A young man with sudden chest pain

A 30-something with history of 2 pack per day smoking complained of sudden left arm and chest pain while working construction.  It was very distressing for him.  He presented by private transportation, stating that his pain was decreasing.

At triage, he had this ECG recorded:
The computer read that there is incomplete right bundle branch block.
QRS duration 102 ms.
What do you think?
















No significant abnormalities were seen in triage, and the patient had to wait 2 hours.  By the time he was roomed, his pain was gone.

A second ECG was recorded, pain free:
If you didn't see anything wrong with the first one, maybe you can see it now by comparison with this one.















His first troponin I, drawn 4 hours after arrival, was 1.6 ng/mL.


Analysis:
--There is subtle ST Elevation in inferior leads II, III, aVF, with reciprocal ST depression in aVL.  This is diagnostic of inferior injury.  The fact that it resolved with resolution of chest pain simply verifies this.
--There is also a decrease in the size of the lateral precordial T-waves.
--Notice that the ST elevation on the first ECG does NOT meet STEMI criteria. There is not 1 mm of STE in any lead.
--But that ECG is diagnostic of injury.


The patient was started on heparin.

Shortly thereafter, he had a run of ventricular tachycardia.  Therefore he was taken urgently to the cath lab.  [Patients with ACS who have persistent refractory pain, hemodynamic or electrical instability, or pulmonary edema, should go emergently to the cath lab]


The angiogram was clean!!  

An MRI was diagnostic of myocarditis.  

--There were no wall motion abnormalities (although they are frequently seen in myocarditis)
--No evidence of microvascular obstruction
--Delayed enhancement sequences obtained at 10 mins after gadolinium administration reveal multiple (at least 3) foci of delayed enhancement, measuring about 2 centimeters in the 
inferior septum, and approximately the same size in the inferior wall.
--There is subendocardial sparing demonstrated (this pretty much establishes myocarditis, as ischemia would preferentially affect the subendocardium.

Troponin I profile:

Time after arrival         Troponin I
4                                     1.613
6.5                                  5.887
13.5                              10.969
15.5                              11.347
19                                   9.001
21.5                                7.521
25                                   6.175  


Learning Points:

1.  Learn to recognize subtle injury. This could have been an early STEMI.  The patient's reperfusion time would have been delayed.
2.  It is particularly easy to miss these when you are shown an ECG completely out of clinical context, as often happens with triage ECGs.
3.  Injury NOT due to ischemia also is high risk: in this case, the risk of ventricular dysrhythmias.
4.  Myocarditis and STEMI are often indistinguishable.  They may have injury on ECG, wall motion abnormalities, and elevated troponins.  ACS may also have a negative angiogram if there is autolysis of thrombus!  MRI makes the diagnosis.

Here is another interesting related case:

A Young Woman with Chest Pressure and Subtle, Focal ST Elevation/Depression

The effect of targeted temperature management on QT and corrected QT intervals in patients with cardiac arrest


Just published online: