II, III, aVF / Inferior Wall / EKG Lay-out
V1, V2 / Septum / I / aVR / V1 / V4
V3, V4 / Anterior Wall / II / aVL / V2 / V5
V5, V6 / Inferior / Lateral Wall / III / aVF / V3 / V6
aVL, I / Superior
P / < 0.10
PRI / 0.10 - 0.20
QRS / 0.06 - 0.14
Rhythm analysis Questions
- Is the patient sick?
- What is the heart rate?
- Are there normal-looking QRS complexes?
- Are there normal-looking P waves?
- What is the relationship between the P wave and the QRS complex
ECG Interpretation
Step 1: -Analyze the QRS complex for regularity and width (QRS = 0.06 – 0.14, generally app. 0.10)
> 0.12 = Ventricular conduction abnormalities.
Step 2: -Analyze the P wave (P = <0.10)
1. Present?
2. Regular?
3. One P wave for each QRS, and a QRS following each P wave?
4. Upright or inverted?
5. All look alike?
Step 3: -Analyze the Rate (60-100 = Norm., 40-60 = Brady., 100 or > = Tachy.)
Step 4: -Analyze the Rhythm
Compare R-R intervals from left to right.
If, the distance is equal or less than 0.16 sec difference, the rhythm is regular.
If, the distance varies by more than 0.16 sec difference,the rhythm is irregular.
Step 5: -Analyze the PRI (PRI = 0.10 – 0.20)
SA Node
- Sinus Bradycardia
Cause:
- Sinus Node Disease
- ↑ Vagal Tone
- Hypothermia
- Hypoxia
- Drugs
- M.I.
Why:
- Rate: < 60 BPM
What:
- ↓ Cardiac output
- Hypotension
- Angina
- Syncope
Treatment:
- Sinus Tachycardia
Cause:
- Fever
- Exercise
- Smoking
- Hypovolemia
- Anemia
- CHF
-Ingestion of Caffeine or ETOH
Why:
- Rate: Greater than 100 BPM
What:
- Not Significant
Treatment:
- Treat the underlying cause
- Sinus Dysrhythmia
Cause:
- Usually is Normal
Why:
- Rate: Varies with respiration, 60 to 99 BPM
- Rhythm: Irregular (changes with patients Respiratory pattern)
What:
- Common
- May be associated with Palpitations, Dizziness, and Syncope
Treatment:
- Seldom Requires Tx.
- Sinus Arrest
Cause:
- ↑ vagal tone
- Hypoxia
- Ischemia
- Hyperkalemia
- Damage to SA Node
- Excessive admin of digitalis or propranolol
Why:
- Rate: Norm to Slow
- Rhythm: Irregular (when arrest is present).
What:
- ↓ Cardiac Output
- Asystole
- Syncope
Treatment:
- Close observation
- TCP
- Atropine (0.5mg q 3-5 min)
Atrial
- Wandering Pacemaker
Cause:
-May be normal
-COPD (Multifocal Atrial Tach.)
Why:
- P wave: Morphology changes from beat to beat.
- Rhythm: Irregular
- PRI: Varies
What:
-Usually does not produce serious S/S
Treatment:
- No management is required
- O2 for Multifocal Atrial Tach.
2.Premature Atrial Complex (PAC)
Cause:
- ↑ Sympathetic Tone
- Caffeine, Tobacco, or ETOH
- Electrolyte Imbalance
- Hypoxia
- Cardiovascular disease
- Sympathomimetic Drugs (Epi., Albuterol, Nor-Epi.)
Why:
- P wave: Varies from the underlying rhythm, may occur early, or be hidden in the proceeding T wave
What:
- Frequent PAC’s may lead to:
Supraventricular Dysrhythmias (Multifocal Atrial Tach.)
A-Tach.
A-Flutter
A-Fib
PSVT
Treatment:
- Observation
- If Pt. develops symptomatic Bradycardia, Tx as indicated (Atropine [0.5mg q 3-5 min], TCP).
3.Paroxysmal Supraventricular Tachycardia (PSVT / SVT)
Cause:
- Stress
- Overexertion
- Tobacco use
- Caffeine
- Wolff-Parkinson-White (WPW) Syndrome
Why:
- P wave: frequently buried in the proceeding T wave
- Rate: 150 – 250 BPM
What:
- Pt.’s with a healthy heart may tolerate it well for short periods
- Compromise cardiac output in Pt.’s with existing heart disease, resulting in:
Syncope
Hypotension
CHF
Treatment:
- Atrial Flutter
Cause:
- Cardiomyopathy
- Cardiac hypertrophy
- Digitalis toxicity
- Hypoxia
- CHF
- Pericarditis
- Myocarditis
Why:
- P wave: Normal P waves are replaced by F waves (resembles a sawtooth pattern).
- Rate: Atrial rate is 250 – 300 BPM, ventricular rate is normal.
What:
- ↓ Cardiac output
- Usually well tolerated.
