Cardiac Arrhythmias During Nonsynchronized Extracorporeal Shock Wave Lithotripsy

Synchronized extracorporeal shockwave lithotripsy may still affect the heart: a case report of perioperative ST-segment elevation myocardial infarction

Extracorporeal shockwave lithotripsy (ESWL) is widely used as a primary treatment for urolithiasis and is performed as an elective outpatient surgical procedure because of its ease of use. However, patients undergoing this treatment rarely develop cardiac complications. In this article, we present the case of a 45-year-old male patient who presented with ST-elevation myocardial infarction during ESWL. Moreover, atypical symptoms and electrocardiogram patterns were recognized by the nursing staff. Early primary evaluation and intervention resulted in favorable outcomes along with patent coronary artery flow following stent placement for stenosis, and no complications were noted.

Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm

The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.

[Cardiac implantable electronic devices : Electromagnetic interference from electrocauterization, lithotripsy and physiotherapy]

The management of patients with a cardiac implantable electronic device (CIED) poses a particular challenge in the peri-interventional and perioperative medical environment due to the many forms of possible electromagnetic interference. Although the devices encountered nowadays are of increasing complexity, the vast majority of procedures can be safely performed in patients. The existing position statements and recommendations, however, have a low level of evidence and are often contradictory. In the context of intraoperative electrocauterization, one of the most important sources of electromagnetic interference in the medical environment, recent studies have suggested an increasingly pragmatically perioperative CIED management, which is not represented in the existing recommendations. This article gives an example of these newer findings and reports the currently used and appropriately adapted perioperative CIED management protocol. Extracorporeal shock wave lithotripsy was thought to cause severe interference in CIED patients based on older studies and in vitro experiments. Although electromagnetic interference is possible, clinical observations with modern devices show that the procedure can generally be safely applied in CIED patients. Physiotherapy often utilizes a variety of electromechanical devices, which can be a relevant source of electromagnetic interference. Although some of these therapies can be safely used, coordination with the responsible CIED unit is recommended.

Changing Patient Position Can Eliminate Arrhythmias Developing During Extracorporeal Shockwave Lithotripsy

INTRODUCTION

Extracorporeal shockwave lithotripsy (SWL) has a low complication rate. While serious complications are rare, cardiac arrhythmias, such as ventricular tachycardia, may occur. The etiology of these arrhythmias is poorly understood, but it appears to be due to stimulation of the heart by the shock waves.

OBJECTIVE

This study examines the effect of rotating the patient 15° to 20° when an arrhythmia occurs.

METHODS

Eight hundred nineteen patients were prospectively evaluated for arrhythmias during SWL. The initial patient position was dependent on the location of the stone and the body mass index (BMI) of the patient. If a sustained arrhythmia developed, treatment was withheld for 2 minutes and then recommenced. If the patient developed an arrhythmia again, the patient was rotated 15°-20° away from the original position and treatment recommenced.

RESULTS

Twenty patients developed significant arrhythmias during SWL. Arrhythmias occurred more frequently in patients with a lower BMI (p < 0.01), of younger age (p = 0.01), and with right-sided stones (p = 0.035). After the first rotation, 11 patients had no further arrhythmias, and 4 patients had a reduction of their arrhythmia to unsustained minor arrhythmias that did not require cessation of the treatment. The remaining five patients required a second repositioning. Three of these patients required gated SWL to abolish the arrhythmia.

CONCLUSION

Changing the position of the patient by rotating the patient by 15 to 20° can eliminate arrhythmias that develop during SWL.

Safety of ungated shockwave lithotripsy in pediatric patients

OBJECTIVE

Ungated extracorporeal shockwave lithotripsy (ESWL) in adults is associated with cardiac arrhythmias. We report on the safety and efficacy of this method for treatment of renal calculi in children.

PATIENTS AND METHODS

Children under 14 years with radio-opaque renal stones were treated by ungated ESWL. Pre-treatment plain radiographs and intravenous urography and post-treatment ultrasonography and plain films were used to follow up clearance of fragments. All children were monitored for arrhythmias.

