Cardiac Output
Total volume of blood pumped by the heart in 1 minute
Formula for Cardiac Output
Heart Rate X Stroke volume = cardiac output
Name 3 categories of arrhythmia that can interfere with cardiac output.
Bradycardia
Tachycardia
Ventricular irritability
List 8 symptoms of reduced cardiac output.
o Anxiety
o Chest pain
o Shortness of breath
o Diaphoresis
o Hypotension
o Cool, clammy skin
o Cyanosis
o Decreased consciousness
Name additional measures that may be needed to support perfusion.
o Ventilation
o Chest compression
o Medication to stabilize blood pressure
Give an overview of the American Heart Advanced Cardiac Life Support recommendations for treating arrhythmias.
o All patients with arrhythmias or the potential for them should be monitored and receive oxygen and an IV line.
o When arrhythmias cause symptoms, treatment should be initiated immediately.
o In addition to treatment of the specific presenting arrhythmia
Normal P wave
atrial depolarization
Normal QRS
ventricular depolarization
Normal T wave
ventricular repolarization
Define a normal PR interval (PRI)
From beginning of P wave to beginning of the QRS complex
Between .12 and .20 seconds
Define a normal QRS interval.
From beginning of Q wave to end of S wave
Less than .12 seconds
List some external factors capable of producing artifact on an EKG tracing.
Muscle tremors
Patient movement
Loose electrodes
60-cycle interference
Normal Sinus Rhythm
Regular rate and rhythm- 60-100 beats per minute - P wave normal and upright - always in front of the QRS - one P wave for every QRS complex
Sinus Bradycardia
Regular rhythm - less than 60 in the adult
Sinus Bradycardia Treatment
-Admin O2
-Atropine Sulfate
-pacemaker
-IV fluids
Sinus Tachycardia
Regular rhythm greater than 100 in the adult - P wave is normal but may be buried in the preceding T wave
Sinus Arrhythmia
irregular rhythm and irregular rate- 60-100 in adult
HR decrease during expiration
HR increase during inpiration
Premature Atrial Contractions
A single premature ectopic beat
P wave of the premature beat will have a different shape than the P waves of the rest of the rhythm strip.
The ectopic beat will have a P wave, but it can be flattened, notched, or otherwise unusual. It may be hidden within
Wandering Pacemaker
Shape of P wave changes from beat to beat
Rhythm slightly irregular
Atrial Tachycardia
Regular rhythm - 150-250 - atrial P wave (looks different than sinus P wave)
Atrial Flutter
Atrial rate between 250 and 400 - ventricular rate between 75 and 150 - P wave is saw-toothed shape
Atrial Fibrillation (A-fib)
Atrial rate is 300-600 - ventricular rate is 120-200 - highly irregular ventricular and atrial rhythm - no P waves seen - cannot measure PR interval
Atrial Fibrillation Treatment
-O2
-anticoagulants (formation of thrombi that can dislodge due to quivering atrium)
-antidysrhythmic drugs
-cardio-version drugs
Premature Junctional Contractions (PJC)
P waves are inverted - P waves can fall before, during or after the QRS complex
Junctional Escape Rhythm
Rate of 40-60
P waves are inverted
Accelerated Junctional Rhythm
Rate of 60-100 - P waves are inverted
Junctional Tachycardia
Rate of 100-180 - P waves are inverted
First-Degree Heart Block
PR interval greater than 0.20 seconds
Second-Degree Heart Block, Type 1, Wenckebach
PR interval becomes longer with each succeeding complex until there is a P not followed by a QRS ("marching off")
Second-Degree Heart Block, Type II
P to QRS ratio is 2:1, 3:1, 4:1, 5:1 and so forth
Third-Degree Heart Block
- Very irregular PR interval
- more P waves than QRS complexes
(most serious degree of heart block-- the pt will code if we don't do something)
Premature Ventricular (PVC)
Irregular rhythm
- shape of QRS is bizarre and abnormal
- P-wave will be absent
Ventricular Tachycardia (V-Tach)
Ventricular rate is 100-200
QRS is 0.12 seconds or more with a bizarre and abnormal shape
Very irregular PR intervals
Usually more QRS complexes than P waves
(if the rhythm is regular with no visible P waves it is supraventricular tachycardia)
Treatment of V-Tach w/ pulse and no signs of decreased cardiac output
- O2
- Antidysrhythmic
Treatment of V-Tach w/ pulse and signs of decreased cardiac output
- O2
- antidysrhythmic
- Vagal maneuver
- synchronized cardioversion
Treatment of pulse-less V-Tach
- CPR
-Defibrillator
(fatal if not terminated in 3-5 mins)
- O2 and antidysrhythmic
Ventricular Fibrillation (V-Fib)
Ventricular rate greater than 300
Extremely irregular rhythm
Idioventricular Rhythm
Rate between 20-40
QRS has a bizarre abnormal shape
Asystole
Absent QRS complexes
Explain the advantage of a 12-lead EKG tracing over a single lead strip.
12 lead EKG shows the heart from 12 different directions providing a more complete picture of cardiac function
� can locate issue damage
� identify abnormally large chambers
� provide more details about conduction
� point out metabolic and chemical abnorm
V1 (EKG Placement)
right side chest - 4th intercostal space - next to sternum
V2 (EKG Placement)
left side chest - 4th intercostal space - next to sternum
V3 (EKG Placement)
left side chest - draw imaginary line between V2 and V4 - halfway in between
v4 (EKG Placement)
left side chest - 5th intercostal space - straight down from nipple
V5 (EKG Placement)
left side chest - 5th intercostal space - draw
imaginary line between V4 and V6 - halfway in between
V6 (EKG Placement)
left side chest - 5th intercostal space - draw imaginary line down from axilla
Define ischemia
Tissue damage caused by a lack of oxygen in a portion of myocardial wall
Define myocardial infarction.
Results of ischemia causing myocardial wall tissues to die completely
Describe EKG changes associated with myocardial damage.
ST segment - depression, elevation
T wave - peaking, flattening, inversion
Q wave - deepening and widening of Q waves
Describe the evolution of ischemic changes (age of infarction.)
As ischemic damage evolves from the first hours through days, weeks and months, the EKG picture will continue to change in a more or less predictable sequence, thus suggesting age of infarction
Define bundle branch block
Conduction defect within the bundle branches, causing a prolonged QRS measurement (>.12 seconds)
State which leads identify damage on specific surfaces of the heart.
Anterior -
Lateral -
Inferior -
Anterior - V1-V2-V3-V4
Lateral - I, AVL, V5, V6
Inferior - II, III, AVF
Describe the appearance of pericarditis on an EKG.
ST changes similar to those of ischemia/infarction. (ST elevation)
Describe the appearance of digitalis on an EKG.
Digitalis toxicity produces scooped ST segments and a shortened QT interval
Describe the appearance of hyperkalemia on an EKG.
peaked T waves and merging of the QRS and T waves
Describe the appearance of hypokalemia on an EKG.
flat T waves, widening of QRS complexes and appearance of "U" waves
Describe the appearance of hypercalcemia on an EKG.
QT intervals that are unexpectedly short for the rate
Describe the appearance of hypocalcemia on an EKG.
QT intervals are longer than expected
Explain the purpose of an artificial pacemaker.
Pacemakers apply an artificial stimulus to the heart muscle and stimulate the ventricles, the atria or both.
Explain the two basic ways pacemakers can initiate pulses.
Triggered pacemakers fire at a predetermined rate.
Inhibit pacemakers fire only when needed.
Describe the appearance of pacemakers on an EKG.
Unnaturally sharp spikes superimposed on the patient's underlying rhythm