My slide during presentation at the 2nd National Emergency and Critical Care Symposium 2015 in Ipoh on 08 August 2015

1. New or Presumed New
LBBB As STEMI?
A Debate
Dr. Chew Keng Sheng, MD, MMED
Universiti Sains Malaysia

2. Five Compelling Reasons Why New or Presumed
New LBBB Should Not Be Treated as STEMI
1. Recent evidences
2. Questionable historical origin
3. Confounding pathogenetic mechanisms
4. Ethical issue of giving fibrinolytics when it is not
needed
5. Unnecessary PCIs.

3. 1. Recent Evidences
• Chang et al (2009) (observational, n = 7937):
– rate of MI is the same (~7%) whether new, old or no
LBBB
• Jain et al (2011) (retrospective, n = 892):
– Only 1/3rd of new or presumed new LBBB have AMI
• Kontos et al (2011) (observational, n = 401):
– rate & size of MI is the same in new, old or no LBBB
• Wong et al (2005) HERO-2 Trial (n = 15640; 300
LBBB):
– rate of MI is the same whether new or old; unless there is
concordant ST changes

4. 2. Questionable Historical Origin
• First recognized in 1917
by Oppenheimer &
Rothschild
• Bauer (1965): many
confounders
• Sgarbossa 2000:
Timing of ECG
recording?

5. “In the prethrombolytic era, the management of patients with
myocardial infarction consisted only of pain relief,
observation, and treatment of complications. In patients with
ECG confounders, such as LBBB, the diagnosis of MI was
confirmed through biochemical determinations over several
hours or days after admission. Because there was no
incentive to collect information on early ECG signs of MI,
most studies on the diagnosis of MI in the presence of
LBBB included ECGs with old infarctions as well as
recordings obtained at widely scattered time-points
after acute infarction”
-­‐ Elena
Sgarbossa
MD
J
Electrocardiol
2000;33
Suppl:87-­‐92.

6. The FTT Data
• Pooled data of 9 trials in the FTT group (1991)
• STEMI with BBB treated with fibrinolytics - lower
mortality rate than placebo (18.7% vs 23.6%)
– increased major bleeding risk (1.3% vs 0.3%)
– increase in stroke (2.1% vs 1.1%)
• 3 caveats:
• Is it LBBB or RBBB?
• Is it new or old?
• Small BBB cohort (3.6% of 58,000)

7. 3. Confounding Pathogenetic Mechanisms
• De novo LBBB due to MI
• Or LBBB secondary to pre-
existing structural heart
disease
• Is the LBBB a cause or
consequence?
• Bauer (1965): true AMI-
related LBBB has very high
mortality
Neeland et al (2012)

8. 4. Ethical Issues
• Giving fibrinolytic when it is not necessary?
• Bleeding risk
– FTT data 1.1 – 1.3% compared to 0.4% in control
• NNT for streptokinase 25
• STEMI with LBBB – higher co-morbidities
www.PresentationPro.com

9. 5. Unnecessary PCIs
• Larson et al (2007)
– N = 1335
– overall false +ve cath lab activation: 14%,
– in the LBBB cohort: 44%!
• Lopes et al (2011)
– N = 98
– 39% new LBBB (including with concordant ST-changes)
have no +ve angio findings
Cost? PCI availability?

10. Reflection
• What if it is your own family member:
Subject to fibrinolysis if:
A. New or presumed new LBBB?
B. New or presumed new LBBB with concordant ST
changes?
Subject to PCI if:
A. New or presumed new LBBB?
B. New or presumed new LBBB with concordant ST
changes?
www.PresentationPro.com

11. Five Compelling Reasons Why New or Presumed
New LBBB Should Not Be Treated as STEMI
1. Recent evidences (the scientific lens)
2. Questionable historical origin (the historical lens)
3. Confounding pathogenetic mechanisms (the basic
science lens)
4. Ethical issue of giving fibrinolytics when it is not
needed (the bioethical lens)
5. Unnecessary PCIs (the socioeconomic lens)

12. • Download a copy of my 6-page notes in pdf at URL:
http://tinyurl.com/pern38t
THANK YOU