Cardiac Monitoring Mar 3 Flashcards
What is Aberrant?
Abnormal
Aberrant refers to any deviation from the normal conduction pathway.
Define Arrhythmia.
Irregularity or absence of a heartbeat.
See dysrhythmia.
What is Asystole?
(Cardiac Arrest, Ventricular Standstill): The absence of a heartbeat.
Asystole indicates a critical condition requiring immediate intervention.
Define Atrioventricular Block.
A cardiac impulse conduction disturbance in the atrioventricular (AV) node, bundle of His, or its branches.
What is an Automatic Beat?
An impulse arising in an automatic focus, independent of the dominant rhythm.
What does AV Dissociation mean?
The independent beating of the atria and ventricles.
Define Bigeminy.
A normal beat alternating with a premature beat.
What is a Block in cardiac conduction?
A pathologic delay or interruption in impulse conduction.
What characterizes Bradycardia?
A heart rate slower than the normal for that pacemaker site; e.g., less than 60 beats/minute for the sinoatrial (SA) node.
Define Bradydysrhythmia.
Any rhythm disturbance causing a slow heart rate (less than 60 beats/minute).
What is a Bundle Branch Block?
An abnormality in cardiac impulse conduction through the fibers of the bundle of His.
What is a Compensatory Pause?
The period following a premature contraction during which the heart regulates itself, allowing the SA node to resume normal conduction.
Define Ectopic Beat.
A beat originating from a source of cardiac stimulus other than the SA node.
What does EKG (or ECG) stand for?
Electrocardiogram; a graphic tracing of the electrical activity of the heart.
What is Electromechanical Dissociation?
Electrical activity without evidence of myocardial contraction.
Define Escape Beat.
An automatic beat that occurs after an interval longer than the dominant cycle.
What is Conduction Time?
The interval between the origination of an impulse at the SA node and the stimulation of ventricular contraction.
What does Coupling refer to in cardiac terms?
The relationship of a premature beat and the preceding beat.
What is Dysrhythmia?
Any disturbance in the normal rhythm of the heartbeat.
Define Extrasystole.
An ectopic beat that occurs before the next dominant beat.
What is Fibrillation?
Quivering or uncoordinated muscular contraction.
What is a Fusion Beat?
Simultaneous activation of one chamber of the heart by two foci.
What is Group Beating?
A pattern of repetitive QRS complexes.
Define Heart Block.
Impairment of cardiac conduction so that electrical impulses from the atria fail to pass through the AV node to the ventricles.
What is Idiojunctional Rhythm?
A relatively slow, independent rhythm that arises in the AV junction.
Define Idioventricular Rhythm.
A relatively slow rhythm that originates from and controls the ventricles.
What characterizes Junctional Dysrhythmia?
The irregular heartbeat that results when the AV node assumes the SA node’s role.
What is Mobitz Type I (Wenckebach) Block?
A second-degree AV block where the P-R interval increases progressively until the atrial impulse is not conducted.
Define Mobitz Type II Block.
A second-degree AV block characterized by sudden nonconduction of an atrial impulse.
What is a Pacemaker?
The SA node, which initiates the electrical impulse for cardiac contractions.
What does Parasystole mean?
An ectopic, independent rhythm that operates concurrently with the dominant rhythm.
Define Paroxysmal.
Recurring suddenly and abruptly.
What is Sinus Arrhythmia?
A slight variation or irregularity in sinus rhythm.
What does Systole refer to?
Contraction of the heart, causing ejection of blood.
What is Tachycardia?
A heart rate faster than the normal for that pacemaker site; e.g., greater than 100 beats/minute.
Define Tachydysrhythmia.
Any rhythm disturbance causing a fast heart rate.
List the steps of Blood Flow through the heart.
- Superior and Inferior Vena Cava
- Right Atrium
- Tricuspid Valve
- Right Ventricle
- Pulmonic Semilunar Valve
- Pulmonary Arteries
- Lungs
- Pulmonary Veins
- Left Atrium
- Bicuspid (mitral) Valve
- Left Ventricle
- Aortic Semilunar Valve
- Body
What does Frank Starling’s Law state?
The more the ventricle is filled with blood during diastole, the greater the volume of ejected blood during systolic contraction.
What is unique about cardiac muscle cells compared to skeletal muscle?
Cardiac muscle cells have a much longer refractory period.
List the four characteristics inherent to cardiac cells.
- Automaticity
- Excitability
- Conductivity
- Contractility
What is the role of the SA node in the conduction system?
The SA node generates an action potential without outside stimulation.
What is the normal heart rate range for the SA node?
60-100 beats per minute.
What is the purpose of the AV node?
To temporarily delay conduction to allow ventricular filling.
What is the significance of Lead II in ECG?
Lead II is the most likely lead to see well-defined rhythm strips.
What does the P wave represent?
Depolarization of the atria.
What does the PR Interval measure?
The time from the beginning of the P wave to the beginning of the QRS complex.
What does the QRS complex represent?
Depolarization of the ventricles.
What is measured during the ST segment?
The beginning of ventricular repolarization.
What is the U Wave in an ECG?
Not visible in all ECG’s and may be due to repolarization of the Purkinje Fibers
Not significant in ECG interpretation
What is the duration of the P Wave in a normal ECG?