RESULTS

Thirty-seven children (28 males, nine females) with a median age of 5 years (range 2-14 years) underwent 69 ungated ESWL sessions for renal calculi. Nineteen children had stones located in the left kidney, 17 had stones located in the right kidney and one child had bilateral renal stones. The stone size ranged from 6 to 25 mm (mean 9.9 mm). Shockwave number ranged from 800 to 3650 (mean of 2500 shockwaves per session). All children underwent lithotripsy with a gradual incremental energy increase from 14 to 20 kV. No patient had cardiac arrhythmias or other intra-procedural complications. No patient required conversion to gated ESWL. The overall stone-free rate was 86%.

CONCLUSION

The results suggest that ungated ESWL is safe in children under 14 years. The efficacy was comparable to that of gated ESWL from previously published series.

Ungated extracorporeal shock wave lithotripsy in children: an initial series

OBJECTIVES

Ungated extracorporeal shock wave lithotripsy (ESWL) is associated with cardiac arrhythmias in adults. However, the incidence of arrhythmias in children undergoing ungated ESWL has not been established. Therefore, we report on the safety and efficacy of ungated ESWL of renal calculi in children.

METHODS

We evaluated all patients younger than 18 years of age who were undergoing ungated ESWL of renal calculi. All patients were monitored for arrhythmias, along with other standard monitoring, by the anesthesiologist.

RESULTS

Eight consecutive children (three boys and five girls) between 3.5 and 17 years of age (median 13.5) underwent 10 ESWL procedures for renal calculi. Of the 10 stones, 9 were located in the left kidney and 1 was located in the right kidney. The stone size ranged from 5 to 19 mm. Six patients underwent 3000 shocks and 2 patients underwent 800 and 2200 shocks. All patients underwent lithotripsy with a gradual incremental energy increase from 17 to 24 kV, except for 1 child (maximum of 18 kV) because of the patient's age (3.5 years). No patient had cardiac arrhythmias or other intraoperative complications. No patient required conversion to gated ESWL. The overall stone-free rate was 90.0% as determined by abdominal radiography and renal/bladder ultrasonography.

CONCLUSIONS

The results of this initial series suggest that ungated ESWL is safe and efficacious in patients younger than 18 years of age. Additional studies are warranted to evaluate further the use of ungated ESWL in the pediatric population.

Does shock wave lithotripsy of renal stones cause cardiac muscle injury? A troponin I-based study

OBJECTIVES

To investigate whether shock wave lithotripsy (SWL) causes cardiac muscle injury that alters the levels of troponin I plasma, a cardio-specific enzyme shown to be useful in diagnosing cardiac muscle injury because of its high specificity.

METHODS

Patients treated by SWL for renal stones participated in the study. They had undergone a baseline 12-lead electrocardiogram (ECG) a few days earlier. One day after SWL, they were queried about any chest discomfort, blood was drawn for evaluation of troponin I and creatine kinase with isoenzymes (CK-MB), and an ECG was carried out.

RESULTS

Thirty-two patients (21 men and 11 women, mean age +/- SD 51.0 +/- 10.6 years) comprised the study group. Fourteen SWL treatments were on the right side and 18 on the left. The mean number of shock waves was 2859 +/- 202. The mean time to evaluation after SWL was 22.3 +/- 1.3 hours. None of the patients reported chest discomfort. The mean value was 6.6 +/- 9.2 mU/mL for CK-MB and 0.02 l +/- 0.04 ng/mL for troponin I. No ECG changes suggestive of myocardial injury were evident. None of the 5 patients who experienced ventricular extrasystoles during SWL had any evidence of cardiac muscle injury.

CONCLUSIONS

We evaluated the symptoms, perioperative ECG changes, and cardiac troponin I and CK-MB plasma levels in patients who underwent SWL for renal stones and did not identify any myocardial damage. Troponin I plasma levels were not elevated after this procedure and, therefore, remain suitable for evaluation of patients complaining of chest pain after SWL.

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.

Premature ventricular contractions during triggered imaging with ultrasound contrast

BACKGROUND

Premature ventricular contractions (PVCs) were observed during triggered second harmonic imaging of a contrast agent for myocardial perfusion assessment, with continuous infusion of the contrast agent. Further investigation into the relation of this phenomenon to both ultrasound energy and the contrast agent was carried out during a subsequent bolus-versus-infusion study.

