![Page 1: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/1.jpg)
Cardiac electrical activity,Arrhythmias
![Page 2: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/2.jpg)
Cardiac conduction system
Automaticity - property of cardiac cells to generate spontaneous action potentials. Spontaneous activity is the result of diastolic depolarization caused by an inward current during phase 4 of the action potential, which progressively brings the membrane potential to threshold.
![Page 4: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/4.jpg)
Components of atrioventricularconduction
His-PurkinjeSystem
AV Node
![Page 5: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/5.jpg)
![Page 6: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/6.jpg)
Einthoven leads: bipolar: I, II, IIIGoldberger leads: unipolar augmented: aVR, aVL, aVF
![Page 7: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/7.jpg)
When a wave of depolarization moves towards the positive electrode of a lead -a positive deflection
![Page 9: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/9.jpg)
ECG measurements
Vertical
• 10 mm = 1 mV
Horizontal
• 25mm/s: 1 mm = 0.04s
![Page 10: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/10.jpg)
Electrical axis – frontal plane
![Page 11: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/11.jpg)
QRS axis deviationLeft axis deviation: ≥ -30° (i.e., lead II is mostly negative)
• Left ventrucular hypertrophy
• Left Anterior Fascicular Block (LAFB): rScomplex in leads II, III, aVF)
• Some cases of inferior MI
• Some cases of LBBB
• Right Axis Deviation (RAD):
Right axis deviation ≥ +90° (i.e., lead I is mostly negative)
• Many causes of right heart overload and pulmonary hypertension
• Left Posterior Fascicular Block (LPFB): rS complex in lead I
• High lateral wall MI with Qr or QS complex in leads I and aVL
• Some cases of RBBB
• Children, teenagers, and some young adults
![Page 13: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/13.jpg)
shift of the septum to the left- right ventricular heart disease- dilated cardiomyopathy
Horizontal plane- clockwise or counterclockwise rotation
![Page 14: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/14.jpg)
Basic ECG analysis
• Measurements HR, PR, QRS, QT, axis
• Rhythm analysis sinus rhythm or not (e.g. Afi);, additional e.g. PVC or PAC, rhythm from atria, AV junction, ventricles;, regularity (e.g. SRA)
• Conduction analysis SA block, AV block, IV block
• Waveform description P waves wide, tall, atypical QRS complexes – wide, voltage;, ST segment –elevation/ depression; T waves inverted, voltage; U waves?
• ECG interpretation (LV hypertrophy, anterior MI, rhythm abnormalities, ST- T abnormalities...)
V6
V5
V4
![Page 15: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/15.jpg)
Normal SR, normal PR int, normal QRS duration , left axisdeviation, (rS in II,III, aVF)
![Page 16: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/16.jpg)
![Page 17: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/17.jpg)
P pulmonale (ie, a P-wave amplitude > 2.5 mm) - predictor of right atrial enlargement(in patients with COPD, the amplitude of the P wave is in fact dynamic, and it tendsto be more prominent during acute exacerbation
![Page 18: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/18.jpg)
Heart rate – calculating - several methods
1) Method 300, 150, 100, 75, 60, 50- Find R wave located on bold line- Then find the next consecutive R wave- The closest bold line represents HR
2) Number of R in 6s interval (30 big boxes)x 10
![Page 19: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/19.jpg)
HR ?
![Page 20: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/20.jpg)
HR?
II
![Page 21: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/21.jpg)
Normal sinus rhythm
![Page 22: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/22.jpg)
Normal sinus rhythm
• HR: 60 - 100 BPM
• Regular
• P waves: Upright, one preceding each QRS complex
• QRS complexes: Narrow, 0.06 - 0.12 sec
• PR Interval: 0.12 - 0.20 sec
![Page 23: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/23.jpg)
Sinus tachycardia
• Anemia• Anxiety• Drug intoxication/coffeine• Hyperthyroidism• Hypovolemia• Infection• Pain• Hypoxia• Myocardial infarction• Heart failure• Pulmonary embolism etc.
![Page 24: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/24.jpg)
AV junctional rhythm• QRS complex normal morphology
• P waves burried
• Initiation of activation between atria and ventricles
• Retrograde activation of atria – negative P wave before, insideor after QRS
![Page 25: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/25.jpg)
Cardiac arrhythmia/dysrhythmia
a variation from the normal
heart rate and/or rhythm
![Page 26: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/26.jpg)
Cardiac arrhythmia
Disordersof impulse formation
Disorders of impulspropagation
SA
other?
CCS
Myocardium
Localised abn Dif. abn.
