Week 2: Dysrhythmias: Life Threatening Rhythms

Premature Ventricular Contractions (PVCs) description

• premature =

• rhythm

• P wave

• PR

• QRS

• T wave

• Premature (early)

• Underlying rhythm usually regular, irregular with PVC

• P waves not present with PVC

• PR – none with the PVC

• QRS wide – usually 0.12 seconds or greater

• T wave is usually large

ECG PQRST

• PR interval and segment

• QRS complex

• ST

• QT

Premature Ventricular Contractions (PVCs)

• associated with what? (4)

• what can happen to a normal heart (1) vs diseased heart (3)

• assess for what (1)

• treatment (4)

• Associated with stimulants, electrolyte imbalances, hypoxia, heart disease

• Not harmful with normal heart. In diseased heart - CO reduction, angina, and HF can result.

• Assess apical-radial pulse deficit

Treatment:

• Correct the cause

• Antidysrhythmic – B-blockers, amiodarone, lidocaine

A patient has a diagnosis of acute myocardial infarction, and his cardiac rhythm is sinus bradycardia with 6 to 8 premature ventricular contractions (PVCs) per minute. The pattern that the nurse recognizes as the most characteristic of PVCs is

a. An irregular rhythm.

b. An inverted T wave.

c. A wide, distorted QRS complex

d. An increasingly long PR interval.

C

Ventricular Tachycardia (VT, V Tach)

• causes (5)

• Types (4)

• why is it life threatening

Causes: heart disease, electrolyte imbalances, stimulants, drugs, CNS disorder

Types:

1. Monomorphic (look the same)

2. polymorphic (different appearance)

3. sustained

4. non-sustained

Considered life-threatening because of decreased CO and the possibility of deterioration to ventricular fibrillation

Ventricular Tachycardia

• intervention (2)

• what does sustained VT cause? (1) which can cause (4)

• Stable vs unstable Pt

• interventions for stable Pts (5)

• interventions for unstable Pts (5)

Find precipitating cause(s) and treat

• e.g. hypoxia, electrolyte disturbance

Sustained VT causes severe decrease in CO

• Hypotension, pulmonary edema, decreased cerebral blood flow, cardiopulmonary arrest

Stable (patient has a pulse)

• Airway, oxygen, monitor, synchronized cardioversion if serious S/S; if no serious S/S and QRS > 0.12 follow ACLS algorithm

Unstable (pulseless) - Advanced Cardiovascular Life Support (ACLS) algorithm

• CPR, Defibrillation, IV, CPR, Epinephrine….. repeat

Ventricular Fibrillation

• associated with (4)

• Pt characteristics (3)

• if not treated what will happen (1)

• treatment (5)

• Associated with MI, ischemia, disease states, procedures

• Unresponsive, pulseless, and apneic

• If not treated rapidly, death will result

• Treat with immediate CPR and ACLS (same as for pulseless VT)

• Defibrillation

• Drug therapy (epinephrine, vasopressin)

Epinephrine

• indications (5)

• considered after what in symptomatic bradycardia (1)

• drug class (1)

• actions (5)

• dosage (1)

Indications: cardiac arrest (pulseless VT, VF, asystole, considered after atropine in symptomatic bradycardia)

• Drug class- alpha & beta adrenergic agonist

• Actions – increases SVR, increased HR, enhanced myocardial contraction, coronary vasodilation, enhanced brain perfusion

• Dosage – 1 mg (1:10,000 solution

Pulseless Electrical Activity

• define (3)

• prognosis (1)

• treatment (4)

• Electrical activity can be observed on the ECG, but no mechanical activity of the heart is evident, and the patient has no pulse (e.g. idioventricular rhythm (IVR), ventricular escape rhythms, post-defibrillation IVR)

• Prognosis is poor unless underlying cause quickly identified and treated

• Treatment – CPR, IV/IO access, Epinephrine, find and treat cause

causes of PEA - 6 Hs, 5 Ts

• don’t need to memorize

Asystole

• describe

• Pt characteristic (3)

• must assess (1)

• usually a result of (3)

• treatment: (4)

• prognosis (1)

• Represents total absence of ventricular electrical activity

• No ventricular contraction

• Patient unresponsive, pulseless, apneic

• Must assess in more than one lead

• Usually result of advanced cardiac disease, severe

conduction disturbance, or end-stage HF

• Treat with immediate CPR and ACLS measures

• Epinephrine

• Intubation

• Poor prognosis

Sudden Cardiac Death (SCD)

• define

• results from (2)

• Death from a cardiac cause

• Majority of SCDs result from ventricular dysrhythmias

• Ventricular tachycardia

• Ventricular fibrillation

DEFIBRILLATION

• treatment of choice for what (2)

• what is it not for (2)

• Most effective when completed within ____ of dysrhythmia onset

• action (2)

• monophasic vs biphasic defibrillators

• Treatment of choice for VF and pulseless VT. NOT for asystole nor PEA.

