Results from the WISE-CRT study have shown that endocardial stimulation for cardiac resynchronisation therapy in heart failure patients with leadless technology is feasible. Patients treated demonstrated a significant improvement of functional status and a significant increase of left ventricular ejection fraction at six-month follow-up.
Angelo Auricchio, Division of Cardiology, Fondazione Cardiocentro Ticino, Lugano, Switzerland, and others reported in Europace the results from the multicentre, prospective, observational, feasibility WISE-CRT (Wireless stimulation endocardially for cardiac resynchronisation therapy) study.
The risk of thrombus formation on the left ventricular lead is a permanent concern when using conventional pacing leads. The leadless technology “is expected to be advantageous for avoiding the risk of thromboembolic events,” write Auricchio et al.
With regards to the relevance of studying a leadless technology for the treatment of heart failure patients, Auricchio told Cardiac Rhythm News: “Several previous pre-clinical and human acute studies have shown that pacing at the optimal individual left ventricular endocardial site yields enhanced left ventricular performance in comparison with conventional coronary sinus site stimulation.”
The device used in this study was the leadless ultrasound-based Wics-LV system (EBR Systems). It comprises a steerable sheath/catheter delivery system and a left ventricle electrode that is attached to the ventricular wall with an anchor-style fixation barb.
Seventeen patients were enrolled in six European centres, they were categorised as: 1) Patients (n=7) in whom attempted coronary sinus lead implantation for cardiac resynchronisation therapy had failed. 2) Patients (n=2) with a previously implanted cardiac resynchronisation therapy device, not responding to therapy. 3) Patients (n=8) with previously implanted pacemakers or implantable cardioverter-defibrillator (ICD) and meeting the standard indications for cardiac resynchronisation therapy. The authors acknowledge that the study was initially designed to enrol 100 patients but had to be suspended due to three pericardial effusions that occurred during electrode implantation.
Auricchio et al report that successful device implantation occurred in 13 patients (76.5%). Twelve patients completed follow-up at one and six months. Of those 11 (92%) patients demonstrated successful and consistent biventricular pacing recorded on a 12-lead ECG analysis at one month and six months, respectively. Left ventricular ejection fraction significantly increased by six points at the six-month follow-up. About two thirds of the patients had at least one functional New York Heart Association (NYHA) class change and six patients reported a moderate-to-marked improvement of their global status; two patients had a mild change, three patients had no change and one patient reported a subjective worsening of his clinical condition.
Conventional Phrenic nerve stimulation a major clinical challenge in many cardiac resynchronisation therapy patients was never observed in this study and no thromboembolic strokes occurred. In addition, there were no adverse events related to a loss of retention of the electrode to the left ventricular wall and there were no embolisations and no migrations of the electrode, the authors comment.
Auricchio et al conclude that the results of this early feasibility stage study were “quite promising for a novel technology […] Cardiac resynchronisation therapy benefits were achieved in a number of patients where the conventional cardiac resynchronisation therapy systems could not be applied or had failed to show benefit for the patient.” They also acknowledge that improvements to the sheath/catheter design and in procedure training need to be warranted to address the risks of the pericardial effusions and that since the end of the trial enrolment those improvements have been made and further study is required to “definitely conclude the safety and performance of the system.”
Auricchio told Cardiac Rhythm News that after improvements of the device, the company [EBR Systems] “is ready to start implantation soon”.