Less than 0.08 sec or 2 boxes
What is the normal range for the PR Interval (PRI)?
0.12-0.20 sec or 3-5 small boxes
What is the maximum duration for the QRS complex?
Less than 0.12 sec or 3 small boxes
What are the two main characteristics to assess in ECG interpretation?
- Rate (Fast/Slow)
- Rhythm (Regular/Irregular)
What does a P Wave to QRS ratio indicate?
Presence and uprightness of the P Wave
What is the significance of a rate that is too fast or too slow on an ECG?
It is the most immediately life-threatening dysrhythmia
How can you measure heart rate using Method #2?
300…150…100…75…60…50…too slow
What does an irregular rhythm imply in ECG interpretation?
No discernable pattern
What is the definition of ‘Regularly irregular’ rhythm?
Has a repeating pattern of irregularity, such as in a sinus arrhythmia
What is the P Wave characteristic in Atrial Fibrillation?
N/A
What is the heart rate range for Normal Sinus Rhythm (NSR)?
60-100 bpm
What are the characteristics of Sinus Bradycardia?
- Rate: < 60 bpm
- Rhythm: regular
- P wave: upright, precedes each QRS, same appearance
- PRI: 0.12-0.2 secs
- QRS: 0.12 secs or less
What causes Sinus Bradycardia?
- Fitness level
- Myocardial Infarction (MI)
- Vagal Stimulation
- Hypothermia
- Medications
What is a characteristic of Atrial Fibrillation?
Irritable myocardiocytes in the atria allow Na to leak in and depolarize them
What is the heart rate in Atrial Flutter?
Depends on AV pause
What feature differentiates a Premature Atrial Complex (PAC)?
P wave is different than others
What is a common cause of Supraventricular Tachycardia (SVT)?
A reentry circuit occurs directly in the AV node
What is the rate for Junctional Escape Rhythm?
40-60 bpm
What are the characteristics of Ventricular Tachycardia?
- Rate: 100-260 bpm (with or without a pulse)
- Rhythm: regular (unifocal), irregular (multifocal)
- QRS: > 0.12 secs, opposite deflection on ‘T’ wave
What does a wide QRS complex indicate?
QRS complexes that originate from below the AV node
What is the heart rate range for Idioventricular Rhythm?
20-40 bpm
What is the characteristic of Ventricular Fibrillation?
Rate: N/A, Rhythm: N/A, P wave: N/A, PRI: N/A, QRS: N/A
What does the ‘T’ Segment represent in an ECG?
Ventricular repolarization
What are the causes of Premature Ventricular Complex (PVC)?
- Myocardial Infarction (MI)
- Medications
- Congestive Heart Failure (CHF)
- Hypoxia
- Exercise
Fill in the blank: The P-R Interval is a direct reflection of the ______.
[AV node pause]
What is the rhythm characteristic of Atrial Flutter?
Regular/irregular with flutter waves
What is the definition of Ventricular Arrhythmias?
QRS complexes that originate from below the AV node
What is the rate of Accelerated Junctional Rhythm?
60-100 bpm
What are the characteristics of Atrial Flutter?
- Rate: Depends on AV pause
- Rhythm: regular/irregular
- P wave: flutter waves
- QRS: 0.12 secs or less
What does PEA stand for?
Pulseless Electrical Activity
What is the heart rate in PEA?
anything
What can the rhythm be in PEA?
anything
What is the significance of P waves in PEA?
may or may not be present
What is the PRI in PEA?
anything
What is the QRS duration in PEA?
anything
What must be used to defibrillate V-Fib or PV-Tach?
AED’s analyze feature
What is First Degree AV Block characterized by?
PRI > 0.2 secs
What is the QRS duration in First Degree AV Block?
0.12 secs or less
What is the rate in First Degree AV Block?
depends on underlying rhythm
In Mobitz I, what happens to the PRI?
gradually lengthens until a QRS is dropped
What is the rhythm in Mobitz I?
atrial rate regular, ventricular rate irregular
What distinguishes Mobitz II from Mobitz I?
Mobitz II has structural damage, not profound conduction delay
What is the PRI in Mobitz II?
constant when preceding a QRS, any length
What is Third Degree AV Block?
Complete failure of the AV node to conduct atrial impulses
What is the rate in Third Degree AV Block?
atrial rate is faster than ventricular rate
What is the typical QRS duration in Third Degree AV Block?
> 0.12 secs if ventricular, < 0.12 secs if junctional
What does AV dissociation refer to?
P waves and QRS complexes occur regularly but do not relate to each other
What are the indications for defibrillation?
- Ventricular Fibrillation
- Pulseless Ventricular Tachycardia
What is cardioversion?
Conversion of one cardiac rhythm to another using medication or electrical cardioversion
What are the indications for external transcutaneous pacing?
- Hemodynamically significant bradydysrhythmias unresponsive to atropine
- Temporary pacing until the underlying cause is corrected
What must be documented when performing ECG interpretation?
- interpretation
- pertinent positives
- pertinent negatives
What are some causes of Asystole?
- MI
- end stage cardiac arrest
- ventricular tachycardia
- ventricular fibrillation
