Cor Vasa 2002, 43(4):192-196
Catheter-based cryoablation in the management of cardiac arrhythmias
- Kardiologické oddělení Nemocnice Na Homolce, Praha, Česká republika
Cryoablation during surgical procedures for managing cardiac arrhythmias has been used since the late 1970s. It was not until the development of controlled transvenous catheters that it became possible to use cryodestruction as an alternative source of energy to the well established and currently predominant radiofrequency ablation. This review article is intended to point to differences which may be used with advantage especially when using catheter-based cryoablation in a complex arrhythmic substrate, e.g., creation of multiple linear lesions in the left ventricular and atrial regions. Use of cryothermy can be characterized by three basic phases-freezing and thawing, inflammation, and hemorrhage and fibrin production. Ice crystal formation may cause mechanical tissue oppression; however, it may also impair the integrity of intracellular organelles. This is followed by a thawing phase associated with changes in myofilament and mitochondrial structural alterations. Clear-cut margins made up by inflammatory infiltrate become evident within 48 hours, and sites of bleeding are well identifiable. Cryothermy is followed (weeks 2-4) by lesion organization with capillary neoformation. Repetition of the freezing/thawing cycle results in a mild increase in lesion size. A typical feature cryothermy is a fully reversible electric conduction block when delivering less aggressive temperatures (from -20 to -30°C), this process can be employed for so called cryomapping. Actual therapy usually makes use of temperatures of -70°C for a period of 1 minute. Its ability to create well defined, structurally intact, adequately transmural yet adequately safe multiple lesions for the patient predetermines catheter-based cryoablation to the management of complex arrhythmogenic substrates such as ischemic ventricular tachycardia or atrial fibrillation.
Keywords: Cardiac arrhytmias; Catheterization cryoablation
Published: April 1, 2002 Show citation