2007 terni, workshop interattivo, caso clinico 1

1. • A 72-year-old woman complained of intermittent
chest pain for 3dys, which became severe and
continuous 4hs before presentation.
Clinical Case(2)
• Her cardiovascular risk factors were NIDDM for 30
yrs, hypertension for ten yrs and dyslipidaemia.
• BP was 148/74 mmHg, and HR was 82/min, whereas
the rest of the examination was unremarkable.

2. Clinical Case(2)

3. • Normal SR, tall R waves in V1  V3
• R wave >0.04s in V1, V2 and V3
• ST segment depression in V1-V4.
• Lateral and inferior leads did not
demonstrate T elevation.
• The EKG done in the ER; what
is the diagnosis?
Clinical Case(2)

4. • Coronary angiography showed an
occlusion of the proximal LCxCA
• Distal L-ADA 80% stenosis, a
dominant RCA with a 60-70%
stenosis in the postero-lateral
branch.
• PCA to the proximal LCxCA was
performed and balloon angioplasty
was also done to the obtuse
marginal branch of the LCxCA.
• A good final result with TIMI3
flow was obtained with resolution
of chest pain.
Clinical Case(2)

5. Clinical Case(2)
BEFORE AFTER

6. • I-PMI occurs in the posterior or postero-basal LV wall,
is rare and usually associated with an inf. or lat. MI(1,2)
.
DISCUSSION
Clinical Case(2)
• Incidence has been estimated at 3-4% of all AMI(3)
.
• ECG of posterior MI as described by Schamroth(4)
are:
- R wave ≥0.04s in V1 or V2
- Upright T waves in contiguous right
precordial leads
- ST segment depression in V1  V3
• R/S ratio ≥1 in leads V1 and V2.
• As MI evolves ST segment depression
decreases and the upright T amplitude
increases.

7. - R wave ≥0.04s in V1 or V2
- Upright T waves in contiguous
right precordial leads
- ST segment depression in V1 
V3
• R/S ratio ≥1 in leads V1 and V2.
• As MI evolves ST segment
depression decreases and the
upright T amplitude increases.
EKG criteria
Clinical Case(2)

8. • Turn ECG upside down and
look at it from the back.
• Changes in V1 and V2 which
might be over-looked at
first glance, will be seen as
abnormal Q waves, ST
elevation and increased T
wave inversion(2)
.
• R>0.04s and R≥S V1, showed
a high specificity (>99%)
and a high positive
predictive value (91%).
• R≥0.04s and R≥S V2, showed
95% of specificity, and 73%
positive predictive value.
Clinical Case(2)

9. • I-PMI has been found to be always due to LCX
occlusion(6)
.
• In another study, an abnormal R wave in V1 had a 96%
specificity for LCxCA vs RCA-related infarction, but
a sensitivity of only 21%(7)
.
• In addition, all patients with LCxCA-related MI and
abnormal R wave in lead V1, had multivessel disease(7)
• In spite of these, true posterior MIs are usually well-
tolerated(1)
.
• Conventional ECG, even with correct placement of the
electrodes, may miss a true I-PMI
Clinical Case(2)

10. • The use of additional chest leads on the posterior
thorax between the angle of the scapula and the
vertebral column, at the level of the 5th
intercostal
space (leads V7-9), will increase the sensitivity
through detection of Q waves(8)
.
• Some have questioned whether the conventional 1mm
ST elevations in the posterior leads were appropriate
and it has been found that the currently-used
criterion of 1mm to detect ischaemia is inadequate to
demonstrate ST segment elevation in the posterior
leads during LCxCA occlusion.
Clinical Case(2)

11. Possible mimics of ECG changes in a posterior
MI include other causes of tall R waves in V1:
– Right ventricular hypertrophy
- Right bundle branch block
- Wolf-Parkinson-White syndrome
- Normal variants
- Ischaemia of the anterior wall of the LV also
produces ST segment depression in leads V1-3 and
this must be differentiated from posterior MI.
Isolated PMI
Clinical Case(2)

12. • A 53-year-old man presented to the ED, and he had a
4 ½ hrs history of chest pain radiating to both arms.
• The onset of chest pain occurred while walking and
was not relieved by rest.
• Associated symptoms included shortness of breath,
nausea and diaphoresis. The patient’s only past
medical history was of hypertension, for which he was
taking losartan, and no other medications.
• He had a 30 pack-year smoking history.
Clinical Case(3)

