1. DYSRHYTHMIAS
NUR – 224
MS. GARDNER

2. DYSRHYTHMIAS
Disorder of conduction of the electrical impulse within the heart.
Cause disturbances with heart rate/heart rhythm or both.
Diagnosed by analyzing the electrocardiographic (ECG/EKG).
Treatment based on frequency and severity of symptoms
Named according to the site of origin of the impulse and the conduction involved.

3. Normal Electrical Conduction
Electrical impulse stimulates and paces the cardiac muscle and normally originates in the SA node.
Rate bpm
All beats appear in a similar pattern, equally spaced, and have three major units:
P wave, QRS complex, and T wave.

4. Heart/ECG
Each wave represents transmission of an electrical impulse through the heart muscle (depolarization)  causes the muscle to contract and eject blood.
P wave – reflects impulse going through the atria.
QRS complex - reflects impulse going through the ventricles.
T wave - is produced by the electrical recovery (repolarization) of the ventricle.
Depolarization – electrical stimulation/contraction
Repolarization – electrical relaxation

6. Normal Electric Pathway
Electrical impulse originates in the sinoatrial (SA) node.
The impulse spreads through the intra-atrial pathways to the atrio-ventricular(AV) node.
The structure of the AV node slows the electrical impulse  giving the atria time to contract and fill ventricles with blood. (atrial kick)
After a brief delay, the impulse continues through the bundle of His, the R/L bundle branches, Purkinje fibers located in the ventricular muscle.
This stimulation causes the ventricles to contract (systole)
The heart rate is influenced by the autonomic nervous system  sympathetic/parasympathetic nerve fibers

8. Electrocardiogram
Electrical impulse travels through the heart  the end product is an ECG.
ECG is obtained by placing electrodes on the body – on the limbs and chest.
The electrodes create an imaginary line  lead. Waveforms that appear on the paper/cardiac monitor represent the electrical current in relation to the lead.
Electrodes are attached to a cable wire which may be connected to ECG machine, cardiac monitor, telemetry monitor, Holter monitoring.
12-lead ECG  10 electrodes, reflects the activity in the left ventricle.

10. Interpretation
ECG waveforms are printed on graph paper that is divided by light and dark vertical and horizontal lines.
ECG waveform moves to the top of the paper  positive deflection
ECG moves toward the bottom of the paper  negative deflection
Each waveform should be compared and examined with others.

12. Interpretation ECG – composed of waveforms (P wave, QRS complex,
T wave)
P wave –
first upward deflection represents atrial depolarization. usually not more than 3 small blocks.
QRS complex –
ventricular depolarization.
consist of three deflections: Q wave, the first downward stroke, R wave first upward stroke; S wave downward stroke following the R wave.
normal duration of the QRS complex is less than three small blocks (0.12 seconds).

13. Interpretation
T wave
represents ventricular repolarization/electrical recovery of the ventricular contraction.
PR interval
measures from the beginning of the P wave to the onset
of the Q wave.
represents conduction of the impulse through the atria and into the AV node.
ST segment
begins at the end of the S wave and ends at the beginning of the T wave.
U wave
Small upward deflection following the T wave. Seldom present.

14. Interpretation PP interval
measured from one P wave to the beginning to the next P wave
used to determine atrial rhythm and atrial rate
RR interval
measured from one QRS complex to the next QRS complex.
RR interval used to determine ventricular rate and rhythm.

16. Analyzing the Rhythm Strip
Count the number of complexes in a 6 –second strip and multiply that number by 10. (useful for irregular rhythms)
Analyze in a systematic manner:
Rhythm – regular
Rate – beats/minute
P wave – present and upright /all shaped alike
PR interval - P wave precedes QRS
duration ( sec.)
time interval same for all beats
QRS interval – present /all shaped alike
duration not more than 3 small squares
(0.12 sec.)

18. Normal Sinus Rhythm Rhythm – regular Rate – 60-100 beats/minute
P wave – present and upright /all shaped alike
PR interval - P wave precedes QRS
duration ( sec.)
time interval same for all beats
QRS interval – present /all shaped alike
duration not more than 3 small squares
(0.12 sec.)

