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Journal of The Association of Physicians of India ■ Vol. 64 ■ September 2016
Original Article
Etiology and Left Ventricular Functions in
Left Bundle Branch Block- A Prospective
Observational Study
Rajeev Bhardwaj
Editorial Viewpoint
Abstract
Purpose of study: Left bundle branch (LBBB) is common ECG finding.
Common causes of LBBB are coronary artery disease (CAD), hypertension
and dilated cardiomyopathy (DCM). Purpose of the study was to find out
the etiology and left ventricular function in patients coming to a territory
care hospital.
Material and methods: All consecutive patients coming to our hospital
as indoor or outdoor patients with ECG suggestive of LBBB were studied.
The detail history and examination was done. Echocardiography was
done in all patients.
Results: 132 patients with LBBB were studied. Mean age was 61.65±13.02
yrs. 70 were male (53.03%) and 62 were female (44.97%). 40 patients
presented with dyspnea ((30.3%) and 34 with chest pain ((24.24%). 23
patients were asymptomatic (17.4%). 63 were hypertensive (47.7%) and
6 were diabetic (4.5%). Left ventricular hypertrophy (LVH) was present in
42 patients (31.8%), with 33 having diastolic and 9 systolic dysfunction.
33 patients had DCM (25%) and 31 patients had evidence of myocardial
infarction (23.48%). 20 patients had normal echocardiography (15.15%).
75 patients had systolic dysfunction (56.8%)
Conclusion: Commonest presentation in patients wih LBBB was
dyspnea followed by chest pain. Majority had hypertension. LVH was the
commonest echocardiographic finding followed by global hypokinesia
and regional wall motion abnormality. More than 50% patients had left
ventricular systolic dysfunction.
L
eft bundle branch block
(LBBB) is essentially an
electrocardiographic (ECG)
diagnosis and so it’s true incidence
in general population is difficult
to assess. Incidence in patients
referred to ECG department was
found to be 1%. 1 We studied the
left ventricular (LV) functions in
patients with ECG evidence of
LBBB.
Material and Methods
132 consecutive patients with
ECG evidence of complete LBBB
coming to our hospital with various
complaints were studied. Detailed
h i s t o r y wa s t a k e n . T h o r o u g h
physical examination was carried
out. All were subjected to detailed
echocardiography. Special
• Commonest presentation
of LBBB was dyspnea and
chest pain.
• C o m m o n e c h o c a r d i o graphy findings were
LVH, global hypokinesia
and regional wall motion
abnormality.
attention was given for wall motion
abnormality. Depending upon the
presentation, some were admitted
and some were followed on OPD
basis. The treatment as per diagnosis
was started. Coronary angiography
(CAG) was done in patients when
there was doubt about the etiology,
especially to differentiate dilated
cardiomyopathy (DCM) from
ischemic LV dysfunction. CAG was
also done in patients undergoing
primary PTCA or patients having
angina.
Acute MI was diagnosed
when patient came with chest
pain suggestive of myocardial
infarction (MI), new LBBB, rise
in troponin levels and presence
of new regional wall motional
abnormality(RWMA).
AMI in presence of preexisting
LBBB was diagnosed by chest pain
suggestive of MI, rise in troponins
and by ECG evidence of one or
more of (1) ST segment elevation
≥ 1mm and with concordant QRS
complex (2) ST depression ≥ 1mm
Professor, Department of Cardiology, Indira Gandhi Medical College, Shimla, Himachal Pradesh
Received: 04.11.2014; Revised: 07.01.2015; Re-revised: 09.11.2015; Accepted: 23.03.2016
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Journal of The Association of Physicians of India ■ Vol. 64 ■ September 2016
Table 1: Clinical characteristics of the
patients
Total patients
Male
Female
Mean age
Hypertensive
Diabetic
Symptoms
Dyspnea
Chest pain
Syncope
Palpitation
Asymptomatic
132
70(53.03%)
62(46.97%).
61.65±13.02 yrs
63(47.7%)
11 (8.33%).
40(30.3%)
34(25.76%)
03((2.27%)
04(3%)
23(17.4%)
Table 2: Echocardiographic findings
Total patients
132
Left ventricular hypertrophy
42(31.8%)
Diastolic dysfunction
33
Systolic dysfunction
9
DCM
33(25%)
Coronary artery disease
31(23.48%)
Old MI
20
Acute MI
11
Intermittent complete heart
03(2.27%)
block
Misc.