13. • BP 177/102mmHg, HR 72b/m
RR 20 breaths/min, T. 36,5°C.
• Prompted by the ST depres-
sion and typical presentation
for MI, a reading for post.
leads V7 through V9 was
immediately obtained and
demonstrated ST elevation
• Standard management
including M.O.N.A. and heparin
• ED ECG showed downsloping
ST depression mostly
prominent in leads V1 V4
and tall R wave in V3 (not in
V1/V2)
Clinical Case(3)

14. • A cardiology consultation was obtained, and the pt
was taken promptly to the Cath. Lab, whereas
Troponin I and other laboratory values were pending
at that time.
• Cath. revealed total occlusion of the LCA, a normal
LDA, a normal left main artery, a 60% proximal lesion
of a small branch of the LCA and luminal irregularities
in LDA.
• Pt underwent uncomplicated stenting of the LCA, and
a subsequent Echo evaluation identified moderate to
severe posterior wall hypokinesis and was otherwise
unremarkable.
Clinical Case(3)

15. • Pt’s initial troponin I level was 1.4 ng/mL (range 0.0–
1.2 ng/mL) with a peak of 172 ng/mL 7 hours after
presentation. Five hours after presentation a single
CK measurement was obtained and was 3730 U/L with
a CK-MB of 191 ng/mL (relative index 5.1%).
• The only complication identified during hospitalization
was a single uncomplicated episode of hematemesis.
• The pt otherwise did well and was discharged home on
hospital day 4.
Clinical Case(3)

16. • No EKG ST elevat nor tall R
V1 or V2
• EKG reveal ST depression
in V1 and V2 and an up-right
T wave in V2
• ST elev. in leads V8 and V9.
• True incidence is unknown but has reported
between 0% to 12% (6,7,9,13,18)
when posterior
leads V7 through V9 is obtained
• Identif. pts with I-PMI with
standard EKG could be
challenging(1,2,10,12–14)
due to the
location of the AMI(1,2,14)
Clinical Case(3)

17. Clinical Case(3)
Introduction
• Posterior wall of LV is typically supplied by the left Cx
coronary artery (1) and is a challenging area of the heart
in which to identify acute ischemia and MI.
• During transmural AMI, the characteristic ST-segment
elevations seen in other areas of the heart are not seen
in isolated posterior myocardial infarctions (IPMI) on
standard 12-lead EKG (1,2)
• If A-IPMI were identified promptly in the emergency
department (ED), these patients could be considered
for thrombolytic therapy or immediate interventional
Cath. Lab. (3–6)

18. • Recently a consensus report from the ACC that was
endorsed by the American College of Emergency
Physicians (16)
use the presence of tall R waves
(typically defined as an R/S ratio ≥ 1 in V1 and V2 to
define posterior MI with ST depression and
carachteristic symptoms .
• Few techniques have been developed to identify IPMI,
including the use of posterior leads V7, V8 and V9 (3–10)
body surface mapping (11,12)
and the development of
specific EKG criteria other than ST elevation (13-15)
• We present a case of an acute I-PMI in which the ECG
lacked tall R waves in leads V1 and V2 and the use of
posterior leads identified ST-segment elevation that
changed pt management resulting in the pt going
promptly to the Cath. Lab.
Clinical Case(3)

19. • Current diagnostic criteria for acute I-PMI include:
horizontal STsegment depression, tall R waves, and
prominent upright T waves in V1, V2 and/or V3 (1,2)
Discussion
• In this case we had down-sloping ST segments and
lacked tall R waves in V1 and V2, an up-right T wave in
V2 and a tall R wave in V3 were present. It has been
suggested that tall R waves in anterior leads (V1, V2
and V3) are simply the electrical equivalent of Q
waves in the posterior leads (V7, V8 and V9)(1,2)
• If this were the case, these two findings would
always occur simultaneously on a 15-lead ECG (a 12-
lead ECG + posterior leads).
• Correlation between anterior R waves, posterior Q waves, and
the time course of their development in I-PMI needs further
study.

20. Clinical Case(1)

21. Clinical Case(1-2)