SURGICAL ANATOMY OF RIGHT ATRIUM

DR KAMAL RASTOGI26TH MARCH 2013

RIGHT ATRIUM

• The right atrium is one of the four hollow chambers of the heart; it is located on the upper right hand side.

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RIGHT ATRIUM

•Location:upper portion of right side of heart consisting of the sinus venosus and the right atrial appendage; contains the sinoatrial node

The right atrium (RA) contains three basic parts, the appendage, the vestibule, and the venous component

RIGHT ATRIAL APPENDAGE

•Location:anterior and medial of the right atrium, overlaps root of aorta

• Function:pumps blood to the right ventricle during artial systole/ventricular diastole

• Importance in cardiovascular diseases:atrial arrhythmias; dilated in tricuspid stenosis and tricuspid regurgitation

• Importance in device delivery:traditional site for lead placement, often excised during cardiopulmonary bypas

RIGHT ATRIAL APPENDAGE

• The junction of the appendage and the venous component is known as the terminal groove (adjacent to the internal crista terminalis). The vestibule is smooth walled myocardium continuous with the leaflets of the tricuspid valve. The pectinate muscles within the RA appendage extend around the entire parietal margin of the atrioventricular junction. These pectinate muscles originate at right angles from the terminal crest. The venous portion of the RA extends from the terminal groove and the interatrial groove; it receives blood from the SVC, inferior vena cava (IVC), and coronary sinus (CS).

CORONARY SINUS OSTIUM

•Location:opening located between the inferior vena cava and the tricuspid valve on the inferior aspect of the interatrial septum; forms a corner of Koch's triangle; its valve is referred to as the Thebesian valve

• Function:opening of the coronary venous system into the right atrium

• Importance in device delivery:pacing or defibrillation lead placement

CORONARY SINUS OSTIUM

CRISTA TERMINALIS

• Location:smooth muscular ridge in superior portion of right atrium that devides musculi pectinati and the right atrial appendage from smooth surface of right atrium

• Importance in device delivery:may be important in the genesis of several atrial arrhythmias, including atrial reentry and focal atrial tachycardia

CRISTA TERMINALIS

FOSSA OVALIS

• Location:oval-shaped depression in the interatrial septum

• Importance in cardiovascular diseases:can have a congenital defect resulting in a right to left shunt called patent foramen ovale; fossa is also preferred site for transseptal puncture

• Importance in device delivery:devices to treat patent foramen ovale; inadvertent left placement of right heart devices

FOSSA OVALIS

INF.VENACAVA OSTIUM

•Location:inferior posterior portion of the right atrium

• Function:returns deoxygenated blood from below the diaphragm to the right atrium

• Importance in cardiovascular diseases:increased venous pressure in right heart failure and tricuspid stenosis

• Importance in device delivery:typical entry route for mapping and ablation catheters

INF.VENACAVA OSTIUM

LATERAL WALL

•Location:The lateral wall is generally considered to include the wall of the right atrium from the ostia of the superior and inferior vena cava anteriorly to the ostium of the right appendage or auricle. The endocardial surface of the lateral wall includes both smooth muscle, in the posterior region between the vena cava and the crista terminalis, and pectinate muscle from the crista terminalis into the right atrial appendage. The anterior region of the lateral wall, surrounding the ostium of the right appendage, is often referred to as the right atrial free wal

LATERAL WALL

• Importance in cardiovascular diseases:The right atrial lateral wall is considered by some to have a role in the genesis of several atrial arrhythmias, including atrial reentry and focal atrial tachycardia.

• Importance in device delivery:The lateral wall is sometimes used to place right atrial pacing leads. The anterior aspect of the lateral wall is one of the thinnest walls of the heart, resulting in a higher than usual risk for perforation when extracting a lead from this location

INTERATRIAL SEPTUM

•Location:wall that separates right from left atrium

• Importance in cardiovascular diseases:atrial septal defects (e.g., patent foramen ovale)

• Importance in device delivery:pacing site for reducing interatrial conduction delay, transseptal puncture for left heart ablation

INTERATRIAL SEPTUM

TRIANGLE OF KOCH

• Location:defined by the following structures within the right atrium: (1) The ostium of the coronary sinus, posteriorly; (2) the anterior portion of the tricuspid valve annulus; and (3) the tendon of Todaro (a tendinous structure connecting the valve of the inferior vena cava ostium to the central fibrous body), posteriorly.

• Importance in cardiovascular diseases:used as an anatomical landmark for location of the atrioventricular node during electrophysiology procedures such as pacing or ablatio

TRIANGLE OF KOCH

TRICUSPID VALVE

•Location:between right atrium and right ventricle

• Function:ventricular diastole: valve opens, allows ventricle to fillventricular systole: valve closes, preventing reflux into atrium

• Importance in cardiovascular diseases:functional abnormalities include tricuspid stenosis and tricuspid regurgitation

• Importance in device delivery:may be affected by lead implants; artificial tricuspid valve is a contraindication for right ventricular endocardial pacing leads