duration is within normal limits.

Answer: C Explanation: In sinus bradycardia, the heart rate is less than 60 beats per minute, and all other measurements are within normal limits.

48) Which of the following statements about sinus dysrhythmia is true? A) The PR interval varies along with the heart rate. B) The QRS duration varies along with the heart rate. C) The intervals between the P-P and R-R waves vary. D) The P waves are usually inverted in deflection.

Answer: C Explanation: In sinus dysrhythmia, the P-P and R-R intervals progressively widen, then narrow, following the patient's breathing pattern.

28) Lack of blood supply to an area of tissue due to a blockage in the circulation to that area is known as: A) infarct. B) interval. C) ischemia. D) dysrhythmia.

Answer: C Explanation: Lack of blood supply to an area of tissue due to a blockage in the circulation to that area is ischemia. The pauses caused by sinus arrest can cause periods of ischemia, when the cells are deprived of oxygen.

6) The normal range for the QRS complex duration is: A) 0.12 to 0.20 second. B) greater than 0.12 second. C) 0.06 to 0.10 second. D) less than 0.06 second.

Answer: C Explanation: Normal QRS duration is 0.06 to 0.10 second.

14) Which of the following are common symptoms of low cardiac output? A) Nausea, vomiting B) Headache, diarrhea C) Shortness of breath, hypotension D) Muscle aches, low back pain

Answer: C Explanation: Normal cardiac output means that the heart is beating adequately, pumping blood to the body's organs to maintain normal function. Low cardiac output can cause dizziness, confusion, shortness of breath, hypotension, pale skin, chest pain, palpitations, and other symptoms.

51) In which rhythm does the SA node initiate an electrical impulse, but the impulse is not conducted to the atria? A) Sinus arrest B) Sinus dysrhythmia C) Sinus exit block D) Sinus bradycardia

Answer: C Explanation: Sinus (SA) exit block occurs when the SA node initiates an electrical impulse that is blocked and not conducted to the atria. The atria and ventricles do not depolarize, and P wave will not be seen until the next conducted complex.

26) Which dysrhythmia occurs when the SA node stops firing, causing a pause in electrical activity? A) Sinus bradycardia B) Sinus tachycardia C) Sinus arrest D) Normal sinus rhythm

Answer: C Explanation: Sinus arrest occurs when the SA node stops firing, causing a pause in electrical activity. During the pause, no electrical impulse is initiated or sent through the normal conduction system to cause either an atrial or a ventricular contraction.

22) Which rhythm shows an irregularity during inspiration and expiration? A) Sinus tachycardia B) Sinus bradycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: C Explanation: Sinus dysrhythmia is a condition in which the heart rate remains within normal limits but is influenced by the respiratory cycle and variations in vagal tone, causing the rhythm to be irregular.

11) Identify a rhythm using these criteria: regular rhythm, ventricular and atrial rates are 74 beats/minute, P wave precedes each QRS, PR interval and QRS duration within normal limits. A) Sinus bradycardia B) Sinus tachycardia C) Normal sinus rhythm D) Sinus dysrhythmia

Answer: C Explanation: Sinus rhythm is the only rhythm for which all five steps are within normal limits.

1) What is evaluated and classified when determining dysrhythmias? A) Rate, artifact, and complexes on the ECG tracing B) Artifact, complexes, and patient symptoms C) Waves, segments, and intervals on the ECG tracing D) Patient condition and symptoms

Answer: C Explanation: The ECG waveform has various components, such as waves, segments, and intervals, that are evaluated and classified based on their size, length of time, and location on the tracing. All of these components help determine the type of cardiac rhythm.

55) The PR interval is measured from the: A) end of the P wave to the end of the T waves B) end of the P wave to the end of the QRS complex C) beginning of the P wave to the beginning of the QRS complex D) beginning of the P wave to the beginning of the T wave

Answer: C Explanation: The PR interval is determined by measuring from the beginning of the P wave to the beginning of the QRS complex.

38) The part of the ECG tracing below that is circled in blue is the: A) QRS complex. B) P wave. C) PR interval. D) ST segment.

Answer: C Explanation: The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex, which is usually the Q wave. If the Q wave is not visible, the PR interval is measured from the beginning of the P wave to the beginning of the R wave.

5) The normal PR interval measurement is: A) 0.06 to 0.12 second. B) 0.20 to 0.24 second. C) 0.12 to 0.20 second. D) 0.10 to 0.16 second.

Answer: C Explanation: The normal range of the PR interval is 0.12 to 0.20 second.