19. Sinus Bradycardia
Dysrhythmias heart rate below 60, complex remain normal
Causes: sleep, athletic training, hypothyroidism,
medications, myocardial infarction
Atropine IV medication of choice for treatment bradycardia

20. Sinus Tachycardia
All complexes are normal. The heart rate is more than100.
Causes:
Physiologic stress
Medication
Treatment: usually secondary to factors outside the heart, treatment is directed to treat the underlying cause

21. Sinus Arrhythmia
All complexes are normal, but the heart rate is irregular.
The rate increases with inspiration and decreases with expiration
Does not cause any significant hemodynamic effect and usually is not treated

22. Atrial Dysrhythmias
Portions of atrial tissue may become excitable and initiate impulses.
These impulses will control the heartbeat if they occur at a rate faster than impulses from the SA node.
Premature atrial complex
Atrial flutter
Atrial fibrillation

23. Premature Atrial Complex
A single complex beat that occurs when an electrical impulse appears early in the cycle – before the next sinus beat.
Cause: caffeine, nicotine, anxiety, hypokalemia
PACs are common normal heartbeats
If infrequent - no treatment is necessary.

24. Atrial Flutter Is a rapid, regular fluttering of the atrium.
The atrial rate is between 250/400 times/minute.
P wave takes on a saw toothed appearance
Cause: open heart surgery, valvular disease
Treatment: Adenosine, vagal maneuvers, electrical cardioversion, medications, catheter ablation

25. Atrial Fibrillation
Uncoordinated atrial electrical activity that causes a rapid disorganization and uncoordinated twitching of the atria
P waves – (fibrillatory waves) assume different shapes because they are coming from different foci in the atrium.
No PR interval can be determined
Cause: CAD, open heart surgery, obesity, diabetes
Treatment:

27. Ventricular Dysrhythmias
Ventricular tissue becomes more excitable as a result of ischemia, drug effect or electrolyte imbalance. These dysrhythmias may diminish the ability of the heart to function as a pump.
Without adequate blood flow, all organs deteriorate.
Premature ventricular complex
Ventricular tachycardia
Ventricular fibrillation
Ventricular asystole

28. Premature Ventricular Complex
Impulse that starts in the ventricles and is conducted throughout the ventricle before the next normal sinus impulse.
Can occur in healthy people  coffee, smoking, alcohol.
PVCs are usually not serious
Treatment: correct the underlying cause, if PVCs are frequent and consistent  amiodarone/lidocaine
Bigeminy, trigeminy, multifocal

29. Multifocal PVC - Quadrigeminy

30. Ventricular Tachycardia
Three or more PVCs in a row, rate exceeds 100 bpm.
Is an emergency the patient is usually unresponsive and pulseless, leads to reduce cardiac output.
Treatment: antiarrhythmic medication, pacing, or cardioversion
If patient is unconscious and without a pulse immediate defibrillation

31. Ventricular Fibrillation
Most common dysrhythmia in patients with cardiac arrest
Rapid, disorganized ventricular rhythm that cause ineffective quivering of the ventricles
No atrial activity is seen on ECG
Characterized by: absence of an audible heartbeat, a palpable pulse, and respirations
There is no coordinated cardiac activity  cardiac arrest and death are imminent if the dysrhythmia is not corrected
Defibrillation/cardiopulmonary resuscitation (CPR)

32. Ventricular Asystole

33. Ventricular Asystole Flatline, No QRS complex
P waves may be apparent for a short duration
There is no heartbeat, no palpable pulse, and no respiration
Without immediately treatment – fatal
Treatment – CPR, intubation, IV access

34. Assessment Cardiac dysrhythmias – either begin/critical
Diagnostic Test
electrocardiogram
cardiac monitoring
electrophysiology

35. Nursing Interventions
Monitoring/ECG monitoring
Administration of medications/medication effects
Adjunct therapy: cardioversion, defibrillation, pacemakers
Other

