Short PR interval

  PR interval < 120 msec (< 3 small squares).

  P wave is normal: upright in leads II, III and avF.

  QRS width is normal.




Lown-Ganong-Levine (LGL) Syndrome

  There are paroxysms of tachycardia (AVNRT, etc.) in addition to the above findings.

  The diagnosis of LGL syndrome should not be made if there are no attacks of paroxysmal tachycardia.




Causes of short PR interval:

  Lown-Ganong-Levine Syndrome.

  Wolff-Parkinson-White (WPW) Syndrome: Short PR interval, normal P wave, delta wave resulting in a wide QRS complex.

  Coronary sinus rhythm (low atrial rhythm): P wave is negative in leads II, III and aVF.

  (in some patients with) Fabry disease.

  (in some patients with) Pompe's disease.





ECG 1. Short PR interval and normal width of QRS complex in a young woman. The absence of delta wave and wide QRS
complex excludes the diagnosis of WPW syndrome.

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ECG 2. The ECG above belongs to a 17 years-old boy who complains of attacks of palpitations. The PR interval is short.

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ECG 3. Short PR interval in a 7 years-old boy. He had previously undergone balloon dilatation for coarctation of the aorta.

Pediatric cardiologist Dr. Mahmut Gokdemir has donated the above ECG to our website.

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ECG 4a. The resting ECG of a 16 years-old male shows short PR interval. He complained of attacks of palpitation.

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ECG 4b. One week later, the same patient's ECG showed supraventricular tachycardia (heart rate is 205/minute).
Now, the diagnosis is Lown-Ganong-Levine (LGL) syndrome.

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ECG 5. Shortening of the PR interval may be too subtle to detect at first glance.
The ECG above belongs to a 14 years-old boy with a PR interval of 110 msec.

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ECG 6. Shortening of the PR interval in a middle-aged woman.

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ECG 7. The ECG above belongs to a 73 years-old man with chronic hypertension. He complained of typical effort angina.
His ECG shows increased voltage suggestive of left ventricular hypertrophy, strain pattern and short PR interval.
Coronary angiography was performed on the same day and 95% stenosis was detected in the LAD coronary artery.
His ECG does not show typical ischemic changes. Patients with stable angina may have normal ECGs during the angina-free
period. If there are no dynamic ECG changes (suggesting unstable angina pectoris) in such a patient, it will be impossible to
diagnose coronary artery disease without performing further diagnostic tests.

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ECG 8. Short PR interval in the ECG of a 51 years-old man with old inferior myocardial infarction. PR interval is 110 msec.
Q waves in II, III, aVF and negative T waves in III and aVF denote to old inferior wall myocardial infarction.

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ECG 9a. The ECG above belongs to an apparently healthy 39 years-old asymptomatic man.
Short PR interval is accompanied by right bundle branch block. PR interval is 110 msec.

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ECG 9b. The same patient's ECG summary is seen above.





ECG 10. Short PR interval (95 ms) in a 13 years-old girl with a normal ECHOcardiogram. No delta wave is seen.

Pediatric cardiologist Dr. Mahmut Gokdemir has donated the above ECG to our website.

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ECG 11. The ECG above is from an 11 years-old girl with no structural heart disease.
Short PR interval (64 msec) and sinus arrhythmia are seen.

Pediatric cardiologist Dr. Mahmut Gokdemir has donated the above ECG to our website.

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ECG 12. Above is the ECG of a 59 years-old man with coronary artery disease and heart failure.
Junctional premature beat is seen.
The P wave preceding the junctional beat is followed by a short PR interval.
This PR interval shortening is not due to accesory pathway, there is no delta wave.
This short PR interval is just due to coincidental timing of the junctional premature beat.
This is not an atrial premature beat since PP intervals and P wave configurations are the same.

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