R-on-T type VPCs

  The presence of a VPC on the preceding T wave.

  When it occurs during the
vulnerable period of ventricular repolarization, it may induce

      ventricular tachycardia (VT) or ventricular fibrillation (VF).

  Anderson et al. has suggested that almost one third of all sustained monomorphic VTs start with

      R-on-T VPCs ventricular tachycardia (VT) or ventricular fibrillation (VF). In such cases, the R-on-T

      type VPC initiating the VT attack has a morphology different than other beats of the VT run.




Reference

  J Cardiovasc Electrophysiol 1999;10:897-904.





ECG 1. The R-on-T phenomenon during the early hours of acute anterior wall myocardial infarction.
The onset of the VPC is close to the apex of the preceding T wave.

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ECG 2. R-on-T phenomenon during
acute inferior wall myocardial infarction.
The onset of the VPC is close to the apex of the preceding T wave.

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ECG 3. During sinus rhythm, the
VPC (R-On-T) converts the rhythm first to VT and then to VF.

Prof. Dr. Remzi Karaoguz has donated the above ECG to our website.





ECG 4a. The rhythm tracing above is from the 3-channel Holter recording of a middle-aged woman.
Because of short coupling intervals, the
VPCs occur on the T wave (R on T).

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ECG 4b. Another rhythm tracing from the same Holter recording is seen above.
Because of short coupling intervals, the
VPCs occur on the T wave (R on T).
The
VPC initiating the VT is morphologically different than other ectopic beats of the VT run.
Above is a non-sustained VT attack.
It looks similar to Type 1 onset of sustained monomorphic VT attack, as described by Anderson.

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ECG 4c. Another rhythm tracing from the same Holter recording is seen above.
Because of short coupling intervals, the
VPCs occur on the T wave (R on T).
The
VPC initiating the VT is morphologically different than other ectopic beats of the VT run.
Above is a non-sustained VT attack.
It looks similar to Type 1 onset of sustained monomorphic VT attack, as described by Anderson.
The coupling interval of the first VPC (RonT) (
385 ms ) is shorter than the first interectopic interval ( 635 ms ).

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ECG 5. The above ECG is from a 67 years-old man with esophageal carcinoma and coronary artery disease.
ECHOcardiography showed left ventricular apical aneurysm with a low Ejection Fraction (25%).
QT interval prolongation and
R on T is seen.

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ECG 6a. The ECG above is from a 67 years-old man with coronary artery disease and esophageal carcinoma.
It was recorded 4 hours before his cardiac arrest.
Three coronary stents had been implanted previously. He also has apical left ventricular aneurysm.
He was complaining of recent-onset chest pain.
The above ECG shows QT interval prolongation, extensive T wave negativity, frequent VPCs and
R-on-T.

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ECG 6b. The above ECG belongs to the same patient and was recorded one minute after ECG 6a.

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