121 Questions
Which organ system is responsible for initiating an impulse to stimulate the mechanical cells of the heart to contract?
Cardiovascular system
What is the term for the process of returning the heart to normal sinus rhythm using a therapeutic dose of electrical energy?
Cardioversion
Which node is responsible for delaying the electrical impulse before it is allowed to pass into the ventricles?
Atrioventricular node
What term is used to describe an abnormally slow heart rate, usually below 60 beats per minute?
Bradycardia
Which medical condition is characterized by an abnormally high level of potassium in the blood?
Hyperkalemia
What term is used to describe the period when the ventricles are at rest and filling with blood?
Ventricular diastole
Which term describes a dysrhythmia in which every other beat is a premature ventricular contraction?
Bigeminy
What is the term for the period when the ventricles are contracting and pushing blood out of the heart?
Ventricular systole
What is the name for a device implanted under the skin that continuously monitors the heart rhythm and delivers an electrical shock to restore a normal heartbeat if necessary?
Cardioverter-defibrillator (ICD)
Which term refers to a condition where more than one site in the atria or ventricles generates electrical impulses, causing a dysrhythmia with different QRS complexes?
Multifocal
What does the electrocardiogram (ECG) directly indicate?
Atrial depolarization
If the SA node fails, what protective mechanism can initiate impulses to maintain heart function?
Escape mechanism
Which node is the primary pacemaker of the heart?
SA node
What does the P wave represent in the cardiac cycle?
Atrial contraction
What does the 12-lead ECG provide views of?
Heart's electrical activity
During which phase does blood get pushed into the ventricles?
Atrial systole
What is the time from the beginning of one heartbeat to the beginning of the next called?
Cardiac cycle
What initiates impulses to stimulate both ventricles to contract?
"Bundle of His"
Which area can initiate impulses as a protective mechanism if necessary?
"Other areas of the heart"
What interval measures the time from the start of the Q wave to the end of the S wave and typically lasts 0.06 to 0.10 seconds?
QRS interval
Which wave represents ventricular repolarization and ends when the wave returns to the isoelectric line?
T wave
What is the name for a small wave occurring shortly after the T wave, most prominent in patients with hypokalemia?
U wave
What interval reflects the time from completion of myocardial contraction to recovery for the next impulse, starting at the end of the QRS and ending at the beginning of the T wave?
ST segment
What does the PR interval measure?
Time from SA node to AV node
Which interval measures the time from start of Q wave to end of T wave, representing ventricular depolarization and repolarization?
QT interval
What represents the time from SA node to AV node and can range from 0.12 to 0.20 seconds?
PR interval
Which complex is composed of Q, R, and S waves and is larger than the P wave due to ventricles' greater muscle mass?
QRS complex
Which interval represents ventricular depolarization and repolarization and can cause dysrhythmias when prolonged or shortened?
QT interval
What does the T wave represent on an ECG?
Ventricular repolarization
What method can be used to calculate heart rate by counting R waves in a 6-second strip and multiplying by 10?
Six-second method
What term is used to describe a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm?
Regularly irregular rhythm
What should be examined for the presence of one P wave in front of each QRS complex, regular occurrence, and similar appearance?
P waves
Which interval is measured to report abnormalities to the healthcare provider?
QT interval
What does an abnormal P wave indicate in ECG interpretation?
Dysrhythmia
Which method for calculating heart rate involves counting small squares between two R waves and dividing by 1500?
One-minute method
What term refers to an irregular rhythm with varying R-to-R spacing on an ECG?
Irregular rhythm
What is the normal range for the PR interval in seconds during ECG interpretation?
0.12-0.20 seconds
What should be noted if there is a variation in the PR interval during ECG interpretation?
Pattern of variation
Which interval in ECG interpretation should have all complexes look alike and be normal and constant?
QRS interval
During which phase does the impulse travel down the bundle of His and stimulates both ventricles to contract?
Ventricular systole
What represents atrial depolarization and is the first wave of the cardiac cycle, appearing as a small hill?
