Effects of extracorporeal shock wave lithotripsy on cardiac pacemakers and its safety in patients with implanted cardiac pacemakers

Pacemakers and implantable cardioverter defibrillators--general and anesthetic considerations

A pacemaking system consists of an impulse generator and lead or leads to carry the electrical impulse to the patient's heart. Pacemaker and implantable cardioverter defibrillator codes were made to describe the type of pacemaker or implantable cardioverter defibrillator implanted. Indications for pacing and implantable cardioverter defibrillator implantation were given by the American College of Cardiologists. Certain pacemakers have magnet-operated reed switches incorporated; however, magnet application can have serious adverse effects; hence, devices should be considered programmable unless known otherwise. When a device patient undergoes any procedure (with or without anesthesia), special precautions have to be observed including a focused history/physical examination, interrogation of pacemaker before and after the procedure, emergency drugs/temporary pacing and defibrillation, reprogramming of pacemaker and disabling certain pacemaker functions if required, monitoring of electrolyte and metabolic disturbance and avoiding certain drugs and equipments that can interfere with pacemaker function. If unanticipated device interactions are found, consider discontinuation of the procedure until the source of interference can be eliminated or managed and all corrective measures should be taken to ensure proper pacemaker function should be done. Post procedure, the cardiac rate and rhythm should be monitored continuously and emergency drugs and equipments should be kept ready and consultation with a cardiologist or a pacemaker-implantable cardioverter defibrillator service may be necessary.

Effects of external electrical and magnetic fields on pacemakers and defibrillators: from engineering principles to clinical practice

The overall risk of clinically significant adverse events related to EMI in recipients of CIEDs is very low. Therefore, no special precautions are needed when household appliances are used. Environmental and industrial sources of EMI are relatively safe when the exposure time is limited and distance from the CIEDs is maximized. The risk of EMI-induced events is highest within the hospital environment. Physician awareness of the possible interactions and methods to minimize them is warranted.

Implications of pacemakers and implantable cardioverter defibrillators in urological practice

PURPOSE

Pacemakers and implantable cardioverter defibrillators are widely used and often encountered in urology practices worldwide. Safety and performance during electrosurgery, extracorporeal shock wave lithotripsy, magnetic resonance imaging, positron emission tomography and radiotherapy are not clearly defined. We reviewed the literature on their use and implications in urological practice.

MATERIALS AND METHODS

We performed a PubMed® search and all relevant articles were studied to understand the basic functioning of these devices along with the technological advances designed to reduce electromagnetic interference.

RESULTS

A modern permanent pacemaker is comprised of a generator and leads connecting to the atrial or ventricular myocardium with sensing and pacing functions. Implantable cardioverter defibrillators respond to episodes of ventricular tachycardia and fibrillation by discharging a defibrillating current. From a device perspective, several protective mechanisms have been developed in the permanent pacemaker/implantable cardioverter defibrillator to reduce the effects of electromagnetic interference. These involve generator material changes, lead modification, and better sensing and pacing algorithms. Magnetic resonance imaging compatible pacemakers have now been developed and are approved for use in Europe. From a urologist's perspective 5 procedures require the close monitoring of permanent pacemaker/implantable cardioverter defibrillator function. 1) For electrosurgery modifications in the device and in the methods of use have been recommended. 2) For extracorporeal shock wave lithotripsy the European Association of Urology provides some guidance with regard to patients with these devices. 3) During positron emission tomography the pulse generator and the lead area should be covered with lead to protect the device. 4) Magnetic resonance imaging is contraindicated but currently trials are under way for a new pacing system for safe use in the magnetic resonance imaging environment. 5) Patients can undergo radiotherapy with standard precautions but those with an abdominal permanent pacemaker/implantable cardioverter defibrillator require careful planning. Finally, implanted devices should have a full evaluation before and after the procedure.

CONCLUSIONS

Clear guidelines are essential given the rapid advances in technology to enhance patient safety. Magnetic resonance imaging should be avoided in patients without a magnetic resonance imaging compatible device. However, patients can undergo extracorporeal shock wave lithotripsy, radiotherapy and positron emission tomography as long as the device is not in the path.

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.

New-generation lithotripters for treatment of patients with implantable cardioverter defibrillator: experimental approach and review of literature

PURPOSE

The influence of shockwaves applied during extracorporeal shockwave lithotripsy on the function of implantable cardioverter defibrillators was evaluated. Mechanical influences as well as proper electrical function were tested in an experimental approach.

