DYSRHYTHMIAS

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 60-100 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 – 60-100 beats/minute • P wave – present and upright /all shaped alike • PR interval - P wave precedes QRS duration (0.12 -0.20 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 (0.12 -0.20 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 – 200 -360 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.