Experimentelle Untersuchungen zur chirurgischen Therapie des Vorhofflimmerns am Tiermodell Schaf

 

 Buy Article Permissions and Reprints

Zusammenfassung

Gegenstand und Ziel: Vorhofflimmern ist die häufigste Ursache für kardiale Arrhythmien beim Menschen. Die Erzeugung zirkulärer transmuraler Läsionen mittels verschiedener Energieformen dient der elektrischen Isolation der autonomen Foci. Ziel der Studie war daher, am Tiermodell Schaf die Effektivität und die Risiken verschiedener Ablationstechniken systematisch zu vergleichen. Material und Methoden: Bei 39 Merinoschafen wurden zirkuläre Läsionen im Bereich des linken Atriums und der Pulmonalvenen erzeugt. Kryotechnik (n = 12), Mikrowellen (n = 9), Laser (n = 6) sowie unipolare (n = 6) und bipolare (n = 6) Hochfrequenz (HF) wurden von endokardial bzw. von epikardial eingesetzt und die Temperatur im Lumen des Ösophagus gemessen. Elektrophysiologische Untersuchungen unmittelbar sowie zwei Stunden nach der Ablation dienten dem Nachweis der erfolgreichen Reizleitungsblockade. Repräsentative Proben von linkem Atrium, Pulmonalvenen und Ösophagus wurden histopathologisch untersucht. Ergebnisse: Alle endokardialen Ablationstechniken führten zu elektrophysiologisch effektiven transmuralen Nekrosen. Im Gegensatz zu Kryoablation und unipolarer HF erzeugten Mikrowellen- und Laserenergie starke Thromben. Die epikardiale Ablation mit Kryotechnik und Mikrowellen war in acht von neun Fällen nicht effektiv, während die bipolare HF zu effektiven transmuralen Läsionen, jedoch mit deutlichen Thromben führte. In 24 von 39 Fällen wurden histologisch auch Alterationen des Ösophagus nachgewiesen. Insbesondere von endokardial applizierte unipolare HF und Kryotechnik führten zu Nekrosen der Ösophaguswand. Schlussfolgerung: Epikardial applizierte bipolare HF war das Verfahren zur Vorhofablation, das von den getesteten Methoden die geringsten Risiken der Ösophagusperforation bei bester Effektivität der Ablation aufwies. Diese Ergebnisse aus den Akutversuchen sollten jedoch noch in Langzeitversuchen überprüft werden.

Summary

Objective: Atrial fibrillation is a common cause of cardiac arrhythmia in humans. Creation of circular transmural lesions by the use of different energy sources results in the insulation of autonomous focal triggers or macro re-entry circuits. The aim of this study was the evaluation of the effectiveness and risks of various ablation methods in a sheep model. Material and methods: Experiments were performed in 39 Merino sheep. Circular lesions were created endo- and epicardially in the oesophagus, left atrium and pulmonary veins using different energy sources: Cryo (n = 12), microwave (n = 9), laser (n = 6), unipolar radiofrequency (RF) (n = 6) and bipolar RF (n = 6). The temperatures inside the oesophagus were measured. Electrophysiological examinations were performed post treatment and two hours after ablation to prove the conduction block. Specimens of the atria and pulmonary veins were investigated histopathologically. Results: Endocardial ablation resulted in transmural lesions, confirmed by electrophysiological examinations in all cases. In contrast to cryoablation and unipolar RF, microwave and laser induced intensive endocardial thrombus formation. Epicardial cryoablation and microwave energy were not successful in eight of nine animals. However, epicardial bipolar RF was efficient but induced marked thrombi. In 24 of 39 sheep alterations of the oesophagus were detected histologically. Especially endocardial unipolar RF and cryoablation induced necroses of the oesophagus wall. Conclusion: Epicardial bipolar RF was the method in our study, which resulted in best effectiveness of ablation and smallest risk of oesophagus perforation. Further mid- and long-term studies are necessary to confirm these results.

