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Surgery for atrial fibrillation abhijit presentation

Abhijit Joshi
Abhijit Joshi

this presentation starts with the description of atrial fibrillation and goes on to describe the basis of it's surgical cure, viz. The Maze procedure. I then describe the technical aspects of Maze 1,2,3,4...

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Surgery for Atrial Fibrillation Abh蝶it Joshi NH
basic mechanisms concept of refractory period a faster source will eventually re-organise cardiac excitation what is re-entry? what are ectopic foci? what is macro and micro re-entry?
so now we know why: ectopic foci/鍖brosis foci cause re-entry e鍖ect of chamber dilatation on macro re-entry
3 atrial tachycardias focal ectopic tachycardia: no re-entry atrial 鍖utter : single wavefront atrial 鍖brillation : multiple (at least 2) wavefronts : multiple simultaneous irregular re entry circuits - unde鍖ned number of spatiotemporally varying wavelets and colli- sions
Surgery for atrial fibrillation abhijit presentation
AF maintaining substrate AF begets AF Structural remodeling (atrial enlargement and 鍖brosis, most typically a鍖ecting the left atrium [LA]), produces relatively 鍖xed reentry substrates Progressive atrial dilation creates longer conduction pathways for reentry. Tissue 鍖brosis slows conduction, makes conduction more heterogeneous, and creates conduction barriers that favor re entry
Surgery for atrial fibrillation abhijit presentation
Surgery for atrial fibrillation abhijit presentation
3 problems in AF (1) palpitations, which cause the patient discomfort and anxiety; (2) loss of synchronous atrioventricular contraction, which compromises cardiac haemodynamics, resulting in varying degrees of ventricular dysfunction; and (3) stasis of blood 鍖ow thromboembolism and stroke contrast this with atrial 鍖utter
鍖utter has an atrial kick regular atrial systoles, evidenced by a waves in the JVP
remodelling in AF electrical remodelling : reduction in atrial e鍖ective refractory periods, increased spatial heterogeneity of refractoriness, and conduction slowing. structural remodelling : atrial dilatation, myocyte hypertrophy, sarcomere loss, glycogen accumulation, mitochondrial abnormalities, and the development of atrial 鍖brosis. Atrial 鍖brosis is thought to be a fundamental component of AF sustenance 鍖brosis promotes AF and AF promotes Fibrosis : AF begets AF
Surgery for atrial fibrillation abhijit presentation
hence AF needs.. a trigger : usually a premature depolarization or runs of focal ectopic depolarizations a macro re-entry circuit surgery for AF is directed at alteration of geometry and anatomy needed to support AF.
Fortunately, the macro-reentrant circuits that we had mapped in both dogs and patients were physically relatively large, that is, more than 5 to 6 cm in diameter in the left atrium and much larger than that in the right atrium. Therefore, atrial incisions placed no more than 5 to 6 cm apart should theoretically prevent the development of macro-reentrant circuits anywhere in the atria. It was clear that if macro-reentrant circuits could not develop in the atria, then the atria could not 鍖brillate. The dilemma was how to place enough lesions on the atriato preclude the development of atrial macro-reentry (鍖brillation) and leave behind an atrium that could be activated by the sinus node and still contract e鍖ectively. - James Cox
if the atrium cannot develop macro re-entry circuits then it cannot 鍖brillate, because thats what a-鍖b is by de鍖nition.
initial surgeries 1980 : James Cox - left atrial isolation - electrical isolation of the LA, after recognition that most triggers are from the LA advantages : controlled the ventricular rate, alleviated palpitations, Right atrial kick was present and surprisingly increased LA preload because of this signi鍖cantly improved haemodynamics drawback : LA still 鍖brillated, thromboembolism risk continued eventually abandoned
Catheter Ablation of the Atrioventricular NodeHis Bundle Complex. 1982 - Scheinman only alleviated palpitations and anxiety necessitated pacemaker no improvement in haemodynamics thromboembolism persists 1985, Giraudons corridor procedure: isolated a strip of atrial septum harboring both the sinoatrial node and the atrioventricular node, thereby allowing the sinoatrial node to drive the ventricles. This procedure corrected the irregular heart beat associated with AF, but both atria either remained in 鍖brillation or developed their own asynchronous intrinsic rhythm because they were isolated from the septal corridor. except for the requirement of a pacemaker, it su鍖ered all the drawbacks of Scheinmans catheter ablation of the Bundle.
to cure AF, what was needed is to have lesions close enough to prevent macro re entry lesions to develop, at the same time maintain the pathway for conduction from SA node to AV node.
