Author + information
- Received March 6, 2019
- Revision received May 9, 2019
- Accepted May 13, 2019
- Published online August 19, 2019.
- Michael Barkagan, MDa,∗,
- Eran Leshem, MD, MHAa,∗,
- Ayelet Shapira-Daniels, MDa,
- Jakub Sroubek, MD, PhDa,
- Alfred E. Buxton, MDa,
- Jeffrey E. Saffitz, MD, PhDb and
- Elad Anter, MDa,∗ ()
- aDivision of Cardiovascular Medicine, Department of Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
- bDepartment of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
- ↵∗Address for correspondence:
Dr. Elad Anter, Division of Cardiovascular Medicine, Department of Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center, 185 Pilgrim Road, Baker 4, Boston, Massachusetts 02215.
Objectives This study sought to characterize the histopathological features of radiofrequency ablation (RFA) in heterogeneous ventricular scar in comparison to those in healthy myocardium.
Background The histopathological features of RFA have been studied largely in normal myocardium. However, its effect on clinically relevant heterogeneous scar is not well understood.
Methods Five swine with chronic infarction underwent RFA using 35-W, 45-s, 10-20 g (Biosense Webster, Irwindale, California) in heterogenous scar tissue (voltage ≤1.5 mV) and healthy myocardium (≥3.0 mV). The location of each application was marked using the electroanatomical mapping system. Histological sections at intervals of 0.5 mm with hematoxylin and eosin and Masson’s trichrome stained intervals were created. A pathologist blinded to the myocardium type characterized the extent of RF injury in cellular, extracellular, and vascular structures.
Results In healthy myocardium, 23 of 23 lesions (100%) were well demarcated and could be precisely measured (width: 11.3 ± 3.3 mm; depth: 7.3 ± 2.0 mm). In scar tissue, only 3 of 30 lesions (10%) were identified, and none could be measured due to a lack of defined borders. Lesions in healthy myocardium had a distinctive architecture showing a coagulative necrosis core surrounded by an outer rim of contraction band necrosis. Lesions in scar had ill-defined tissue injury without a distinct architecture. In all ablated regions, viable myocytes remained interspersed between necrotic myocytes exhibiting characteristics of both coagulative and contraction band necrosis. Connective tissue was more resistant to thermal injury in comparison to cardiomyocytes.
Conclusions RFA in scarred myocardium results in irregular tissue injury and unpredictable effect on surviving cardiomyocytes. This may be related to biophysical differences between healthy and scarred myocardium.
↵∗ Drs. Barkagan and Leshem contributed equally to this work and are joint first authors.
Dr. Anter has received research grants, speaker honoraria, and consultant fees from Boston Scientific, Biosense Webster, and Itamar Medical; and holds stock options in Itamar Medical and Affera Inc. Dr. Buxton has received research grants from Biosense-Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received March 6, 2019.
- Revision received May 9, 2019.
- Accepted May 13, 2019.
- 2019 American College of Cardiology Foundation
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