Dysrhythmia and Conduction Problems-1

Chapter 27

Management of Patients With Dysrhythmias and

Conduction Problems

Chapter 27

Management of Patients With Dysrhythmias and

Conduction Problems

Christie M. Candelaria, MA, RN, CCRN

Learning Outcomes/Objectives:Learning Outcomes/Objectives:• Identify clinical characteristics and ECG patterns of

normal sinus rhythm and common dysrhythmias as follows:

– sinus bradycardia

– sinus tachycardia

– atrial fibrillation

– atrial flutter

– ventricular tachycardia

– ventricular fibrillation

• Describe the nursing and collaborative management of patients with common dysrhythmias mentioned above.

Cardiac conductionCardiac conduction

• SA Node

• AV node

• Bundle of HIS

• Right & Left

Bundle Branches

• Purkinje Fibers

http://www.youtube.com/watch?v=H04d3rJCLCE&feature=related



Cardiac CycleCardiac Cycle

Refers to the a repetitive pumping process that includes all of the events associated with blood flow through the heart

Depolarization- electrical stimulation

Systole—period during which ventricles mechanically contract and blood is being ejected

Repolarization – electrical relaxation

Diastole—period of mechanical relaxation in which ventricles are filling

EKG PaperEKG Paper

EKG Paper EKG Paper

Components of EKG WaveformComponents of EKG Waveform

P WAVE

• Indicates atrial depolarization, contraction of the atrium

• Normal duration is not longer than 0.11 seconds (less than 3 small squares)

• Amplitude (height) is no more than 3 mm

• Normally no notching or peaking

Components of EKG WaveformsComponents of EKG Waveforms

PR Interval

• Indicates AV conduction time

• Duration time is 0.12 to 0.20 seconds


QRS Complex• Indicates ventricular depolarization, or contraction of the

ventricles

• Shortly after depolarization begins, the ventricles contract

• Normal duration is 0.08-0.12

QRS complexQRS complex

Q Wave– 1st downward deflection in the depolarization of the ventricle (many times may be absent)

QRS ComplexQRS Complex

R Wave– 1st upward deflection of the QRS (may follow a Q wave or be present by itself)

QRS complexQRS complex

ST Segment

• terminal portion of QRS, represents the delay time after depolarization and waiting for repolarization

• Normally not depressed more than 0.5mm

• May be elevated slightly in some leads (no more than 1 mm)

(this is EXTREMELY important in diagnosing MI)


T Wave (ahhh rest)

• Indicates ventricular repolarization

• Not more than 5mm in amplitude in standard leads and 10mm in precordial leads

• Rounded and asymmetrical

• Last 1/3 of vulnerable area of time—if a ventricular response is initiated here, such as a PVC, V-Tach can occur

• Also useful in diagnosing ischemia or MI


QT Interval

• Indicates repolarization time

• General Rule: duration is less than half the preceding R-R interval

• Will lengthen and shorten as the rate changes

U WaveU Wave

• Represents repolarization of His-Purkinje system

• Not present on every strip

• A prominent U wave may be due to hypercalcemia, hypokalemia, or digoxin toxicity

Putting it all together:Putting it all together:

DysrhythmiasDysrhythmias

• Disorders of formation or conduction (or both) of electrical impulses within heart

• Can cause disturbances of

– Rate

– Rhythm

– Both rate, rhythm

• Potentially can alter blood flow, cause hemodynamic changes

• Diagnosed by analysis of electrographic waveform

Tips for applying electrodesTips for applying electrodes

• Make sure skin is thoroughly dry.

• Clip chest hair.

• Remove any excess skin oil with alcohol.

• Apply tincture of benzoin if keeping electrodes is difficult.

• Connect each lead wire to a disc before applying it to the chest.

• Make sure the center of the electrode disc is moist.

• Avoid applying electrodes over these areas:

– Bony areas skin folds

– Scar tissue breast tissue

– Muscle mass (significant) heart apex

Assessment of Cardiac RhythmAssessment of Cardiac Rhythm

Copyright © 2007, 2004, 2000, Mosby, Inc., an affiliate of Elsevier Inc. All Rights Reserved.