MATERIALS AND METHODS

Two implantable defibrillators (Ventak Mini 1743 and AVII 1821) were exposed to the shockwaves of a new-generation lithotripter. Each of the antidysrhythmic devices was tested at several distances from and within the focus of the lithotripter. All studies were performed with maximum energy and the number of shockwaves used for stone treatment. The devices were connected to an ECG simulator, and continuous recording of a surface ECG, a shock ECG, and marker channel was performed.

RESULTS

No macroscopic and microscopic mechanical damage was observed. The detection function of the implantable defibrillators was not altered by any electromagnetic artifacts even when brought into the focus of the shockwaves. All induced ventricular dysrhythmias were terminated properly regarding artifact sensing. However, after defibrillation, the pacing function of the Ventak Mini cardioverter defibrillator, which was programmed into the demand mode, failed. In this case, there was no post-shock pacing in the period of post-defibrillation asystole. The failure was caused by artifact oversensing.

CONCLUSION

In patients with implanted cardiac devices undergoing treatment with a new-generation lithotripter, deactivation of the defibrillator is not mandatory. For safety reasons, continuous ECG recording is recommended. To avoid pacing failure by artifact oversensing, the shockwaves should be applied in a R-wave synchronous mode.

Bilateral extracorporeal shock wave lithotripsy in a spinal cord injury patient with a cardiac pacemaker

OBJECTIVES

To review the precautions to be observed before and during extracorporeal shock wave lithotripsy (ESWL) in spinal cord injury (SCI) patients with a cardiac pacemaker and the safety of bilateral ESWL performed on the same day.

DESIGN

A case report of bilateral ESWL in a SCI patient with a permanent cardiac pacemaker.

SETTING

The Regional Spinal Injuries Centre, Southport, the Lithotripsy Unit, the Royal Liverpool University Hospitals NHS Trust, Liverpool, and the Department of Cardiology, Manchester Royal Infirmary, Manchester, UK.

SUBJECT

A 43-year-old male sustained a T-4 fracture and developed paraplegia with a sensory level at T-2. During the post-injury period, he developed episodes of asystole requiring implantation of a dual chamber (DDD) permanent pacemaker. Twenty-one months later, he developed a right ureteric calculus with hydronephrosis. A radio-opaque shadow was seen in the left kidney with no hydronephrosis. During right ureteric stenting, the ureteric stone was pushed into the renal pelvis. 1,500 shock waves were delivered to this stone on the right side, followed by ESWL to the left intra-renal stone with 1250 shock waves.

RESULTS

The patient tolerated ESWL to both kidneys. The pacemaker was reprogrammed to a single chamber ventricular pacing mode at 30 beats per minute with a reduced sensitivity during lithotripsy. There were no untoward cardiac events during or after lithotripsy. The serum creatinine was 45 micromol/l before lithotripsy and 44 micromol/l two weeks after ESWL.

CONCLUSION

SCI patients with a cardiac pacemaker may be able to undergo extracorporeal shock wave lithotripsy following temporary reprogramming of the pacemaker. Bilateral, simultaneous ESWL is safe in the vast majority of patients provided that there is no risk of simultaneous ureteric obstruction by stone fragments. However, it should be remembered that a decrease in renal function could occur following bilateral ESWL of renal calculi.

Effects of extracorporeal shock wave lithotripsy on tiered therapy implantable cardioverter defibrillators

The effects of extracorporeal shock wave lithotripsy (ESWL) were tested on four advanced generation implantable cardioverter-defibrillators (ICDs) in vitro and in vivo in two patients. During in vitro testing, advancement of nonsustained episode counters occurred in one device, and a set screw and power source cell loosened in another, which was connected to an external power source. No arrhythmias occurred during in vivo procedures, but programmed parameters were reset and elective replacement indicated after one procedure. ESWL can be performed safely in selected patients with ICDs, but testing should be performed afterwards to confirm satisfactory function and component continuity.

Permanent cardiac pacing

Implantation of a permanent pacemaker is the most commonly performed surgical operation involving the heart. The modern cardiac pacemaker is a complex device that can sense and pace in both the atrium and ventricle. It also modulates the pacing rate based on sensed physiologic parameters. This article reviews the fundamental principles of pacemaker technology and provides the emergency physician with approaches to common pacemaker problems.

Shockwave lithotripsy and pacemakers: experience with 20 cases

Lithotripsy treatment of urinary tract calculi initially excluded patients with cardiac pacemakers. Continued research and clinical study of patient outcomes has promoted a change in that initial concept. The Oklahoma Lithotripsy Center has successfully treated 20 patients with various types of pacemakers. No significant cardiovascular events occurred during treatment. Patients should be evaluated before the procedure by a cardiologist, and dual-chamber pacemakers should be reprogrammed to the single-chamber mode. Patients who cannot tolerate this should not undergo SWL. Rate-responsive pacemakers should be programmed to the non-rate-responsive (VVI) mode. The pacemaker should be at least 5 cm from the blast path. With these precautions and careful monitoring, SWL can be performed safely in most patients with pacemakers.

