Anaesthesia-free extracorporeal shock wave lithotripsy in patients with renal calculi

Modern extracorporeal shock wave lithotripsy can be performed with combined ECG and respiratory triggered shock wave release. Disconnecting the ECG triggering increases the risk of ventricular arrhythmias, including potentially malignant ones. The aim of this study was to assess the relationship of any sympatho-adrenal excitation as a possible explanation for the occurrence of cardiac arrhythmia. Plasma catecholamine levels were assessed in 5 patients during and after 50 min of anaesthesia-free extracorporeal shock wave lithotripsy for the treatment of calculi in the upper pole of the left kidney. Venous blood sampling showed no significant increase in catecholamines (epinephrine, norepinephrine and dopamine) during or after treatment. The heart rate and arterial blood pressure were measured simultaneously and showed no significant increase when shock waves were released during ECG triggering. However, when disconnecting the ECG-triggering mode, the incidence of ventricular extrasystoles on Holter monitoring became more apparent during respiratory triggered shock wave release only, although there was no rise in plasma catecholamine levels. These data suggest that cardiac arrhythmias are related to direct and accidental mechanical stimulation of the heart rather than to any sympatho-adrenal discharge during shock wave release.