Arrhythmia during extracorporeal shock wave lithotripsy

Atrial flutter following Shockwave Intravascular Lithotripsy during percutaneous intervention of left anterior descending disease

A 72-year-old woman undergoing percutaneous intervention to a calcified proximal left anterior descending (LAD) coronary artery lesion using Shockwave Intravascular Lithotripsy (S-IVL) developed new atrial flutter. She then returned to sinus rhythm after treatment with amiodarone. S-IVL can cause cardiomyocyte depolarization. We hypothesize that pacing can occur during atrial repolarization, inducing supraventricular tachyarrhythmias and even triggering atrial macro re-entrant circuits. We recommend synchronizing shock wave delivery with R waves on the electrocardiogram to lower the risk of arrhythmias.

Routine Preoperative Electrocardiograms in Patients at Low Risk for Cardiac Complications During Shockwave Lithotripsy: Are They Useful?

INTRODUCTION

Routine preoperative electrocardiogram (ECG) before shockwave lithotripsy (SWL) is frequently performed despite recommendations against its use in asymptomatic patients undergoing low-risk surgical procedures. This study assesses whether routine preoperative ECG before SWL is useful in patients at low risk for cardiac complications.

MATERIALS AND METHODS

A retrospective study of SWL at our center (2003-2013) reviewed all cardiac-related preoperative cancellations, intraoperative complications, postoperative admissions, and emergency department presentations in patients at low risk for cardiac complications. Patients received SWL with sedation and continuous five-lead ECG monitoring.

RESULTS

Of 30,892 referrals, preoperative ECG triggered 13 (0.04%) cancelations in low-risk patients (1 with new atrial fibrillation and 12 with ischemia/previous infarction). Of these patients, 1 had a subsequent abnormal cardiac work-up and 11 underwent uncomplicated SWL without cardiac intervention (2 had unknown history). Of 27,722 treatments, 5 (0.02%) were stopped prematurely in low-risk patients because of arrhythmia (3 had normal preoperative ECG, 1 had abnormal ECG, and 1 did not complete ECG). Three patients developed an arrhythmia with sedation and 2 patients were admitted postoperatively because of cardiac complications (1 for atrial fibrillation and 1 for hypertension), of whom all had normal preoperative ECG. No patients presented to our emergency department with cardiac complications after SWL.

CONCLUSIONS

In patients at low risk for cardiac complications, preoperative ECG triggered very few cancellations and did not predict early termination of treatment or cardiac complications after SWL. These findings suggest that in low-risk patients, routine preoperative ECG has little effect on treatment or complication rate and should be omitted.

Atypical cardioversion in unstable arrhythmia caused by clavicle surgery

We report on a 54-year old male with traumatic brain injury, flail chest and floating shoulder undergoing intramedullary stabilization of a midshaft clavicle fracture in beach chair position. Intraoperatively the patient developed instable atrial fibrillation triggered by implantation of intramedullary nail. Secondary this case shows feasibility of cardioversion in latero-lateral electrode-position due to inaccessible standard positions and patient fixation between the operation table and the X-ray apparatus.

Impact of shock wave lithotripsy on heart rate variability in patients with urolithiasis

The physiological response of the cardiac autonomic nervous system during shock wave lithotripsy (SWL) remains unclear. Heart rate variability (HRV) is an index of cardiac autonomic balance. This study aimed to analyze HRV during SWL in patients with urolithiasis. Electrocardiograms of patients who underwent SWL were obtained. Recordings were obtained before and after SWL. For each time point, the recordings were obtained continuously for 6 min, after which R wave-to-R wave (RR) intervals were extracted. The time digital sequence derived from RR intervals was the HRV signal. Time-domain analysis revealed that the mean of RR intervals (MRR) and standard deviation of normal beat-to-normal beat (NN) intervals (SDNN), but not the square root of the mean squared difference of successive NNs (RMSSD) or triangular interpolation of NN intervals (TINN), significantly increased during SWL. The increase in SDNN persisted after SWL but MRR returned to the initial level. Frequency-domain analysis revealed that very low frequency (VLF), low frequency (LF), and LF/high frequency (HF) ratio significantly increased after SWL, while there was no statistically significant difference in HF. Thus, the patients had significantly high MRR and SDNN during SWL and significantly high SDNN, VLF, LF, and LF/HF ratio after SWL. SWL could alter the functioning of the cardiac autonomic nervous system, resulting in reduction in sympathetic activity and increase in parasympathetic activity. Further studies with larger samples are required to confirm these findings and understand the underlying mechanisms.