James Cox That question was answered one Saturday afternoon while I was studying some of the BoineauSchuessler experimental maps of atrial 鍖brillation in my o鍖ce at Barnes Hospital. To better visualize the relationship between atrial anatomy and atrial electrophysiology, a rectangle was drawn to represent the entire mass of both atria 2-dimensionally.
While studying this 2-dimensional representation of the atria with the superimposed electrophysiology of atrial 鍖brillation, I suddenly realized that everything necessary to abolish atrial 鍖brillation, while leaving the atrial activation and contraction intact afterward, could be accomplished by creating a pattern of lesions in the atria that was essentially that of a simple maze. The lesions could be placed close enough to prevent atrial macro-reentry, and if placed in a maze pattern, the SA node could serve as the site of entry of electrical activity into the atria and the AV node as its site of exit from the atria. One contiguous true route of conduction would be left intact between the entrance and exit sites, and multiple blind alleys o鍖 this main conduction route would allow activation of all of the atrial myocardium, thereby preserving atrial contractility (Figure1, D). One entrance, one exit, one true route between the two and multiple blind alleys the pattern and principle of a maze.
Surgery for atrial fibrillation abhijit presentation
Surgery for atrial fibrillation abhijit presentation
Maze 1 compromised the normal sinus tachycardia response LA conduction delayed both these : chronotropic incompetence high rate of pacemaker implantation
Surgery for atrial fibrillation abhijit presentation
Bachmanns bundle allows almost simultaneous activation of the 2 atria Maze 1 led to LA activation delay to the extent that LA was activated when the impulse had reached the LV
Surgery for atrial fibrillation abhijit presentation
Maze 2 required SVC transection and was too di鍖cult abandoned soon
Surgery for atrial fibrillation abhijit presentation
Maze 3
Operation is performed via median sternotomy. Cannulae for venous uptake are placed in superior vena cava and through the low right atrium into inferior vena cava. Small venous cannulae (24F) and vacuum-assisted venous return are employed. Cardiopulmonary bypass is established, and tourniquets are tight- ened around venae cavae. First incision divides right atrial appendage and extends obliquely to midpoint of right atrial free wall. Medially, incision extends to atrioven- tricular groove. Longitudinal incision is made from superior to inferior vena cava along crista terminalis. Lower 2 cm of inci- sion is closed with a continuous suture of 4-0 polypropylene to prevent tearing during retraction. Vertical incision is made from point of closure to atrioventricular groove
Vertical incision is extended to tricuspid valve anulus in area of posterior lea鍖et (2-oclock position, surgeons view), working on endocardial surface of atrium cutting through the entire atrial wall. Residual myocardial 鍖bers are ablated by applying a 3-mm cryolesion (70属C for 2 minutes) at tricuspid anulus. This portion of incision is closed with 4-0 polypropyl- ene suture.
Incision of medial aspect of right atrial appendage is continued into atrial groove to tricuspid valve anulus (10- oclock position, surgeons view) by dis- secting on endocardial surface. A cryolesion is placed at anulus of tricuspid valve to ablate residual myocardial 鍖bers. This portion of incision is closed with 4-0 poly- propylene suture.
Aorta is occluded. Coronary sinus is cannulated, and cold cardioplegic solution is administered to achieve total electromechanical arrest. Left atrium is opened on right side behind interatrial groove and in front of pulmonary veins. Incision is extended superiorly and inferiorly. Atrial septum is divided at level of right superior pulmonary vein. This incision is curved inferiorly to divide the membrane of fossa ovalis.
Atrial septum is retracted anteriorly. Pulmonary vein encircling incision is developed, working within left atrium by extending incision across back wall of atrium above and below left pulmonary veins.
