Variables influencing the likelihood of cardiac dysrhythmias during extracorporeal shock wave lithotripsy

Introduction: Extracorporeal shock wave lithotripsy (ESWL) is a safe and effective treatment of upper urinary tract calculi. While serious side effects are rare, transient cardiac dysrhythmias (CD) may be associated with ESWL. The exact etiology of these events, which are often unpredictable, is poorly understood. Awareness of CD during ESWL and identification of risk factors for developing them could help clinicians predict and manage them safely and effectively. The current study examines selected variables to determine whether they may predispose individuals to developing CD during ESWL. Methods: We compared 16 patients who experienced CD during ESWL to 56 control patients. Cases and controls were compared with respect to several continuous and discrete variables, including age, pre-treatment heart rate, number of shocks received during treatment, energy setting of the lithotripter, gender, presence of a ureteric stent, previous ESWL and side being treated. Results: Cardiac dysrhythmias occurred more frequently in younger patients and in those being treated for right-sided stones. The other variables did not influence the likelihood of CD. All CD resolved promptly following conversion to electrocardiogram (ECG)-gating. Conclusion: Younger age and right-sided treatment predisposed individuals to developing CD during ESWL. Careful ECG monitoring should be performed during treatment.