EKG ROUNDS Bundle Branch Blocks

1
EKG ROUNDSBundle Branch Blocks

• 07. 04. 2005
• Nadim Lalani

2
OUTLINE

• RBBB
• LBBB
• HEMiBLOCKS/ FaSCicULAR BLOCKS

3
Case

• A 13-year-old male.presents with a history of
  Syncpoe
• What else do you want to know on hx?

4
(No Transcript)
5
Brugada Syndrome

• Described in 1992
• Syndrome consisting of syncopal episodes and/or
  sudden death in patients with a structurally
  normal heart.
• Characteristic ECG with a pattern of right bundle
  branch block with an ST segment elevation in
  leads V1 to V3 was
• In 1998 recognised poor prognosis of patients
  with the syndrome not receiving an implantable
  defibrillator.

6
Brugada Syndrome

• Epid
• incidence of 0.05 to 0.6.
• Mostly SE Asian / Japan
• an autosomal dominant mode of transmission.
• Who?
• Adults 30-40
• (first case reports were kids)
• Related to defect of SCN5a Fast sodium channel
  predisposing pt to re-entry circuit.

7
Brugada Syndrome Clinical manifestations

• The complete syndrome is characterised by
  episodes of rapid polymorphic VT in patients.
  Resulting in syncopal attacks.
• When the episodes are sustained, cardiac arrest
  and eventually sudden death occur.
• There exist asymptomatic individuals in whom the
  atypical ECG is detected during routine
  examination.
• NB now known some variation in the EKG (three
  types of ST changes/ a-fib c)

8
Brugada Syndrome

• Diagnosis
• the typical ECG pattern and there is a history of
  aborted sudden death or syncopes caused by a
  polymorphic VT.
• There are also many patients with a normal ECG.
  Syndrome only recognised a posteriori when the
  typical pattern appears in a follow-up ECG or
  after the administration of pro-arrythmics.
• Additional diagnostic problems are caused by the
  changes in the ECG induced by the autonomous
  system and by antiarrhythmic drugs.

9
Brugada Syndrome

• Prognosis and treatment
• implantation of a cardioverter-defibrillator is
  mandatory in these patients.
• Case report of a 23 yold patient being managed
  on amiodarone until implantation

10
Case

• Mrs M. 39 yo female had a pulmonary artery
  prosthesis and ASD repair 3 weeks ago. Helathy
  otherwise . On Lipitor. Presents with migratory
  arthralgias/myalgias.
• EKG Diagnosis?
• Axis?

11
RBBB, axis 0-30 deg
12
RBBB

• Three phases
• ?Septal depolarisation.
• ?Left ventricular depolarization.
• ?Delayed stimulation of the right ventricle.

13
RBBB
septal depolarization produces a small septal r
wave in V1 and a small septal q wave in V6
depolarization of LV produces an S in V1 and an R
in V6
delayed right ventricular depolarization produces
a wide R wave in V1 and a wide S wave in V6
14
RBBB Summary

• Right Leads ( V1 eg) show an rSR complex with a
  wide R wave.
• Occasionally, however, the S wave never quite
  makes its way below the baseline. Consequently,
  the complex in lead V1 has the appearance of a
  large notched R wave (rabbit ears)
• Left Leads (I,V6) show a qRS pattern with a wide
  S wave.

15
Case 2

• Mr R . 55 yo admited to FMC after head-on MVC in
  which he sustained Multiple rib s, L Hip and
  L ulna. 2 days post-admit develops acute SOB with
  sat 80.
• EKG Diagnosis?
• Axis?
• Comment on T waves?

16
RBBB, ?RAD, TWIs
Primary TWIs
17
ST changes

• TWIs in the right chest leads are a
  characteristic finding with RBBB.
• These inversions are referred to as secondary
  changes because they reflect just the delay in
  ventricular stimulation.
• By contrast, TWIs in V5,V6 are primary T wave
  abnormalities reflect an actual change in
  repolarization (ie ischemia c.)