Heart is retracted inferiorly and to the right to expose left atrial appendage on external surface of heart. Two ori- entation sutures of 3-0 polypropylene are placed through left pulmonary vein encircling incision at level of left superior and left inferior pulmonary veins. Encircling incision is completed between orientation sutures (dashed line). Left atrial appendage is excised at its base. Atrial wall between atrial appendage and encircling incision is divided (dashed line).
Orientation sutures are tied, then used to close left atrium between them. Separate suture of 3-0 polypropylene is used to close bridge to and base of left atrial appendage.
Exposure returns to interior of left atrium. Orientation sutures are passed inside left atrium and used to close encircling incision superiorly to midpoint and inferiorly for about 2 cm of posterior wall of left atrium. Vertical incision is developed between encircling incision and mitral valve anulus. Incision is through entire left atrial wall into epicardial fat in atrioventricular groove, exposing coronary sinus. A cryolesion is made on exterior surface of coronary sinus, using a 15-mm cryoprobe applied for 3 minutes. After 1 minute, a 3-mm cryoprobe is placed on mitral valve anulus and a 2-minute cryolesion is made. Vertical incision is closed with 4-0 polypropylene. Mitral valve repair or
Pulmonary vein encircling incision is closed to pulmonary veins on right side. Retraction is switched to right atrium, allowing all but 鍖nal centimeter of encircling incision to be closed. Left ventricular venting catheter is placed through separate incision in right superior pulmonary vein.
Surgery for atrial fibrillation abhijit presentation
Surgery for atrial fibrillation abhijit presentation
ONCE AGAIN !
Maze 4
Surgery for atrial fibrillation abhijit presentation
Hassaiguerre et al - 1998, NEJM studied 45 patients with frequent episodes of atrial 鍖brillation refractory to drug therapy. The spontaneous initiation of atrial 鍖brillation was mapped with the use of multielectrode catheters Three foci were in the right atrium, 1 in the posterior left atrium, and 65 (94 percent) in the pulmonary veins (31 in the left superior, 17 in the right superior, 11 in the left inferior, and 6 in the right inferior pulmonary vein). laid down the basis for PVI
RA is the trigger source in 15% also, addressing only the RA, frequent post procedure 鍖utter is there
Surgery for atrial fibrillation abhijit presentation
Energy sources for ablation
Surgery for atrial fibrillation abhijit presentation
Thank You

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Surgery for atrial fibrillation abhijit presentation

  • 2. basic mechanisms concept of refractory period a faster source will eventually re-organise cardiac excitation what is re-entry? what are ectopic foci? what is macro and micro re-entry?
  • 3. so now we know why: ectopic foci/鍖brosis foci cause re-entry e鍖ect of chamber dilatation on macro re-entry
  • 4. 3 atrial tachycardias focal ectopic tachycardia: no re-entry atrial 鍖utter : single wavefront atrial 鍖brillation : multiple (at least 2) wavefronts : multiple simultaneous irregular re entry circuits - unde鍖ned number of spatiotemporally varying wavelets and colli- sions
  • 6. AF maintaining substrate AF begets AF Structural remodeling (atrial enlargement and 鍖brosis, most typically a鍖ecting the left atrium [LA]), produces relatively 鍖xed reentry substrates Progressive atrial dilation creates longer conduction pathways for reentry. Tissue 鍖brosis slows conduction, makes conduction more heterogeneous, and creates conduction barriers that favor re entry
  • 9. 3 problems in AF (1) palpitations, which cause the patient discomfort and anxiety; (2) loss of synchronous atrioventricular contraction, which compromises cardiac haemodynamics, resulting in varying degrees of ventricular dysfunction; and (3) stasis of blood 鍖ow thromboembolism and stroke contrast this with atrial 鍖utter
  • 10. 鍖utter has an atrial kick regular atrial systoles, evidenced by a waves in the JVP
  • 11. remodelling in AF electrical remodelling : reduction in atrial e鍖ective refractory periods, increased spatial heterogeneity of refractoriness, and conduction slowing. structural remodelling : atrial dilatation, myocyte hypertrophy, sarcomere loss, glycogen accumulation, mitochondrial abnormalities, and the development of atrial 鍖brosis. Atrial 鍖brosis is thought to be a fundamental component of AF sustenance 鍖brosis promotes AF and AF promotes Fibrosis : AF begets AF
  • 13. hence AF needs.. a trigger : usually a premature depolarization or runs of focal ectopic depolarizations a macro re-entry circuit surgery for AF is directed at alteration of geometry and anatomy needed to support AF.
