ECG: Cardiac Malpositions

1. DR.G .BALAJIDR.G .BALAJI
PROF.DR.S.RAMASAMY’PROF.DR.S.RAMASAMY’
S UNITS UNIT

3. ECG shows…ECG shows…
Rate - 70/minRate - 70/min
Rhythm - SinusRhythm - Sinus rhythm; Regularrhythm; Regular
P Wave P Wave
Duration - 0.04 Sec.Duration - 0.04 Sec.
Amplitude - 0.04 Sec.Amplitude - 0.04 Sec.
Morphology – Negative in I, II ,a VLMorphology – Negative in I, II ,a VL
Positive in a VRPositive in a VR

4. QRS complexQRS complex
Duration - 0.08 Sec.Duration - 0.08 Sec.
Axis - approx. 130 degrees (RAD)Axis - approx. 130 degrees (RAD)
Poor R wave progressionPoor R wave progression
Ventricular activation time - <0.04 Ventricular activation time - <0.04
secsec
ST segment - mild ST elevation II, III, a ST segment - mild ST elevation II, III, a
VFVF

T wave - Negative in I, a VL T wave - Negative in I, a VL

5. ECG findings is classical ofECG findings is classical of
SITUS INVERSUS DEXTROCARDIASITUS INVERSUS DEXTROCARDIA
NEGATIVE NEGATIVE P waves P waves
QRS wavesQRS waves
T waves T waves
in conventionally recordedin conventionally recorded
LEAD ILEAD I
Right Axis DeviationRight Axis Deviation
POSITIVE P waves in LEAD III, a VF POSITIVE P waves in LEAD III, a VF

6. CONTINUES………CONTINUES………
UPRIGHT EQUIPHASIC P waves in aVRUPRIGHT EQUIPHASIC P waves in aVR
QRS Complex dominantly positive in QRS Complex dominantly positive in
LEAD III & a VF & a VR. Dominantly LEAD III & a VF & a VR. Dominantly
negative in I & a VLnegative in I & a VL
Reversed QRS pattern, tallest in lead V1, Reversed QRS pattern, tallest in lead V1,
and diminishing progressively towards and diminishing progressively towards
lead V6lead V6

8. CARDIAC MALPOSITIONCARDIAC MALPOSITION
Prevalence-0.10 per 1000 live births.Prevalence-0.10 per 1000 live births.
It is defined as an abnormal intra It is defined as an abnormal intra
thoracic location of the heart or a thoracic location of the heart or a
location that is abnormal (inappropriate) location that is abnormal (inappropriate)
relative to the position of the abdominal relative to the position of the abdominal
viscera. viscera.

9. Ventricular LoopVentricular Loop : : Right or Left bend Right or Left bend
(loop)that forms in the straight heart tube of (loop)that forms in the straight heart tube of
the embryo. the embryo.
d-loop:d-loop: Normal right ward (dextro) bend Normal right ward (dextro) bend
in the embryonic heart tube. This designation in the embryonic heart tube. This designation
as applied to the developed heart indicates that as applied to the developed heart indicates that
the sinus/inflow portion of the morphologic the sinus/inflow portion of the morphologic
right ventricle lies to the right of the right ventricle lies to the right of the
morphologic left ventricle.morphologic left ventricle.

10. l-loop:l-loop: A leftward (levo) bend in the A leftward (levo) bend in the
embryonic heart tube. The l-loop designation embryonic heart tube. The l-loop designation
as applied to the developed heart indicates that as applied to the developed heart indicates that
sinus or inflow portion of the morphological sinus or inflow portion of the morphological
right ventricle lies to the left of the right ventricle lies to the left of the
morphological left ventricle .morphological left ventricle .

Concordant LoopConcordant Loop:: It refers to a ventricular It refers to a ventricular
loop that agrees with the visceroatrial situs.loop that agrees with the visceroatrial situs.
d-loop: situs solitus d-loop: situs solitus
l-loop: situs inversus. l-loop: situs inversus.

