This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Avitall, B. Articles by Gupta, G. N. Search for Related Content PubMed PubMed Citation Articles by Avitall, B. Articles by Gupta, G. N.

CLINICAL STUDIES

The creation of linear contiguous lesions in the atria with an expandable loop catheter

Boaz Avitall, MD, PhD, FACC^*, Ray W. Helms, BSE^*, Joseph B. Koblish, BS, Wayne Sieben, BSE, Alexey V. Kotov, MD^* and Gopal N. Gupta, BS^*

^* Section of Cardiology, University of Illinois at Chicago, Chicago, Illinois, USA
Boston Scientific Corporation/EP Technologies, San Jose, California, USA

Manuscript received October 28, 1997; revised manuscript received October 26, 1998, accepted December 17, 1998.

Reprint requests and correspondence: Dr. Boaz Avitall, The University of Illinois at Chicago, Department of Medicine, Section of Cardiology, 840 South Wood Street (M/C 787), Chicago, Illinois 60612
BAvitall{at}uic.edu

OBJECTIVES

This article describes a catheter system designed to create linear atrial lesions and identifies electrophysiologic markers that are associated with the creation of linear lesions.

BACKGROUND

Atrial fibrillation (Afib) is the most common arrhythmia in humans and causes a significant morbidity. The success of surgical interventions has provided the impetus for the development of a catheter-based approach for the ablation of Afib.

METHODS

We tested a catheter system with 24 4-mm ring electrodes that can create loops in the atria. The electrodes can be used to record electrical activity and deliver radiofrequency power for ablation. In 33 dogs, 82 linear lesions were generated using three power titration protocols: fixed levels, manual titration guided by local electrogram activity and temperature control. Bipolar activity was recorded from the 24 electrodes before, during and after lesion generation. Data were gathered regarding lesion contiguity, transmurality and dimensions; the changes in local electrical activity amplitude; the incidence rate of rapid impedance rises and desiccation or char formation; and rhythm outcomes.

RESULTS

Catheter deployment usually requires <60 s. Linear lesions (12 to 16 cm in length and 6 ± 2 mm wide) can be generated in 24 to 48 min without moving the catheter. Effective lesion formation can be predicted by a decrease of greater than 50% in the amplitude of bipolar recordings. Splitting or fragmentation of the electrogram and increasing pacing threshold (3.1 ± 3.3 mV to 7.1 ± 3.8 mV, p < 0.01) are indicative of effective lesion formation. Impedance rises and char formation occurred at 91 ± 12°C. Linear lesion creation does not result in the initiation of Afib. However, atrial flutter was recorded after the completion of the final lesion in 3/12 hearts. When using temperature control, no char was noted in the left atrium, whereas 8% of the right atrium burns had char.

CONCLUSIONS

This adjustable loop catheter forces the atrial tissue to conform around the catheter and is capable of producing linear, contiguous lesions up to 16 cm long with minimal effort and radiation exposure. Pacing thresholds and electrogram amplitude and character are markers of effective lesion formation. Although Afib could not be induced after lesion set completion, sustained atrial flutter could be induced in 25% of the hearts.

Abbreviations and Acronyms   Afib = atrial fibrillation   ANOVA = analysis of variance   IVC = inferior vena cava   LA = left atrium/atrial   LAH = left atrial horizontal lesion   LAV = left atrial vertical lesion   LEA = local electrical activity   MV = mitral valve   PV = pulmonary vein   RA = right atrium/atrial   RAA = right atrial appendage   RAI = right atrial isthmus lesion   RF = radiofrequency   TEE = transesophageal echocardiography   TV = tricuspid valve

This article has been cited by other articles:

				B. Avitall, A. Urbonas, S. Millard, D. Urboniene, and R. Helms Ablation of atrial fibrillation in the rapid pacing canine model using a multi-electrode loop catheter J. Am. Coll. Cardiol., May 1, 2001; 37(6): 1733 - 1740. [Abstract] [Full Text] [PDF]

				A. Natale, K. H. Newby, E. Pisano, F. Leonelli, R. Fanelli, D. Potenza, S. Beheiry, and G. Tomassoni Prospective randomized comparison of antiarrhythmic therapy versus first-line radiofrequency ablation in patients with atrial flutter J. Am. Coll. Cardiol., June 1, 2000; 35(7): 1898 - 1904. [Abstract] [Full Text] [PDF]