  • 14. Fortunately, the macro-reentrant circuits that we had mapped in both dogs and patients were physically relatively large, that is, more than 5 to 6 cm in diameter in the left atrium and much larger than that in the right atrium. Therefore, atrial incisions placed no more than 5 to 6 cm apart should theoretically prevent the development of macro-reentrant circuits anywhere in the atria. It was clear that if macro-reentrant circuits could not develop in the atria, then the atria could not 鍖brillate. The dilemma was how to place enough lesions on the atriato preclude the development of atrial macro-reentry (鍖brillation) and leave behind an atrium that could be activated by the sinus node and still contract e鍖ectively. - James Cox
  • 15. if the atrium cannot develop macro re-entry circuits then it cannot 鍖brillate, because thats what a-鍖b is by de鍖nition.
  • 16. initial surgeries 1980 : James Cox - left atrial isolation - electrical isolation of the LA, after recognition that most triggers are from the LA advantages : controlled the ventricular rate, alleviated palpitations, Right atrial kick was present and surprisingly increased LA preload because of this signi鍖cantly improved haemodynamics drawback : LA still 鍖brillated, thromboembolism risk continued eventually abandoned
  • 17. Catheter Ablation of the Atrioventricular NodeHis Bundle Complex. 1982 - Scheinman only alleviated palpitations and anxiety necessitated pacemaker no improvement in haemodynamics thromboembolism persists 1985, Giraudons corridor procedure: isolated a strip of atrial septum harboring both the sinoatrial node and the atrioventricular node, thereby allowing the sinoatrial node to drive the ventricles. This procedure corrected the irregular heart beat associated with AF, but both atria either remained in 鍖brillation or developed their own asynchronous intrinsic rhythm because they were isolated from the septal corridor. except for the requirement of a pacemaker, it su鍖ered all the drawbacks of Scheinmans catheter ablation of the Bundle.
  • 18. to cure AF, what was needed is to have lesions close enough to prevent macro re entry lesions to develop, at the same time maintain the pathway for conduction from SA node to AV node.
  • 19. James Cox That question was answered one Saturday afternoon while I was studying some of the BoineauSchuessler experimental maps of atrial 鍖brillation in my o鍖ce at Barnes Hospital. To better visualize the relationship between atrial anatomy and atrial electrophysiology, a rectangle was drawn to represent the entire mass of both atria 2-dimensionally.
  • 20. While studying this 2-dimensional representation of the atria with the superimposed electrophysiology of atrial 鍖brillation, I suddenly realized that everything necessary to abolish atrial 鍖brillation, while leaving the atrial activation and contraction intact afterward, could be accomplished by creating a pattern of lesions in the atria that was essentially that of a simple maze. The lesions could be placed close enough to prevent atrial macro-reentry, and if placed in a maze pattern, the SA node could serve as the site of entry of electrical activity into the atria and the AV node as its site of exit from the atria. One contiguous true route of conduction would be left intact between the entrance and exit sites, and multiple blind alleys o鍖 this main conduction route would allow activation of all of the atrial myocardium, thereby preserving atrial contractility (Figure1, D). One entrance, one exit, one true route between the two and multiple blind alleys the pattern and principle of a maze.
