Discussion
The results show that using the 3830 lead it is possible to create potential clinically relevant lesion sizes (they vary between similar or bigger to standard RF lesions area -42mm2- when the proximal and bigger surface end of the 3830 lead is used, and also bigger than cryoablation lesions area -20mm2- when the distal and smaller tip is used)3. Depending on the required lesion location and size, it is possible to deliver RF energy choosing the proximal or distal ends of the 3830 lead (signal acquisition for mapping and visualization in a 3-D mapping system is possible using standard crocodile connectors in humans), either in a direct fashion (3830 lead as an extension of the ablation catheter) or using it as the equivalent of a return patch; a bigger lesion area can be created when the RF is applied close to the 3830 lead which acts as a return patch. Small powers (W) are needed since the 3830 lead is embedded in the flesh (no irrigation increases sharply the impedances and precludes current flow with higher powers) and 1W to 10W are enough to create a lesion while keeping the impedances in a physiological range which prevents tissue boiling and tissue adherence to the 3830 lead. If most of the research direction points to irrigation to achieve deeper lesions, the opposite is possible with this 3830 (or other small catheters) as we can bring the ‘tip’ of our catheter or the ‘return patch’ closer to the arrhythmia foci, even deeper in flesh.
The search for deeper lesions when using RF ablation has successfully passed animal trials (early 2000s)4,5 and has begun on small group of patients using a needle catheter.6,7
The main advantage of 3830 leads for future use is that they are flexible and small enough to be directed (subclavian or jugular access) from the right side of the heart to any place in the ventricular septum or the left ventricular summit using a deflectable introducer. Longer distances (more than 1cm from the right ventricular surface) can be reached choosing 3830 lead both proximal and distal ends to target the delivery of RF energy in a direct way (3830 lead as an extension of the RF catheter keeping stability -it is screwed- in potential dangerous areas as the left ventricular summit. Finally, the ability to use the 3038 lead as a return patch showed bigger lesion formation, but il also opens the door to a modified -and closer- bipolar RF delivery, as, instead of using another ablation catheter to close the RF circuit, any small catheter with easier deployment properties car be used as return patch either to create small lesion (RF delivered just in the blood) or bigger lesions (RF touching the tissue close to the pacing lead)