12. BASIC CARDIAC MALPOSITIONBASIC CARDIAC MALPOSITION
BILATERAL ASYMMETRY:BILATERAL ASYMMETRY:
1. Visceroatrial situs inversus with 1. Visceroatrial situs inversus with
dextrocardiadextrocardia
2. Visceroatrial situs solitus with 2. Visceroatrial situs solitus with
dextrocardiadextrocardia
3. Visceroatrial situs inversus with 3. Visceroatrial situs inversus with
levocardialevocardia

13. BILATERAL SYMMETRY:BILATERAL SYMMETRY:
1. Visceral heterotaxy with right isomerism1. Visceral heterotaxy with right isomerism
2. Visceral heterotaxy with left isomerism2. Visceral heterotaxy with left isomerism

14. SITUS SOLITUSSITUS SOLITUS
The normal position of the heart and The normal position of the heart and
viscera.viscera.
The base to a apex axis which points to The base to a apex axis which points to
the left because the straight heart tube of the left because the straight heart tube of
the embryo initially bends to the right (d-the embryo initially bends to the right (d-
loop) and then pivots to the left until the loop) and then pivots to the left until the
ventricular portion comes to occupy its ventricular portion comes to occupy its
normal left thoracic position.normal left thoracic position.

17. BILATERAL ASYMMETRYBILATERAL ASYMMETRY
SITUS INVERSUS WITH DEXTROCARDIA:SITUS INVERSUS WITH DEXTROCARDIA:
1. Incidence is one in 8000 births.1. Incidence is one in 8000 births.
2. Heart, thoracic and abdominal viscera are 2. Heart, thoracic and abdominal viscera are
mirror images of normal situs.mirror images of normal situs.
3. 3. Incidence of congenital heart disease is Incidence of congenital heart disease is
5%5%

18. 4. Heart is right sided: Right hemi 4. Heart is right sided: Right hemi
diaphragm lower than the left.diaphragm lower than the left.
5. Anatomical right ventricle lies to the left 5. Anatomical right ventricle lies to the left
of the anatomical left ventricle (l-loop) of the anatomical left ventricle (l-loop)
which is normal for situs inversus. which is normal for situs inversus.

21. ECG FEATURES:ECG FEATURES:
1.Inverted P-wave, negative QRS 1.Inverted P-wave, negative QRS
complex and inverted T-wave in lead I, complex and inverted T-wave in lead I,
2.Reversal of the QRS pattern in 2.Reversal of the QRS pattern in
lead aVR and aVL.lead aVR and aVL.
3.Reversal of corresponding right 3.Reversal of corresponding right
and left precordial leads.and left precordial leads.
(atrial depolarisation from left sinus node) (atrial depolarisation from left sinus node)

22. SITUS SOLITUS WITH DEXTROCARDIA:SITUS SOLITUS WITH DEXTROCARDIA:
1. Lungs and abdominal viscera are situs solitus, 1. Lungs and abdominal viscera are situs solitus,
but the heart is on the right side but the heart is on the right side
(dextrocardia)(dextrocardia)
22. . Incidence of the congenital heart Incidence of the congenital heart
disease is around 98%.disease is around 98%. Most common Most common
is TGA (congenitally corrected). Others are is TGA (congenitally corrected). Others are
shunt lesions.shunt lesions.
3. Ascending aorta and aortic knuckle occupy 3. Ascending aorta and aortic knuckle occupy
their normal position and descending aorta their normal position and descending aorta
runs its normal course along the left.runs its normal course along the left.

23. 4. The base to the apex axis points to the right 4. The base to the apex axis points to the right
and the right hemi diaphragm is lower than and the right hemi diaphragm is lower than
the left.the left.
5. Anatomical right ventricle lies to the right of 5. Anatomical right ventricle lies to the right of
the anatomical left ventricle(d-loop). Heart the anatomical left ventricle(d-loop). Heart
tube is initially bent in a rightward direction tube is initially bent in a rightward direction
and but then fail to the pivot into the left and but then fail to the pivot into the left
chest.chest.