  • 23. Maze 1 compromised the normal sinus tachycardia response LA conduction delayed both these : chronotropic incompetence high rate of pacemaker implantation
  • 25. Bachmanns bundle allows almost simultaneous activation of the 2 atria Maze 1 led to LA activation delay to the extent that LA was activated when the impulse had reached the LV
  • 27. Maze 2 required SVC transection and was too di鍖cult abandoned soon
  • 30. Operation is performed via median sternotomy. Cannulae for venous uptake are placed in superior vena cava and through the low right atrium into inferior vena cava. Small venous cannulae (24F) and vacuum-assisted venous return are employed. Cardiopulmonary bypass is established, and tourniquets are tight- ened around venae cavae. First incision divides right atrial appendage and extends obliquely to midpoint of right atrial free wall. Medially, incision extends to atrioven- tricular groove. Longitudinal incision is made from superior to inferior vena cava along crista terminalis. Lower 2 cm of inci- sion is closed with a continuous suture of 4-0 polypropylene to prevent tearing during retraction. Vertical incision is made from point of closure to atrioventricular groove
  • 31. Vertical incision is extended to tricuspid valve anulus in area of posterior lea鍖et (2-oclock position, surgeons view), working on endocardial surface of atrium cutting through the entire atrial wall. Residual myocardial 鍖bers are ablated by applying a 3-mm cryolesion (70属C for 2 minutes) at tricuspid anulus. This portion of incision is closed with 4-0 polypropyl- ene suture.
  • 32. Incision of medial aspect of right atrial appendage is continued into atrial groove to tricuspid valve anulus (10- oclock position, surgeons view) by dis- secting on endocardial surface. A cryolesion is placed at anulus of tricuspid valve to ablate residual myocardial 鍖bers. This portion of incision is closed with 4-0 poly- propylene suture.
  • 33. Aorta is occluded. Coronary sinus is cannulated, and cold cardioplegic solution is administered to achieve total electromechanical arrest. Left atrium is opened on right side behind interatrial groove and in front of pulmonary veins. Incision is extended superiorly and inferiorly. Atrial septum is divided at level of right superior pulmonary vein. This incision is curved inferiorly to divide the membrane of fossa ovalis.
  • 34. Atrial septum is retracted anteriorly. Pulmonary vein encircling incision is developed, working within left atrium by extending incision across back wall of atrium above and below left pulmonary veins.
  • 35. Heart is retracted inferiorly and to the right to expose left atrial appendage on external surface of heart. Two ori- entation sutures of 3-0 polypropylene are placed through left pulmonary vein encircling incision at level of left superior and left inferior pulmonary veins. Encircling incision is completed between orientation sutures (dashed line). Left atrial appendage is excised at its base. Atrial wall between atrial appendage and encircling incision is divided (dashed line).
  • 36. Orientation sutures are tied, then used to close left atrium between them. Separate suture of 3-0 polypropylene is used to close bridge to and base of left atrial appendage.
  • 37. Exposure returns to interior of left atrium. Orientation sutures are passed inside left atrium and used to close encircling incision superiorly to midpoint and inferiorly for about 2 cm of posterior wall of left atrium. Vertical incision is developed between encircling incision and mitral valve anulus. Incision is through entire left atrial wall into epicardial fat in atrioventricular groove, exposing coronary sinus. A cryolesion is made on exterior surface of coronary sinus, using a 15-mm cryoprobe applied for 3 minutes. After 1 minute, a 3-mm cryoprobe is placed on mitral valve anulus and a 2-minute cryolesion is made. Vertical incision is closed with 4-0 polypropylene. Mitral valve repair or
  • 38. Pulmonary vein encircling incision is closed to pulmonary veins on right side. Retraction is switched to right atrium, allowing all but 鍖nal centimeter of encircling incision to be closed. Left ventricular venting catheter is placed through separate incision in right superior pulmonary vein.
  • 44. Hassaiguerre et al - 1998, NEJM studied 45 patients with frequent episodes of atrial 鍖brillation refractory to drug therapy. The spontaneous initiation of atrial 鍖brillation was mapped with the use of multielectrode catheters Three foci were in the right atrium, 1 in the posterior left atrium, and 65 (94 percent) in the pulmonary veins (31 in the left superior, 17 in the right superior, 11 in the left inferior, and 6 in the right inferior pulmonary vein). laid down the basis for PVI
  • 45. RA is the trigger source in 15% also, addressing only the RA, frequent post procedure 鍖utter is there
  • 47. Energy sources for ablation