1. Arrhythmia Surgery in Patients With and Without Congenital Heart Disease 
Constantine Mavroudis, MD, Barbara J. Deal, MD, Carl L. Backer, MD, Sabrina Tsao, MD 
The Annals of Thoracic Surgery 
Volume 86, Issue 3, Pages (September 2008)
DOI: /j.athoracsur
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

2. Fig 1
(A) Cavotricuspid-isthmus dependent macro-reentrant atrial tachycardia. As depicted, the “playing field” is the right atrium, where a premature atrial contraction might encounter block in the atrial septum (broken line) and proceed in an alternate route down the right atrial free wall. The wave front may encounter an area of slow conduction (squiggly arrow), in this case between the inferior vena cava, tricuspid valve, and the coronary sinus (CS). The delay encountered as the wave front traverses the area of slow conduction allows the atrial septum to recover conduction. The wave front exits the isthmus and proceeds up the atrial septum. Interruption of this circuit is targeted at the inferior isthmus due to the clearly identified landmarks in proximity. (AV = atrioventricular; SA = sinoatrial.) (B) Schematic representation of the possible lines of ablation to treat macro-reentrant atrial tachycardia in the presence of various atrial anomalies associated with complex congenital heart disease. These atrial anomalies do not generally occur together, and the demonstrated lines of block are not meant to be incorporated into every operation. They are depicted only as guidelines on which to base an ablative operation when unusual anatomic obstacles are encountered in the performance of the maze procedure. (avn = atrioventricular node; CS = coronary sinus; FO = foramen ovale; HV = hepatic vein; IVC = inferior vena cava; LAA = left atrial appendage; LSVC = left superior vena cava; MV = mitral valve; PV = pulmonary veins; RAA = right atrial appendage; RSVC = right superior vena cava; TAPVR = total anomalous pulmonary venous return; TV = tricuspid valve.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

3. Fig 2
Slow-fast or “typical” form of atrioventricular (AV) nodal reentry tachycardia. Atrioventricular conduction encounters a block in the normal fast pathway fibers superior to the compact AV node. The wave front proceeds towards the atrial isthmus, between the coronary sinus (CS) and tricuspid valve, and encounters slowing through the “slow pathway” fibers of the AV node. Exiting the isthmus, conduction is now able to reenter the fast pathway fibers, located anteriorly and superiorly, and perpetuate a reentrant circuit; simultaneously, conduction proceeds inferiorly to the ventricles. Of note, conduction to the ventricles is not relevant to the tachycardia circuit. Cryoablation of the inferior isthmus region will interrupt the circuit. (SA = sinoatrial.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

4. Fig 3
(A) Atrioventricular (AV) reciprocating tachycardia. Wolff-Parkinson-White (WPW) syndrome or manifest accessory connection. During sinus rhythm with preexcitation, conduction from the sinus node to the ventricles proceeds simultaneously over two routes, the atrioventricular node and the accessory connection. The wave front traversing the accessory connection depolarizes ventricular tissue first, because of intrinsic slowing of conduction at the atrioventricular node. The accessory connection thus “preexcites” ventricular depolarization, giving rise to the delta wave. As depicted, there is blocked conduction in the atrioventricular node, with conduction proceeding to the ventricles via the accessory connection (preexcited). Conduction delay is encountered in ventricular muscle, allowing the wave front to proceed up the atrioventricular node (which has had time to regain conduction) to the atrium. This reentrant circuit is termed “antidromic reciprocating tachycardia”; the “playing field” includes the atria, accessory connection, ventricles, and the atrioventricular node. (B) AV reciprocating tachycardia (concealed) accessory connection. Orthodromic reciprocating tachycardia, the more common form of tachycardia, utilizing an accessory connection. Conduction is blocked in the accessory connection, thus losing the delta wave (now “concealed”). Conduction proceeds normally through the AV node to the ventricle. The delay encountered in the AV node allows the accessory connection to regain electrical function, and the electrical impulse then enters the atria from the opposite direction, from ventricle to atrium, across the accessory connection. This “playing field” includes the atria, atrioventricular node, ventricles, and accessory connection. (CS = coronary sinus; SA = sinoatrial node.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

5. Fig 4
Right focal atrial tachycardia. Focal atrial tachycardia, a localized area of “impulse initiation” that is most commonly automatic in mechanism, firing repeatedly, rapidly, and independent of normal sinus function, which is inhibited. Impulse conduction is spread in a centripetal fashion across the atria, thence to the atrioventricular (AV) node and ventricles. Ablative therapy is aimed at obliteration or isolation of this localized discrete area (“hot spot”). (CS = coronary sinus; SA = sinoatrial node.)
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions

6. Fig 5
Freedom from arrhythmia recurrence for all atrial (AT, dashed line) and ventricular tachycardia (VT, solid line) patients. Graphs constructed using the life-test procedure for product-limit survival estimates.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2008 The Society of Thoracic Surgeons Terms and Conditions