The Radial Procedure for Atrial Fibrillation · The Radial Procedure for Atrial Fibrillation Takashi Nitta, MD T he radial procedure was developed as an out-growth of an alternative

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he radial procedure was developed as an out-growth of an alternative to the maze procedure.

he atrial incisions are designed to radiate from theinus node toward the atrioventricular annular mar-ins and parallel the atrial activation sequence and thetrial coronary arteries. And the procedure avoids iso-ation of any atrial segments. The procedure has beenhown to preserve a physiological atrial activation se-uence, recruit more myocardium for the atrial trans-ort function, and to prevent thromboembolism moreffectively.

The lesion set of the radial procedure in the right

Atrial incisions, ablation lines, and sites of cryothermichemas represent the anterior and posterior views of the andicate the pulmonary vein orifices. The right lower panelut-and-sew incisions and the full lines indicate the bipolandicate the cryothermia at the atrioventricular annuli. The ro preserve the secretion of the atrial natri-uretic peptid

perative Techniques in Thoracic and Cardiovascular Surgery, Vol 9

trium (RA) are the same as the maze procedure, ex-ept for the excision of the right atrial appendage. Theifferences are in the left atrium (LA) and interatrialeptum. The LA incisions, complying with the radialoncept, recruit the posterior LA as a contractile com-onent and preserve a physiological activation se-uence and the atrial coronary arteries. The septal

ncision is reversed horizontally to preserve the bloodupply to the posterior septum. The radial procedure isechnically easier than the maze procedure, becausehe incisions are more linear and there is no isolationncision in the LA.

the radial procedure are shown. The left upper and middle, respectively. The four circles in the posterior left atriumesents the interatrial septum. The broken lines indicate thediofrequency (RF) linear ablation lines. The small circlesatrial appendage is not excised, unlike the maze procedure,he left atrial appendage is excised to prevent systemic

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hromboembolism due to thrombosis in the left atrial appendage.MV, mitral valve; TV, tricuspid valve; RAA, right atrial appendage; LAA, left atrial appendage; SVC, superior vena cava;

VC, inferior vena cava; FO, fossa ovalis; CS, coronary sinus.

, No 1 (Spring), 2004: pp 83-95 83

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SURGICAL TECHNIQUE

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reparation for Cardiopulmonary Bypass

he chest is opened through a mid-line sternotomy.oth the superior vena cava (SVC) and inferior venaava (IVC) are snared. The pericardium between theVC and the right inferior pulmonary vein (PV) isissected extensively, so that the oblique sinus be-ween the right and left PVs is exposed. The patient
s cannulated in the ascending aorta, SVC, and lower P
A. A normothermic cardiopulmonary bypass ishen initiated.

We usually isolate the right and left PVs by meansf a bipolar radiofrequency (RF) device before mak-ng the RA incisions in patients with paroxysmal AF.omplete electrical isolation is verified by the dem-nstration of conduction block during pacing withhe maximal output from the isolated right and left
Vs while the heart is beating.
A small incision is made at the top of the right atrial appendage. The appendage is not excised, but all the majorrabeculae inside the appendage are divided to prevent microreentry. The incision is extended inferiorly by a pair of scissorsr a bipolar RF device. One jaw of the bipolar RF device is inserted into the RA and a linear ablation line is made on the lateralA. The distal end of this incision should be 4 cm above the IVC cannula. A horizontal incision is made on the lower RAetween the lateral RA incision and the IVC cannula. At least 2 cm of distance should be kept between the distal end of the

ateral RA ablation line and the horizontal incision to allow the sinus impulse to propagate into the anterior RA between theateral incision and the atrioventricular groove. The horizontal incision is extended posteriorly, crossing the crista terminalis,own to the interatrial septum. A marker in the middle of the incision assists later closure.

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RADIAL PROCEDURE FOR ATRIAL FIBRILLATION 85

This incision is then extended, using angled scissors, all the way up to the SVC, where no myocardium is visible. Thencision is made posteriorly to the crista terminalis, and care is needed to be taken to avoid any injury to the sinoatrial nodeocated at the junction of the RA and the SVC.

