Cardiac Dysrhythmias
NURS 2106
Dysrhythmias (arrhythmias):
 Most common complication post MI
 Disturbance of rate, rhythm or conduction of electrical impulses within the heart
 Prompt assessment of dysrhythmias and the patient’s response to the rhythm is critical
Classifications of arrhythmias:
 Sites:
o SA node (sinus rhythm)
o Atrial (atrial rhythms)
o AV node (nodal or junctional rhythm)
o Ventricles (ventricular rhythms)
 Type:
o Flutter
o Fibrillation
o Block
Prognosis:
 Minor – no immediate concern
 Major – reduction of efficiency of the heart
 Lethal – requires immediate treatment or resuscitation, death producing
Dysrhythmias symptoms:
 Some dysrhythmias  no symptoms
 Some dysrhythmias  life threatening (sudden collapse, death)
 Typical symptoms:
o Dizziness
o Weakness
o Decreased exercise tolerance
o Shortness of breath
o Fainting
o Palpitations or “heart has skipped a beat”
Common causes of dysrhythmias:
 Cardiac causes
o Accessory pathways, conduction defects
o Cardiomyopathy, heart failure
o Myocardial cell degeneration (ischemia, injury, infarction)
o Valve disease
 Other conditions
o Acid-base imbalances
o Electrolyte disturbances
o Caffeine, tobacco, alcohol
o Drug effects (antidysrhythmia, stimulants, beta-blockers)
o Emotional crisis, herbal supplements, connective tissue disorders
o Hypoxia, shock
o Metabolic conditions (thyroid dysfunction)
o Near-drowning, poisoning
2
Sinus Bradycardia
Identifying EKG characteristics:
 Rate: < 60 beats a minute
 Rhythm: Regular
 P waves: Normal and precede each QRS
 PR interval: Normal range (0.12 – 0.20)
 QRS: Normal (< 0.12)
Etiology:
 May be normal in physically conditioned adults and during sleep
 Increased vagal tone (Valsalva maneuver, endotracheal suctioning, vomiting, gagging)
 Medication effect (narcotics, cardiac glycoside, beta blockers, calcium channel blockers)
 Pathology (hypothermia, hypothyroidism, increased intracranial pressure, obstructive jaundice, MI--inferior wall MI involves right coronary artery). Ischemia of sinus node slows rate.
Clinical significance:
 May be asymptomatic.
 Symptoms are associated with decreased cardiac output:
o Hypotension, dizziness, syncope
o Pale, cool skin
o Weakness
o Confusion or disorientation
o Shortness of breath
o Angina
o Decreased urinary output
Treatment:
 Treat only is symptomatic
 Atropine IVP (0.5 – 1 mg)
 If due to medication  discontinue or reduce dose
 Pacemaker may be required
Nursing implications:
 Assess for signs and symptoms of decreased cardiac output
 Observe for premature ventricular contractions (PVCs) or other ectopic beats
 Assist with medical treatment: atropine if ordered, preparation for pacemaker insertion
3
Sinus Tachycardia
Identifying EKG characteristics:
 Rate: > 100 beats a minute (usually 101 – 200 bpm)
 Rhythm: Regular
 P waves: Present, normal in shape; may not be clearly identified if encroach on preceding T waves
 PR interval: Normal
 QRS: Normal
Etiology:
 Physiological response to exercise, stress, fever, caffeine, pain, emotion, hyperthyroidism,
hypoglycemia
 Treatment with medications such as adrenergics, anticholinergics, amphetamines, caffeine, nicotine,
cocaine
 Compensatory mechanism for decreased cardiac output (heart failure, hypoxia, hypotension, anemia,
hypovolemia)
 In acute MI occurs more often with anterior MI because of left ventricular failure
Clinical significance:
 May be asymptomatic or may feel a “fluttering” in the chest
 Cardiac output may diminish due to decreased chamber filling time resulting in dizziness, dyspnea,
hypotension, syncope
 Increased myocardial oxygen consumption may lead to angina or increase in infarct size in MI
Treatment:
 Determined by underlying cause
o Antipyretics to treat fever
o Analgesics to treat pain
o Treatment for hypovolemia or hypervolemia, hypoxia
o Medications: Beta-blockers, calcium channel blockers, tranquilizes, antianxiety agents, IV adenosine
(Adenocard)
 Adenocard may cause brief asystole. Monitor EKG continuously.
Nursing implications:
 Assess for possible causes
 Administer medications as ordered
4
Atrial Flutter
Identifying EKG characteristics:
 Rate: Atrial rate: 250 – 350 bpm. Ventricular rate: Varies
o Ventricular rate depends on number of impulses that are conducted through AV node---2:1, 3:1,
4:1.
 Rhythm: Atrial is regular. Ventricular may be regular or irregular.
 P waves: No normal P wave. Saw tooth-shaped flutter waves.