• Literatur

• 1 Aupperle H, Doll N, Walther T, Ullmann C, Schoon H-A, Mohr F-W. Histological findings induced by different energy sources in experimental atrial ablation in sheep. Interact Cardiovasc Thorac Surg 2005; 4: 450-455.
  CrossrefPubMedGoogle Scholar
• 2 Aupperle H, Doll N, Walther T, Kornherr P, Ullmann C, Mohr F-W, Schoon H-A. Ablation of atrial fibrillation and esophageal injury: Impacts of energy source and ablation technique. J Thorac Cardiovasc Surg 2005; 130: 1549-1554.
  CrossrefPubMedGoogle Scholar
• 3 Brakel T, Blolotin G, Salleng KJ, Nifomg LW, Allessie MA, Chitwood R, Maessen JG. Evaluation of epicardial microwave ablation: Histology versus electrophysiology. Ann Thorac Surg 2004; 78: 1397-1402.
  CrossrefPubMedGoogle Scholar
• 4 Cox JL, Schuessler RB, D’Agostino HJ, Stone CM, Chang BC, Cain ME, Corr PB, Boineau JP. The surgical treatment of atrial fibrillation: III. Development of a definitive surgical procedure. J Thorac Cardiovasc Surg 1991; 101: 569-583.
  PubMedGoogle Scholar
• 5 Cox JL, Schuessler RB, Lappas DG, Boineau JP. An 8-year clinical experience with surgery for atrial fibrillation. Ann Surg 1996; 224: 267-273.
  CrossrefPubMedGoogle Scholar
• 6 Doll N, Kornherr P, Aupperle H, Fabricius AM, Kiaii B, Ullmann C, Schneider K, Dhein S, Schoon H-A, Rastan A, Walther T, Mohr FW. Epicardial treatment of atrial fibrillation using cryoablation in an acute off-pump sheep model. Thorac Cardiovasc Surg 2003; 51: 267-273.
  Article in Thieme ConnectPubMedGoogle Scholar
• 7 Doll N, Borger M, Fabricius A, Stephan S, Gummert J, Mohr FW, Hauss J, Kottkamp H, Hindricks G. Esophageal perforation during left atrial radiofrequency ablation: is the risk to high?. J Thorac Cardiovasc Surg 2003; 125: 836-842.
  CrossrefPubMedGoogle Scholar
• 8 Doll N. Experimentelle Evaluierung verschiedener Verfahren zur chirurgischen Therapie des Vorhofflimmerns: Bewertung von Sicherheit und Effektivität sowie der möglichen Schädigung umliegender Gewebsstrukturen. Habilitationsschrift, Medizin. Fak. Univ. Leipzig: 2004
  PubMedGoogle Scholar
• 9 Fujino H, Thompson RP, Germoth PG, Harold ME, Swindle MM, Gillette PC. Histologic study of chronic catheter cryoablation of atrioventricular conduction in swine. Am Heart J 1993; 125: 1632-1637.
  CrossrefPubMedGoogle Scholar
• 10 Jais P, Weerasooriya R, Shah DC, Hocini M, Macle L, Choi K-J, Scavee C, Haissaguerre M, Clementy J. Ablation therapy for atrial fibrillation (AF): Past, present and future. Cardiovasc Res 2002; 54: 337-346.
  CrossrefPubMedGoogle Scholar
• 11 Gallagher MG, Camm AJ. Classification of atrial fibrillation. Pacing Clin Electrophysiol 1997; 20: 1603-1605.
  CrossrefPubMedGoogle Scholar
• 12 Gillinov M, Pettersson G, Rice TW. Esophageal injury during radiofrequency ablation of atrial fibrillation. J Thorac Cardiovasc Surg 2001; 122: 1239-1240.
  CrossrefPubMedGoogle Scholar
• 13 Gillinov AM, McCarthy PM. Atricure bipolar radiofrequency clamp for intraoperative ablation of atrial fibrillation. Ann Thorac Surg 2002; 74: 2165-2168.
  CrossrefPubMedGoogle Scholar
• 14 Lemola K, Sneider M, Desjardins B, Case I, Han J, Good E, Tamirisa K, Tsemo A, Cugh A, Bogun F, Pelosi F, Kazerooni E, Morady F, Oral H. Computed tomographic analysis of the anatomy of the left atrium and the esophagus. Circulation 2004; 110: 3655-3660.
  CrossrefPubMedGoogle Scholar
• 15 Lustgarten DL, Keane D, Ruskin J. Cryothermal ablation: Mechanism of tissue injury and current experience in the treatment of tachyarrhythmias. Prog Cardiovasc Disease 1994; 41: 481-498.