![Page 27: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/27.jpg)
Pacemaker Hierarchy
SA
Node
(+Atria)
AV Junction
(=AVN/His Bundle)
Ventricles
(= Distal Purkinje System)
Intrinsic Rate of Firing
60-100 min−1
40-60 min−1
30-40 min−1
![Page 28: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/28.jpg)
![Page 29: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/29.jpg)
Rhythm disorders
Irregular arrhythmias - sinus arrhythmia
- atrial fib
Extrasystoles – prematurecomplexes
Escape systoles
Rapid arrhythmias:
tachycardia 150-250 bpmflutter 250-350 bpmfibrillation 230-600 bpm
Bradyarrhythmias:BradycardiaSA blockAV block
![Page 30: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/30.jpg)
Irregular - sinus arrhytmia
• Sinus rhythm
• Difference RR int more than 0.16 s
• Respiratory: increased HR in inspirium, slowing in expirium
![Page 31: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/31.jpg)
Irregular - atrial fibrillation
![Page 32: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/32.jpg)
Extrasystoles
Ectopic foci – abnormalpacemaker sites outsideof the SA node
![Page 33: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/33.jpg)
Bigeminy
Trigeminy
![Page 34: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/34.jpg)
![Page 35: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/35.jpg)
Ventricular flutter
![Page 36: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/36.jpg)
![Page 37: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/37.jpg)
A 45 year old lady with palpitations and history of chronic renal failure
Ventricular tachycardia
![Page 38: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/38.jpg)
![Page 39: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/39.jpg)
Bradyarrhythmias
![Page 40: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/40.jpg)
Sinus bradycardia
1. Physiological slowing of impulse formation in SA node
2. Parasympathetic activity3. Pathological SA dysfunction
![Page 41: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/41.jpg)
Carotid sinus hypersensitivitymediated by the vagus nerve
• Bradycardia
• Hypotension
• Particularly in cancer pts (masses, neurosurgery)
• Increase in blood pressure may lead result in reflex bradycardia
![Page 42: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/42.jpg)
Seizure activity
• may induce an abnormal stimulation of vagus nerve
• Ictal bradycardia
![Page 43: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/43.jpg)
Symptoms of bradycardia
• Dizzines
• Fatigue
• Changes of mental status
• Syncope
• Heart failure
![Page 44: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/44.jpg)
Sinus node dysfunction(Sick Sinus Syndrome)• Abnormalities of SA structure or increased vagal tone
• Manifestation:
- sinus bradycardia
- sinus arrest
- tachycardia-bradycardia (Afi, Afl interspersed with sinus arrest or bradycardia)
![Page 45: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/45.jpg)
Sick sinus syndrome (SSS)
• inability to increase heart rate during physical activity or adrenergicstimulation
![Page 46: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/46.jpg)
SA damage
• Gradual degenerative process (in the elderly)
• Drugs (e.g. cytostatics)
• Metabolic abnormalities
• Tumours
• Radiation
• Amyloidosis
• ATS of coronary a. within SA node
![Page 47: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/47.jpg)
Sinoatrial Block
• First Degree: Prolonged SA conduction time (non-
detectable on EKG; no missing P waves)
• Second Degree: Intermittent non-conduction
(intermittent absence of P waves)
• Third Degree: Persistent non-conduction (complete
absence of P waves; escape rhythms only)
![Page 48: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/48.jpg)
Sinus Arrest → Asystole
Sinus rhythm
Sinus brady.
→ Sinus arrest
→ V. escape
rhythm
Failure of V.
escape rhythm
→ Asystole
P P P
P P P P
P
![Page 49: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/49.jpg)
SA Exit Block
P P P P
4:3 pattern
Missing
P wave
•PP intervals shorten prior to block
•Note unaffected, fixed PR intervals
PP:
![Page 50: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/50.jpg)
Treatment of SA dysfunction in symptomaticpts• Reverse underlying cause
• Atropine
• Ephedrine
• Teophyllin
• Temporary pacing
• Pacemaker
![Page 51: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/51.jpg)
Left bundle branch
Left anterior fascicle
Septal fascicle
Left posterior
fascicle
Right bundle branch
Conduction system
(AV node)
His bundle
![Page 52: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/52.jpg)
AV Block - definitions
• First Degree: Prolonged conduction time
• Second Degree: Intermittent non-conduction
• Third Degree: Persistent non-conduction
![Page 53: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/53.jpg)
AV block first degree
![Page 54: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/54.jpg)
First Degree AV Block(PR > .20 sec [1 big box])
II
P P P
.36
![Page 55: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/55.jpg)
II
Block
P P P PP
• 4:3 conduction ratio
Prolonging PR
Second Degree AV Block - Type I(Wenkebach or Mobitz I block)
![Page 56: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/56.jpg)
IIP P P P P P
2:1 Second Degree AV block
Fixed PR interval
![Page 57: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/57.jpg)
Third Degree AV Block(Complete Heart Block)
P P P P P P
Atrial and ventricular activity are unrelated
II
![Page 58: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/58.jpg)
![Page 59: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/59.jpg)
•1st and 2nd degree AV block may occur
in settings of increased vagal tone (e.g.,
sleep, Valsalva maneuver, well-trained
athletes)
•BUT… persistent 3rd degree AV block is
always pathological
![Page 60: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/60.jpg)
Causes of pathological AV Block• Ischemia
• Cardiomyopathy
• Degenerative changes
• Infiltration (e.g., primary cardiac tumor, mts)
• Drugs that depress AV conduction• digoxin, beta blockers, calcium channel blockers,
antiarrhythmic drugs that depress the inward sodium current
• Myocardial infection,
• Trauma (e.g., surgery; therapeutic ablation)
• Congenital abnormalities
![Page 61: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/61.jpg)
Normal activation of the heart
![Page 62: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/62.jpg)
Right Bundle Branch Block (RBBB)
Late
right ventricular
activation
RV is activated
via the left bundle
![Page 63: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/63.jpg)
Right bundle branchblock
With QRS widening
( .12 sec with “complete”
RBBB)
rSR’
pattern
![Page 64: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/64.jpg)
A 55 year old man with 4 hours of "crushing" chest pain.
![Page 65: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/65.jpg)
Left Bundle Branch Block (LBBB)
LV is activated
via the right bundle
![Page 66: Cardiac electrical activity, Arrhythmias · Left axis deviation: ≥ -30°(i.e., lead II is mostly negative) •Left ventrucular hypertrophy •Left Anterior Fascicular Block (LAFB):](https://reader033.vdocuments.site/reader033/viewer/2022060802/6086a5f68ce2e83e5f25dcab/html5/thumbnails/66.jpg)
QRS pattern inducedby LBBB
Broad
monophasic
R wave
Entire QRS dominated by
marked leftward delay
and is wide ( .12 sec)
Broad
S wave