 PR interval: Unable to measure
 QRS: Usually normal
Etiology:
 CAD, hypertension, mitral valve disorder, pulmonary embolus, COPD, cor pulmonale, cardiomyopathy,
hyperthyroidism, medications (digoxin, quinidine, epinephrine)
Clinical significance:
 High ventricular rates (>100) and loss of the atrial “kick” can decrease CO and precipitate heart failure,
angina
 Risk for stroke due to risk of thrombus formation in the atria from the stasis of blood
Treatment:
 Primary goal is to slow ventricular response by increasing AV block
o Drugs to slow HR: Calcium channel blockers, beta-blockers
o Electrical cardioversion
o Antidysrhythmia drugs to convert atrial flutter to sinus rhythm or to maintain SR: amiodarone
(Cordarone), propafenone (Rythmol), procainamide (Pronestyl), ibutilide (Corvert), flecainide
(Tambocor), dronedarone (Multaq)
o Radiofrequency catheter ablation can be curative therapy for atrial flutter
Nursing implications:
 Assess for rapid heart rate and signs of decreased cardiac output --- angina, dyspnea, SOB, hypotension,
fatigue, dizziness, palpitations
 Assess for signs of stroke
 Assist with cardioversion, radiofrequency catheter ablation
 Administer medications as ordered---antidysrhythmic and/or anticoagulant
 Monitor anticoagulant therapy---INR, PT
5
Atrial Fibrillation
Identifying EKG characteristics:
 Rate: Atrial rate: 350 – 600 bpm
o Ventricular rate: 50 - 180 bpm
o Total disorganization of atrial electrical activity due to multiple ectopic foci resulting in loss of
effective atrial contraction
 Rhythm: Grossly irregular
 P waves: No P wave. Instead chaotic, small “F” waves (fibrillatory waves). Wavy baseline.
 PR interval: Unable to measure. Nonexistent.
 QRS: Usually normal
Etiology:
 Usually underlying heart disease---CAD, cardiomyopathy, HF, pericarditis, rheumatic heart disease, after
cardiac surgery, hypertension
 Also, COPD, hyperthyroidism, alcohol intoxication, caffeine use, electrolyte disturbance
Clinical significance:
 Can result in decreased cardiac output due to rapid rate and loss of atrial kick
 Atrial thrombi may form due to blood stasis (embolus is breaks away may cause a stroke)
Treatment:
 Goals:
o Decrease ventricular rate
o Prevent embolic stroke
 Drugs for rate control: digoxin, beta-blockers, calcium channel blockers
 Drugs to maintain sinus rhythm: amiodarone, sotalol, ibutilide, dronedarone
 Long-term anticoagulation: Coumadin
 Cardioversion
 Radiofrequency catheter ablation
Nursing implications:
 Assess for signs of decreased cardiac output
 Assess for signs of stroke
 Administer medications as ordered
 Assist with cardioversion, radiofrequency catheter ablation
 Monitor anticoagulant therapy (INR, PT)
6
Premature Ventricular Contractions (PVCs)
Identifying EKG characteristics:
 Rate: Varies due to intrinsic rate and # of PVCs
 Rhythm: Irregular
 P waves: None associated with PVC; usually lost in the PVC or retrograde P wave
 PR interval: Not measurable with the PVC
 QRS: Wide and bizarre (> 0.12 sec), occurs prematurely
 T wave: Frequently in the opposite direction of the QRS complex
Etiology:
 Stimulants: caffeine, alcohol, nicotine, aminophylline, epinephrine, isoproterneol
 Digoxin
 Electrolyte imbalances: Especially hypokalemia and hypomagnesemia
 Hypoxia, acidosis
 Fever
 Exercise, emotional distress
 Disease states: MI, mitral valve prolapse, HF, CAD
Clinical significance:
 In normal heart, usually benign
 In heart disease, PVCs may decrease CO and precipitate angina and HF
 PVCs in CAD may lead to ventricular tachycardia (VT) or ventricular fibrillation (VF)
Treatment:
 Treat the underlying cause
o Oxygen therapy for hypoxia
o Electrolyte replacement
o Drugs: Beta-blockers, procainamide, amiodarone, lidocaine
Nursing implications:
 Monitor for increased frequency, multiform, runs or R on T
 Assess for decreased cardiac output and administer medications as ordered.
7
Ventricular Tachycardia
Identifying EKG characteristics: A run of 3 or more PVCs = V tach
 Rate: 150 – 250 beats per minute
 Rhythm: Usually regular
 P wave: None identified
 PR interval: Not measurable
 QRS: Wide, bizarre (> 0.12)
Etiology:
 Reflects advanced myocardial irritability caused by: MI, CAD, electrolyte imbalances, cardiomyopathy,
mitral valve prolapse, long QT syndrome, digitalis toxicity, CNS disorders
Clinical significance:
 Recognize can be life threatening. May degenerate into ventricular fibrillation.
