ECG in single ventricleSIMPLICITY IS THE FINEST ART

SV of LV morphology with NRGA

Van Praagh et al.1964

1. Type A, DILV ; absence of right ventricular sinus.

2. Type B, DIRV; absence of left ventricular sinus.

3. Type C, Double-inlet ventricle of mixed morphology (absence of

the ventricular septum); and

4. Type D, Double-inlet ventricle of indeterminate or

undifferentiated morphology.

Single ventricle

Apply to a double-inlet/single inlet or common-inlet ventricle opening into one ventricular chamber

1858, Thomas Peacock

“The auricular sinuses are separated by a more or less complete septum, and there are generally two auriculo-ventricular apertures, while the ventricle is either wholly undivided or presents only a very rudimentary septum. The arteries which are given off are usually two in number—an aorta and a pulmonary artery”

ANATOMY

A=NON INVERTED AND NO PS

B=INVERTED +NO PS

C=NON INVERVETED +PS

D=INVERTED+PS

VENTRICULAR TOPOLOGY

Refresh yours as the conductions bundles just rounds around the pulmonary arterySometimes anterior, sometimes posterior, then right side and then left side

Normal development

Ventricular components of the conduction axis are carried on the crest of the muscular ventricular septum, and the atrioventricular node, or in some instances nodes, is formed at the point, or points, of union of the septum with the atrioventricular junctions

Abnormalities continued….

Ring of specialized tissue with AV ring-forms special node anterolateral.

AV connection affects location of AV node

Location of rudimentary ventricle-decides location of contact B/W septum and conduction tissue.

Atrial Situs –sidedness of SA node and AV node.

Morphologic left ventricle

Non inverted outlet Inverted outlet A long non branching

penetrating bundle runs down the right parietal wall of the single ventricle toward the outlet foramen before bifurcating into right and left bundle branches

Inlet portion of the ventricular mass absent The QRS axis is directed inferior and to the right, away from

the inverted outlet chamber and toward the main ventricular mass

The posterior AV node is hypoplastic and does not form a His bundle or establish a ventricular connection

A well-developed anterior accessory AV node gives rise to the His bundle and establishes atrioventricular connections

Penetrating bundle encircles the outflow tract of the single ventricle before branching at the outlet foramen

The left bundle branch is concordant with left ventricular morphology of the single left ventricle and Right bundle branch is concordant with the outlet chamber

SV-LV-INVERTED OUTLET-ANGIOGRAM

Morphologic Right Ventricle

An inlet septum is also lacking in univentricular hearts with a morphologic right ventricle

Outflow tract is rudimentary posterior trabecular pouch

However, the ventricular segment between the morphologic right ventricle and the trabecular pouch extends to the crux where a regular posterior AV node and His bundle are formed

Distribution of the bundle branches apparently depends on the right/left orientation of the trabecular pouch

morphologically indeterminate

No outlet chamber, no trabecular pouch

No the inlet septum nor trabecular septal tissue reaches the crux

AV node is anterior or anterolateral

Penetrating bundles descend as single fascicles among free-running trabeculae.

ECG

Features depends upon

Anatomic variations

Ventricular morphology

Physiologic derangements

When pulmonary blood flow is increased ,P waves show left atrial or biatrial abnormalities

When pulmonary blood flow is reduced P waves show right atrial abnormalities

The PR interval tends to be normal with normal atrioventricular conduction despite an elongated nonbranching penetrating bundle

Non inverted outlet +morphologic LV

QRS axis tends to be directed leftward and superior—left axis deviation axis deviation

Initial depolarization is anterior and leftward, so small Q waves occasionally appear in left precordial leads

Left ventricular hypertrophy

Pulmonary blood flow is increased and the single ventricle is volume overloaded

Precordial QRS complexes then exhibit voltages of remarkably great amplitude and patterns that are stereotyped

precordial leads may show a dominant R wave in leadV1 and large equidisphasic RS complexes in midprecordial leads

LV morphology and inverted outlet

the QRS axis is inferior and to the right, directed away from the inverted outlet chamber toward the main ventricular mass

Conduction problem

PR interval prolongation

Complete heart block is occasional and progressive

The P wave axis shifts to the left, so tall peaked right atrial P waves appear in mid and left precordial leads . This pattern also occurs with noninversion of the outlet chamber ventricular depolarization is clockwise, so Q waves appear in leads 2, 3, and aVF

Because initial forces of ventricular depolarization are posterior and leftward, Q waves may be present in right precordial leads but not in left precordial leads

Even though the univentricular heart is morphologically a left ventricle, In univentricular hearts with a morphologic right ventricle and a trabecular pouch,.

Morphologic right ventricle

Atrioventricular conduction is normal because a regular posterior AV node and His bundle are formed at the crux

Right axis deviation and tall stereotyped precordial R waves

The QRS axis is usually rightward but occasionally is leftward and superior

AV conduction abnormal

PR prolongred—CHB

P wave

◦ left axis

◦ Tall peaked RT atrial P waves in mid to left precordial leads

QRS axis inferior and right

Clockwise loop-Q in 2,3,aVF

Q in RT precordial leads

Dominant R in V1 and RS in mid precordial leads

DILV-inverted outlet chamber

ECG

DILV-noninverted outlet chamber

◦ PR normal

◦ P wave-

LAE in increased PBF

RAE in decreased PBF

◦ QRS axis away from inverted outlet chamber

◦ LAD- Counterclockwise loop

◦ Small Q in left leads

◦ Stereotyped complexes

ECG

Dominant RV Normal posterior AV

node and HIS bundle

RAD

Tall stereotyped R in precordial leads.

Summary

DOMINANT VENTRICLE

LEFT (A) RIGHT(B)COMMON AND INDETERMINATE(C&D)

ABNORMAL ANTERIOR ACCESSORY NODE

INVERTED NON INVERTED

ANTERIOR TO PA LATERAL TO PA

No septum

Normal

TOPOLOGY

RT(NON INV) LT (INV)

SLING OF CONDUCTION TISSUE BETWEEN ANT AND REG NODE

Very difficult ! I can not hear that