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Beta-Blockers (Intoxication)

Beta blockers overdose, toxicity

Sympathetic Nervous System
Beta-Blockers (BB)
ECG and Beta-Blockers (Intoxication)
ECG and Propranolol, Sotalol (Intoxication)

Sympathetic Nervous System

Beta blockers, adrenergic beta receptors, adrenaline, noradrenaline

The sympathetic system increases the body's performance

Activated during stress (physical, psychological)
The parasympathetic system acts antagonistically (oppositely)

Activated during rest

Mediators are catecholamines (Stress hormones):

Adrenaline and Noradrenaline
Bind to beta-adrenergic receptors

which are primarily on the heart and blood vessels

Adrenaline

Released into circulation from the adrenal glands
At extremely high levels, it can cause

Takotsubo Cardiomyopathy

Noradrenaline

Released from nerve endings

including those innervating the heart

At extremely high levels, it can cause

Stunned Myocardium

Beta-Blockers (BB)

Beta blockers, inhibition cardiac functions (sa node, av node, conduction, impulse generation), heart rate, av conduction, contractility

They are sympatholytics

The suffix "-lytic" means interruption, blockade

They bind to beta-adrenergic receptors

Blocking catecholamines in:

They protect the heart from overload

Lower blood pressure
The heart works in "economy mode"

Each BB has the -ol suffix

Propranolol, Sotalol, Acebutolol...

Cardio-selective BB

Bind only to receptors in the heart

Cardio-nonselective BB

Bind to receptors both in and outside the heart

ECG and Beta-Blockers (Intoxication)

ECG beta blockers toxicity, prolonged PR, 1st first degree av block

BB and Calcium Channel Blockers produce the same ECG changes during intoxication
Main Signs of BB Intoxication

AV Block I Degree (is the first sign of intoxication)
Sinus Bradycardia

Secondary Signs of BB Intoxication

ECG and Propranolol, Sotalol (Intoxication)

Propranolol and Sotalol are BB blockers that also block:

Sodium, or potassium channels
Therefore, they are more dangerous in case of intoxication

Risk of malignant ventricular arrhythmia

ECG beta blocker propranolol toxicity, positive R wave aVR

Propranolol (Intoxication)

Also blocks sodium channels

like Tricyclic Antidepressants

ECG findings include

Wide QRS ( > 120ms )
Positive R in aVR ( > 3mm )

Risk of ventricular tachycardia

ECG beta blocker sotalol toxicity, overdose, prolongation QT interval, signs of sodium channel blockade

Sotalol (Intoxication)

Also blocks potassium channels
ECG findings include

Prolonged QT interval ( > 440ms )

Risk of Torsades de Pointes

ECG beta blocker toxicity, overdose, poisoning, sinus bradycardia, first 1st degree av block

Beta Blockers (Intoxication)

AV Block Grade I

PQ interval > 0.2s
is the first sign of beta-blocker intoxication

Sinus Bradycardia (45/min)
The patient has overdosed on a beta-blocker

Calcium channel blockers can create the same ECG pattern

ECG beta blockers toxicity, overdose, poisoning junctional rhythm, narrow qrs, no visible p waves

Beta Blockers (Intoxication)

Junctional Rhythm

Frequency: 30/min
No P waves visible
Narrow QRS complexes

The patient has overdosed on a beta-blocker

Calcium channel blockers can create the same ECG pattern

ECG beta blockers, overdose, toxicity, 3rd degree av complete heart block, sinus rhythm, slow escape ventricular, or junctional rhythm rbbb

Beta Blockers (Intoxication)

AV Block Grade III

Frequency of P waves: 90/min.
Frequency of QRS: 30/min.
AV Dissociation

P waves and QRS complexes are independent of each other because the atria and ventricles are electrically isolated

QRS complexes have the shape of Right Bundle Branch Block, which may indicate:

Junctional Rhythm with RBBB
Ventricular Rhythm with an ectopic focus in the left ventricle

The patient has overdosed on a beta-blocker

Calcium channel blockers can create the same ECG pattern

ECG beta blockers toxicity, overdose, sinus bradycardia, long QT interval

Sotalol (Intoxication)

Sotalol is a beta blocker that also blocks potassium channels
Prolonged QT Interval (0.6s)

A prolonged QT interval, regardless of the cause, increases the risk of Torsades de Pointes

Sinus Bradycardia (43/min.)

Torsades de Pointes

Torsades de Pointes

Is a polymorphic ventricular tachycardia that occurs with a prolonged QT interval

Wide QRS complexes (>0.12s)

Width and amplitude change (QRS "dance around their axis")

Risk of ventricular fibrillation and patient death

ECG flecainid overdose, first av block, sinus rhythm

Flecainide (Intoxication)

On the ECG, signs of intoxication are similar to those of sodium channel blockade

Wide QRS > 120ms
Positive R ( > 3mm) in aVR

AV block I degree (PQ interval > 0.2s)
Sinus rhythm: 75/min.
Flecainid is an antiarrhythmic drug of the Ic group

Blocks only the sodium channel

Propranolol is a beta-blocker (BB)

Has the effect of BB and blocks sodium channels

On the ECG, Flecainid intoxication (an antiarrhythmic drug that blocks calcium channels, without BB effect) shows

Intoxication with propranolol has an identical ECG picture, but with bradycardia

ECG flecainid toxicity, broad qrs, dominant R aVR, AV block 1st degree

Flecainide (Intoxication)

On the ECG, signs of intoxication include sodium channel blockade

Wide QRS > 120ms
Positive R' ( > 3mm) in aVR

AV block 1st degree (PQ interval > 0.2s)
Sine rhythm 75/min.
On the ECG, intoxication with Flecainide (an antiarrhythmic that blocks sodium channels, with no BB effect)

