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Premature Junctional Complex (PJC)

Premature Junctional Complex (PJC), Junctional Ectopics, Junctional Extrasystoles, Junctional Premature Beats, Junctional Premature Depolarisations, Atrioventricular junctional premature complexes

Heart Rhythm
Premature Junctional Complex (PJC)
ECG and Premature Junctional Complex (PJC)
Retrograde P Wave and Premature Junctional Complex (PJC)
Incomplete Compensatory Pause
Complete Compensatory Pause
Aberrant Premature Junctional Complex (PJC)

Heart Rhythm

sinus rhythm, junctional ectopic rhythm, ventricular ectopic rhythm

Basic Heart Rhythms

Heart rhythm is determined by the site (sites) that generates impulses with the highest frequency (overdrive suppression)
We know 3 basic heart rhythms

Sinus Rhythm (Impulses generated by the SA node)
Junctional Rhythm (Impulses generated by the AV junction)
Ventricular Rhythm (Impulses generated by the Purkinje fibers in the ventricles)

Sinus rhythm is the physiological heart rhythm

Because the sinoatrial (SA) node generates impulses with the highest frequency (overdrive suppression)
The SA node is referred to as the primary pacemaker (rate setter)

Premature Junctional Complex (PJC)

Premature junctional complex, depolarisation vectors from AV junction

AV junction (SA node and His bundle) is a secondary pacemaker

Begins to generate impulses when there is a failure of the SA node, leading to a junctional rhythm

PJC occurs due to premature depolarization of the AV junction

Most commonly during sinus rhythm

PJC commonly occurs due to:

Stress, caffeine, alcohol, smoking...

PJC is the rarest type of extrasystole, more common is

PJC can trigger re-entry tachycardia:

AVNRT (AV nodal re-entry tachycardia)
AVRT (Atrioventricular re-entry tachycardia)
Ventricular tachycardia
Torsades de Pointes

We recognize 3 types of extrasystoles:

Supraventricular:

Atrial extrasystole
Premature Junctional Complex (PJC)

Ventricular extrasystole

ECG and Premature Junctional Complex (PJC)

ECG showing AV junction depolarization and Premature Junctional Complex (PJC) with beat and depolarization

Retrograde (negative) P wave

Is negative in inferior leads (II, III, aVF)
Can be before, within, or after the QRS
Vector of the retrograde P wave

Points from the AV junction towards the SA node

Retrograde (negative) P wave occurs:

Also in atrial extrasystole

If the atrial focus is at the AV junction

The difference is in the PQ interval

PQ interval < 0.12s - Premature Junctional Complex (PJC)
PQ interval > 0.12s - Atrial extrasystole

Narrow QRS complexes (<0.12s)

Because the ventricles are activated through the conduction system

On the ECG, it is always earlier than the expected sinus QRS
Incomplete compensatory pause

PJC always resets the SA node

Retrograde P Wave and Premature Junctional Complex (PJC)

Upper AV junction depolarization, Premature Junctional Complex (PJC)

Middle AV junction depolarization, Premature Junctional Complex (PJC)

Lower AV junction depolarization, Premature Junctional Complex (PJC)

Retrograde (negative) P wave before the QRS

PJC is generated in the upper part of the AV junction
The atria are activated earlier (P wave) than the ventricles (QRS)

Hidden P wave within the QRS complex

PJC is generated in the middle part of the AV junction
The atria and ventricles are activated simultaneously
The retrograde P wave is hidden within the QRS complex

Retrograde (negative) P wave after the QRS

PJC is generated in the lower part of the AV junction
The ventricles (QRS) are activated earlier than the atria (P wave)

Incomplete Compensatory Pause

Junctional ectopic focus depolarization, and junctional extrasystoles

ECG Laddergram, Junctional Premature Complex, Non-compensatory Pause

Premature Junctional Complex (PJC) and Incomplete Compensatory Pause

Laddergram illustrates the propagation of impulses through the conduction system
PP (RR) interval with PJC is shorter than 2 times the PP (RR) interval without PJC

Because PJC resets the SA node

Incomplete compensatory pause is created by:

Atrial extrasystole
Premature Junctional Complex (PJC)
Very rarely Ventricular extrasystole (VES)