P wave
What term is used to describe the time from the beginning of one heartbeat to the beginning of the next, which includes the P wave, QRS complex, and T wave?
Cardiac cycle
Which interval measures the time from the start of the Q wave to the end of the S wave and typically lasts 0.06 to 0.10 seconds?
QRS interval
What does the 12-lead ECG provide views of?
Heart's electrical activity
What represents the time from SA node to AV node and can range from 0.12 to 0.20 seconds?
PR interval
Which wave represents ventricular repolarization and ends when the wave returns to the isoelectric line?
T wave
What should be examined for the presence of one P wave in front of each QRS complex, regular occurrence, and similar appearance?
Electrical activity in the heart
What is used to describe a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm?
Sinus arrhythmia
What is the term for the period when the ventricles are at rest and filling with blood?
ST segment
If the SA node fails, what protective mechanism can initiate impulses to maintain heart function?
Purkinje fibers
Which interval in ECG interpretation should have all complexes look alike and be normal and constant?
PR interval
What does the electrocardiogram (ECG) directly indicate?
Heart rate
What represents the time from SA node to AV node and can range from 0.12 to 0.20 seconds?
PR interval
Which node is responsible for delaying the electrical impulse before it is allowed to pass into the ventricles?
AV node
What does an abnormal P wave indicate in ECG interpretation?
Atrial repolarization
What initiates impulses to stimulate both ventricles to contract?
Purkinje fibers
What does the regularity of an ECG rhythm refer to?
The varying R-to-R spacing
How is heart rate calculated using the one-minute method?
Count the small squares between two R waves and divide by 1500
What is examined to determine the presence of dysrhythmia in ECG interpretation?
PR interval variation
Which interval in ECG interpretation should have a normal and constant appearance?
QRS interval
What is the normal range for the PR interval in seconds during ECG interpretation?
$0.12 - 0.20$
What does the T wave represent on an ECG?
Ventricular repolarization
Which term describes a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm?
Regularly irregular
What represents the time from SA node to AV node and can range from $0.12$ to $0.20$ seconds?
$PR$ interval
If the SA node fails, what protective mechanism can initiate impulses to maintain heart function?
AV node
What process involves returning the heart to normal sinus rhythm using a therapeutic dose of electrical energy?
$Cardioversion$
What does the wave representing ventricular repolarization and ending when the wave returns to the isoelectric line on an ECG indicate?
Ventricular repolarization
Which node is the primary pacemaker of the heart?
Sinoatrial node
What term is used to describe an abnormally slow heart rate, usually below 60 beats per minute?
Bradycardia
Which wave represents ventricular repolarization and ends when the wave returns to the isoelectric line on an ECG?
T wave
What method can be used to calculate heart rate by counting R waves in a 6-second strip and multiplying by 10?
Standard method
What interval measures the time from start of Q wave to end of T wave, representing ventricular depolarization and repolarization?
QT interval
Which organ system is responsible for initiating an impulse to stimulate the mechanical cells of the heart to contract?
Nervous system
What does an abnormal P wave indicate in ECG interpretation?
Dysfunction in atrial conduction pathways
During which phase does blood get pushed into the ventricles?
Ventricular systole
What term refers to a condition where more than one site in the atria or ventricles generates electrical impulses, causing a dysrhythmia with different QRS complexes?
Multifocal
What does the QRS complex represent in an ECG?
Time for electrical impulse to travel from AV node to ventricles
What is the normal range for the QT interval during ECG interpretation?
$0.34$ to $0.43$ seconds
What does an inverted T wave on an ECG indicate?
Coronary ischemia
What is the U wave on an ECG most prominent in patients with?
Hypokalemia
Which segment reflects the time from completion of myocardial contraction to recovery for the next impulse in an ECG?
ST segment
What is the primary pacemaker of the heart?
SA node
Which wave represents atrial depolarization and is the first wave of the cardiac cycle?
P wave
What does the PR interval measure in ECG interpretation?