Treatment:
- Stable:
- Cardizem (Diltiazem)[Bolus IVP @ 0.25 mg/kg, followed by Drip @ 5-15mg/hr]
- Unstable:
- Cardiovert with synchronized shocks of 100 followed by 200, 300, and 360 J if needed.
- Atrial Fibrillation (A-Fib)
Cause:
- Rheumatic Heart Disease
- CHF
Why:
- P wave: P waves are absent, replaced by F waves (which may be fine and wave, or appear flat (isoelectric) line. F waves are irregularly shaped, and dissimilar.
- Rate: Atrial rate cannot be counted, and ventricular rate varies greatly (average of 150 to 180 BPM)
- Irregularly Irregular
- PRI: None
What:
- Atrial kick is lost
- ↓ Cardiac Output
- Cardiovascular Decompensation (Angina Pectoris, M.I., CHF, Cardiogenic Shock.)
Treatment:
- Stable:
- Cardizem (Bolus IVP @ 0.25 mg/kg, followed by Drip @ 5-15mg/hr)
- Unstable:
- Cardiovert with synchronized shocks of 50 J, increased to 100, 200, 300, 360 J, if needed.
Atrioventricular
- Premature Junctional Complex (PJC)
Cause:
- Digitalis Toxicity
- Medications
- ↑ Vagal Tone
- Hypoxia
- CHF
- Damage to AV Junction
Why:
- P waves: Can be absent, or inverted and occur before during, or after the normal QRS complex.
What:
- Not significant.
Treatment:
- No Management is required.
- Junctional Escape Rhythm
Cause:
- ↑ Vagal Tone
- Slowing of the Sinoatral Discharge
- Complete AV Block
Why:
- P wave: May be absent. If present, they may occur before, during, and after the QRS complex.
- Rate: Usually 40 – 60 BPM
What:
- ↓ Cardiac output (possibly resulting in S/S of Bradycardia.)
Treatment:
- Stable (No S/S): No treatment needed
- Unstable (presenting with S/S): atropine (0.5 – 1 mg) if unresponsive, TCP.
- Accelerated Junctional Rhythm
Cause:
- Digitalis toxicity
Excessive catecholamine administration
- Damage to AV Junction
- Inferior wall M.I.
Why:
- P wave: May be absent, or buried in the QRS complex. If present, waves are usually inverted.
- Rate: 60 – 99 BPM
What:
- Usually well tolerated.
Treatment:
- Generally requires no immediate treatment.
Ventricular
- Ventricular escape complexes
Cause:
- SA Node pace falls below that of the ventricles
- AV junction falls below that of the ventricles
Why:
- QRS complex: Generally exceed 0.12 sec, and are bizarre in appearance.
- P wave: May be absent
- Rate: usually 20 to 40 BPM
- PRI: If present is irregular
What:
- Hypotension
- ↓ Cardiac output
- ↓ Perfusion of the brain resulting in:
Syncope
Shock
Treatment:
- O2
- TCP and/ or Dopamine
- Premature Ventricular Complex (PVC)
Cause:
- Myocardial ischemia
- Hypoxia
- Electrolyte imbalance
- Hypokalemia
- CHF
- ↑ Sympathetic tone
- Stimulants
- Drugs
Why:
- QRS complex: > 0.12 sec
- Rhythm: PVC interrupts the regularity of the underlying rhythm.
What:
- Pt’s without heart disease usually do not produce S/S, but may complain of skipped beats.
- Pt’s with heart disease, PVC’s (dependant on frequency, and grouping) may produce lethal ventricular rhythms.
Treatment:
- Artificial pacemaker rhythms
Cause:
- Internal defibrillator
Why:
- QRS complex: Are 0.12 sec or greater. If the pacemaker is capturing, a spike elicits a QRS complex. If only the atrial are being paced the QRS complex will be normal.
- P wave: May be absent, or present, normal or abnormal. Dependant on the location of the pacemaker’s stimulation, dual chamber pacemakers will produce a spike followed by a P wave.
What:
Regulates Pt’s heart rate
Treatment:
Rapid transport (true emergency)
- Ventricular Tachycardia (V-Tach)
Cause:
- Electrolyte imbalance
- CHF
- ↑ catecholamine/ Sympathetic tone (as in emotional stress)
- Stimulants
- Drugs
- Prolonged Q-T interval
Why:
- P wave: May be absent. If present, P waves will be superimposed on the QRS complexes.
- Rate: usually between 100 and 250 BPM
What:
- ↓cardiac output
- May or may not be perfusing.
Treatment:
- Ventricular Fibrillation (V-Fib)
Cause:
- Myocardial ischemia
- A.M.I.
- 3rd degree AV Block
- Cardiomyopathy
- Digitalis toxicity
- Hypoxia
- Acidosis
- Electrolyte imbalance
- Electrical injury
- Drug toxicity
Why:
- QRS complex: Absent
- P wave: Absent
- Rate: No coordinated ventricular contractions are present
- Rhythm: Irregularly irregular
- PRI: Absent
What:
- Causes all life functions to cease, because of lack of circulating blood flow.
