A PROSPECTIVE-STUDY OF NON-ECG GATED ELEC TROCONDUCTIVE LITHOTRIPSY -HOLTER MONITORING DURING AN ALTERNANCE OF PERIODS WITH AND WITHOUT R-WAVE TRIGGERING

Introduction : Electrohydraulic lithotripters use a R-wave triggering system as episodes of cardiac arrhythmia were observed during early cl inical experiments. This study was designed to assess the safety of no n triggered shock wave treatments using an external fixed rate device (120/min) on the Sonolith 4000 Plus (), a non bathtub electroconducti ve lithotripter. Methods : Our study is the first prospective evaluati on of non-EKG-gated lithotripsy where the patient under continuous Kel ter monitoring served as his own control during a randomized alternanc e of periods with or without R-wave triggering. This design allowed fo r a direct comparison of the effect of EKG-gated and non-EKG-gated lit hotripsy respectively. The sequence of the different periods was rando mly assigned. The recordings were compared to a pre-treatment recordin g, the cardiologist ignoring the randomization. Results : 25 consecuti ve patients without cardiac history have been treated for urinary ston es. Ventricular and supraventricular excitability disorders have been noted in 7 patients, always during a non-EKG-triggered period. There w as no correlation with stone location. No cardiac rhythm disturbances have been observed during triggered periods in the 25 patients. Auricu lar extrasystoles (0.1-0.5/min) were observed in 6 patients, and auric ular couplets (0.5/min) in one. Ventricular extrasystoles were noted i n 4 patients, and ventricular couplets in one. One patient had an asym ptomatic non sustained ventricular tachycardia which resolved spontane ously. No clinically significant disorder occurred. Treatment time and analgesics requirements were reduced by non-EKG-triggering. Conclusio ns : Non-EKG-triggering lithotripsy has a definite potential for cardi ac disturbances, but appeared to be clinically safe in these patients with no cardiac history.