Time from SA node to AV node
During which phase does blood get pushed into the ventricles?
Atrial depolarization phase
During which phase does blood get pushed into the ventricles?
Atrial systole
What interval measures the time from the start of the Q wave to the end of the S wave and typically lasts 0.06 to 0.10 seconds?
QRS complex
What is the term for the period when the ventricles are at rest and filling with blood?
Ventricular diastole
What does an abnormal P wave indicate in ECG interpretation?
Atrial depolarization
What represents atrial depolarization and is the first wave of the cardiac cycle, appearing as a small hill?
P wave
Which node is responsible for delaying the electrical impulse before it is allowed to pass into the ventricles?
Atrioventricular node
What term refers to a condition where more than one site in the atria or ventricles generates electrical impulses, causing a dysrhythmia with different QRS complexes?
Multifocal
What does the T wave represent on an ECG?
Ventricular repolarization
Which medical condition is characterized by an abnormally high level of potassium in the blood?
Hyperkalemia
Which method can be used to calculate heart rate by counting R waves in a 6-second strip and multiplying by 10?
One-minute method
What is the term for the period when the ventricles are contracting and pushing blood out of the heart?
Systole phase
What represents the time from SA node to AV node and can range from 0.12 to 0.20 seconds?
PR interval
What does an abnormal P wave indicate in ECG interpretation?
Atrial dysrhythmia
What term is used to describe a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm?
Regularly irregular
Which wave represents ventricular repolarization and ends when the wave returns to the isoelectric line?
T wave
During which phase does the impulse travel down the bundle of His and stimulates both ventricles to contract?
Ventricular systole phase
What should be examined for the presence of one P wave in front of each QRS complex, regular occurrence, and similar appearance?
$P$ wave appearance
What is used to describe a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm?
Regularly irregular
What does the electrocardiogram (ECG) directly indicate?
Electrical activity of the heart
What is the primary pacemaker of the heart?
Sinoatrial (SA) node
Which wave represents ventricular repolarization on an ECG?
T wave
What does the P wave represent in the cardiac cycle?
Atrial depolarization
During which phase does blood get pushed into the ventricles?
Atrial systole
What term describes a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm?
Dysrhythmia
What represents the time from SA node to AV node and can range from 0.12 to 0.20 seconds?
PR interval
Which wave represents ventricular depolarization and repolarization on an ECG?
QRS complex
Regularly irregular rhythm indicates a predictable pattern of irregularity in R-to-R spacing on an ECG rhythm.
True
The one-minute method for calculating heart rate involves counting R waves in a 6-second strip and multiplying by 10.
False
Abnormal P waves on an ECG indicate dysrhythmia, requiring further examination.
True
The PR interval measures the time from the start of the P wave to the start of the QRS complex.
False
The QRS interval should have all complexes look alike and be normal and constant.
True
The QT interval is measured to report abnormalities to the healthcare provider.
True
An irregularly irregular rhythm on an ECG indicates a varying R-to-R spacing with no pattern of irregularity.
True
The six-second method for calculating heart rate involves counting small squares between two R waves and dividing by 1500.
False
The PR interval measures the time from the start of the P wave to the start of the T wave.
False
The importance of a systematic method for interpreting ECG rhythms is to decrease understanding and overlook items.
False
Study Notes
-
Six-step process for interpreting ECG rhythms for identifying dysrhythmias
-
Regularity of the rhythm:
- Determined by R-to-R spacing on ECG
- Normal rhythm: same R-to-R spacing, rarely varies
- Irregular rhythm: varying R-to-R spacing
- Regularly irregular: predictable pattern of irregularity
- Irregularly irregular: no pattern of irregularity
-
Methods for calculating heart rate:
- One-minute method: count small squares between two R waves and divide by 1500
- Six-second method: count R waves in a 6-second strip and multiply by 10
-
P waves:
- Examined for presence of one P wave in front of each QRS complex, regular occurrence, and similar appearance
- Abnormal P waves indicate dysrhythmia, requiring further examination
-
PR interval:
- Normal interval: 0.12-0.20 seconds
- Variation: note if there is a pattern
-
QRS interval:
- Normal and constant
- All QRS complexes look alike
-
QT interval:
- Measured to report abnormalities to healthcare provider
-
Importance of systematic method for interpreting ECG rhythms to increase understanding and avoid overlooking items.