26. ECG FEATURES:ECG FEATURES:
1.Upright P-wave in lead I. 1.Upright P-wave in lead I.
2. Normal P-wave pattern in leads 2. Normal P-wave pattern in leads
aVR and aVL (atrial situs solitus). aVR and aVL (atrial situs solitus).
3.Major precordial QRS voltage lies 3.Major precordial QRS voltage lies
in the right hemi thorax .in the right hemi thorax .
(atrial depolarisation from normal right (atrial depolarisation from normal right
sinus node) sinus node)

27. SITUS INVERSUS WITH LEVO CARDIA:SITUS INVERSUS WITH LEVO CARDIA:
Situs inversus of thoracic and abdominal Situs inversus of thoracic and abdominal
viscera in the presence of left thoracic heart viscera in the presence of left thoracic heart
(levo cardia)(levo cardia)
Incidence of cyanotic congenital Incidence of cyanotic congenital
heart disease is 100%heart disease is 100%
Left hemi diaphragm is lower than the right Left hemi diaphragm is lower than the right
because apex is on the left.because apex is on the left.
Embryonic l-loop which is concordant for situs Embryonic l-loop which is concordant for situs
inversus fails to pivot into the right side of the inversus fails to pivot into the right side of the
chestchest
or embryonic d-loop which is discordant for or embryonic d-loop which is discordant for
situs inversus fails to pivot into the left side situs inversus fails to pivot into the left side

30. ECG FEATURES:ECG FEATURES:
1.Inverted P-wave in lead I, a VL. 1.Inverted P-wave in lead I, a VL.

2.upright P-wave in lead a VR (atrial situs 2.upright P-wave in lead a VR (atrial situs
inversus).inversus).
3. The major precordial QRS complex resides 3. The major precordial QRS complex resides
in the left of the midline.in the left of the midline.

31. BILATERAL SYMMETRYBILATERAL SYMMETRY
HETEROTAXY : just means different arrangement.HETEROTAXY : just means different arrangement.
ISOMERISM : Refers to bilateral symmetry.ISOMERISM : Refers to bilateral symmetry.
Visceral heterotaxy occurs in 0.8% of cases of Visceral heterotaxy occurs in 0.8% of cases of
congenital heart diseases.congenital heart diseases.
In right isomerism (Asplenia) and left isomerism In right isomerism (Asplenia) and left isomerism
(Polysplenia), the liver is typically transverse (B/L (Polysplenia), the liver is typically transverse (B/L
symmetric) and SVC are typically bilateral i.e, there is symmetric) and SVC are typically bilateral i.e, there is
no perfect rigid relationship.no perfect rigid relationship.

32. Bronchus, lung, atrial appendages Bronchus, lung, atrial appendages
relationship is strong but not invariably relationship is strong but not invariably
concordant.concordant.
There is a consistent relationship There is a consistent relationship
relationship that exists between the type of relationship that exists between the type of
isomerism and the type of congenital heart isomerism and the type of congenital heart
disease.disease.
VISCERAL HETEROTAXYVISCERAL HETEROTAXY
1.Right Isomerism1.Right Isomerism
2.Left isomerism2.Left isomerism

33. DEXTROCARDIA d/t TECHNICAL FAULT:DEXTROCARDIA d/t TECHNICAL FAULT:
1.Due to interchanging of a VR and a VL.1.Due to interchanging of a VR and a VL.
2.ECG shows negative P wave, negative 2.ECG shows negative P wave, negative
QRS complex, negative T wave in lead I.QRS complex, negative T wave in lead I.
3.But the 3.But the QRS progression is QRS progression is
normal.normal.