Effect of extracorporeal shock wave lithotripsy on implantable cardioverter defibrillator

Extracorporeal shock wave lithotripsy (ESWL) is frequently used for nephrolithiasis of the upper urinary tract. Because of the powerful shock wave and electromechanical forces created, this therapy has been contraindicated in the patient with an implantable cardioverter defibrillator (ICD). To determine whether or not ESWL affects ICD devices, we subjected ten devices to a full course of ESWL. The devices were then returned to the manufacturer to undergo bench analysis, which revealed no abnormalities in function. Additionally, one device was placed in the pathway of the shock wave, resulting in a discharge of the device despite a frequency of ESWL of 100 shocks/min (well below the rate cutoff of that device). Manufacturer analysis of this device, likewise, revealed no abnormalities even though the device had been exposed to the focal point of the shock wave. We conclude that contralateral ESWL is not contraindicated for the patient with an ICD. We do, however, recommend a post-procedure evaluation to ensure appropriate function of the ICD.

Extracorporeal shock wave lithotripsy in patient with cardiac pacemaker in an abdominal location: case report and review of the literature

A 75-year-old man with complete heart block and a ventricular demand pacemaker with the generator in a left upper-quadrant subcutaneous pouch underwent extracorporeal shock wave lithotripsy (SWL) for a 2-cm proximal right ureteral calculus, receiving 2000 shocks at 24 kV. There was no damage or malfunction of the pacemaker, and the Dornier HM3 lithotripter had no difficulty sensing all paced ventricular complexes. The patient had excellent fragmentation of his calculus. Extracorporeal shock wave lithotripsy may be performed safely on patients with pacemakers directly in the path of the shock waves at maximal kilovoltage when appropriate peri-SWL guidelines are followed. Specifically, the treatment should be approved by a cardiologist knowledgeable about the patient and the pacemaker, and a cardiologist should be nearby with the equipment necessary to deal with any problems. Dual-chamber pacemakers should be reprogrammed to the single-chamber mode, and single-chamber rate-responsive devices should have the activity mode programmed off. Patients with the latter type of pacemaker implanted in the abdomen should not have SWL if the device will be close to F2.

National High Blood Pressure Education Program (NHBPEP) review paper on complications of shock wave lithotripsy for urinary calculi

This decade has witnessed dramatic advances in the surgical management of urinary calculi. Today, most stones can be removed by minimally invasive means. In fact, the treatment of choice in 60% to 90% of patients with renal and ureteral calculi that need to be surgically removed is extracorporeal shock wave lithotripsy (ESWL). This article reviews indications for ESWL and discusses deleterious effects of ESWL.

Renal extracorporeal shock wave lithotripsy performed in patient with implantable cardioverter defibrillator

The effect of extracorporeal shock wave lithotripsy on the automatic implantable cardioverter defibrillator is unknown. To evaluate what effect might occur, a non-implanted automatic implantable cardioverter defibrillator was subjected to a full course of extracorporeal shock wave lithotripsy while inactive. Bench testing by the manufacturer after lithotripsy demonstrated normal function of the device. A patient with an automatic implanted cardioverter defibrillator who required contralateral extracorporeal shock wave lithotripsy then underwent this procedure. The right renal calculus was destroyed successfully with no apparent damage to the automatic implantable cardioverter defibrillator. A test of the automatic implantable cardioverter defibrillator after lithotripsy demonstrated normal sensing and conversion of induced ventricular tachycardia.

Treatment of pacemaker patients with extracorporeal shock wave lithotripsy: experience from 2 continents

Patients with cardiac pacemakers currently are treated by extracorporeal shock wave lithotripsy only by agreement between individual physicians and patients. We present the results of a survey of patterns of extracorporeal shock wave lithotripsy treatment (or nontreatment) of patients with pacemakers in the United States and Europe. Letters of inquiry regarding treatment of pacemaker patients were sent to 141 United States extracorporeal shock wave lithotripsy sites and 55 sites in Europe. Responses were received from 81 (57%) and 17 (31%) sites, respectively. A total of 131 patients received 142 treatments and pacemaker-related complications occurred in 4 (none was lethal, 3 were minor and all were corrected immediately). No patient required replacement of the pacemaker. No correlation existed between complications and pacemaker type or manufacturer. Urologists who treat patients with a pacemaker required previous clearance of the patients by the cardiologist, a cardiologist in or near the extracorporeal shock wave lithotripsy suite and standby of corrective equipment or temporary pacemakers.