radiofrequency heating applicator , located at the distal end of a coaxial line catheter , produces deeper and more uniform heat dissipation . the active applicator element is a conductor helix fed via the coaxial line . the applicator has provisions for interception of intracardiac electrogram signal . a cardiac ablation system using the above catheter , ablates cardiac tissue responsible for ventricular tachycardia . the ablation system provides means to monitor intracardiac electrograms and to control the rf power . a variation of the helical applicator can be used in a hyperthermia system for treatment of malignant tumors .