Pacemakers, implantable cardioverter/defibrillators, and extracorporeal shockwave lithotripsy: evidence-based guidelines for the modern era

Early work examining interactions between extracorporeal shockwave lithotripsy (SWL) and implantable pacemakers or implantable cardioverter/defibrillators suggested that shockwave oversensing may result in inappropriate suppression of pacing, delivery of antitachycardia pacing therapy, delivery of inappropriate shock therapy, or outright damage to such devices. In the absence of national guidelines, those provided by manufacturers are nonuniform and practice patterns vary between centers. Improvements in SWL energy delivery as well as in device shielding and discrimination technologies have demonstrated improved safety data in recent years. We review these advances in both technologies as well as the most recent data to construct practice guidelines for the modern era.

Extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy

This article reviews the basic anesthetic considerations for ESWL and PCNL. General principles governing the operation of lithotripters, elements of treatment that impinge on safety, and effective intraoperative anesthesia and complications that may be encountered in the perioperative period are discussed. Factors influencing blood loss and concerns arising from positioning patients prone are addressed in the sections devoted to PCNL.

Cardiac dysrhythmias induced by extracorporeal shockwave lithotripsy

PATIENTS AND METHODS

We evaluated in 269 consecutive patients the incidence and gravity of dysrhythmic complications during nonsynchronized extracorporeal shockwave lithotripsy (SWL) using an electromagnetic lithotripter.

RESULTS

Dysrhythmia occurred during treatment in 22 patients (8.8%) with no previous cardiac dysrhythmia. Ventricular extrasystoles occurred in 14 patients, atrial extrasystoles in 7 patients, and sinus bradycardia in 1 patient. It was not necessary to terminate treatment because of the occurrence of dysrhythmia in any of the patients. For 13 of the 22 patients (59%), it was sufficient to interrupt the treatment momentarily to obtain resumption of the normal rhythm. For 8 patients (36%), treatment was continued after triggering the release of the shockwaves with the refractory phase of the heart cycle. For one case of bradycardia (42 beats/min), it was possible to continue with the treatment after intravenous administration of atropine 0.5 mg. Pretreatment dysrhythmias were revealed by the electrocardiographic examination in 16 of the patients studied (6.3%).

CONCLUSIONS

Extracorporeal shockwave lithotripsy without ECG triggering has been found to be fast and efficient and not correlated with the occurrence of dysrhythmic episodes of any particular clinical significance. No significant correlation was found between the occurrence of dysrhythmia, the side treated, the number and strength of the shockwaves, or the administration of analgesics. It was found, however, that dysrhythmia occurred almost exclusively in treatments involving the kidneys. The ECG-triggering option was indispensable in some patients in order to complete the lithotripsy without complications.

Cardiac arrhythmias with external fixed-rate signal generators in shock wave lithotripsy with the Medstone lithotripter

OBJECTIVES

To evaluate the incidence and outcome of cardiac arrhythmias associated with an external fixed-rate generator and the Medstone lithotripter with regard to stone location, anesthesia type, patient age, and gender.

METHODS

Data were obtained on 933 patients who underwent shock wave lithotripsy (SWL) with the Medstone lithotripter. Patients were randomly divided into two study groups, including those with pre-existing cardiac disease, hypertension, and cardiac medications. Group 1 (576 patients) were treated with the external fixed-rate signal generator (cardiac simulator). Group 2 (357 patients) underwent electrocardiogram-gated SWL (no simulator). All patients were monitored for arrhythmias during SWL. Patients who developed arrhythmias on the simulator were converted to gated SWL.