Only when VES retrogradely passes through the AV node and resets the SA node

ECG premature junctional complex and non-compensatory pause

Premature Junctional Complex (PJC) and Incomplete Compensatory Pause

PP (RR) interval with PJC (36) is shorter than 2 times the PP (RR) interval without PJC (2x20)
Premature Junctional Complex (PJC)

Occurs earlier than the expected sinus beat
Narrow QRS complex (<0.12s)
Retrograde P wave is before the QRS complex

Complete Compensatory Pause

ventricular ectopic, and premature ventricular complex

ECG Laddergram, ventricular premature complex, Fully compensatory pause

Premature Ventricular Complex (PVC) and Complete Compensatory Pause

A complete compensatory pause occurs almost always with Premature Ventricular Complex (PVC)
PP (RR) interval with PVC is exactly 2 times the PP (RR) interval without PVC

Because PVC originates in the ventricle and does not pass through the AV node, PVC does not reset the SA node

The SA node thus generates impulses regularly (sinus rhythm)

Rarely, PVC may retrogradely pass through the AV node and reset the SA node

Therefore, PVC may rarely cause an incomplete compensatory pause

ECG premature ventricular complex, and fully compensatory pause, PP interval

Premature Ventricular Complex (PVC) and Complete Compensatory Pause

PP (RR) interval with PVC (42) is exactly 2 times the PP (RR) interval without PVC (2x21)
Premature Ventricular Complex (PVC)

Occurs earlier than the expected sinus QRS complex
Wide QRS complex (>0.12s)
Indicated P wave just after the QRS
PVC did not reset the SA node because PVC did not pass through the AV node

Aberrant Premature Junctional Complex (PJC)

Aberrant Premature Junctional Complex (PJC)

During the conduction of PJC to the ventricles, some part of the conduction system may be in the refractory phase
Therefore, after a precisely timed PJC, the following can occur:

Aberrant Premature Junctional Complex (PJC) most commonly has the appearance of a Right Bundle Branch Block

Because the right bundle branch has the longest refractory phase

$ecg sinus rhythm without aberrant conduction, righ left bundle refractory period$

Sinus Rhythm Without Premature Junctional Complex (PJC)

SA node generates impulses regularly (P waves), which are conducted to the ventricles (QRS complexes)
LTR: Duration of the refractory period of the Left Bundle Branch
PTR: Duration of the refractory period of the Right Bundle Branch
The refractory period occurs shortly after an impulse has passed through the conduction system

During the refractory period, the conduction system does not conduct impulses

$ECG left right bundle refractoriness, aberrant premature junctional complex rbbb pattern$

Aberrant Premature Junctional Complex (PJC)

PJC occurs at a time when the left bundle branch is no longer in the refractory phase

But the right bundle branch is still in the refractory phase, the PJC is blocked in the right bundle branch

Therefore, the PJC (QRS complex) has the morphology of a right bundle branch block

A retrograde P wave precedes the QRS

ECG premature junctional complex and sinus rhythm

Premature Junctional Complex (PJC)

PJC (P´) occurs at a time when the bundle branches are no longer in the refractory phase
PJC (QRS complex) has a shape exactly like a sinus QRS

muddle av junction depolarisaton,junction extrasystole

ECG premature junctional complex, no P wave, narrow qrs complex

Premature Junctional Complex (PJC)

Narrow QRS complex (< 0.12s)
Occurs earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P wave is hidden within the QRS complex

muddle av node depolarisaton, junction extrasystole

ECG junctional extrasystoles, no p waves, narrow qrs, noncompensatory pause

Premature Junctional Complex (PJC)

Two premature junctional complexes are seen on the ECG
Narrow QRS complex (< 0.12s)
Occurred earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P waves are hidden within the QRS complex

premature junctional complex, upper av junction depolarisation

ECG premature junctional complex, retrograde p wave, short PR interval, Non-compensatory pause

Premature Junctional Complex (PJC)

Narrow QRS complex (< 0.12s)
PQ interval < 0.12s

If the PQ interval were > 0.12s, it would be an atrial extrasystole
which has an ectopic focus at the AV junction

Occurred earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P wave is before the QRS complex

