Transcript Document

The Prevalence and
Prognostic Significance of
ECG Abnormalities
7/16/2015
For: ECG in Ischemic
Heart Disease
By: V. Froelicher, MD
Palo Alto VAHCS and
Stanford University
Cardiology Dept.
Study Selection:
Using MEDLINE we reviewed the
literature over a period of 33 years
from 1966 to 1999
Studies where a randomly selected
asymptomatic population (no
history heart disease) had ECG
then followed for 5 years for death
Study Selection:
Studies that excluded or analyzed
separately, individuals with known
cardiovascular disease were of key
interest.
Some studies made no exclusions
The Manitoba study followed an
initially young and fit population
over many years observing them
for cardiovascular disease.
Study Selection:
The pooling project excluded all
those with major Q waves
However, many more excluded
participants on the basis of more
than one criterion including
physician history of MI or angina
pectoris, medical examination, and
ECG.
The ECG Studies (1 of 3):
The Framingham Heart Study
The Seven Countries Study
The US Pooling project
The Finnish Social Insurance study
The Manitoba Study
The Busselton Health Studies,
Busselton City, Australia
Chicago Heart Association Detection
Project in Industry
The ECG Studies (2 of 3):
Chicago Western Electric Study
Copenhagen City Heart Study
White Hall study
British Regional Heart Study
Italian Risk Factors and Life
Expectancy Pooling Project
The Tecumseh community health
Belgian Inter-university Research on
Nutrition and Health
The ECG Studies (3 of 3):
The WHO European study
Multiple Risk Factor Intervention Trial
The Honolulu Heart program
Evans County Study
Charleston Heart Study
The Cardiovascular Health Study
The ECG and survival in the very old
Results:
All ECG abnormalities increase
with age
Q waves and RBBB are more
prevalent in men
ST depression and LBBB are
more prevalent in women
Results:
Several ECG abnormalities are
associated with significant risk:
ST depression inclusive-LVH has a
33% five-year mortality in men and a
21% five-year mortality in women
 Asymptomatic (silent) Q wave
infarction is associated with the same
risk as symptomatic infarction
 ST depression is poorly reproducible
yet risk increases with its prevalence

Results:
Early repolarization is benign
The prognostic impact of bundle
branch block depends on the
population in which it appears
The prevalence of atrial fibrillation
rises exponentially with age and is
associated with higher risk than any
other ECG abnormality in the Elderly
Results:
T wave inversion and high voltage
QRS are more common in Blacks
than whites, but in general, do not
predict coronary heart disease to
the same extent
Elevated heart rate, but not
ventricular premature beats, is an
independent risk factor for sudden
cardiac death
Results:
We estimated the utility of the ECG as a
screening tool by calculating sensitivity and
specificity values from some of the studies
that used stringent exclusion criteria.
We found that, for individual ECG
abnormalities as well as for pooled
categories of abnormalities, the sensitivity
of the ECG for future death was too low for it
to be practical as a screening tool.
Results:
This almost certainly relates to
the low prevalence of these
abnormalities in the populations
considered.
However, all abnormalities
increase with age, and ECG
screening is a consideration in
the elderly.
Results:
Multivariate equations can
identify those who would benefit
from additional therapy or health
promotion
Among those who are already
symptomatic with ischemic or
myocardial disease, the ECG can
identify a subset at particularly
high risk.
Results:
We hypothesize that this would
extend to those at high risk from
diabetes, HBP and those with
high-risk scores.
The Framingham data suggest
that although conventional risk
factors relate to long-term risk,
ECG abnormalities are better
predictors of short term risk
Results: what’s wrong with
the Finns??
Very High prevalence of LVH
(20% vs 1%, others High: Moscow
12%, Copenhagen 18%, blacks)
Can’t perform ECGs?
High HBP prevalence and death
rate
Hi Prevalence Abnormalities in Women
20
18
16
Q waves (Ashley)
Q waves (VA)
LVH (Ashley)
14
12
10
LVH (VA)
ST depression (Ashley)
ST depression (VA)
8
6
4
2
0
20-29
30-39
40-49
50-59
60-69
>70
Low Prevalence Abnormalities in Women
6
5
LBBB (Ashley)
LBBB (VA)
RBBB (Ashley)
4
3
RBBB (VA)
Afib (Ashley)
Afib (VA)
2
1
0
20-29
30-39
40-49
50-59
60-69
>70
High Prevalence Abnormalities in Men
30
25
Q waves (Ashley)
Q waves (VA)
20
LVH (Ashley)
LVH (VA)
ST depression (Ashley)
ST depression (VA)
15
10
5
0
20-29
30-39
40-49
50-59
60-69
>70
Low Prevalence Abnormalities in Men
9
8
7
LBBB (Ashley)
LBBB (VA)
RBBB (Ashley)
RBBB (VA)
Afib (Ashley)
Afib (VA)
6
5
4
3
2
1
0
20-29
30-39
40-49
50-59
60-69
>70