ECG A: first part.

Domina Petric, MD
ECG A: part I

Accelerated Idioventricular
Rhythm (AIVR)
Burns E. Accelerated Idioventricular Rhythm (April 10, 2017). Retrieved
from https://lifeinthefastlane.com/ecg-library/aivr/
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• Results when the rate of an ectopic ventricular
pacemaker exceeds that of the sinus node.
• It is often associated with increased vagal tone
and decreased sympathetic tone.
AIVR
Quora.com
AIVR is classically seen in the
reperfusion phase of an
acute STEMI (post
thrombolysis).

ECG features
Regular
rhythm.
Rate 50-110
bpm.
Three or more
ventricular
complexes.
QRS
complexes
>120 ms.
Fusion and
capture beats.

Fusion beat
A fusion beat occurs when electrical
impulses from different sources act upon
the same region of the heart at the same
time.
If it acts upon the ventricular chambers it is
called a ventricular fusion beat.
Colliding currents in the atrial
chambers produce atrial fusion beats.
Understanding Electrocardiography 8 Ed. Elsevier Health Sciences. 2003. p. 245

Capture beat
Capture beat is the return of
atrial control over
ventricular contraction,
following a period of
atrioventricular dissociation.

Fusion vs. capture beat
Capture beat
Fusion beat

Isorhythmic AV dissociation

Causes of AIVR
• Reperfusion phase of an acute myocardial infarction is
the most common cause!
• Beta-sympathomimetics: isoprenaline, adrenaline!
• Drug toxicity: digoxin, cocaine and volatile
anaesthetics (desflurane)!
• Electrolyte abnormalities!
• Cardiomyopathy, congenital heart disease,
myocarditis!
• Return of spontaneous circulation (ROSC) following
cardiac arrest!
• Athletic heart!

Treatment
It is important to treat the
underlying cause.
It is self limiting and resolves
when sinus rate exceeds that
of the ventricular foci.

Accelerated Junctional Rhythm
(AJR)
Burns E. Accelerated Junctional Rhythm (April 10, 2017).
Retrieved from https://lifeinthefastlane.com/ecg-
library/accelerated-junctional-rhythm/

AJR
Accelerated junctional rhythm (AJR) occurs
when the rate of an AV junctional pacemaker
exceeds that of the sinus node:
• increased automaticity in the AV node
• decreased automaticity in the sinus node
AV node

Causes
Digoxin
toxicity
Beta-agonists
(isoprenaline,
adrenaline)
Myocardial
ischaemia
Myocarditis
Cardiac
surgery

Classification by the rate
Junctional Escape Rhythm: 40-60 bpm.
Accelerated Junctional Rhythm: 60-100 bpm.
Junctional Tachycardia: >100 bpm.

Classification by aetiology

ECG features
• Narrow complex rhythm: QRS duration <120 ms.
• Ventricular rate usually 60-100 bpm.
• Retrograde P waves may be present and can appear
before, during or after the QRS complex.
• Retrograde P waves are usually inverted in the inferior
leads (DII, DIII, aVF), but upright in aVR + V1.
• AV dissociation may be present with the ventricular
rate usually greater than the atrial rate.
• There may be associated ECG features of digoxin effect
and toxicity.

Retrograde P wave occuring after the
QRS complex.

Note!

Example
Negative P waves in DII, DIII and aVF!
Positive P waves in aVR and V1!
Rate 115 bmp

Anterior STEMI
Burns E. Accelerated Junctional Rhythm (April 10, 2017).
Retrieved from https://lifeinthefastlane.com/ecg-
library/anterior-stemi/

Anterior STEMI
• Anterior STEMI results from the occlusion of the
left anterior descending artery (LAD).
HeartUpdate.com

Anterior STEMI
STEMI nomenclature based on the location of
the maximal ST elevation:
Septal STEMI V1-V2
Anterior STEMI V2-V5
Anteroseptal STEMI V1-V4
Anterolateral STEMI V3-V6, DI, aVL
Extensive anterior/anterolateral V1-V6, DI, aVL

Anterior-inferior STEMI
• It is due to occlusion of a “wraparound” LAD.
ECG pattern:
• simultaneous ST elevation in the precordial
and inferior leads due to occlusion of a variant
(type III) LAD
Type III LAD wraps around the cardiac apex to
supply both the anterior and inferior walls of the
left ventricle.