03(2.27%)
Normal cardiovascular system 20(15.15%)
Systolic dysfunction
75(56.8%)
Table 3 : Age distribution of LBBB
patients
Age (yrs)
18-40
40-49
50-59
60-69
70-79
>80
Male
1
6
11
25
20
7
Female
4
7
16
21
9
5
Total
5
13
27
46
29
12
in leads V1, V2,V3 (3) ST elevation
of ≥ 5mm and discordant with QRS
complex and new RWMA. In cases
of doubt, CAG was done.
Coronary artery disease was
diagnosed by presence of acute
MI, old records of MI or old CAG
report, record of PTCA or bypass
grafting.
Duration of QRS was measured
in each patient.
Inclusion Criteria: All
consecutive patients coming to our
OPD/ admitted in our hospital with
ECG changes of complete LBBB.
Exclusion Criteria: Patients with
ECG showing incomplete LBBB.
Patients who did not report for
echocardiography.
Table 4: Age distribution of etiology of LBBB
Etiology
HT with LV dysfunction
Coronary artery disease
DCM
Heart block
Misc.
Normal
18-39
(N 5)
0
2
2
40-49
(N 13)
4
1
2
1
50-59
(N 27)
9
7
8
1
5
3
Results
Overall 132 patients were
studied. Table 1 shows the clinical
characteristics of the patients.
Mean age was 61.65±13.02 yrs. 70
were male and 62 were female.
C o m m o n e s t p r e s e n t a t i o n wa s
dyspnea, in 40 patients; 34 patients
presented with chest pain and 3
patients presented with syncope.
23 patients had LBBB without
symptoms. 20 of these had referral
for ECG changes after preanesthetic check up before surgery
or other interventions.
Table 2 shows the diagnosis
after echocardiography and other
investigations.
Commonest abnormality in
echocardiography was left
ventricular hypertrophy (LVH)
seen in 42 patients, 33 of whom
had diastolic dysfunction and 9 had
systolic dysfunction. 33 patients
had coronary artery disease (CAD)
w i t h LV s y s t o l i c d y s f u n c t i o n .
20 of these had old myocardial
infarction (MI) and 11 had acute
MI. One patient had rheumatic
heart disease with severe mitral
regurgitation (MR) with severe
aortic regurgitation (AR), with
severe LV dysfunction; one had
calcific aortic valve with severe AR
with mild LV dysfunction and one
had hypertrophic cardiomyopathy.
Three patients presenting with
syncope were found to have
intermittent complete heart block.
Left ventricular systolic
dysfunction was present in 75
patients (56.8%); mild in 10 patients
(13.3%), moderate in 16 patients
(21.3%) and severe in 49 patients
(65.3%).
Twenty patients were found to
60-69
(N 46)
18
9
10
1
2
6
70-79
(N29)
12
8
7
>80
(N 12)
5
1
3
1
1
3
have normal cardiovascular system.
Out of 23 asymptomatic patients,
20 were found to have normal
echocardiography while 3 had
DCM with mild LV dysfunction.
Table 3 shows the age distribution
of LBBB patients. It can be seen that
it is more common in older age
group. Most of the patients were
between 50-70 yrs of age.
Ta b l e 4 s h o w s t h e a g e w i s e
distribution of etiology of LBBB. It
can be seen that in less than 40yrs
of age, CAD and DCM are more
common causes. After 40 yrs of age
hypertensive heart disease, CAD
and DCM are the common causes,
in almost equal proportion.
Mean QRS duration was
131±9.11ms.
I n p a t i e n t s w i t h m i l d LV
dysfunction, QRS duration was
125±5.86ms, with moderate LV
dysfunction it was 132±6.28ms
and in patients with severe LV
dysfunction, it was 137±10.20ms.
Coronary angiography was done
in 15 patients due to various reasons.
S e ve n h a d n o r m a l c o r o n a r i e s .
Single vessel disease was present in
3 patients, two vessel disease in 2
patients and three vessel disease in
3 patients. Two patients underwent
primary angioplasty and one
patient underwent coronary artery
bypass grafting.