 VT can be stable (patient has a pulse) or unstable (patient is pulseless)
 Sustained VT: Severe decrease in CO---hypotension, pulmonary edema, decreased cerebral blood flow,
cardiopulmonary arrest
Treatment:
 Unstable pulseless: CPR, defibrillate, epinephrine, vasopressin, antiarrhythmics (IV amiodarone or lidocaine)
 Stable with a pulse: Antiarrhythmics (procainamide, sotalol, amiodarone or lidocaine), synchronized
cardioversion
 Must treat if only V. tach only briefly and stops abruptly****
Nursing implications:
 Assess for underlying cause
 ACLS protocol, O2, code cart, intubation equipment at bedside
 Administer medications as ordered
8
Ventricular Fibrillation
Identifying EKG characteristics:
 Rate: Ventricles are “quivering” ----no effective ventricular contraction; no rate
 Rhythm: Irregular and chaotic
 P waves: Not visible
 PR interval: Not measurable
 QRS: Not measurable
Etiology:
 Acute MI, CAD, cardiomyopathy
 May occur during cardiac pacing or cardiac catheterization
 May occur with coronary reperfusion after fibrinolytic therapy
 Accidental electrical shock
 Hyperkalemia
 Hypoxia
 Acidosis
 Drug toxicity
Clinical significance:
 Unresponsive, pulseless, and apneic state
 If not treated rapidly, death will result
Treatment:
 Immediate initiation of CPR and ACLS measures with the use of defibrillation and definitive drug therapy
Nursing implications:
 Assess patient, CPR, ACLS
9
Asystole
Identify EKG characteristics:
 Rate: Absent
 Rhythm: Absent
 P waves: Absent or occasionally can be seen
 PR interval: Absent
 QRS: Absent
Etiology:
 Advanced cardiac disease
 Severe cardiac conduction system disturbance
 End-stage HF
 Electrolyte imbalances, drug overdose, trauma
Clinical significance:
 Unresponsive, pulseless, and apneic state
 Prognosis for asystole is extremely poor
Treatment:
 CPR with initiation of ACLS measures (e.g. intubation, transcutaneous pacing, and IV therapy with
epinephrine and atropine)
Nursing implications:
 Identity patients at risk for asystole
 CPR, ACLS
 Family support
10
Practice Strips: V tach
Rhythm: Regular Rate: 170
P wave: no p wave PR interval: no pr interval
QRS interval: 0.24 QT interval: no QT ST segment and T wave:
Rhythm interpretation: V tach
2.
Rhythm: irregular Rate:70
P wave: P wave is present and irregular PR interval: 0.24
QRS interval: 0.04 QT interval: 0.48 ST segment and T wave: 0.24
Rhythm interpretation: Atrial fibrillation
3.
11
Rhythm: regular Rate: 100 P wave: yes PR interval:0.12
QRS interval: 0.04 QT interval: 0.28 ST segment and T wave
Rhythm interpretation: second degree av block
4.
Rhythm: irregular Rate:70
P wave: no PR interval: not measurable
QRS interval: 0.04 QT interval:0.44 ST segment and T wave: \
Rhythm interpretation: junctional rhythm
12
5.
Rhythm: irregular Rate: 80
P wave: yes PR interval: not measureable
QRS interval: not measureable
QT interval:0.24 ST segment and T wave: 0.12
Rhythm interpretation: Premature ventricular contraction
6.
Rhythm: irregular Rate:70 P wave: No PR interval: unmeasurable
QRS interval: 0.06 QT interval: 0.48 ST segment and T wave: ___________________
Rhythm interpretation: Third degree block
13
7.
Rhythm: irregular Rate:90
P wave: yes PR interval: 0.12
QRS interval: 0.08 QT interval: 0.28 ST segment and T wave: 0.20
Rhythm interpretation: atrial flutter
8.
Rhythm: Irregular Rate: P wave: 70 PR interval: 0.12
QRS interval:0.08 QT interval: 0.44 ST segment and T wave: ___________________
Rhythm interpretation: afib
14
9.
Rhythm:irregular Rate:250
P wave: no PR interval: non measureble
QRS interval:0.16 QT interval: non measurable ST segment and T wave: non measurable
Rhythm interpretation: ventricular fibrillation
10.
Rhythm:regular
Rate: 20
P wave: _yes PR interval: 0.12
QRS interval: 0.08 QT interval: ST segment and T wave: 0.20
Rhythm interpretation: sinus bradycardia
15
11.
Rhythm: irregular and chaotic
Rate: not measureableP wave: not visible
PR interval: Not
measurable
QRS interval: not measurable
QT interval: not measurable ST segment and T wave: not
measurable
Rhythm interpretation: ventricular fibrillation
12.
Rhythm:regular
Rate:110
P wave: yes PR interval: 0.08
QRS interval: 0.06 QT interval: 0.24 ST segment and T wave: normal
Rhythm interpretation: sinus tachycardia
16
13.
Rhythm:irregular Rate:100
P wave: yes PR interval: 0.20
QRS interval: 0.12 QT interval: ST segment and T wave: ___________________
Rhythm interpretation: pvc
14.
Rhythm: irregular Rate: 100 P wave: yes
PR interval:0.12
QRS interval: 0.04 QT interval: 0.24 ST segment and T wave: 0.08
Rhythm interpretation: atrial fibrillation
17
The End!!
02/04/2011
BN
