Ex‐vivo histopathologic examination of irrigated radiofrequency ablation utilizing half‐normal saline of the human heart

INTRODUCTION: Radiofrequency ablation (RFA) utilizing half-normal saline (HNS) irrigation is a promising intervention to circumvent commonly encountered limitations during radiofrequency ablation of deep myocardial substrate. Few studies to date have analyzed the morphologic changes in the human myocardium following HNS RFA. METHODS AND RESULTS: Three patients with symptomatic ventricular tachycardia (VT) who underwent RFA with HNS irrigation underwent pathological specimen examination at time of autopsy or following native heart explant at the time of cardiac transplantation. Gross evaluation of the heart was performed fresh and after fixation in 10% formalin. A routine examination was performed with fixation in 10% formalin. Sections of lesioned tissue were paraffin embedded and evaluated using standard hematoxylin and eosin (H&E) staining. CONCLUSION: Irrigated RF ablation with HNS irrigant produces coagulative necrosis as well as several delayed histopathological changes with a deeper field of effective ablation. Transmurality may not be obtained in the ventricular myocardium with endocardial, epicardial, or sequential unipolar HNS ablation.