  PubMedGoogle Scholar
• 16 Manasse E, Colombo P, Roncalli M, Gallotti R. Myocardial acute and chronic histological modifications induced by cryoablation. Europ J Cardio Thorac Surg 2000; 17: 339-340.
  PubMedGoogle Scholar
• 17 Melo JQ, Santiago T, Gouivea RH, Martins AP. Atrial ablation for the surgical treatment of atrial fibrillation: Principles and limitations. J Card Surg 2004; 19: 207-210.
  CrossrefPubMedGoogle Scholar
• 18 Mohr FW, Fabricius AM, Falk V, Autschbach R, Doll N, von Oppell U, Diegeler A, Kottkamp H, Hindricks G. Curative treatment of atrial fibrillation with intraoperative radiofrequency ablation: Short-term and midterm results. J Thorac Cardiovasc Surg 2002; 123: 919-927.
  CrossrefPubMedGoogle Scholar
• 19 Nattel S. New ideas about atrial fibrillation 50 years on. Nature 2002; 415: 219-226.
  CrossrefPubMedGoogle Scholar
• 20 Nickel R, Schumacher A, Seiferle E. Lehrbuch der Anatomie der Haustiere III. 2. Aufl. Berlin, Hamburg: Parey; 1984: 63.
  Google Scholar
• 21 Nitta T, Lee R, Watanabe H, Harris KM, Erikson JM, Schuessler RB, Boineau JP, Cox JL. Radial approach: a new concept in surgical treatment for atrial fibrillation. II. Electrophysiologic effects and atrial contribution to ventricular filling. Ann Thorac Surg 1999; 67: 36-50.
  CrossrefPubMedGoogle Scholar
• 22 Pappone C, Oral H, Santinelli V, Vicedomini G, Lang CC, Manguso F, Toracca L, Benussi S, Alfieri O, Hong R, Lau W, Hirata K, Shikuma N, Hall B, Morady F. Atrio-esophageal fistula as a complication of percutaneous transcatheter ablation of atrial fibrillation. Circulation 2004; 109: 2724-2726.
  CrossrefPubMedGoogle Scholar
• 23 Romeis n. Mikroskopische Technik, 17. Aufl. Böck P. Hrsg. München, Wien, Baltimore: Urban & Schwarzenberg; 1989: 595-596.
  Google Scholar
• 24 Ryder KM, Benjamin EJ. Epidemiology and significance of atrial fibrillation. Am J Cardiol 1999; 84: 131-138R.
  CrossrefPubMedGoogle Scholar
• 25 Santiago T, Melo JQ, Gouveia RH, Martins AP. Intra-atrial temperatures in radiofrequency endocardial ablation: histologic evaluation of lesions. Ann Thorac Surg 2003; 75: 1495-1501.
  CrossrefPubMedGoogle Scholar
• 26 Santiago T, Melo J, Gouveia RH, Neves J, Abecasis M, Adragao P, Martins AP. Epicardial radiofrequency applications: in vitro and in vivo studies on human atrial myocardium. Eur J Cardiothorac Surg 2003; 24: 481-486.
  CrossrefPubMedGoogle Scholar
• 27 Scanavacca MI, Dávila A, Parga J, Sosa E. Left atrial-esophageal fistula following radiofrequency catheter ablation of atrial fibrillation. J Cardiovasc Electrophys 2004; 15: 960-962.
  CrossrefPubMedGoogle Scholar
• 28 Sie HT, Beukema WP, Ramdat Misier AR, Elvan A, Ennema JJ, Wellens HJ. The radiofrequency modified Maze procedure. A less invasive approach to atrial fibrillation during open-heart surgery. Eur J Cardiothorac Surg 2001; 19: 443-447.
  CrossrefPubMedGoogle Scholar
• 29 Sonmez B, Demirsoy E, Yagan N, Unal M, Arbatli H, Sener D, Baran T, Ilkova F. A fatal complication due to radiofrequency ablation for atrial fibrillation: Atrio-esophageal fistula. Ann Thorac Surg 2003; 76: 281-283.
  CrossrefPubMedGoogle Scholar
• 30 Viola N, Williams MR, Oz MC, Ad N. The technology in use or the surgical ablation of atrial fibrillation. Sem Thorac Cardiovasc Surg 2002; 14: 198-205.
  CrossrefPubMedGoogle Scholar
• 31 Watanabe H, Hayshi J, Sugawara M, Hiratsuka M, Egushi S. Experimental application of microwave tissue coagulation to ventricular myocardium. Ann Thorac Surg 1999; 67: 666-671.
  CrossrefPubMedGoogle Scholar