DR.G .BALAJIDR.G .BALAJI

PROF.DR.S.RAMASAMPROF.DR.S.RAMASAMY’S UNITY’S UNIT

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 Morphology – Negative in I, II ,a

VLVL Positive in a VRPositive in a VR

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 - Ventricular activation time - <0.04 sec<0.04 sec

ST segment - mild ST elevation II, ST segment - mild ST elevation II, III, a VFIII, a VF

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

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

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 Reversed QRS pattern, tallest in lead V1, and diminishing progressively V1, and diminishing progressively towards lead V6towards lead V6

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.

Ventricular LoopVentricular Loop : : Right or Left Right or Left bend (loop)that forms in the straight bend (loop)that forms in the straight heart tube of the embryo. heart tube of the embryo.

d-loop:d-loop: Normal right ward (dextro) Normal right ward (dextro) bend in the embryonic heart tube. This bend in the embryonic heart tube. This designation as applied to the developed designation as applied to the developed heart indicates that the sinus/inflow heart indicates that the sinus/inflow portion of the morphologic right ventricle portion of the morphologic right ventricle lies to the right of the morphologic left lies to the right of the morphologic left ventricle.ventricle.

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

Concordant LoopConcordant Loop:: It refers to a It refers to a ventricular loop that agrees with the ventricular loop that agrees with the visceroatrial situs.visceroatrial situs.

d-loop: situs solitus d-loop: situs solitus

l-loop: situs inversus. l-loop: situs inversus.

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

BILATERAL SYMMETRY:BILATERAL SYMMETRY:

1. Visceral heterotaxy with right 1. Visceral heterotaxy with right isomerismisomerism

2. Visceral heterotaxy with left 2. Visceral heterotaxy with left isomerismisomerism

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

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 2. Heart, thoracic and abdominal viscera are mirror images of normal situs.are mirror images of normal situs.

3. 3. Incidence of congenital heart Incidence of congenital heart disease is 5%disease is 5%

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 5. Anatomical right ventricle lies to the left of the anatomical left the left of the anatomical left ventricle (l-loop) which is normal for ventricle (l-loop) which is normal for situs inversus. situs inversus.

ECG FEATURES:ECG FEATURES:

1.Inverted P-wave, negative 1.Inverted P-wave, negative QRS complex and inverted T-wave in QRS complex and inverted T-wave in lead I, lead I, 2.Reversal of the QRS 2.Reversal of the QRS pattern in lead aVR and aVL.pattern in lead aVR and aVL.

3.Reversal of corresponding 3.Reversal of corresponding right and left precordial leads.right and left precordial leads.

(atrial depolarisation from left sinus (atrial depolarisation from left sinus node) node)

SITUS SOLITUS WITH DEXTROCARDIA:SITUS SOLITUS WITH DEXTROCARDIA:

1. Lungs and abdominal viscera are situs 1. Lungs and abdominal viscera are situs solitus, but the heart is on the right side solitus, but the heart is on the right side (dextrocardia)(dextrocardia)

22. . Incidence of the congenital Incidence of the congenital heart disease is around 98%.heart disease is around 98%. Most common is TGA (congenitally Most common is TGA (congenitally corrected). Others are shunt lesions.corrected). Others are shunt lesions.

3. Ascending aorta and aortic knuckle 3. Ascending aorta and aortic knuckle occupy their normal position and occupy their normal position and descending aorta runs its normal course descending aorta runs its normal course along the left.along the left.

4. The base to the apex axis points to the 4. The base to the apex axis points to the right and the right hemi diaphragm is right and the right hemi diaphragm is lower than the left.lower than the left.

5. Anatomical right ventricle lies to the 5. Anatomical right ventricle lies to the right of the anatomical left ventricle(d-right of the anatomical left ventricle(d-loop). Heart tube is initially bent in a loop). Heart tube is initially bent in a rightward direction and but then fail to rightward direction and but then fail to the pivot into the left chest.the pivot into the left chest.

ECG FEATURES:ECG FEATURES:

1.Upright P-wave in lead I. 1.Upright P-wave in lead I.

2. Normal P-wave pattern in 2. Normal P-wave pattern in leads aVR and aVL (atrial situs solitus). leads aVR and aVL (atrial situs solitus).

3.Major precordial QRS voltage 3.Major precordial QRS voltage lies in the right hemi thorax .lies in the right hemi thorax .

(atrial depolarisation from normal (atrial depolarisation from normal right sinus node) right sinus node)

SITUS INVERSUS WITH LEVO CARDIA:SITUS INVERSUS WITH LEVO CARDIA:1.1. Situs inversus of thoracic and abdominal Situs inversus of thoracic and abdominal

viscera in the presence of left thoracic viscera in the presence of left thoracic heart (levo cardia)heart (levo cardia)

2.2. Incidence of cyanotic congenital Incidence of cyanotic congenital heart disease is 100%heart disease is 100%

3.3. Left hemi diaphragm is lower than the Left hemi diaphragm is lower than the right because apex is on the left.right because apex is on the left.

4.4. Embryonic l-loop which is concordant for Embryonic l-loop which is concordant for situs inversus fails to pivot into the right situs inversus fails to pivot into the right side of the chestside of the chest

or embryonic d-loop which is discordant or embryonic d-loop which is discordant for situs inversus fails to pivot into the for situs inversus fails to pivot into the left side left side

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 3. The major precordial QRS complex resides in the left of the midline.resides in the left of the midline.

BILATERAL SYMMETRYBILATERAL SYMMETRY HETEROTAXY : just means different HETEROTAXY : just means different

arrangement.arrangement.

ISOMERISM : Refers to bilateral symmetry.ISOMERISM : Refers to bilateral symmetry.

Visceral heterotaxy occurs in 0.8% of Visceral heterotaxy occurs in 0.8% of cases of congenital heart diseases.cases of congenital heart diseases.

In right isomerism (Asplenia) and left In right isomerism (Asplenia) and left isomerism (Polysplenia), the liver is typically isomerism (Polysplenia), the liver is typically transverse (B/L symmetric) and SVC are transverse (B/L symmetric) and SVC are typically bilateral i.e, there is typically bilateral i.e, there is no perfect rigid no perfect rigid relationship.relationship.

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 relationship that exists between the type of isomerism and the type of congenital of isomerism and the type of congenital heart disease.heart disease.

VISCERAL HETEROTAXYVISCERAL HETEROTAXY

1.Right Isomerism1.Right Isomerism

2.Left isomerism2.Left isomerism

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.