Feasibility of Subcutaneous ECG Leads for Synchronized Timing of a Counterpulsation Device

Abstract

A counterpulsation device (Symphony) that works synchronously with the native heart to provide partial circulatory support was developed to treat patients with advanced heart failure. Symphony is implanted in a 'pacemaker pocket' without entry into the chest, and requires timing with ECG for device filling and ejection. Surface leads are limited to short-term use due to signal distortion and lead management. Transvenous leads are a clinical standard for pacemakers and internal defibrillators, but increase the complexity of the implant procedure. In this study, the feasibility of using subcutaneous leads for synchronized timing of Symphony was investigated. ECG waveforms were simultaneously measured and recorded using epicardial (control) and subcutaneous (test) leads in a bovine model for 7-days (n = 6) and 14-days (n = 2) during daily activity and treadmill exercise. Landmark features and R-wave triggering detection rates for each lead configuration were calculated and compared. Lead placement, migration, durability, and infection were quantified using fluoroscopy and histopathological examination. There were 2,849 data epochs (30-s each) recorded at rest (133,627 analyzed beats) and 35 data epochs (20 min each) recorded during treadmill exercise (37,154 analyzed beats). The subcutaneous leads provided an accurate and reliable triggering signal during routine daily activity and treadmill exercise (99.1 ± 0.4% positive predictive value, 96.8 ± 1.5% sensitivity). The subcutaneous leads were also easily placed with minimal lead migration (0.5 ± 0.1 cm), damage (no fractures or failures), or infection. These findings demonstrate the feasibility of using subcutaneous leads for synchronized timing of mechanical circulatory support while offering the advantage of less invasive surgery and associated risk factors.

Control Strategies for Afterload Reduction With an Artificial Vasculature Device

“…[1][2][3]36,37 The ability of the AVD system to handle heart rate variability and arrhythmias is essential to maintain the ventricular afterload to a user-defined value. [38][39][40][41] The washing mode will prevent blood stasis and thrombosis, maintain end-organ perfusion, and provide lower ventricular afterload similar to an asynchronous VAD. [36][37][38] These algorithms will be incorporated to track heart rate variability and handle arrhythmias.…”

Efficacy of Subcutaneous Electrocardiogram Leads for Synchronous Timing During Chronic Counterpulsation Therapy

“…The LEMO connectors have a threaded enclosure as well as an extended end to provide strain-relief. 16, 22, 23 …”

“…Counterpulsation devices require a reliable ECG signal for timing inflation and deflation of balloon or sac 16–23 . Synchronous timing for chronic counterpulsation therapy with temporary/surface leads may be a significant clinical challenge 16 due to motion artifact and frequent need to replace surface electrodes.…”

“…To overcome these limitations, we have developed and tested subcutaneous lead configuration to provide an accurate, reliable ECG signal for chronic counterpulsation therapy. 23 …”

A review of implantable pulsatile blood pumps: Engineering perspectives

“…49,53 The pump body is to be placed in the pacemaker-like pocket in the infraclavicular fossa of the right side of the patient and connected to the subclavian artery with a single short graft. 48,53,54 The counter-pulsation of the pump was controlled by ECG signals. 53 The Symphony, in comparison to a 40-mL IABP, was capable of providing higher overall coronary, carotid, and aortic flows and eliminating retrograde flow.…”