Diagnostic criteria

  Heart rate is 40-60/minute.

  QRS complexes are
narrow ( <120ms ) since the impulses do not originate from the ventricles.

  AV nodal rhythm emerges when no impulse arises from sinus node or ectopic atrial focus (
atrial mutism). Therefore no P waves precede QRS complexes.



References

  Neth Heart J 2012;20:294-295.

  N Engl J Med 1988;318:358-365.

  Josephson ME. Clinical cardiac electrophysiology: techniques and interpretations. Lippincott Williams & Wilkins, 2008:226.






ECG 1. Junctional rhythm. Narrow QRS complexes with no preceding P waves.

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ECG 2. Junctional rhythm in another patient. P waves are absent and QRS complexes are narrow.

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ECG 3. This heart failure patient under digoxin therapy also has accompanying hypothyroidism. There are intermittent
nodal
beats
with no preceding P waves. Some sinus beats have P waves preceding the QRS complex. The U waves are best seen in
middle chest leads (in C2 of the above figure) and especially during bradycardia. The amplitude of the
U wave increases in
patients under digoxin treatment
.

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ECG 4. (Idio)nodal rhythm. P waves are not seen. QRS complexes are narrow. Heart rate is about 40/minute.

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ECG 5a. The ECG above belongs to a 58 years-old man with chest pain and shows acute inferior myocardial infarction.
There is also nodal rhythm. No P waves preceed QRS complexes. The
ST elevation and tall T waves in inferior leads show
acute inferior myocardial infarction. The
ST segment depression in I, aVL and anterior leads are reciprocal changes.
After this ECG was recorded, the patient underwent immediate coronary angiography and the right coronary artery was
stented successfully.

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ECG 5b. The next day, nodal rhythm disappeared and sinus rhythm was restored. Second beat from the left is atrial premature
contraction. There are only
small q waves to suggest old inferior myocardial infarction.

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ECG 6. The ECG above belongs to a 67 years-old woman who is taking Digoxin.
There is (idio)nodal rhythm and right bundle branch block.
P waves are absent. QRS complexes are wide.

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ECG 7. The 3-channel rhythm tracing above shows junctional rhythm and
retrograde atrial activation which results in the
appearance of
negative P waves in the ST segment.
The heart rate is about 40/minute. The narrow QRS complexes lack preceding P waves (nodal rhythm).

The ECG above has been donated by Assoc. Prof. Dr. Ilyas Atar to our website.

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ECG 8. The ECG above is from a 67 years-old woman with a diagnosis of alcoholic dilated cardiomyopathy and
paroxysmal atrial flutter. She was admitted to Cardiology department because of repeated pre-syncope.
She was on carvidilol, quinapril, spironolactone, bumetanide, atorvastatin and
digoxin therapy.
Her ECG on admission is seen above. This is a junctional escape rhythm in the setting of digitalis intoxication.
Sinus bradycardia, sinus arrest and sinus Wenckebach conduction are not uncommon in digitalis toxicity.
The reason why the sinus node is inhibited in this patient is due to digitalis intoxication with extreme sinus bradycardia/SA
block combined with overdrive suppression by the retrograde P waves. The slow junctional escape rhythm conducts
retrogradely - suggested by the superior P wave axis - with a long ventriculoatrial (VA) interval. Besides slowing the antegrade
atrioventricular (AV) conduction, it has also been shown that digitalis slows/blocks the retrograde fast pathway conduction.
The reason why the retrograde impulse conducts via the retrograde slow pathway - suggested by the long VA interval - is
probably due to retrograde fast pathway block in the setting of digitalis intoxication or due to the absence of retrograde fast
pathway conduction. The impulse then re-enters the ventricle via the fast pathway and initiates the so-called
ventricular echo beat (Figure 8). The RP interval is longer than the PR interval, signifying that the impulse is travelling
in a retrograde fashion via the slow pathway and then antegradely down to the ventricle via the fast pathway.