Anterior-inferior STEMI

Left main coronary artery occlusion
• Widespread ST depression with ST elevation in
aVR that is bigger than in V1.
Healio.com

Wellen´s syndrome
• Deep precordial T wave inversions or biphasic T waves in
V2-V3, indicating critical proximal LAD stenosis.
Type A with biphasic
T waves (25%).
Type B with deeply
and symmetrically
inverted (75%).

De Winter´s T waves
• Upsloping ST depression with symmetrically
peaked T waves in the precordial leads: indicates
acute LAD occlusion.

Arrhythmogenic Right Ventricular
Cardiomyopathy (ARVC)
Burns E. Arrhythmogenic Right Ventricular Cardiomyopathy
(August 29, 2017). Retrieved from
https://lifeinthefastlane.com/ecg-library/basics/arrhythmogenic-
right-ventricular-cardiomyopathy/

ARVC
• An inherited myocardial disease associated
with paroxysmal ventricular
arrhythmias and sudden cardiac death.
• Naxos disease: ARVC, woolly hair and skin
changes.
• The second most common cause of sudden
cardiac death in young people, after
hyperthrophic obstructive cardiomyopathy.

ECG features
Prolonged S-wave upstroke and QRS widening in V2.

Atrial flutter
Burns E. Atrial flutter (April 10, 2017). Retrieved from
https://lifeinthefastlane.com/ecg-library/atrial-flutter/

Atrial flutter
Atrial flutter is a type of supraventricular tachycardia caused
by a re-entry circuit within the right atrium.
The length of the re-entry circuit corresponds to the size of
the right atrium.
Atrial rate is around 300 bpm (range 200-400).
Ventricular rate is determined by the AV conduction ratio
(degree of AV block).

Atrial flutter
Atrial flutter with 1:1
conduction is associated
with severe haemodynamic
instability and progression
to ventricular fibrillation.

ECG features

Ventricular rate
Ventricular rate is a fraction of the atrial rate.
Ventricular rate Block
150 bmp 2:1
100 bmp 3:1
75 bmp 4:1

Anticlockwise reentry atrial flutter
• This is the commonest form of atrial
flutter (90% of cases).
Retrograde atrial conduction produces:
• inverted flutter waves in leads DII, DIII
and aVF
• positive flutter waves in V1

Clockwise reentry atrial flutter
Anterograde atrial conduction
produces:
•positive flutter waves in leads DII,
DIII and aVF
•broad, inverted flutter waves in V1

Clinical Gate

Atrial fibrillation
Burns E. Atrial fibrillation (August 29, 2017). Retrieved from
https://lifeinthefastlane.com/ecg-library/atrial-fibrillation/

Atrial fibrillation
• It is the most common sustained
arrhythmia.
Complications of AF include:
• haemodynamic instability
• cardiomyopathy
• cardiac failure
• embolic events

Causes
• ischaemic heart disease
• hypertension
• valvular heart disease
(mitral stenosis and
regurgitation)
• acute infections
• electrolyte disturbance
(hypokalaemia,
hypomagnesaemia)
• thyrotoxicosis
• drugs
(sympathomimetics)
• pulmonary embolus
• pericardial disease
• acid-base disturbance
• pre-excitation syndromes
• cardiomyopathies
• phaeochromocytoma

ECG changes
• Irregularly irregular rhythm.
• No P waves.
• Absence of an isoelectric baseline.
• Variable ventricular rate.
• QRS complexes usually <120 ms.
• Fibrillatory waves can be fine (amplitude <0.5mm)
or coarse (amplitude >0.5mm).

Atrial fibrillation classification
AF with rapid ventricular response is when the
ventricular rate is >100 bpm.
Slow AF is when the ventricular rate is <60 bpm.
Causes of slow AF are hypothermia, digoxin toxicity
and sinus node dysfunction.

Atrial fibrillation classification
• First episode is the initial detection of AF regardless of
symptoms or duration.
• Recurrent AF is when more than 2 episodes of AF
occure.
• Paroxysmal AF is self terminating episode that lasts
less than 7 days.
• Persistent AF is not self terminating episode with
duration more than 7 days.
• Long-standing persistent AF lasts up to 1 year.
• Permanent AF lasts more than 1 year in which rhythm
control interventions are not pursued or are
unsuccessful.

Literature
• Lifeinthefastlane.com
• Healio.com
• Quora.com
• Clinicalgate.com

ECG A: first part.

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ECG A: first part.