Discussion
The association between LBBB
a n d c a r d i o va s c u l a r m o r b i d i t y
has been investigated, but given
conflicting results, controversy
regarding the prognosis of LBBB
persists. Fahy et al observed a
higher rate of developing overt
c a r d i o va s c u l a r d i s e a s e a m o n g
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Journal of The Association of Physicians of India ■ Vol. 64 ■ September 2016
people with isolated LBBB. 2
Azadani et al followed 1688
individuals without cardiovascular
disease or heart failure for 6 years.
2.5% had LBBB on baseline ECG.
In multivariable logistic regression
analysis adjusting for potential
confounders, participants with
baseline LBBB remained nearly
three (2.85) times more likely to
develop CHF. Unadjusted mortality
r a t e f r o m c a r d i o va s c u l a r a n d
cardiac diseases was higher among
patients with LBBB compared to
those without LBBB. In bivariate
analysis, patients with LBBB had
4.34 times greater odds of dying
from cardiovascular disease. 3
E ve n i n p a t i e n t s w i t h h e a r t
failure, LBBB carries a poorer
prognosis. In a cohort of 5517
p a t i e n t s w i t h c o n g e s t i ve H F , 4
patients with LBBB (n = 1391)
showed a higher 1-year all-cause
mortality and sudden death
than controls free of LBBB. An
unfavorable prognosis of LBBB
was also observed in a cohort of
patients with acute HF one year
after admission. 5
In 1979, the Framingham Study 6
(5,209 subjects, 55 with LBBB)
showed a clear association between
LBBB and main cardiovascular
diseases, such as hypertension,
cardiac enlargement, and coronary
heart disease. Our study showed
that around 48% patients with
LBBB had hypertension, 25% had
DCM and around 23% had CAD.
Systolic dysfunction of LV was
present in about 56% patients. Only
about 15% patients had normal
echocardiography. How many
of these develop cardiovascular
disease on follow up remains to be
seen. Boyle and Fenton found that
69 % of patients with LBBB had
CAD and /or hypertension. 7. 88%
of their patients were aged 50yrs or
more. Similar was the case with our
study, where 87% patients were 50
yrs or older. 34% of their patients
were 70yrs or older. Similarly 30%
of our patients were 70yrs or older.
LBBB may occur in asymptomatic
individuals, patients with
extensive myocardial infarction,
and in those with heart failure,
especially in dilated, nonischemic cardiomyopathies. In
some patients, LBBB (sometimes
rate dependent) may be the first
manifestation of heart disease
whereas the clinical presentation of
a dilated cardiomyopathy develops
only some years later.8 Early studies
reported a mean survival of less
than 5 years after documentation
of LBBB. 9
The etiology of LBBB plays a role
in determining the H-V interval.
Nearly all patients with congestive
(dilated) cardiomyopathy exhibited
a prolonged H-V interval whereas
in other groups, both normal and
abnormal values occurred. 10
Seventy-five patients (56.8%)
i n o u r s t u d y h a d LV s y s t o l i c
dysfunction. Out of these 49
patients had severe LV systolic
dysfunction. Patients of severe
LV dysfunction had mean QRS
duration 137±10.20ms as against
125±5.86 in patients with mild
LV d y s f u n c t i o n . I n p a t i e n t s
with dilated cardiomyopathy,
a p r o g r e s s i ve i n c r e a s e i n Q R S
duration and the presence of a
L B B B p a t t e r n we r e r e l a t e d t o
disease progression. 11 In 14 of 18
patients with congestive (dilated)
cardiomyopathy, progression of
disease was accompanied by a
movement of the QRS frontal plane
vector from a normal axis to left axis
deviation which mainly occurred
during the first 2 years after clinical
manifestation of cardiomyopathy.
From the prognostic point of view,
increased QRS duration in patients
with heart failure has been shown
by several studies to be correlated
to a poor prognosis. 12
Conclusion
Prevalence of LBBB increases
with age. Majority of patients of
LBBB had cardiovascular disease.
Hypertensive heart disease, DCM
and CAD are the common causes.
Majority have LV dysfunction.
QRS duration was more in patients
with severe LV dysfunction. So
all cases of LBBB require proper
management and follow up.
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