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4 This lesion can bereplaced by the bipolarRF device. The device isproperly placed at theposterior RA betweenthe crista terminalis andthe interatrial septum,anterior to the right su-perior and inferior PVs,so that a transmural lin-ear ablation lesion ismade along the entirelength.

A linear lesion be-ween the horizontal inci-ion and the IVC is thenade with the bipolar RFevice.

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The horizontal inci-ion made in the lower RAs extended anteriorly to-ard the atrioventricularroove. The atrial myocar-ium in the atrioventricu-

ar groove is carefully dis-ected by means of a #15calpel from inside the RA.t is extremely importanto divide all the muscle fi-ers across this incision.hen the distal end of thetriotomy is cryoablatedsing a 5-mm cryoprobeor 2 minutes at �60°C.

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7 The incision made atthe top of the right atrialappendage is extended an-tero-medially toward theright atrioventricular fatpad. Usually, the sino-atrialnodal artery from the rightcoronary artery can beidentified close to this inci-sion, and care needs to betaken to avoid any injury toor traction on this artery.The lateral RA is lifted us-ing a couple of forceps andthe incision is extendeddown to the tricuspid valveannulus by means of a #15scalpel. The dissection endsat the annulus 1 to 2 cmabove the membranous sep-tum. Then the distal end ofthe atriotomy at the annu-lus is cryoablated. The inci-sion is closed with a 3-0 Pro-lene continuous suture. Thelower RA incision is alsoclosed in the same fashion.As the top of the atrioven-tricular groove is reached,the RA flap is turned backdown, and the incision isclosed from outside the RAto one third of its length.

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The ascending aorta is cross-clamped and cardioplegic solution is infused antegradely and retrogradely. A vertical septalncision is made at the fossa ovalis and extended infero-posteriorly. Then the posterior RA is incised, and extended to theeptal incision.

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From the junction of the septal incision and the posterior RA incision, the lower LA is incised transversely toward theosterior mitral valve annulus. Again, a marker in the middle of the incision assists later closure. The incision ends at theosterior mitral annulus between the middle (P2) and postero-medial scallops (P3) of the posterior mitral leaflet. This isecause the distal ends of the left circumflex coronary artery and right coronary artery converge at the level of P2-P3 junction

n most patients so that the dissection of the atrioventricular fat pad can be safely performed. However, approximately 10%f humans are said to have a large posterior interventricular artery that perfuses the right and almost half of the leftentricles. In these particular patients, the LA incision should be directed more craniad at the posterior mitral annulus. Forhis reason, preoperative coronary angiography is recommended in all patients who are scheduled for surgery for AF.

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0 The atrial myocardium at the atrioventricular groove is carefully dissected in the same fashion as in the RA. Thenhe distal end of the incision at the mitral annulus and the coronary sinus (CS) are cryoablated. A 5-mm and a 15-mmryoprobe are used for the mitral annulus and the CS ablation, respectively. During the CS ablation, the cardioplegia catheternserted into the CS is pulled back to make a complete circumferential cryolesion on the CS.

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1 The left atrial appendage is safely excised from outside the heart. The operating table is inclined toward the surgeonnd the main trunk of the pulmonary artery is displaced toward the right side by a retractor to expose the left atrialppendage. The appendage is totally removed and any atrial myocardium having a trabecula is excised.

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2 The bipolar RF device is introduced into the left superior PV through the excised appendage orifice with the tipirected into the left superior PV and a linear ablation is made between the orifice and the PV. The left superior PV isissected between the left pulmonary artery, and the superior and inferior PVs are taped. The LA is clamped 1 cm proximalo the orifice of the left superior and inferior PVs, and RF energy is applied to electrically isolate the PVs from the LA. Then
he left atrial appendage is closed with a 3-0 Prolene continuous suture.

