الفهرس 
Anatomy and diseases of left mainOnly 14 pages are availabe for public view
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Abstract
Risk assessment (on admission) is extremely valuable for
patients with NSTEMI, for management strategy and optimization
of resources.
ECG is a very easy, rapid and applicable way of risk
assessment and is of great value especially in developing countries
with low resources.
So, this study was designed for investigating the value of
ST-segment elevation in lead avr in the surface ecg as a predictor
of detecting left main coronary artery lesions of patients suffering
from NON-ST-Segment Elevation Myocardial Infarction
(NSTEMI) and its relation to the severity of left main coronary
artery disease. This represents an easy way for risk assessment
and better management.
The study consisted of 100 patients that were classified into
groups according to the elevation of ST-segment in lead aVR;
1- Patients without ST- segment elevation in lead aVR or
with ST-segment elevation of < 0.05 mV.
2- Patients with ST-segment elevation ≥ 0.05 mV .
Patients must have had chest pain for more than 20 minutes
with a significant rise in cardiac enzymes to be considered in these
groups.
All patients who had ST-segment elevation in leads other
than aVR and V1, LBBB, previous ST-segment elevation
myocardial infarction, previous CABG or with pacemaker were
excluded.
All patients had the following: medical history taken, clinical
examination, admission ECG, cardiac enzymes level measured,
recording of the clinical complications and hospital outcome,
echocardiography and coronary angiography done within 1 month.
In this study, it was found that:
Male gender and dyslipidemia were found in the aVR group
while hypertension ,diabetes mellitus, smoking, and positive
family history were statistically insignificant in both groups.
As regard distribution of risk factors for ischemic heart
disease among both groups; hypertension was present in 18
(69.2%) patients in group 1 and in 40 (54.1%) patients in group 2,
diabetes mellitus was present in 30 (40.5%) patients in group 2
and 12 (46.2%) patients in group 1 .Dyslipedemia was found more
evident in group 2 ,60 (81.1%) patients versus 16 (61.5%)patients
in group 1, as regard positive family history for IHD it was found
in 26(35.1%) patients in group 2 and in 10(38.5%) patients in
group 1, while smoking was nearly equally present in the two
groups, 16 (61.5%) patients in group 1 and 46 (62.2%) patients in
group 2 . But none of these differences were statistically
significant as shown in table 1 except for Dyslipidemia.
Changes in ECG that are well-known to be of ischemic cause
were closely associated more with elevation of ST-segment in
aVR, especially the number of contiguous leads showing STsegment
depression.
And regarding the site of ST-segment depression it was
found that the anterior chest leads were the site of ST-segment
depression in 6 ( 23 %) patients in group 1 and in 62 (83.8%)
patients in group 2, lateral chest leads were 4 (15.3%) in patients
in group 1 and in 40 (54.1 %) patients in group 2 and the inferior
chest leads were the site of ST-segment depression were 3 (11.5%)
in patients in group 1 and in 24 (32.4 %) patients in group 2 and
all these changes were statistically significant (P value is <0.001)
As regard the site of T-wave inversion, the anterior chest
leads were the site of T-wave inversion in 12 (66.7 %) patients in
group 1 and is 12 (54.5 %) in group 2, lateral leads in 10 (55.6 %)
patients in group 1 and in 10 (45.5 %) patients in group 2 and the
inferior leads in 10 (55.6 %) patients in group 1 and in 8 (36.4 %)
patients in group 2, but non of these differences was statistically
significant (P values 0.44 , 0.53 and 0.22 respectively).
In-hospital complications in the form of prolonged repeated
anginal attacks, heart failure, re-infarction and death were
collectively higher in aVR group with high statistical significance
for heart failure, but insignificant for death , re-infarction and
anginal attacks.
Eight (10,8%) patients in group 2 died during hospital
admission while none (0%) of patients in group 1 died, reinfarction
was recorded in 6 (8,1%) patients in group 2 while non
of the patients in group 1 (0%) had this complication during the
in-hospital course.
Prolonged or recurrent anginal attacks occurred in 58 (78,4%)
patients in group 2 and in 16 (61,5%) patients in group 1, which
was statistically insignificant (P value < 0.09)
Just 28 (37,8%) patients in group 2 were complicated with
heart failure while non (0%) patients in group 1 had been
complicated by heart failure and this difference was highly
statistically significant (P value <0.001) as show in table 8 Figure
9.
And as a final and visual proof, angiographic survey in this
study showed more angiographic lesions to be highly associated
with the aVR group, and more complex and critical lesions too,
which again favors the early invasive approach, with a good
positive correlation between the severity of angiographic lesions
and the elevation of ST-segment in lead aVR.
Patients were divided according the severity of LMCA lesions
to two subgroups :sub group had the lesion below 80% stenosis
and another subgroup having the lesion 80% stenosis or more .
Twenty eight patients (37.8%) had Left Main coronary disease
in group 2 ,less than 80 % stenosis compared to 18 (75%)
patients in group 1.
While 46 patients (62,2 %) had Left Main stenosis more than
80% In group 2,compared to 6 patients ( 25%)in group 1, the
differences between subgroups were statistically significant
difference (P value <0.001) as show in table 9 figure 10.
-Prevalence of non-asteal lerion is significantly more than
that of the osteal lesion in both groups (p value <0.001).
Osteal lesion is more prevalent in group 2 while non-osteal
lesion is more prevalent in group 1(p< value 0.001).
All these findings illuminated the path for new, previously
neglected, easily applied and very sensitive ECG prognostic
criteria.