Assessment of the Extravascular Implantable Defibrillator: Feasibility of Substernal Ventricular Pacing

作者：Brouwer Tom F^*; Smeding Lonneke; Berger Wouter R; Driessen Antoine H G; DE Groot Joris R; Wilde Arthur A M; Knops Reinoud E

来源：Journal of Cardiovascular Electrophysiology, 2017, 28(6): 674-676.

DOI：10.1111/jce.13195

• ICD
• implantable cardioverter-defibrillator
• pacing
• substernal

Substernal Pacing in Humans
IntroductionThe objective of this study was to assess feasibility of ventricular pacing and thresholds from within the substernal space to examine a new extravascular ICD configuration with pacing capabilities.
MethodsIn patients undergoing midline sternotomy, a duodecapolar diagnostic pacing catheter was positioned in the substernal space anterior to the pericardium, and a cutaneous patch in left lateral position. Different unipolar and bipolar pacing configurations were assessed. Strength-duration curves were performed to identify the optimal output, starting at 25 mA with a pulse width of 10 milliseconds.
ResultsEight patients with mean age 69 9 years were included. In 5, ventricular capture was achieved in 1 configuration. The mean bipolar pacing thresholds at PW 10, 5, 3, 1 milliseconds were 12.4 +/- 3.7 mA (5 patients), 13.3 +/- 5.8 mA (3 patients), 18.3 +/- 5.7 mA (3 patients), and 25 +/- 0 mA (2 patients), respectively. The 60-mm electrode spacing was the most successful bipolar configuration. Unipolar pacing was successful in 3 out of 4 patients with mean thresholds of 10 +/- 0 mA at 10 milliseconds (3 patients), 15 +/- 0 mA at 5 milliseconds (3 patients), 16.7 +/- 2.9 mA at 3 milliseconds (3 patients), and 20 +/- 7.1 mA at 1 milliseconds (2 patients).
ConclusionVentricular pacing from the substernal space in patients with midline sternotomy is feasible. Closed sternum studies are needed to determine pacing thresholds more accurately.

• 出版日期2017-6