Catheter microwave ablation therapy for cardiac arrhythmias

Thermal Therapy, Part III: Ablation Techniques

“…389 Numerous antenna designs have been presented in the literature for microwave ablation. 23,286,364,365,[390][391][392][393][394][395][396][397][398][399][400][401][402] Several of the designs are targeted for cancer treatment and others for cardiac ablation. Antennas are grouped into three categories, namely, the monopolar antennas, dipole antennas, and helical coil antennas.…”

“…385 In general, microwave catheter antennas can broadly be categorized into two types-those antennas that are designed to produce radiation mainly around the antenna tip [393][394][395] and those that produce radiation normal to the antenna axis. 364,394 Nevels et al 364 observed that coating the catheter with a Tefl on ® sheath prevents a radiation "hot spot" at the feed line-antenna junction and antenna tip. It was shown that a disk placed at the end of the antenna probe forces the radiated power forward, toward the probe tip, which is the part of the antenna in closest contact with the tissue.…”

“…Tissue temperature can easily reach 100°C or higher, depending on the delivery system and duration of the process. 394 Some of the common lasers used for such a purpose are the neodymium yttrium-aluminum-garnet (Nd:YAG, wavelength of 1064 nm) and CO 2 lasers. The Nd:YAG laser is one of the most versatile and safest laser sources, and the safest used in therapy.…”

A Novel Microwave Catheter Can Perform Noncontact Circumferential Endocardial Ablation in a Model of Pulmonary Vein Isolation

“…A model of antral pulmonary vein ablation was constructed using a perspex well (Fig. ) in which a microwave myocardial equivalent phantom material was used to approximate a longitudinal section through a human pulmonary vein with a diameter of 12 mm, mean pulmonary vein ostial diameters being on average 9–13 mm measured on CT scan . The phantom material was embedded with a custom thermochromic liquid crystal (TLC) sheet that displayed a gradual transition in colors for temperatures between 50 °C and 78 °C.…”

Treatment planning in microwave thermal ablation: clinical gaps and recent research advances

“…Thermal ablation is achieved when the temperature of the tissue reaches at least 55-60 C: at these temperatures an almost instantaneous irreversible cellular damage occurs [1,2]. Potential therapeutic applications of MTA procedures are whenever unhealthy tissue should be destroyed, as in the case of cardiac arrhythmias [3] or endometrial disorders [4]; nevertheless, the most recent and widespread applications are the treatment of several types of tumours, for example, in the liver, lung, kidney, etc. [5][6][7][8].…”