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The ECG above has been used with the permission of Netherlands Heart Journal.

Click here to read the relevant article by Alzand B.S.N.




Figure 8. Above is the ladder diagram explanining the mechanism of the group beating in ECG 8.
An AV nodal escape rhythm is travelling in a retrograde fashion to the atrium via the slow pathway
and then antegradely to the ventricle (
echo beat) via the fast pathway.

The ECG above has been used with the permission of Netherlands Heart Journal.

Click here to read the relevant article by Alzand B.S.N.





ECG 9a. The ECG above belongs to a 60 years-old man with acute anterior myocardial infarction.
It was recorded 60 minutes before coronary angiography. The rhythm is sinus.

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ECG 9b. The same patient was immediately transferred to the coronary angiography laboratory where his infarct-related LAD
artery was successfully opened by a stent. The above single-channel rhythm tracing was recorded by the defibrillator
during the procedure. After the revascularization, first
accelerated idioventricular rhythm appeared, which rapidly
turned to
sinus rhythm. A P wave is seen in the last ventricular beat of the accelerated idioventricular rhythm (evidence
of AV dissociation
).

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ECG 9c. Ten seconds after the ECG 9b,
his rhythm was sinus (left side of the above tracing). The recording was then stopped.
Two minutes later, the recording was started again when
accelerated junctional rhythm emerged.
Now the QRS complexes lack preceding P waves. Instead,
the retrograde negative P waves are seen in the ST segment.
This rhythm also subsided quickly and sinus rhythm appeared again.

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ECG 10a. The above ECG is from a 78 years-old man with coronary artery disease.
It was recorded immediately before triple coronary bypass surgery + mitral ring annuloplasty.
The rhythm is normal.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 10b. The above ECG is belongs to the same patient. It was recorded 5 days after the cardiac operation.
The patient was under positive inotrope therapy during this time.
What is your diagnosis?

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 10c. There are no P waves preceding the QRS complexes.
Small deflections (waves) following the QRS complexes are difficult to notice at first glance. .
Sometimes P waves may follow QRS complexes during nodal rhythm (as is above).
The patient was under positive inotrope therapy when this ECG was being recorded.
The diagnosis is nodal rhythm.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 10d. The above ECG was also recorded on 5th postoperative day.
P waves following QRS complexes are difficult to notice at first glance.
The diagnosis is nodal rhythm.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 10e. The above ECG was recorded after cessation of positive inotrope therapy.
P waves following QRS complexes are more clear now.
The diagnosis is nodal rhythm.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 11a. The ECG above belongs to an 84 years-old woman with chronic renal failure, hyperkalemia (6.9 mmol/L)
and coronary artery disease. This ECG is recorded at a standard
calibration of 10 mm/mV.

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ECG 11b. This ECG belongs to the same woman.
It was recorded 30 seconds after the ECG 11a, but at a
calibration of 20 mm/mV.
Now
P waves are easily discernible. The rhythm is junctional (nodal) rhythm.
Junctional beats do not have preceding P waves.
Some
atrial extrasystoles with P waves are also seen.

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ECG 12. The ECG above is from a 75 years-old woman with chronic renal insufficeny and heart failure (left ventricular
systolic dysfunction). At the time the above ECG was recorded, her serum potassium level was measured as 8.6 mmol/L.
She was also under Digoxin therapy.
Nodal rhythm is seen. P waves are not visible.
QRS complexes are widened and the T waves in right precordial leads are relatively prominent.
The above ECG was recorded at a paper speed of 25mm/second.

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ECG 13a. The ECG above belongs to an 80 years-old woman with acute inferior wall myocardial infarction.
Leads III and aVF show
ST segment elevation while leads I, aVL and V1 show ST segment depression.
The rhythm is
nodal rhythm with a heart rate of 44/minute. P waves are not visible.
This ECG was recorded immediately before stenting of her Right Coronary Artery (RCA).

