Post on 16-Dec-2015
ECG InterpretationECG Interpretation
Arrhythmias of Arrhythmias of FormationFormation
Chapters 4-5Chapters 4-5
Types of Arryhthmias:Types of Arryhthmias:Sinus Problems: Formed in the sinus
node, but irregularEctopic Problems: Formed outside
of the sinus nodeConduction Problems: Formed in the
sinus node, but conduction in errorPre-Excitation Problems: “Short
circuits” in normal conduction
Causes of Arrhytmias: Causes of Arrhytmias: Hypoxia: Lung disease Ischemia: CAD, angina (local hypoxia) Sympathetic Stimulation: Nervous,
exercise, CHF, hyperthyroidism Drugs: Caffeine, cocaine, stimulants…many
antiarryhtmic drugs… Electrolyte Disturbances: K+, Ca++, Mg++
Bradycardia: “Escape” rhythms… Stretch: CHF, hypertrophy, valve disease
Rhythm ID: AlgorithmRhythm ID: Algorithm
P-Wave: rate and rhythmQRS: rate and rhythm - shapeP-R Interval: Is AV conduction
normal? P:QRS regular?T Wave and QT IntervalAny unusual complexes?IS IT DANGEROUS?
Clinical Manifestations:Clinical Manifestations:Asymptomatic – generally benignPalpitations – Awareness may
cause anxietyCompromised CO – SyncopeMyocardial Ischemia – tachyCHF – Chronic insufficiency Sudden Death – Cardiac arrest
Define “Normal”Define “Normal”Regular Atrial and Ventricular
Rhythms: 1P : 1 QRSRates: 60-100P Morphology: small, round, regular
and positive in Lead IIQRS Morph: Similar size and shapePositive T waves in Lead II
P-Wave: P-Wave: 1.SA Node “fires” 2. Right and Left
Atria Depolarize 3. AV Node
“pauses” Questions:
P waves present?
Regular rhythm?
1/QRS?
SA Node
LA/RADepol
AV Node
Sinus RhythmsSinus RhythmsNormal Sinus Rhythm:
1P/QRS: 60-100 bpmSinus brady: 1P/QRS: <60 bpmSinus tachy: 1P/QRS: >100 bpmSinus Arrhythmia: 1P/QRS
Normal Irregularities caused by inspiration/expiration – more noticeable in children / elderly
ABSENT PQRS Complex: ABSENT PQRS Complex: Sinus Arrest: Sinus Arrest: Causes:
Heart disease, acute infection, VAGAL stimulation (Bush’s Pretzel Problem?)
Sick Sinus Syndrome: Usually in elderly – more irregular
DANGER?Rare and asymptomaticFrequent and symptomatic
Atrial Arrhythmias: Atrial Arrhythmias:
PAC: Premature Atrial Contraction
Atrial Tachycardias: SVT – with or without blocks, PAT
Atrial Flutter:Atrial Fibrillation
Premature Atrial Contractions:Ectopic Triggered by: Alcohol, nicotine,
anxiety, fatigue, fever, and infections
Usually benignClinical Manifestations:
Palpitations or “skipped beats”
PAC - ID:PAC - ID:
Irregular P-R rhythmsPremature, irregular P waves
(sometimes “lost” in the T wave)
Atrial Tachycardias:Atrial Tachycardias:Also: Supra Ventricular Tachycardia
(PSVT)Rates: 100-250 bpmRegular Rhythms“Hidden” P waves (could be inverted
– indicating a Junctional focus PSVT)PAT = Common in warm-up/cool down
and doesn’t respond to Carotid Massage (don’t try this!)
Afib – Aflut…Afib – Aflut…
Atrial Fibrillation: Atrial Fib and/or PSVT?
Atrial Flutter: 2:1 Ventricular “capture”Ventricles can only respond to every other Atrial conduction
Fibrillation vs. Flutter?Fibrillation vs. Flutter?Multi-focal
origins -chaoticRate: >400 bpm IRREGULAR-RAtrial Cardiac
Output is lost :
One focus - organized
Rate: 200-400 bpm
Atrial Cardiac Output is compromised
Atria contribute ~20% of the totalCardiac output: A-Fib is non-lethal
Summarize: Sinus and Atrial Summarize: Sinus and Atrial RhythmsRhythms
Sinus: Normal, Tachy, BradyAbsent P: Sinus Arrest, A-fib,
Junctional (PSVT), PATWeird P: A-Flut, PAC
Formation ArrhythmiasFormation Arrhythmias
Junctional and Junctional and Ventricular Ventricular
Chapters 6-7Chapters 6-7
Junctional:Junctional:Form in the AV (Junction) NodeMay be an “Escape” rescue if SA
node fails to fire or conductEscape Rate ~40-60 bpm
May be an “Ectopic” Irritable FocusEctopic Rate ~ 60-100 bpm
Responds to vagal stimulus P Waves inverted, missing or after
the QRS
Ventricles: QRS RhythmsVentricles: QRS RhythmsRegular rhythms?
R-R intervals equivalentRegular “irregular” rhythms?
R-R intervals equivalent with occasional irregularities
Irregular rhythms?R-R intervals irregular
Regular “Irregular”Regular “Irregular”Premature Beats: PVC
Widened QRS, not associated with preceding P wave
Usually does not disrupt P-wave regularity
T wave is “inverted” after PVCOften Followed by
compensatory ventricular pause
Notice a Pattern in the PVC’s?
PVC Patterns:PVC Patterns:PVC: 1 Isolated beatCouplet: 2 consecutive PVC’sBigeminy: PVC every other
beatNon-Sustained VT: >3 beats
for less than 1 minuteSustained VT: > 1 minute of
ventricular tachycardia
Irregular Ventricular Irregular Ventricular Rhythms: CHAOTICRhythms: CHAOTICVentricular Fibrillation:
Multi-focal originsIrregular wave morphologiesCardiac Output = 0Coarse vs. Fine V-Fib
Clinical Manifestations – Clinical Manifestations – PVC’sPVC’s Often benign
BUT Compromised
CO Possibly
precipitate a lethal arrhythmia: Vtach, VFib
More on PVC’sMore on PVC’sCardiac Output: Pulse deficit =
reduced CO (~20%)One PVC usually asymptomaticSymptoms: LOC or dizziness
demand treatment Risk of Lethal Arrhythmias:
V-Tach more dangerous in CAD
Rules of Malignancy: Rules of Malignancy:
Frequency: > 6 / minuteRuns: 3+ consecutiveMultiform“R on T”PVC’s during MI
What is the threat of What is the threat of sustained Ventricular sustained Ventricular Tachycardia?Tachycardia? 1. What happens to diastole? 2. What happens to Cardiac Output? 3. What happens to myocardial perfusion? 4. What happens to myocardial VO2?
Winslow Homer: “The Stile”