18
Case 3

• 80 yo guy with HTN. Presents with this EKG

19
RBBB, Axis apprx 30-90deg, Atrial Flutter
20
Sometimes can be Rate Dependent
21
COMPLETE AND INCOMPLETE RBBB

• Depends on the width of the QRS complex
• ?Complete RBBB is defined by a QRS that is 0.12
  second or more with an rSR in lead V1 and a qRS
  in lead V6.
• ?Incomplete RBBB shows the same QRS patterns, but
  its duration is between 0.1 and 0.12 second

22
(No Transcript)
23
Case 4

• 77 yo M with HTN, and known CAD

24
LBBB
25
Left Bundle Branch Block

• With LBBB the septum depolarizes from right to
  left .Therefore the EKG loses the normal septal r
  wave in lead V1 and the normal septal q wave in
  lead V6.
• Left ventricular depolarization is prolonged,
  yielding a wide QRS.
• Lead V6 you see a wide, entirely positive (R)
  wave.
• In the right chest leads (e.g., V1 ) you see a
  negative QRS (QS) complex.

26
Lose septal r in V1 And septal q in V6
Wide QS (sometimes rS) in V1 Wide R in Left Leads
27
(No Transcript)
28

• Congenital septal lesions, CAD, anterior MI
  (occlusion of proximal LAD), pulmonary
  hypertension, normal variant in 0.2 adults

29
Summary RBBB vs LBBB
30
R
R
r
q
S
S
R
QS
31
Fascicular Blocks (Hemiblocks)

• The RBB is a single pathway consisting of just
  one main fascicle or bundle.
• In contrast the LBB has an anterior fascicle and
  a posterior fascicle.

32
The Trifascicular Highway
33
EKG Changes

• Hemiblock (unlike a full LBBB or RBBB) does not
  widen the QRS complex.
• Main effect is a change in the QRS axis
• ? Left anterior fascicular block results in
  marked left axis deviation (-30 or more)
• ? Left posterior fascicular block produces marked
  right axis deviation (120 or more).

34
(No Transcript)
35

• Left anterior hemiblock shifts the QRS axis to
  the left by delaying activation of the more
  superior and leftward portions of the left
  ventricle.
• Left posterior hemiblock shifts it to the right
  by delaying activation of the more inferior and
  rightward portions of the left ventricle.
• In both cases the QRS axis therefore is shifted
  toward the direction of delayed conduction.

36
Axis?
Between -30 and -90 deg ? LAD
37
Axis?
RAD
38
Case

• 67 yo M Obese, Hx CHF. Presents with SOB
• EKG Dx?
• Is he having an MI?

39
(No Transcript)
40
LBBB and acute MI
41
Sgarbossa et. al.

• 131 patients from GUSTO-I trial who had LBBB with
  MI. Matched with controls. Came up with following
  criteria
• ? ST-segment elevation . 1 mm concordant with QRS
  complex 73 sens and 92 spec for acute MI.
• ? ST-segment depression . 1 mm in lead V1, V2 or
  V3 highly specific (96) but less sensitive
  (25) for MI
• ? ST-segment elevation . 5 mm discordant with QRS
  complex 31 sens, 92 spec.

42
Concordant ST ?
ST ?
Discordant ST ?
ST ?
43
Shlipak MG, Lyons WL, Go AS, et al. Should the
electrocardiogram be used to guide therapy for
patients with left bundle branch block and
suspected myocardial infarction? JAMA
199928171419.

• Reviewed patients presenting with LBBB and an
  acute cardiopulmonary history and assessed the
  usefulness of the Sgarbossa criteria.
• Criteria had a sensitivity of 10 and a
  specificity of 100.
• Most (90) patients with AMI will not meet the
  criteria.
• Support thrombolysing all patients (except those
  with contraindications) who have a history
  suggestive of AMI and LBBB.

44
Practice Time
45
Case A

• 65 yo M smoker with DM presents with 4 hours
  RSCP
• EKG Diagnosis?
• Axis?

46
(No Transcript)
47
Case B
RBBB, ? Primary TWIs V4,V5
48
Case C
LBBB
49
Case D
50
LBBB, ? LAD
51
Case E
RBBB
52
Case F
LBBB
53
Case G
RBBB with PACs
54
Case H
Bifascular RBBB with LAFB
55
Case I
RBBB with Primary TWIs
56
Case J
RAD
57
Case K
RAD ?LPFB
58
References

• Goldberger Clinical Electrocardiography A
  Simplified Approach, 6th ed.,1999 Mosby, Inc.
• Brugada P, Brugada J Right bundle branch block,
  persistent ST segment elevation and sudden
  cardiac death a distinct clinical and
  electrocardiographic syndrome. A multicenter
  report. J Am Coll Cardiol 1992 Nov 15 20(6)
  1391-6