This ECG illustrates an acute anterior wall M.I. in a patient with a previous history of inferior wall M.I.  The anterior wall M.I. can be seen in the classic signs in V1 through V6:  ST elevations with coved upward shape (tombstones), T waves inverting beginning around V2 and continuing through V6, and pathological Q waves in V1 through V6.

The patient had a history of previous inferior wall M.I., unknown age.  This is normally seen in Leads II, III, and aVF.  The first two complexes on the strip are wide QRS complexes without associated P waves, presumably ventricular.  It is impossible to know from this ECG whether the first complex is a PVC or escape beat, but the second appears to be escape.  So, to evaluate the ST segments, T waves, and pathological Q waves in the inferior wall, all we have are aVF and the Lead II rhythm strip at the bottom.  These show pathological Q waves (necrosis), and some slight elevation of ST, with coving or horizontal flattening.  From this, we know there is damage in the inferior wall, but the age of the M.I. is undetermined.

This patient went to the cath lab, and received angioplasty with stenting of the proximal left anterior descending branch of the left coronary artery.

This ECG was obtained from a 78-year-old woman who had been experiencing intermittant chest pain for two days.  When she finally presented to the Emergency Department, her ECG showed ST elevation in the inferior leads II, III, and aVF.  She also has ST depression in I and aVL, which represents reciprocal changes seen in the high lateral leads, which are opposite the inferior wall.  In addition, V1 and V2 show some ST depression, with early transition of the R waves (taller than normal for V2 and V3).  This is a common finding in IWMI, and indicates posterior wall involvement.  The injury is continuous from the inferior wall of the left ventricle, up the posterior wall, because both were supplied in this case by the right coronary artery.

This ECG has three rhythm strips.  The more rhythm strips you have, the easier it is to determine the rhythm.  In this case, the rhythm is normal sinus rhythm.  But the extra rhythm strips would allow you to compare P wave morphology in three views if the rhythm was in question.  Instructors:  ask your students what they think about this rate (78 per minute) in the setting of acute M.I.   Is it within normal range? Is it optimal for the injured heart?   Another good point to bring up is the use of additional right-side leads to assess the right ventricle.  V3R and V4R can be very useful in determining whether right ventricular M.I. is also present.  Some practitioners skip this step and evaluate the RV using echocardiography.  In the emergency setting, however, it can be very helpful to know the condition of the RV.  RVMI is always a possiblity in RCA occlusion, and RVMI can increase mortality significantly.  BP must be protected, since the injured right ventricle is very dependent on preload to function adequately as a pump, providing preload for the left side of the heart.

This patient was lost to followup.

This ECG was taken from a 66-year-old woman who presented to the emergency department complaining of chest pain and shortness of breath.  She attributed her symptoms to her COPD, but stated that her aerosol treatment had not helped.  She waited for some time before deciding to go to the hospital, then drove herself. In the emergency department, she had blood drawn, an I.V. started, and an aerosol treatment of albuterol.  She was then taken to the radiology dept. for a chest xray.  When she returned, a 12-lead ECG was done.  45 minutes had passed since she first arrived at the hospital.  This ECG is shown here.  It shows ST elevation in the inferior leads:  II, III, and aVF.  The patient was taken immediately to the cath lab, where her right coronary artery was found to have a 100% occlusion. (See image accompanying this ECG).  Angioplasty was successful, and stents were placed in the artery.  The patient was found to have anemia, with a hemoglobin of 5.5, and she was given a blood transfusion.  During the cath procedure, a ventriculogram was performed, which showed a stunned and akinetic inferior wall.  Unfortunately, subsequent ventriculogram performed several weeks later showed the lack of motion of the inferior wall to be permanent.  The ventriculogram is also posted here, and at this YouTube link, so you will be able to show your students the mechanical effects on the heart of a delay to treatment in acute STEMI.  See our YouTube site for more ventriculograms and cath videos.

This week's ECG of the Week is from an elderly woman who suffered an acute occlusion of the right coronary artery.  The ECG clearly shows ST elevation in leads II, III, and aVF, indicating inferior wall injury.  In this case, this ECG was obtained in the field by paramedics, and was the second ECG done on this patient. For this tracing, the paramedics obtained V3 and V4 on the right side to better view the right ventricle. V3 and V4 right clearly show ST elevation as well, indicating RVMI.  The slight coving and elevation observable in V1 is also an indication of RV involvement, and the ST depression in V2 indicates posterior wall injury.  All of this results from a proximal lesion of the RCA in this patient.  Such a lesion carries a high morbidity and mortality.

Taking the time to obtain a right ventricular lead is controversial in some settings.  Some believe the patient's hemodynamic condition should be treated, regardless of the presence or absence of ST elevation in right chest leads.  Others find it very helpful to know that the right ventricle is affected.  In this case, paramedics in this community have a protocol to avoid the use of nitroglycerine in RVMI patients, even when the BP is adequate.  So, for them, it is important to have the information gathered from V Right leads.

The rhythm here is interesting, as well, and not at all uncommon for IWMI patients.  The baseline artifact makes it a bit difficult to march out all the P waves, but it appears they are sinus P waves that are slightly irregular at a rate of 52 to 54.  The PR intervals appear to be progressively prolonging, but there is no "grouped beating" observable on this short strip.  A lack of a concurrent Lead II rhythm strip also makes it difficult to determine the rhythm, as Lead II does have very visible P waves, and would be helpful.  The regularity of the narrow complex bradycardia points to a junctional escape rhythm, which would make this a third-degree AVB at the AV node level, which is very common with IWMI.  What do you think?

This month's strip from Jason Roediger's ECG Challenge blogpost is a nice complement to the strip presented here.  His is much clearer, and has a Lead II rhythm strip.  Do you think these ECGs show the same rhythm, or two different rhythms?

For an excellent discussion of "AV Dissociation" vs. "AV Block", go to Christopher Watford's Ask the Expert post.  Thanks very much to ECG Guru Sebastian Garay for this interesting ECG.