The use of ungating with the Medstone lithotriptor

Area of Science:

• Urology
• Cardiology

Background:

• Extracorporeal shock wave lithotripsy (ESWL) requires cardiac gating to prevent arrhythmias in patients with irregular heart rhythms.
• The Medstone lithotriptor system was evaluated for its ungated treatment capabilities.

Purpose of the Study:

• To evaluate the safety and efficacy of ungated lithotripsy using the Medstone lithotriptor.
• To assess the feasibility of treating patients with irregular cardiac rhythms without gating.

Main Methods:

• A total of 3,288 patients were treated by 200 urologists across 46 sites.
• Ungating was employed in 58 treatments (1.8%) for 57 patients, primarily due to clinically insignificant irregular cardiac rhythms.
• Cardiac simulators were set at 85 shocks/minute for irregular rhythms and 120 shocks/minute for elective ungated treatments.

Main Results:

• Forty-eight treatments in patients with irregular cardiac rhythms (average age 66.4) averaged 41 minutes of shock time.
• One patient experienced a clinically significant arrhythmia that resolved with gating.
• Ten elective ungated treatments (normal rhythm) averaged 34 minutes of shock time in older patients (average age 60.4).
• 3,231 gated treatments averaged 40 minutes of shock time in younger patients (average age 51).

Conclusions:

• Ungating with the Medstone lithotriptor is a safe and effective method for treating patients with irregular cardiac rhythms.
• The shock time for ungated treatments in patients with irregular rhythms was comparable to that of gated treatments in patients with normal rhythms.