Leadless pacing ‘feasible’ in heart failure

22 June 2009



MedWire News: Researchers say they have demonstrated the feasibility of leadless pacing in heart failure patients, using ultrasound-mediated left ventricular stimulation.

An implantable cardiac resynchronization therapy (CRT) pacing system incorporating leadless left ventricular stimulation is under development, to counter problems associated with use of a pacing lead, including inability to select the optimal location for ventricular stimulation, that stimulation is epicardial rather than endocardial, and high complication rates.

The system involves energy transfer from an implantable pulse generating ultrasound transmitter (in a left precordial location) to a receiver electrode (implanted in endcardium at a selected stimulation site), and an external programmer/pacing system analyzer.

Kathy Lee (Queen Mary Hospital, Hong Kong, China) and colleagues tested the use of such leadless stimulation technology in 10 patients with advanced heart failure and left ventricular fraction of 35% or less.

They report in the journal Heart Rhythm that ultrasound-mediated pacing was successful in all 10 patients.

Transmission of acoustic energy enabled consistent pacing in all 10 patients at the standard location (fifth intercostal space [ICS]) and all patients had acoustic windows demonstrated in more than one ICS.

The acoustic window measured on average 39.6 cm² and decreased with rightward tilt and increased with upward and leftward tilt; measurements correlated with transthoracic echocardiography and computed tomography measurements.

“The acoustic window size was adequate for ultrasound transmission from the chest surface to a receiver electrode in the left ventricle, regardless of the patient’s position or respiratory phase,” the authors write.

“We believe our study will generate further interest in leadless pacing and encourage future technological advancements in this area,” Lee commented.

Heart Rhythm 2009; 6: 742–748