• Most effective when completed within 2 minutes of dysrhythmia onset

• Passage of DC electrical shock through the heart to depolarize myocardial cells

• Allows SA node to resume pacemaker role (120-200 joules)

• Monophasic defibrillators deliver energy in one direction (360 joules)

• Biphasic defibrillators deliver energy in two directions

• Use lower energies

• Fewer post-shock ECG dysrhythmia

which type of defilation is preferred

Biphasic

DEFIBRILLATION process (8)

1. Start CPR while obtaining and setting up defibrillator

2. Turn on and select energy

3. Make sure sync button is turned off

4. Apply gel pads

5. Charge

6. Position paddles firmly on chest

7. Ensure “All clear”!!!!!

8. Deliver charge

Synchronized Cardioversion (DCCV)

• used for (3)

• action

• similar to defibrillation except ___

• if pt is stable ___ prior

• initial ____ energy

• _____ joules (biphasic)

• ____ joules for afib

• what to do if pt becomes pulseless

Used for STABLE Tachyarrhythmias -

A-fib, A-flutter; VT with pulse

• Synchronized circuit delivers a countershock on the R wave of the QRS complex of the ECG

• Procedure similar to defibrillation except sync button turned ON

• If patient stable, sedate prior

• Initial lower energy

• 50-100 joules (biphasic)

• 120 joules for afib

• If patient becomes pulseless, turn

sync button off and defibrillate

A patient in the coronary care unit develops ventricular fibrillation. The first action the nurse should take is to

a. Prepare for synchronized cardioversion.

b. Perform defibrillation

c. Initiate CPR.

d. Administer IV antidysrhythmic drugs per protocol.

B

NCLEX key terms

• p wave =

• QRS wave =

• lack of QRS complexes =

• wide bizarre QRS complexes =

• chaotic or unorganized =

• chaotic rhythm with no p wave =

• chaotic rhythm without QRS complexes

The monitor of a patient in the coronary care unit abruptly

shows a chaotic rhythm without QRS complexes. The

first action the nurse should take is to

a. Prepare for synchronized cardioversion.

b. Perform defibrillation

c. Initiate CPR.

d. Administer IV antidysrhythmic drugs per protocol

B

Premature atrial contraction

• define

• p wave (3)

• QRS (1)

• could be caused by (10) (5 big ones)

 Contraction originating from ectopic focus in atrium in location other than SA node

 Travels across atria by abnormal pathway, creating distorted P wave

 P wave could be flattened, notched, or

hidden in T wave

 QRS normal but comes early

Could be caused by…

Stress

anxiety

Caffeine

Tobacco

Alcohol

Fatigue

Hypoxia

Electrolyte imbalance

Disease states e.g. HF

Digitalis toxicity

Premature Atrial Contraction (PACs)

• manifestations (feels like…) (3)

• treatment (5)

Manifestations (Feels Like…)

 Palpitations

 Heart “skips a beat”

 Unknown, unaware

Treatment – treat cause & slow it down

 Withhold sources of stimulation

 β-blockers

 Monitor for more serious dysrhythmias

Paroxysmal Supraventricular Tachycardia (PSVT)

• manifestations (7) what is the key? (1) (HR)

• what to think about

• reentrant phenomenon

• paroxysmal refers to ____

• associated with (6)

Manifestations

HR is 150–250 beats/minute

HR > 180 leads to decreased cardiac

output and stroke volume

Recognizing unstable tachycardia is KEY

• Hypotension, Dyspnea, Angina, Altered cognition, Acute heart failure

Is the tachycardia causing the S/S or are S/S producing the tachycardia

reentrant phenomenon:

• PSVT triggers a run of repeated premature beats

 Paroxysmal refers to an abrupt onset and termination

Associated with

overexertion, stress, deep inspiration, stimulants, disease, digitalis toxicity

Paroxysmal Supraventricular Tachycardia (PSVT)

• treatment (5)

• if symptoms persist (1)

Treatment – slow it down

Vagal stimulation (Valsalva maneuver)

IV β-blockers

Calcium channel blockers

IV adenosine (slows heart)

If symptoms persist – synchronized cardioversion

Atrial fibrillation

• define (HR)

• controlled when

• uncontrolled when

• 3 major chacteristics

• assessing pulse with a fib where?

 Atria – fibrillating 350-600/min (inadequate filling or contraction)

 Ventricular response

 Controlled when HR 60-100

 Uncontrolled when HR > 100

 3 major characteristics

1. No P waves

2. Normal QRS configuration

3. Fibrillatory waves (F waves)

 Assessing pulse with A-fib - apical

Atrial fibrillation (Afib)

• most common ____

• define

• prevalence increases with __

• occurs in pts with (6)

• high risk of ____ is ___

Paroxysmal (comes & goes) or persistent

Most common dysrhythmia

Prevalence increases with age

Usually occurs in patients with underlying heart disease e.g. MI, HTN, valve disease

Other – digitalis toxicity, COPD

High risk of clots and stroke if HR >100

Atrial fibrillation (Afib)

• goals (3)

• treatment:

• rate control: duration and options (4)

• convert rhythm: duration and options (2)

• if a-fib for > 48 hours or unknown (3) other considerations (2)

• if not responding to tx or becomes unstable (1) other (2)

- dabigatran (Pradaxa), rivaroxaban (Xarelt) = blood thinners used to prevent and treat dangerous blood clots

Atrial Flutter

• rate?

• P wave

• PR

• Atrial oscillations

• must calculate what (2)

• associated with (1)

• s/s result from ___ which causes __

• increased risk of ___

 Atrial Rate generally – 250-350

 Atria so rapidly that the AV node can’t respond to every impulse. The ventricular rate depends on the number of atrial impulses that pass through the AV node (will see ventricular response)

 No P waves. No PR-interval to measure

 Atrial oscillations – flutter waves (f waves), saw-toothed or picket fence appearance

• must calculate atrial and ventricular rates

•  Typically associated with disease

   Symptoms result from high ventricular rate and

  loss of atrial “kick” → decreased CO → heart

  failure

   Increases risk of strok