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ECG 13b. The ECG above belongs to the same woman. It was recorded one day after the ECG 13a.
Now, the rhythm is
low atrial rhythm with negative P waves in inferior leads
The heart rate is 61/minute and compatible with
ectopic atrial rhythm. She is not under beta blocker therapy.

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ECG 14a. The ECG above belongs to an 65 years-old woman with lung cancer, acute renal failure and right heart failure
(probably due to acute pulmonary embolism).
Her serum potassium level was measured as 8.0 mmol/L while her serum creatinine level was 2.1 mg/dL.
Sharp, pointed T waves with narrow bases and relatively short QT interval should raise the suspicion of hyperkalemia.
Nodal rhythm with no preceding P waves and right bundle branch block are seen.
This ECG was recorded at a standard calibration of
10 mm/mV.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 14b. The above ECG belongs to the same woman. It is recorded after the ECG 14a but at a calibration of
20 mm/mV.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 14c. The 6-channel rhythm tracing above belongs to the same woman. It is recorded shortly after the ECG 14b.
Irregular junctional rhythm (
junctional arrhythmia / nodal arrhyhtmia ) is seen.
In leads II, III and aVF, some junctional beats have preceding retrograde P waves with short PR intervals, and some do not.
Calibration is 20m mm/mV.

Dr. Sinan Altan Kocaman has donated the above ECG to our website.

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ECG 15a. The ECG above belongs to a 63 years-old man with mechanical mitral valve prosthesis.
ECHOcardiography showed dilation of left atrium, right atrium and right ventricle with normal left ventricular systolic function.
Right bundle branch block is seen. What about the rhythm? Is it nodal rhythm or atrial fibrillation?
This ECG was recorded at
standard calibration of 10 mm/mV.

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ECG 15b. The ECG above belongs to the same man.
It was recorded a few minutes after the ECG 15a,
at a calibration of 20 mm/mV.
Now baseline undulations due to
fibrillatory waves are clearly seen. The rhythm is atrial fibrillation.

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ECG 16a. The ECG above belongs to a 68 years-old man.
It was recorded one day before his coronary artery bypass grafting surgery.
Nodal rhythm and
retrograde P waves are seen.
This ECG was recorded at standard calibration of 10 mm/mV.

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ECG 16b. The ECG above belongs to the same man.
It was recorded a few seconds after the ECG 16a,
at a calibration of 20 mm/mV.
Nodal rhythm and
retrograde P waves are seen.

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ECG 17a. The ECG above belongs to a 6 years-old child. It was recorded just before permanent pacemaker implantation.
He had undergone Atrial Septal Defect (ASD) closure 2 years ago.
This ECG shows nodal rhythm with
post-QRS retrograde P waves.
The fourth beat from the left is compatible with Posterior Fascicular Block.
This beat, may be a fascicular premature beat or an ECHO beat.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 17b. The ECG above belongs to the same child.
The basic rhythm is nodal rhythm with post-QRS retrograde P waves.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 17c. The ECG above belongs to the same child.
The basic rhythm is nodal rhythm with post-QRS retrograde P waves.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 17d. The ECG above belongs to the same child.
He had undergone Atrial Septal Defect (ASD) closure 2 years ago.
This ECG shows nodal rhythm with
post-QRS retrograde P waves.
The fourth beat from the left is compatible with Posterior Fascicular Block.
This beat, may be a fascicular premature beat or an ECHO beat.
In patients with nodal (junctional) rhythm and post-QRS retrograde P waves, the prominent P waves in lead V1 and V2
may mimic Epsilon waves, at first glance.

Pediatric Cardiologist Prof. Dr. Tevfik Karagoz has donated the above ECG to our website.

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ECG 18a. The ECG above belongs to a 74 years-old woman.
It was recorded after experiencing syncope.
This ECG shows nodal rhythm with
post-QRS retrograde P waves.

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ECG 18b. The ECG above belongs to the same woman.
The basic rhythm is nodal rhythm with
post-QRS retrograde P waves.

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