Fig. 36-5

Assessment of Cardiac RhythmAssessment of Cardiac Rhythm


Fig. 36-9

Assessment of Cardiac Rhythm Assessment of Cardiac Rhythm


Heart Rate DeterminationHeart Rate Determination

Evaluation of DysrhythmiasEvaluation of Dysrhythmias

• Holter monitoring

• Event recorder monitoring

• Exercise treadmill testing

• Signal-averaged ECG

• Electrophysiologic study

Normal Sinus RhythmNormal Sinus Rhythm Originates in the sinoatrial node (SA)

Rhythm: atrial/ventricular regular

Rate: atrial/ventricular rates 60 to 100 bpm

P waves: present, consistent configuration

One P wave before each QRS

PR interval: 0.12 to 0.20 second and constant

QRS duration: 0.04 to 0.10 second and constant

Normal Sinus RhythmNormal Sinus Rhythm

• Sinus node fires 60 to 100 bpm

• Follows normal conduction pattern


Fig. 36-8

Normal Sinus Rhythm Normal Sinus Rhythm

Sinus BradycardiaSinus Bradycardia


• Clinical associations

– Occurs in response to

•Carotid sinus massage

•Hypothermia

•Increased vagal tone

•Administration of parasympathomimetic drugs

Sinus BradycardiaSinus Bradycardia• Clinical associations

– Occurs in disease states

• Hypothyroidism

• Increased intracranial pressure

• Obstructive jaundice

• Inferior wall MI


•Clinical significance

– Dependent on symptoms• Hypotension

• Pale, cool skin

• Weakness

• Angina

• Dizziness or syncope

• Confusion or disorientation

• Shortness of breath


• Treatment

– Atropine

– Pacemaker may be required

PacemakersPacemakers


Fig. 36-27


Fig. 36-25 Fig. 36-26


Fig. 36-24 B


Fig. 36-24 A

Pacer spikesPacer spikes

Sinus TachycardiaSinus Tachycardia

Tachycardia Tachycardia

Heart rate greater than 100 bpm

Shorten diastolic time = perfusion time

Initial CO and B/P

Ventricular filling = stroke volume = aortic pressure

Eventually = CO and B/P

Increases the work of the heart, increasing myocardial O2 demand

Sinus Tachycardiahttp://ems-ed.net/Video/ems-edbasicecg2.html

Sinus Tachycardiahttp://ems-ed.net/Video/ems-edbasicecg2.html

•Discharge rate from the sinus node is increased as a result of vagal inhibition and is >100 bpm


http://ems-ed.net/Video/ems-edbasicecg2.html






– Associated with physiologic stressors

•Exercise

•Pain

•Hypovolemia

•Myocardial ischemia

•Heart failure (HF)

•Fever


• Clinical significance

– Dizziness and hypotension due to decreased CO

– Increased myocardial oxygen consumption may lead to angina


• Treatment

– Determined by underlying cause

-Adrenergic blockers to reduce HR and myocardial oxygen consumption

•Antipyretics to treat fever

•Analgesics to treat pain

Atrial FlutterAtrial Flutter



– Usually occurs with

• CAD

• Hypertension

• Mitral valve disorders

• Pulmonary embolus

• Chronic lung disease

• Cardiomyopathy

• Hyperthyroidism

• Drugs: Digoxin, quinidine, epinephrine



– High ventricular rates (>100) and loss of the atrial “kick” can decrease CO and precipitate HF, angina

– Risk for stroke due to risk of thrombus formation in the atria


• Treatment

– Primary goal is to slow ventricular response by increasing AV block

• Drugs to slow HR: Calcium channel blockers, -adrenergic blockers

• Electrical cardioversion may be used to convert the atrial flutter to sinus rhythm emergently and electively


• Treatment

– Primary goal is to slow ventricular response by increasing AV block

• Antidysrhythmia drugs to convert atrial flutter to sinus rhythm or to maintain sinus rhythm (e.g., amiodarone, propafenone)

• Radiofrequency catheter ablation can be curative therapy for atrial flutter

Atrial FibrillationAtrial Fibrillation

Atrial Fibrillation Atrial Fibrillation


– Usually occurs with

•Underlying heart disease, such as rheumatic heart disease, CAD

•Cardiomyopathy

•HF

•Pericarditis



– Often acutely caused by

•Thyrotoxicosis

•Alcohol intoxication

•Caffeine use

•Electrolyte disturbance

•Cardiac surgery



– Can result in decrease in CO due to ineffective atrial contractions (loss of atrial kick) and rapid ventricular response