RESULTS

In group 1, 463 patients (80%) had no arrhythmias during treatment, whereas 113 patients (20%) developed cardiac arrhythmias (primarily premature ventricular contractions [PVCs]) and were successfully converted to gated SWL. Only 1 patient in group 2 (0.3%) had a documented arrhythmia (PVC). Group 1 patients who developed arrhythmias with a cardiac simulator were more likely to have renal rather than ureteral stones. Chi-square analysis showed a significant correlation between patients with and without arrhythmias in group 1 with regard to stone location (P <0.0001). In group 1, regional anesthesia, intravenous anesthesia, and general anesthesia had an arrhythmia rate of 14%, 27%, and 38%, respectively. The only patient in group 2 who developed arrhythmias was under general anesthesia. The differences between groups 1 and 2, with regard to anesthesia type and arrhythmia, were statistically significant (P <0.001). No patients required additional medical therapy or hospitalization for cardiac events, and all patients safely completed the SWL treatment.

CONCLUSIONS

With careful monitoring and adequate precautions, external fixed-rate signal generators are safe, effective methods for pacing the Medstone shock wave lithotripter and probably other extracorporeal shock wave lithotripters.

Safety and effectiveness of Lithostar shock tube C in the treatment of urinary calculi

Over 14 years of clinical use of extracorporeal shockwave lithotripsy (SWL), great technical modifications resulted in the development of many second-generation lipthotripters. The Siemens Lithostar machine, with its standard shockwave tube, was introduced in 1986. The objective of this study was to assess the safety and effectiveness of the newly proposed Lithostar shock tube C in the treatment of urinary calculi. Between July 1992 and August 1993, 319 patients (214 males and 105 females, average 49.7 years) with 433 renal or ureteral stones or both were treated at five centers in Canada and the United States. Most of the stones (72%) were located in the kidneys, while 28% were located in the ureters. Most (81%) of the treated sides (side = kidney and ureter) presented with single stones, 11% presented with two stones, and 8% presented with three or more stones. The average stone burden was 13.6 mm. The average duration of treatment for the whole population of patients was 39.3 minutes using an average number of shockwaves of 3633 in a minimum and maximum energy setting of 0.11 and 3.82, respectively. The majority of treatments (92%) were performed without anesthesia. Fragmentation was achieved in 93.5% of treatments, with a 3-month stone-free rate of 62.5% and a success rate (stone free or fragment < 5 mm) of 72%. Auxiliary procedures were necessary in conjunction with 108 treatments, and most of them were in form of catheter/stent placement. Treatment applied on a separate occasion to different stones but in the same collecting system (either a kidney or a ureter) were considered retreatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Ungated Medstone outpatient lithotripsy

Ungated lithotripsy has raised the specter of possible cardiac arrhythmias. We reviewed ungated outpatient lithotripsy performed on 82 patients to evaluate the incidence of arrhythmias encountered and time saved. All patients were chosen in a random nonselected, prospective fashion. All treatments were performed on a mobile Medstone 1050 STS lithotriptor. The incidence of arrhythmias was 21%. All but 2 arryhthmias were benign and all reversed with gating. No arrhythmias occurred during treatment of right ureteral stones. In the left ureter only 1 patient had benign premature ventricular contractions during treatment. Arrhythmias occurred at 20 to 24 kv. in 20% of patients with right renal stones and 31% with left renal stones. All arrhythmias resolved with gating. No arrhythmias were encountered at an energy level of less than 20 kv. There was no evidence of electrocardiographic changes up to 1 hour after treatment. Pharmacological manipulation to maintain a heart rate of 100 may allow a treatment time of approximately 24 minutes. With ungating the rate may reach 120, allowing for a treatment time of approximately 20 minutes. In this series average ungated lithotripsy time was 36 minutes. In comparison, the average treatment time in 20 patients undergoing gated lithotripsy was 38.7 minutes. It is not clear from this study whether persistent ungated lithotripsy would have precipitated any life threatening arrhythmias since our practice has been to terminate the procedure and re-gate the shocks at the first sign of any persistent change in cardiac rhythm. Our data indicate that ungated lithotripsy with the Medstone device is safe when simple monitoring rules are followed.