METHODS AND RESULTS

Two open-label studies in healthy male volunteers were performed. The initial study was a dose-response study in 10 subjects, which compared 3 infusion rates. Each volunteer received 3 continuous infusions with different infusion rates of the contrast agent for either 10 (n = 6) or 20 (n = 4) minutes. End-systolic triggered imaging with a mechanical index (MI) of 1.5 was used throughout this part of the study. The second study compared bolus injection with a continuous infusion in 9 volunteers, with a single-dose level but different imaging modalities: end-systolic and end-diastolic triggered imaging at MIs of both 1.1 and 1.5. Spontaneous baseline PVCs were uncommon: 10 in 344 minutes (0.03 PVC/min, maximal 1 PVC/min) of baseline imaging. During end-diastolic triggering, no increase in PVCs was seen, irrespective of MI. A significant increase to 1.06 PVC/min (P <.001) was seen during end-systolic imaging with an MI of 1.5, but not with an MI of 1.1. The increase in PVC rate was dose-dependent in the initial study.

CONCLUSION

Imaging of contrast agents with high acoustic pressures can cause PVCs if end-systolic triggering is used. This effect is related to both the dose of contrast agent and acoustic pressure. It does not occur during end-diastolic triggered imaging. Precautionary measures would include using lower MIs or end-diastolic triggering.

Does the rate of extracorporeal shock wave delivery affect stone fragmentation?

OBJECTIVES

To evaluate the effect of the rate of shock wave delivery on stone fragmentation, because the optimal rate of shock wave administration has not yet been established.

METHODS

Standard phantom, ball-shaped, ceramic stones were placed in a net-like basket with a hole size of 2.2 mm and immersed in a specially designed water bath coupled with the Econolith 2000 lithotripter. One hundred eighteen stones (mean diameter 9.5 mm) were used. Shock waves were delivered at rates of 30, 60, 90, 120, and 150 shocks/min and at intensities of 15, 20, and 22.5 kV (electrohydraulic). The number of shocks required for complete fragmentation, determined by all fragmented particles falling through the basket holes, was recorded.

RESULTS

The most effective (fewer shocks needed for complete stone fragmentation) rate of shock wave delivery was 60 shocks/min. A statistically significant difference was demonstrated between the mean number of shocks required for complete stone fragmentation at the rate of 60 shocks/min and faster rates at all energy levels (P <0.01) but not between the rate of 60 shocks/min and the rate of 30 shocks/min at all energy levels.

CONCLUSIONS

The rate of shock wave administration during extracorporeal shock wave lithotripsy seems to influence stone disintegration. We demonstrated that extracorporeal shock wave lithotripsy is most effective when waves are delivered at 60 shocks/min.

Effects of single-shot and twin-shot shockwaves on urinary enzyme concentrations

BACKGROUND AND OBJECTIVE

Extracorporeal shockwave lithotripsy (SWL) remains the first-line treatment of urinary calculi. However, a number of studies have shown that adverse effects on the kidneys and the surrounding tissues may be encountered in short- and long-term follow-up. The aim of this study was to compare the effects of single-shot and twin-shot SWL techniques to identify the safest modality in terms of urinary enzyme excretion.

PATIENTS AND METHODS

In this prospective, investigator-blinded, randomized study, urinary enzymes, beta2-microglobulin, microalbumin, Na, K, Ca, and creatinine concentrations were analyzed in 59 consecutive patients. Measurements were performed in urine specimens collected immediately before and after the SWL procedure and also on the 3rd and 7th days after treatment, which was performed on a Dornier MFL-5000 lithotripter utilizing the twin-shot technique (Group 1; N = 30) or the single-shot technique (Group 2; N = 29) with 3000 shockwaves at 18 kV per treatment.

RESULTS

Although there was no statistically significant difference in the results between the groups, urinary levels of microalbumin, alanine and aspartate aminotransferases, beta-2-microalbumin, gamma-glutamyltranspeptidase, Na, K, and Ca rose acutely after SWL, reaching maximum levels on the 3rd day, and returned to the baseline by the 7th day following the treatment in both groups.

CONCLUSION

This study demonstrates that SWL performed by either a single-shot or twin-shot shockwave technique has a transient detrimental effect on renal function, as assessed by urine enzyme concentrations. It is recommended that the twin-shot shockwave technique be used in routine lithotripsy in consideration of the cost-effectiveness provided by the shorter treatment time.