The QDOT Micro™ catheter (Biosense Webster, Inc., CA, USA) is a new radiofrequency ablation catheter based on the SmartTouch SF™ (Biosense Webster, Inc.). It combines diffuse external irrigation with six thermocouples located within the outer metal shell and three additional microelectrodes in a 3.5 mm-tip contact force radiofrequency catheter. This article focuses on the different characteristics of the catheter, which incorporates the ability of high power delivery, irrigation flow control based on temperature sensing through the six thermocouples and the generation of microelectrograms. An outline of its performance in preclinical and clinical setting is presented, showing promising results, especially concerning procedural efficiency and short-term safety. Additional studies need to confirm long-term effectiveness, and durability studies should evaluate whether superiority on a lesion quality level can be achieved.
Keywords: arrhythmias; atrial fibrillation; atrial tachycardia; cardiac catheterization; electrophysiology.
Lay abstract Radiofrequency (RF) energy is the most widely used type of energy in the field of catheter ablation, an invasive treatment for heart rhythm disorders. In patients with atrial fibrillation (AF; the most frequent type of problem with the rhythm of the heart), catheter ablation aims at delivering RF energy around the pulmonary veins (PVs). PVs have been shown to contain AF triggers. Catheter ablation results in electrical isolation of the PV, making them less likely to trigger AF. The latest technical developments resulted in better success rate of the procedure (up to 90% success rate after 1 year follow-up) without increasing complication rates. During the last decade, the catheter used to isolate the PV has improved a lot and includes now contact force measurement in addition to the delivery mechanism for RF energy and can record the local electrical activity. The newly developed QDOT Micro™ catheter (Biosense Webster, Inc., CA, USA), presented in this article, combines different aspects of further technical development. These include the integration of smaller electrodes, resulting in higher local electrical signal resolution, more accurate feedback of local tissue temperature during the procedure and the ability to use higher RF power which reduces the RF delivery time and therefore reduced the duration of the procedure. An outline of its performance in preclinical and clinical setting is presented in this paper. These studies have shown promising results, especially concerning procedural efficiency and short-term safety. However, additional studies need to confirm long-term treatment success and potential superiority in comparison with other ablation approaches.