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94 NITTA

SUMMARY

equence of the Proceduresf the radial procedure is not the lone procedure and isoncomitant to other cardiac procedures, there areonsiderations for the sequence of the procedures. Aitral valve repair or replacement is safely performed

fter all the radial incisions are made. After completionf the mitral valve surgery, the displacement of theeart can be unsafe and the exposure of the left atrialppendage and inside of the LA is limited to somextent. Coronary artery bypass grafting is also per-ormed after completion of the radial procedure for theame reason. The distal coronary anastomosis can beerformed even on the beating heart after the release of

3 The inclined table is restored, and the right superiuperior and inferior PVs are taped. The LA at the junction oF device, and the PVs are isolated in the same fashion as onV and the posterior LA incision with the bipolar RF devic

inear ablation is made between the left inferior PVs and thAfter the completion of the radial incisions, all the atrial

ontinuous suture is started from the distal end of the LA inciyocardium are closed over the atrioventricular fat pad

ull-thickness stitches on the infero-posterior LA free wall. Ind of the LA incision to prevent bleeding from the suture linlosed. The LA is deaired most effectively from the interatriross-clamp is removed and the heart is reperfused. The intercower RA are closed. Lastly, the remaining incision at the top

he aortic cross-clamp. Aortic valve replacement, par-icularly in patients with aortic valve regurgitation, iserformed before the LA incisions are made, after theorta is cross-clamped. In this way, the time for selec-ive infusion of cardioplegic solution directly into theoronary artery ostia can be saved. The atrial septalefect is closed at the time of closure of the septal

ncision of the radial procedure. The tricuspid valveepair is usually performed after the LA is closed, andhe aortic cross-clamp is released.

odifications of the Radial Proceduren the radial procedure, the longitudinal septal inci-ion, which is extended down to the mitral valve annu-us, provides an excellent exposure of the mitral valve,

V is dissected between the right pulmonary artery and thee right superior and inferior PVs is clamped with the bipolarleft side. A linear ablation is made between the right inferiorblock the reentrant circuit around the right PVs. Another

sterior LA incision in the same fashion.sions are closed with a 3-0 Prolene continuous suture. Theat the posterior mitral annulus. The atrial endocardium andd the CS. The continuous suture makes a transition tomportant to avoid making a dog ear at the epicardial distalhe inferior LA, interatrial septum, and the posterior RA areptum while keeping the suture loosely tied. Then the aorticincision in the posterior RA and the horizontal incision in thee right atrial appendage is closed while deairing from the RA.

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hich is satisfactory to undergo complex valve repair.he septal incision can be replaced by a right-sided LA

ncision in patients who do not require complex mitralalve repair. In that case, the postero-inferior inter-trial septum should be ablated by crythermia or RFnergy to interrupt the potential reentrant circuitround the fossa ovalis.Recently developed ablation devices may enable min-

mally invasive procedures for AF without undergoingardiopulmonary bypass. It is extremely important toreserve the concept of the radial procedure in the

esion set for the off-pump AF procedure to resume ahysiological atrial activation and sufficient atrialransport function, and to most surely prevent throm-oembolism.

linical Resultsetween October 1997 and December 2003, we per-

ormed the radial procedure in 100 patients. Thereere 53 male and 47 female patients, and the averagege was 62 � 10 years. Of those patients, 82 patientsad valvular heart disease and 9 patients were associ-ted with congenital heart disease, while the remainingpatients had no structural heart disease. There were

7 patients with continuous AF and 33 with intermit-ent AF. Thirteen patients had experienced thrombo-mbolic events before the surgery. Seven patients hadeft atrial thrombi present at the time of surgery. Thereere two surgical mortalities, not related to the radialrocedure. The success rate for AF was 91%. A pace-aker implantation was required in six patients. In all

he patients who were cured of AF, a significant con-raction of the LA was detected by transthoracic Dopp-er echocardiography postoperatively. During the fol-ow-up period of up to 74 months (median 35 months),o patient has experienced thromboembolic events.hese results suggest that the radial procedure pro-ides a greater atrial transport function and preventshromboembolism, and thus may represent a physio-ogical alternative to the maze procedure as a surgicalrocedure for AF.

From the Department of Cardiothoracic Surgery, Nippon Medical School 1-1-5,endagi, Bunkyo-ku, Tokyo, 113-8603, Japan.Address correspondence to Takashi Nitta, MD, Department of Cardiothoracic

urgery, Nippon Medical School 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603,apan.

© 2004 Elsevier Inc. All rights reserved.1522-2942/04/0901-0009$30.00/0doi:10.1053/j.optechstcvs.2004.04.001

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The Radial Procedure for Atrial Fibrillation · The Radial Procedure for Atrial Fibrillation Takashi Nitta, MD T he radial procedure was developed as an out-growth of an alternative