– Thrombi may form in the atria as a result of blood stasis

– Embolus may develop and travel to the brain, causing a stroke

Atrial Fibrillation Atrial Fibrillation • Treatment

– Goals

•Decrease ventricular response

•Prevent embolic stroke– Drugs for rate control: digoxin, -

adrenergic blockers, calcium channel blockers

– Long-tern anticoagulation: Coumadin


– For some patients, conversion to sinus rhythm may be considered

•Antidysrhythmic drugs used for conversion: Amiodarone, propafenone

•cardioversion may be used to convert atrial fibrillation to normal sinus rhythm


• Treatment

– If patient has been in atrial fibrillation for >48 hours, anticoagulation therapy with warfarin is recommended for 3 to 4 weeks before cardioversion and for 4 to 6 weeks after successful cardioversion


– Radiofrequency catheter ablation

– Maze procedure

– Modifications to the Maze procedure

•Use of cold (cryoablation)

•Use of heat (high-intensity ultrasound)

LETHAL DYSRHYTHMIASLETHAL DYSRHYTHMIAS

Ventricular TachycardiaVentricular Tachycardia

Ventricular FibrillationVentricular Fibrillation

AsystoleAsystole

Nursing Process: Care of the Patient with a Dysrhythmia - AssessmentNursing Process: Care of the Patient with a Dysrhythmia - Assessment

• Assess indicators of cardiac output and oxygenation, especially changes in level of consciousness

• Physical assessment include

– Rate, rhythm of apical, peripheral pulses

– Heart sounds

– Blood pressure, pulse pressure

– Signs of fluid retention

Nursing Process: Care of the Patient with a Dysrhythmia – Assessment (cont’d)Nursing Process: Care of the Patient with a Dysrhythmia – Assessment (cont’d)

• Health history: include presence of coexisting conditions, indications of previous occurrence

• Medications

Nursing Process: Care of the Patient with a Dysrhythmia - DiagnosesNursing Process: Care of the Patient with a Dysrhythmia - Diagnoses

• Decrease cardiac output

• Anxiety

• Deficient knowledge

Collaborative Problems/Potential ComplicationsCollaborative Problems/Potential Complications

• Cardiac arrest

• Heart failure

• Thromboembolic event, especially with atrial fibrillation

Nursing Process: Care of the Patient with a Dysrhythmia - PlanningNursing Process: Care of the Patient with a Dysrhythmia - Planning

• Goals

– Eradicating or decreasing occurrence of dysrhythmia to maintain cardiac output

– Minimizing anxiety

– Acquiring knowledge about dysrhythmia, its treatment

Decreased Cardiac OutputDecreased Cardiac Output

• Monitoring

– ECG monitoring

– Assessment of signs, symptoms

• Administration of medications, assessment of medication effects

• Adjunct therapy: cardioversion, defibrillation, pacemakers

Other InterventionsOther Interventions

• Anxiety

– Use calm, reassuring manner

– Measures to maximize patient control to make episodes less threatening

– Communication, teaching

• Teaching self-care

– Include family in teaching

Cardioversion and DefibrillationCardioversion and Defibrillation

• Treat tachydysrhythmias by delivering electrical current that depolarizes critical mass of myocardial ceils

– When cells repolarize, sinus node usually able to recapture role as heart pacemaker

• In cardioversion, current delivery synchronized with patient’s ECG

• In defibrillation, current delivery is unsynchronized

DefibrillationDefibrillation


Fig. 36-21

DefibrillationDefibrillation


Fig. 36-20 A and B

Paddle Placement for DefibrillationPaddle Placement for Defibrillation

Implantable Cardioverter Defibrillator (ICD)Implantable Cardioverter Defibrillator (ICD)

• Device that detects, terminates life-threatening episodes of tachycardia or fibrillation

• NASPE-BPEG code

• Antitachycardia pacing

Invasive Methods to Diagnose and Treat Recurrent DysrhythmiasInvasive Methods to Diagnose and Treat Recurrent Dysrhythmias

• Electrophysiologic studies

• Cardiac conduction surgery

– Maze procedure

– Catheter ablation therapy

hyperkalemiahyperkalemia

hypocalcemiahypocalcemia

ST elevation or flagST elevation or flag

“How will I know what to do?” you ask“How will I know what to do?” you ask

• Treat the patient, not the rhythm - is a good place to start

• Anticipate the problem

• Know your drugs

• Know CPR

Dysrhythmia and Conduction Problems-1

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