First-in-man implantation of leadless ultrasound-based cardiac stimulation pacing system: novel endocardial left ventricular resynchronization therapy in heart failure patients.

AIMS The importance of specific-site pacing is increasingly recognized in cardiac resynchronization therapy (CRT). Using current pacing technology, site selection is still largely limited by coronary vein anatomy, whereas left ventricular (LV) endocardial pacing using current lead technology is risky and challenging. To overcome limitations and complications with current LV pacing, the feasibility of a new technology enabling LV endocardial stimulation without the use of a lead is being evaluated in patients. METHODS AND RESULTS Patients presented in this report are part of the Wireless Stimulation Endocardially for CRT Trial (WiSE-CRT) study investigating the safety and performance of the WiCS(®)-LV system, an implantable cardiac pacing system capable of leadless pacing based on converting ultrasound energy to electrical energy. Three patients are presented: (i) a patient with an existing implantable defibrillator, (ii) a patient with a CRT system whose LV lead does not capture, and (iii) a CRT patient classified as a non-responder. All three patients were successfully treated. Acute electrical pacing thresholds ranged from 0.7 to 1.0 V at 0.5 ms; all patients retained captured at 6 months. Functional New York Heart Association class significantly changed (Pre: III in two patients, and IV in one patient; Post: I in one patient, II in one patient, and II-III in one patient), and LV ejection fraction increased from 23.7 ± 3.4% to 39 ± 6.2% (P < 0.017). CONCLUSION This report on three first-in-man cases shows that leadless endocardial pacing may be safely applied and effective, conferring short- to-mid-term symptomatic benefits. These promising findings are yet to be substantiated by larger ongoing studies. CLINICAL TRIAL REGISTRATION INFORMATION http://clinicaltrials.gov/ct2/show/NCT01294527.