15) The ECG tracing is considered a legal document and needs to be included in the patient's medical record. What four items must be on each ECG tracing? A) Patient's date of birth, today's date and time, physician's name B) Patient's Social Security number, diagnosis, today's date and time C) Patient's name, today's date and time, initials of the ECG technician D) Patient's name, patient's date of birth, diagnosis, type of insurance the patient has

Answer: C Explanation: The patient's name, the date and time of the recording, and the initials of the person performing the ECG must be identified on each rhythm strip.

18) Which of the following serves as the pacemaker in a normal heart? A) AV node B) Bundle of His C) SA node D) Bundle branches

Answer: C Explanation: The sinoatrial node (SA node) is the normal or primary pacemaker of the heart. Rhythms that originate at the SA node are called sinus rhythms.

44) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus bradycardia B) Sinus tachycardia C) Sinus dysrhythmia D) Sinus arrest

Answer: C Explanation: The tracing is within the specifications for normal sinus rhythm, except that the heart rate is irregular. This is sinus dysrhythmia.

30) A condition in which no rhythm or electrical current travels through the cardiac conduction system is known as: A) atrial kick. B) apnea. C) syncope. D) asystole.

Answer: D Explanation: Asystole is a condition in which no electrical current travels through the cardiac conduction system.

20) Sinus tachycardia is considered serious or life-threatening in patients who have had a recent: A) stress test. B) loss of consciousness. C) viral infection. D) myocardial infarction.

Answer: D Explanation: If the patient has had a recent myocardial infarction, sinus tachycardia is considered serious or even life-threatening.

46) Which of the following is not characteristic of sinus tachycardia? A) The R-R intervals and the P-P intervals are equal and constant. B) The heart rate is between 100 and 150 beats per minute. C) The PR interval is between 0.12 and 0.20 second. D) The QRS duration is between 0.10 and 0.16 second.

Answer: D Explanation: In sinus tachycardia, the heart rate is between 100 and 150 beats per minute. All other characteristics, including the QRS duration, are within normal limits.

49) Which of the following patients is most likely to exhibit signs and symptoms of low cardiac output? A) A 55-year-old female athlete with a resting heart rate of 56 beats per minute B) A 60-year-old male with a heart rate of 74, whose tracing shows infrequent periods of sinus arrest lasting 1 second C) A 43-year-old female who has been walking on a treadmill and has a heart rate of 110 beats per minute D) A 48-year-old male with a heart rate of 52, whose tracing shows frequent periods of sinus arrest lasting 2.5 seconds

Answer: D Explanation: Sinus arrest may cause a low cardiac output if the patient's heart is not pumping enough blood to provide oxygen and nutrients to the body cells; 52 beats per minute is slower than normal, and since the patient is also experiencing frequent episodes of sinus arrest, he is likely to show signs and symptoms of low cardiac output.

8) Measuring the PR interval requires the ECG technician to measure from the: A) beginning of the Q wave to the J point. B) beginning of the Q wave to the beginning to the T wave. C) beginning of the P wave to the end of the R wave. D) beginning of the P wave to the beginning of the QRS complex.

Answer: D Explanation: The PR interval is determined by measuring from the beginning of the P wave to the beginning of the QRS complex.

52) Sinus exit block and sinus arrest result in similar ECG tracings. The distinguishing factor is that in sinus exit block, the: A) QRS is slightly wider than normal. B) P waves are inverted or entirely absent. C) pause duration is usually greater than 6 seconds. D) pause duration is a multiple of the R-R or P-P interval.

Answer: D Explanation: The duration of the pause in sinus exit block is in a direct multiple (ratio) of the R-R or P-P interval of the underlying rhythm. Sinus arrest does not have this specific feature.

25) In sinus dysrhythmia, if the heart rate decreases to 40 to 50 beats per minute, the patient may complain of: A) decreased urinary output. B) lung congestion, cough. C) hypertension, pale skin. D) palpitations, dizziness.

Answer: D Explanation: The patient may complain of palpitations or dizziness, depending on how slowly the heart beats when the SA node is suppressed by respiratory or vagal influences.

39) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus bradycardia B) Sinus tachycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: D Explanation: The tracing shows a regular rhythm at 68 beats per minute. All other measurements are within normal limits, so this is normal sinus rhythm.

41) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus bradycardia B) Sinus tachycardia C) Sinus dysrhythmia D) Normal sinus rhythm

Answer: D Explanation: The tracing shows a regular rhythm at 68 beats per minute. All other measurements are within normal limits, so this is normal sinus rhythm.

43) You have performed an ECG on a patient, resulting in the following ECG tracing. How would you classify the patient's rhythm? A) Sinus bradycardia B) Sinus tachycardia C) Sinus dysrhythmia D) Sinus arrest

Answer: D Explanation: The tracing shows a regular rhythm within the specifications for normal sinus rhythm, except for one 2.5-second R-R interval. You would classify this as sinus arrest.