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Dr. Mete ALPASLAN
Atrial Infarction and the ECG
Last update: May 2020
Diagnostic criteria
Localized PR segment elevation or depression may be observed. The displacement of PR interval during atrial infarction is best appreciated in patients with AV block.
Atrial arrhythmias may develop.
In patients with atrial infarction, Ta wave depression is seen more often than Ta wave elevation.
References
Int J Cardiol 2016;202:904-909.
Journal of Electrocardiology 2011;44:635-640.
Am J Cardiol 1973;31(4):450-456.
Surawicz, Knilans. Chou's electrocardiography in clinical practice. 6th edition. Saunders. Philadelphia 2008.
ECG 1. Atrial infarction during acute inferior myocardial infarction. Circumflex coronary artery (Cx) was totally occluded by
thrombus just before giving the left atrial branch. The right coronary artery (RCA) had 70% stenosis. Localized depression of
PR segment is observed.
Click here for a more detailed ECG
ECG 2a. The ECG above belongs to a 73 years-old man with coronary artery disease, old myocardial infarction,
mild left ventricular systolic dysfunction and chronic renal failure. Several coronary stents had been implanted in the past.
ECHOcardiography did not show pericardial effusion.
He does not have chest pain or dyspnea at the moment.
He also does not have clinical or laboratory evidence of acute pericarditis.
PR depression is seen in right precordial leads.
The above ECG was recorded at a standard calibration of 10 mm/mV.
Click here for a more detailed ECG
ECG 2b. The ECG above was recorded immediately before the ECG 2a.
It was recorded at a calibration of 20 mm/mV to depict PR depression (Ta depression) clearly.
The initial part of the P wave is positive and the terminal part of the P wave is negative in precordial leads.
However, the terminal negativity of the P wave is not solely responsible for the observed PR depression.
The PR segment after termination of the P wave is still depressed. This finding suggests that the patient had
infarction of atrial myocardium in the past.
Click here for a more detailed ECG
ECG 2c. Above is a zoomed view from a section of the ECG 2b showing PR depression (Ta depression) clearly.
ECG 3a. The above ECG shows both complete AV block and interatrial block. It was recorded during acute inferior wall myocardial infarction. P waves are not related to the QRS complexes. Therefore, some P waves are buried in QRS complexes. The P wave width is slightly more than 120 milliseconds: interatrial block. This ECG was recorded at a calibration of 20 mm/mV to show interatrial block. The P wave morphology and PR interval are also compatible with atrial infarction. Displacement of the PQ interval is considered the most useful sign of atrial infarction. The displacement of PQ interval during atrial infarction is best appreciated in patients with AV block.
Click here for a more detailed ECG
A close-up view of PR segment elevation from the ECG 3a is seen above. This is a magnified view of the P wave before the 8th QRS complex in lead II from the ECG 3a. The PR segment is elevated when compared with the baseline (TP segment).
ECG 3b. Above is his ECG at a standard 10 mm/mV calibration.
It is difficult to see interatrial block, PR segment elevation and complete AV block, at first glance.
Click here for a more detailed ECG
Last update: May 2020
Diagnostic criteria
Localized PR segment elevation or depression may be observed. The displacement of PR interval during atrial infarction is best appreciated in patients with AV block.
Atrial arrhythmias may develop.
In patients with atrial infarction, Ta wave depression is seen more often than Ta wave elevation.
References
Int J Cardiol 2016;202:904-909.
Journal of Electrocardiology 2011;44:635-640.
Am J Cardiol 1973;31(4):450-456.
Surawicz, Knilans. Chou's electrocardiography in clinical practice. 6th edition. Saunders. Philadelphia 2008.
ECG 1. Atrial infarction during acute inferior myocardial infarction. Circumflex coronary artery (Cx) was totally occluded by
thrombus just before giving the left atrial branch. The right coronary artery (RCA) had 70% stenosis. Localized depression of
PR segment is observed.
Click here for a more detailed ECG
ECG 2a. The ECG above belongs to a 73 years-old man with coronary artery disease, old myocardial infarction,
mild left ventricular systolic dysfunction and chronic renal failure. Several coronary stents had been implanted in the past.
ECHOcardiography did not show pericardial effusion.
He does not have chest pain or dyspnea at the moment.
He also does not have clinical or laboratory evidence of acute pericarditis.
PR depression is seen in right precordial leads.
The above ECG was recorded at a standard calibration of 10 mm/mV.
Click here for a more detailed ECG
ECG 2b. The ECG above was recorded immediately before the ECG 2a.
It was recorded at a calibration of 20 mm/mV to depict PR depression (Ta depression) clearly.
The initial part of the P wave is positive and the terminal part of the P wave is negative in precordial leads.
However, the terminal negativity of the P wave is not solely responsible for the observed PR depression.
The PR segment after termination of the P wave is still depressed. This finding suggests that the patient had
infarction of atrial myocardium in the past.
Click here for a more detailed ECG
ECG 2c. Above is a zoomed view from a section of the ECG 2b showing PR depression (Ta depression) clearly.
ECG 3a. The above ECG shows both complete AV block and interatrial block. It was recorded during acute inferior wall myocardial infarction. P waves are not related to the QRS complexes. Therefore, some P waves are buried in QRS complexes. The P wave width is slightly more than 120 milliseconds: interatrial block. This ECG was recorded at a calibration of 20 mm/mV to show interatrial block. The P wave morphology and PR interval are also compatible with atrial infarction. Displacement of the PQ interval is considered the most useful sign of atrial infarction. The displacement of PQ interval during atrial infarction is best appreciated in patients with AV block.
Click here for a more detailed ECG
A close-up view of PR segment elevation from the ECG 3a is seen above. This is a magnified view of the P wave before the 8th QRS complex in lead II from the ECG 3a. The PR segment is elevated when compared with the baseline (TP segment).
ECG 3b. Above is his ECG at a standard 10 mm/mV calibration.
It is difficult to see interatrial block, PR segment elevation and complete AV block, at first glance.
Click here for a more detailed ECG