In the inferior leads (II, III, aVF), the P wave from the SA node is always positive

junctional ectopic depolarisation in lower av junction

ECG prejature juncional complex, retrograde p wave after narrow qrs complex

Junctional Extrasystole

Narrow QRS complex (< 0.12s)
Occurred earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P wave is after the QRS complex

In the inferior leads (II, III, aVF), the P wave from the SA node is always positive

middle av junction depolarisation, and junctional extrasystole

ecg premature junctional complex, aberrant conduction, no p wave, rbbb pattern

Aberrant Junctional Extrasystole

Wide QRS complex (> 0.12s)

with right bundle branch block pattern

QRS appeared earlier than the expected sinus beat
Incomplete compensatory pause
QRS does not have a P wave

Retrograde P wave is hidden within the QRS complex

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 /

Premature Junctional Complex (PJC)

Premature Junctional Complex (PJC), Junctional Ectopics, Junctional Extrasystoles, Junctional Premature Beats, Junctional Premature Depolarisations, Atrioventricular junctional premature complexes

Heart Rhythm
Premature Junctional Complex (PJC)
ECG and Premature Junctional Complex (PJC)
Retrograde P Wave and Premature Junctional Complex (PJC)
Incomplete Compensatory Pause
Complete Compensatory Pause
Aberrant Premature Junctional Complex (PJC)

Heart Rhythm

Basic Heart Rhythms

Heart rhythm is determined by the site (sites) that generates impulses with the highest frequency (overdrive suppression)
We know 3 basic heart rhythms

Sinus Rhythm (Impulses generated by the SA node)
Junctional Rhythm (Impulses generated by the AV junction)
Ventricular Rhythm (Impulses generated by the Purkinje fibers in the ventricles)

Sinus rhythm is the physiological heart rhythm

Because the sinoatrial (SA) node generates impulses with the highest frequency (overdrive suppression)
The SA node is referred to as the primary pacemaker (rate setter)

Premature Junctional Complex (PJC)

AV junction (SA node and His bundle) is a secondary pacemaker

Begins to generate impulses when there is a failure of the SA node, leading to a junctional rhythm

PJC occurs due to premature depolarization of the AV junction

Most commonly during sinus rhythm

PJC commonly occurs due to:

Stress, caffeine, alcohol, smoking...

PJC is the rarest type of extrasystole, more common is

PJC can trigger re-entry tachycardia:

AVNRT (AV nodal re-entry tachycardia)
AVRT (Atrioventricular re-entry tachycardia)
Ventricular tachycardia
Torsades de Pointes

We recognize 3 types of extrasystoles:

Supraventricular:

Atrial extrasystole
Premature Junctional Complex (PJC)

Ventricular extrasystole

ECG and Premature Junctional Complex (PJC)

Retrograde (negative) P wave

Is negative in inferior leads (II, III, aVF)
Can be before, within, or after the QRS
Vector of the retrograde P wave

Points from the AV junction towards the SA node

Retrograde (negative) P wave occurs:

Also in atrial extrasystole

If the atrial focus is at the AV junction

The difference is in the PQ interval

PQ interval < 0.12s - Premature Junctional Complex (PJC)
PQ interval > 0.12s - Atrial extrasystole

Narrow QRS complexes (<0.12s)

Because the ventricles are activated through the conduction system

On the ECG, it is always earlier than the expected sinus QRS
Incomplete compensatory pause

PJC always resets the SA node

Retrograde P Wave and Premature Junctional Complex (PJC)

Retrograde (negative) P wave before the QRS

PJC is generated in the upper part of the AV junction
The atria are activated earlier (P wave) than the ventricles (QRS)

Hidden P wave within the QRS complex

PJC is generated in the middle part of the AV junction
The atria and ventricles are activated simultaneously
The retrograde P wave is hidden within the QRS complex

Retrograde (negative) P wave after the QRS

PJC is generated in the lower part of the AV junction
The ventricles (QRS) are activated earlier than the atria (P wave)

Incomplete Compensatory Pause

Premature Junctional Complex (PJC) and Incomplete Compensatory Pause

Laddergram illustrates the propagation of impulses through the conduction system
PP (RR) interval with PJC is shorter than 2 times the PP (RR) interval without PJC

Because PJC resets the SA node

Incomplete compensatory pause is created by:

Atrial extrasystole
Premature Junctional Complex (PJC)
Very rarely Ventricular extrasystole (VES)

Only when VES retrogradely passes through the AV node and resets the SA node

Premature Junctional Complex (PJC) and Incomplete Compensatory Pause

PP (RR) interval with PJC (36) is shorter than 2 times the PP (RR) interval without PJC (2x20)
Premature Junctional Complex (PJC)

Occurs earlier than the expected sinus beat
Narrow QRS complex (<0.12s)
Retrograde P wave is before the QRS complex

Complete Compensatory Pause

Premature Ventricular Complex (PVC) and Complete Compensatory Pause

A complete compensatory pause occurs almost always with Premature Ventricular Complex (PVC)
PP (RR) interval with PVC is exactly 2 times the PP (RR) interval without PVC

Because PVC originates in the ventricle and does not pass through the AV node, PVC does not reset the SA node

The SA node thus generates impulses regularly (sinus rhythm)

Rarely, PVC may retrogradely pass through the AV node and reset the SA node

Therefore, PVC may rarely cause an incomplete compensatory pause

Premature Ventricular Complex (PVC) and Complete Compensatory Pause

PP (RR) interval with PVC (42) is exactly 2 times the PP (RR) interval without PVC (2x21)
Premature Ventricular Complex (PVC)

Occurs earlier than the expected sinus QRS complex
Wide QRS complex (>0.12s)
Indicated P wave just after the QRS
PVC did not reset the SA node because PVC did not pass through the AV node

Aberrant Premature Junctional Complex (PJC)

Aberrant Premature Junctional Complex (PJC)

During the conduction of PJC to the ventricles, some part of the conduction system may be in the refractory phase
Therefore, after a precisely timed PJC, the following can occur:

Aberrant Premature Junctional Complex (PJC) most commonly has the appearance of a Right Bundle Branch Block

Because the right bundle branch has the longest refractory phase

$ecg sinus rhythm without aberrant conduction, righ left bundle refractory period$

Sinus Rhythm Without Premature Junctional Complex (PJC)

SA node generates impulses regularly (P waves), which are conducted to the ventricles (QRS complexes)
LTR: Duration of the refractory period of the Left Bundle Branch
PTR: Duration of the refractory period of the Right Bundle Branch
The refractory period occurs shortly after an impulse has passed through the conduction system

During the refractory period, the conduction system does not conduct impulses

$ECG left right bundle refractoriness, aberrant premature junctional complex rbbb pattern$

Aberrant Premature Junctional Complex (PJC)

PJC occurs at a time when the left bundle branch is no longer in the refractory phase

But the right bundle branch is still in the refractory phase, the PJC is blocked in the right bundle branch

Therefore, the PJC (QRS complex) has the morphology of a right bundle branch block

A retrograde P wave precedes the QRS

Premature Junctional Complex (PJC)

PJC (P´) occurs at a time when the bundle branches are no longer in the refractory phase
PJC (QRS complex) has a shape exactly like a sinus QRS

Premature Junctional Complex (PJC)

Narrow QRS complex (< 0.12s)
Occurs earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P wave is hidden within the QRS complex

Premature Junctional Complex (PJC)

Two premature junctional complexes are seen on the ECG
Narrow QRS complex (< 0.12s)
Occurred earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P waves are hidden within the QRS complex

Premature Junctional Complex (PJC)

Narrow QRS complex (< 0.12s)
PQ interval < 0.12s

If the PQ interval were > 0.12s, it would be an atrial extrasystole
which has an ectopic focus at the AV junction

Occurred earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P wave is before the QRS complex

In the inferior leads (II, III, aVF), the P wave from the SA node is always positive

Junctional Extrasystole

Narrow QRS complex (< 0.12s)
Occurred earlier than the expected sinus beat
Incomplete compensatory pause
Retrograde P wave is after the QRS complex

In the inferior leads (II, III, aVF), the P wave from the SA node is always positive

Aberrant Junctional Extrasystole

Wide QRS complex (> 0.12s)

with right bundle branch block pattern

QRS appeared earlier than the expected sinus beat
Incomplete compensatory pause
QRS does not have a P wave

Retrograde P wave is hidden within the QRS complex

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