Intoxication with propranolol has an identical ECG pattern, only with bradycardia

Sources

ECG from Basics to Essentials Step by Step
litfl.com
ecgwaves.com
metealpaslan.com
medmastery.com
uptodate.com
ecgpedia.org
wikipedia.org
Strong Medicine
Understanding Pacemakers

Home /

Beta-Blockers (Intoxication)

Beta blockers overdose, toxicity

Sympathetic Nervous System
Beta-Blockers (BB)
ECG and Beta-Blockers (Intoxication)
ECG and Propranolol, Sotalol (Intoxication)

Sympathetic Nervous System

The sympathetic system increases the body's performance

Activated during stress (physical, psychological)
The parasympathetic system acts antagonistically (oppositely)

Activated during rest

Mediators are catecholamines (Stress hormones):

Adrenaline and Noradrenaline
Bind to beta-adrenergic receptors

which are primarily on the heart and blood vessels

Adrenaline

Released into circulation from the adrenal glands
At extremely high levels, it can cause

Takotsubo Cardiomyopathy

Noradrenaline

Released from nerve endings

including those innervating the heart

At extremely high levels, it can cause

Stunned Myocardium

Beta-Blockers (BB)

They are sympatholytics

The suffix "-lytic" means interruption, blockade

They bind to beta-adrenergic receptors

Blocking catecholamines in:

They protect the heart from overload

Lower blood pressure
The heart works in "economy mode"

Each BB has the -ol suffix

Propranolol, Sotalol, Acebutolol...

Cardio-selective BB

Bind only to receptors in the heart

Cardio-nonselective BB

Bind to receptors both in and outside the heart

ECG and Beta-Blockers (Intoxication)

BB and Calcium Channel Blockers produce the same ECG changes during intoxication
Main Signs of BB Intoxication AV Block I Degree (is the first sign of intoxication) Sinus Bradycardia Secondary Signs of BB Intoxication AV Blocks II and III Degree Junctional Rhythm Ventricular Rhythm

ECG and Propranolol, Sotalol (Intoxication)

Propranolol and Sotalol are BB blockers that also block:

Sodium, or potassium channels
Therefore, they are more dangerous in case of intoxication

Risk of malignant ventricular arrhythmia

Propranolol (Intoxication)

Also blocks sodium channels

like Tricyclic Antidepressants

ECG findings include

Wide QRS ( > 120ms )
Positive R in aVR ( > 3mm )

Risk of ventricular tachycardia

Sotalol (Intoxication)

Also blocks potassium channels
ECG findings include

Prolonged QT interval ( > 440ms )

Risk of Torsades de Pointes

Beta Blockers (Intoxication)

AV Block Grade I

PQ interval > 0.2s
is the first sign of beta-blocker intoxication

Sinus Bradycardia (45/min)
The patient has overdosed on a beta-blocker

Calcium channel blockers can create the same ECG pattern

Beta Blockers (Intoxication)

Junctional Rhythm

Frequency: 30/min
No P waves visible
Narrow QRS complexes

The patient has overdosed on a beta-blocker

Calcium channel blockers can create the same ECG pattern

Beta Blockers (Intoxication)

AV Block Grade III

Frequency of P waves: 90/min.
Frequency of QRS: 30/min.
AV Dissociation

P waves and QRS complexes are independent of each other because the atria and ventricles are electrically isolated

QRS complexes have the shape of Right Bundle Branch Block, which may indicate:

Junctional Rhythm with RBBB
Ventricular Rhythm with an ectopic focus in the left ventricle

The patient has overdosed on a beta-blocker

Calcium channel blockers can create the same ECG pattern

Sotalol (Intoxication)

Sotalol is a beta blocker that also blocks potassium channels
Prolonged QT Interval (0.6s)

A prolonged QT interval, regardless of the cause, increases the risk of Torsades de Pointes

Sinus Bradycardia (43/min.)

Torsades de Pointes

Torsades de Pointes

Is a polymorphic ventricular tachycardia that occurs with a prolonged QT interval

Wide QRS complexes (>0.12s)

Width and amplitude change (QRS "dance around their axis")

Risk of ventricular fibrillation and patient death

Flecainide (Intoxication)

On the ECG, signs of intoxication are similar to those of sodium channel blockade

Wide QRS > 120ms
Positive R ( > 3mm) in aVR

AV block I degree (PQ interval > 0.2s)
Sinus rhythm: 75/min.
Flecainid is an antiarrhythmic drug of the Ic group

Blocks only the sodium channel

Propranolol is a beta-blocker (BB)

Has the effect of BB and blocks sodium channels

On the ECG, Flecainid intoxication (an antiarrhythmic drug that blocks calcium channels, without BB effect) shows

Intoxication with propranolol has an identical ECG picture, but with bradycardia

Flecainide (Intoxication)

On the ECG, signs of intoxication include sodium channel blockade

Wide QRS > 120ms
Positive R' ( > 3mm) in aVR

AV block 1st degree (PQ interval > 0.2s)
Sine rhythm 75/min.
On the ECG, intoxication with Flecainide (an antiarrhythmic that blocks sodium channels, with no BB effect)

Intoxication with propranolol has an identical ECG pattern, only with bradycardia

Sources

ECG from Basics to Essentials Step by Step
litfl.com
ecgwaves.com
metealpaslan.com
medmastery.com
uptodate.com
ecgpedia.org
wikipedia.org
Strong Medicine
Understanding Pacemakers