36. Adjunctive Modalities
Medications not working
Common therapies:
elective cardioversion
defibrillation
implantable devices
internal cardio defibrillators

37. Pacemakers
Is a pulse generator used to provide an electrical stimulus to the heart when the heart fails to generate/conduct its own rate that maintains cardiac output.
Are programmed to stimulate the atria or the ventricles, or both
Pacing is detected on the ECG strip by the presence of pacing artifact – a sharp spike is noted
Power source may be internal/external
Several different types:
Temporary
Permanent

38. Pacemaker Paces the heart when normal conduction pathway is damaged.
Basic unit – power source, one or more conducting leads
The electrical signal travels from the pacemaker, through the leads, the walls of the myocardium.
The myocardium is “captured” and stimulated to contract

39. Pacemaker Permanent Implanted totally within the body
The power source is placed subcutaneously, usually over the pectoral muscle on the patient’s nondominant side
The pacing leads are leads are threaded transvenously to right atrium and one/both ventricles and attached to the power source.

41. Pacemakers Temporary Power source is outside the body Different types
Epicardial pacing
Transvenous pacing
Transcutaneous pacing

42. Epicardial pacing

45. Pacing on Demand

46. Pacemaker Patient teaching Follow-up care Report s/s infection
Keep incision dry
Avoid lifting arm on pacemaker site
Airport travel is not restricted
Carry pacemaker information card
Wear Medic-alert ID band

47. Cardioversion and Defibrillation
Treat tachy dysrhythmias by delivering electrical current that depolarizes myocardial cells
When cells repolarize, sinus node usually able to recapture role as heart pacemaker
Cardioversion  current delivered is synchronized with patient’s ECG
Defibrillation  current delivered is unsynchronized and immediate

48. Paddle placement

49. Cardioversion
A synchronized circuit in the defibrillator delivers a direct electrical current synchronized with the patient’s heart rhythm.
Countershock that is programmed to occur with the R wave of the QRS complex.
Used for nonemergency basis –
Used to treat – atrial fibrillation, atrial flutter, stable ventricular tachycardia
Patient is awake/hemodynamically stable
Sedation prior to the procedure
Patent airway
Initial energy less than what is needed for defibrillation – 50 – 100 joules

50. Defibrillation
Choice of treatment of choice to terminate VF/pulseless VT.
Defibrillation is accomplished by delivering direct current without regard to the cardiac cycle.
The output of the defibrillator is measured in joules/watts – joules
If defibrillation is unsuccessful, CPR is immediately initiated
Defibrillation, CPR, medication administration continues until a stable rhythm resumes or until it is established that the patient will not recover.

51. Safety Measures Assure good contact between skin, pads or paddles
Use conductive medium, 20 to 25 pounds of pressure
Place paddles so they do not touch bedding or clothing, are not near medication patches or oxygen flow
If cardioverting, turn synchronizer on
If defibrillating, turn synchronizer off
Do not charge device until ready to shock
Call “clear” three times; follow checks required for clear
Assure no one is in contact with patient, bed, or equipment

52. Implantable Cardioverter Defibrillator (ICD)
Detect changes in cardiac rhythm and automatically delivers an electric shock to convert the dysrhythmia back into normal sinus rhythm.
Used for sudden death survivors, recurrent ventricular tachycardia
Monitors the heart rate and rhythm and identifies VT. Approximately 25 seconds after system detects a lethal dysrhythmia, the mechanism delivers 25 joules or less of shock to the patient’s heart.
If the first shock is unsuccessful , the generator will recycle itself and continue to deliver shock

53. ICD

54. Nursing Management
Complications similar to those associated with pacemaker insertion
Avoid driving until instructed by HCP
No MRI
Air travel not restricted
If ICD fires – contact HCP immediately
If fires and client does not feel well – contact HCP
Medic-Alert ID
Caregivers should know CPR
Teaching – lifestyle changes, periodic device monitoring, safety, surgical site care