- Initially light-headedness immediately followed by:
Loss of consciousness
Apnea
Death
Treatment:
- Asystole
Cause:
- Often follows V-Tach., V-Fib., PEA, or an agonal escape rhythm
Why:
- QRS complex: Absent
- P wave: Absent
- Rate: Absent
- Rhythm: Absent
- PRI: Absent
What:
- No cardiac output.
Treatment:
Conduction Disorders
AV Block
- 1st Degree AV Block
Cause:
- None
- Associated with:
- Myocardial ischemia
- AMI
- Digitalis toxicity
- ↑ vagal tone
Why:
- PRI: Prolonged (>0.20 sec.)
What:
- No clinical significances
- Can progress to a more serious AV block
Treatment:
- Usually requires no treatment
- 2nd Degree AV Block Type I (Wenckebach or Mobitz I)
Cause:
- AMI
- Acute Myocarditis
- ↑ vagal tone
- Ischemia
- Drug toxicity
- Head Injury
- Electrolyte imbalance
Why:
- PRI: Progressively lengthens before the non-conducted P wave
What:
- Usually transient, however can progress into a more serious AV Block
- Can cause S/S of ↓ cardiac output (if there is frequent dropped beats).
Treatment:
- No management if Pt is asymptomatic
- Symptomatic Pt’s
- Atropine (if pulse rate indicates)
And/or
- TCP
3.2nd Degree AV Block Type II (Mobitz II)
Cause:
- AMI in the septum
Why:
- P waves: Constant, but may not be followed by QRS complexes
- PRI: Constant for conducted beats, and may be > 0.20 sec.
What:
- May result in S/S of hypoperfusion
- May progress to a more severe heart block
Treatment:
- Internal pacemaker is the definitive treatment.
- Symptomatic Pt’s:
- TCP
- Atropine (consider)
- 3rd Degree AV Block
Cause:
- ↑Vagal Tone
- Septal necrosis
- Myocarditis
- Toxicity
- Electrolyte imbalance
Why:
- QRS complex: Most commonly wide.
- P waves: Present but with no relationship to the QRS complex.
- PRI: No relation exists between the atrial and ventricular activity.
What:
- Severe bradycardia
- ↓ Cardiac output
Treatment:
- Internal pacemaker is the definitive treatment.
- Symptomatic Pt’s:
- TCP
- Dopamine (2-20 μg/kg/min)
- EPI (1mg)
Ventricular Conduction Disturbances
- Pre-excitation Syndromes: Wolff-Parkinson-White Syndrome (WPW)
Cause:
- None
Why:
- PRI: short, less than 0.12 seconds.
- QRS complex: normal to widening.
- Delta wave
What:
- Pt’s are highly susceptible to bouts of PSVT.
- Can precipitate CHF and even death from V-Fib.
Treatment:
- A Pt with a normal heart rate needs no treatment.
- Adenosine and calcium channel blockers (Cardizem) should NOT be administered
- Vagal maneuvers and cardioversion for severe clinical deterioration
- Amiodarone is the first line drug of choice for presumed SVT and SVT with abnormal conduction (Procainamide is an alternative drug that may be used).
- Bundle Branch Blocks (BBB) -Electrical impulses are blocked from passing through the right and left bundle branches.
Cause:
-One ventricle polarizes and contracts before the other. Ventricular activation no longer occurs at the same time, due to conduction delay’s …
Why:
- QRS Complex: equal to or greater than 0.12 seconds (often with a slurred or notched appearance known as rabbit ears).
What:
-
Treatment:
- No specific treatment is necessary for bundle branch blocks (BBB).
- If caused by other conditions (hypoxia, ischemia, electrolyte imbalance, or drug toxicity), the underlying condition should be treated.
٭Sgarbossa’a Criteria:
- Diagnosis of an AMI (Acute Myocardial Infaction) in the presence of a LBBB.
1. ST segment elevation ≥ 1mm that is concordant (the same direction) with the QRS complex.
2. ST segment depression≥ 1mm in leads V1, V2, or V3.
3. ST segment elevation ≥ 5mm that is discordant (the opposite direction) with the QRS complex.
2.Pulseless Electrical Activity – Any rhythm without a pulse (except for V-Fib, and V-Tach.)
Cause:
- Correctable:
- Cardiac Tamponade
- Tension Pneumothorax
- Hypoxemia
- Acidosis
- Hyperkalemia
- Hypothermia
- Overdose
- Less Correctable:
- Massive MI Damage
- Prolonged ischemia
- Profound hypovolemia
- Massive pulmonary embolism
- Profound shock of any type
Why:
- All wave forms can be normal
- NO palpable pulse
What:
- Cardiac arrest
Treatment:
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