-
Six-step process for interpreting ECG rhythms for identifying dysrhythmias
-
Regularity of the rhythm:
- Determined by R-to-R spacing on ECG
- Normal rhythm: same R-to-R spacing, rarely varies
- Irregular rhythm: varying R-to-R spacing
- Regularly irregular: predictable pattern of irregularity
- Irregularly irregular: no pattern of irregularity
-
Methods for calculating heart rate:
- One-minute method: count small squares between two R waves and divide by 1500
- Six-second method: count R waves in a 6-second strip and multiply by 10
-
P waves:
- Examined for presence of one P wave in front of each QRS complex, regular occurrence, and similar appearance
- Abnormal P waves indicate dysrhythmia, requiring further examination
-
PR interval:
- Normal interval: 0.12-0.20 seconds
- Variation: note if there is a pattern
-
QRS interval:
- Normal and constant
- All QRS complexes look alike
-
QT interval:
- Measured to report abnormalities to healthcare provider
-
Importance of systematic method for interpreting ECG rhythms to increase understanding and avoid overlooking items.
-
The cardiac monitor or electrocardiogram (ECG) records electrical activity in the heart, but it does not directly indicate the contraction of heart muscle cells.
-
To determine heart muscle contraction and subsequent blood pumping, assess the patient's blood pressure and apical and peripheral pulses.
-
The sinoatrial (SA) node located in the upper posterior wall of the right atrium is the primary pacemaker of the heart, which normally fires at a rate of 60 to 100 beats per minute (bpm).
-
If the SA node slows or fails, other areas of the heart can initiate impulses as a protective mechanism, known as escape.
-
The atria contract during atrial systole, resulting in blood being pushed into the ventricles during ventricular diastole.
-
The impulse travels down the bundle of His and stimulates both ventricles to contract, known as ventricular systole.
-
The cardiac cycle is the time from the beginning of one heartbeat to the beginning of the next, which includes the P wave, QRS complex, and T wave.
-
The 12-lead ECG provides 12 different views of the heart's electrical activity, while continuous monitoring may use one lead.
-
The P wave represents atrial depolarization and is the first wave of the cardiac cycle, appearing as a small hill.
-
The SA node is the primary pacemaker of the heart, but other areas can initiate impulses to maintain heart function if necessary.
-
Six-step process for interpreting ECG rhythms for identifying dysrhythmias
-
Regularity of the rhythm:
- Determined by R-to-R spacing on ECG
- Normal rhythm: same R-to-R spacing, rarely varies
- Irregular rhythm: varying R-to-R spacing
- Regularly irregular: predictable pattern of irregularity
- Irregularly irregular: no pattern of irregularity
-
Methods for calculating heart rate:
- One-minute method: count small squares between two R waves and divide by 1500
- Six-second method: count R waves in a 6-second strip and multiply by 10
-
P waves:
- Examined for presence of one P wave in front of each QRS complex, regular occurrence, and similar appearance
- Abnormal P waves indicate dysrhythmia, requiring further examination
-
PR interval:
- Normal interval: 0.12-0.20 seconds
- Variation: note if there is a pattern
-
QRS interval:
- Normal and constant
- All QRS complexes look alike
-
QT interval:
- Measured to report abnormalities to healthcare provider
-
Importance of systematic method for interpreting ECG rhythms to increase understanding and avoid overlooking items.
Learn how to measure the intervals of each component of a cardiac cycle using an electrocardiogram (ECG) graph paper, which is calibrated with small squares and heavy lined blocks. Each small square is 0.04 seconds wide, making it easier to measure the time intervals of heart rhythms.
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