Vesical pacing in patients with overactive bladder: Technique and results

Objectives: A recent study has demonstrated that the electric activity of the overactive bladder (OAB) is `dysrhythmic'. The cause was attributed to a disordered vesical pacemaker which discharges these waves. In a subsequent study, the dysrhythmic waves have been `normalized' by vesical pacing and the optimal parameters which are required to achieve normalization have been defined. We investigated the hypothesis that vesical pacing of the OAB might improve not only the vesical electric activity but also the symptoms. Methods: Vesical pacing was used in 9 patients (age 39.2 ± 10.3; 5 women, 4 men) with OAB. Under anesthesia, the pacemaker was implanted in an inguinal subcutaneous pocket and connected to 2 pacing electrodes implanted into the vesical vault. The normalization of the waves was tested by 2 recording electrodes which were temporarily applied to the vesical wall and removed post-testing. The pacemaker was then programmed for home pacing to be activated at given times. Results: Vesical pacing effected normalization of the dysrhythmic electric waves with disappearance of the OAB symptoms in 7 patients and failed in 2. Vesical pacing was abandoned in 3/7 patients after a few months following the spontaneous disappearance of the symptoms. Conclusions: Vesical pacing has normalized the dysrhythmic electric activity and suppressed the symptoms of the OAB in 77.7% of patients. The pacemaker was removed in 5 patients: 2 failures and 3 after spontaneous waves normalization. No complications were encountered. Vesical pacing is suggested as a treatment for OAB when commonly used therapeutic modalities have failed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Colonic pacing: a therapeutic option for the treatment of constipation due to total colonic inertia

HYPOTHESIS: The treatment of constipation caused by total colonic inertia is problematic and its results are unsatisfactory. We speculated that colonic pacing would initiate electric activity in the inertial colon and effect rectal evacuation. METHODS: Nine patients with constipation due to total colonic inertia (age range, 39-52 years; 7 women, 2 men) were enrolled in the study. One pacing electrode was applied to each of the 4 potential colonic pacemaker sites, and 2 to 3 temporary recording electrodes were applied distally. A stimulator was embedded subcutaneously in the inguinal area. Home pacing was practiced after patients were trained; the recording electrodes were removed before home pacing was started. RESULTS: Colonic pacing evoked electric waves, which effected defecation in 6 of the 9 patients. Three of these 6 patients had spontaneous defecation after a few months of pacing, and their electrodes and stimulators were removed. In the other 3 of these 6 patients, the pacemakers are still in place and continue to effect rectal evacuation. Colonic pacing did not produce rectal evacuation in 3 patients and is believed to have failed because of an advanced stage of colonic inertia. CONCLUSION: Colonic pacing induced rectal evacuation in 66.6% of the patients with total colonic inertia. No complications were encountered. We suggest that colonic pacing be considered as a new therapeutic option in the treatment of total colonic inertia.     

Study of the rectal electric activity of the uninhibited rectal detrusor (overactive rectum): a new concept of pathogenesis

BACKGROUND/OBJECTIVE: One of the causes of fecal incontinence is uninhibited rectal detrusor syndrome (URDS). Patients with this condition either perceived the first rectal sensation after the onset of involuntary rectal contraction or not at all. We investigated the hypothesis that the abnormal rectal contractility in URDS may be caused by deranged rectal electric activity. METHODS: Twenty-five patients with URD (14 women and 11 men; age, 44.7 +/- 10.3 years) and 10 healthy volunteers (6 women and 4 men; age, 42.8 +/- 8.7 years) were studied. URDS was diagnosed by rectometry and provocative test. A transcutaneous EMG was performed with one electrode placed lateral to each sacroiliac joint and the third one midway between the greater trochanter and the ischial tuberosity. Two 20-minute recording sessions were performed for each subject. RESULTS: Slow waves (SWs) with regular rhythm and similar parameters (frequency, amplitude, conduction velocity) from the 3 electrodes were recorded from the healthy volunteers. They showed a significant increase in the parameters on saline filling of the rectum. The SWs of patients with URDS exhibited a "dysrhythmic" pattern with irregular parameters, which were different in the 3 electrodes and inconsistent during recording. They showed areas of tachyrhythmia, bradyrhythmia, and arrhythmia. On provoking rectal overactivity, the SWs showed an increased dysrhythmic activity. CONCLUSIONS: The patients with URD exhibited a "dysrhythmic" electric pattern with areas of variable electric activity. The tachyrhythmic areas seem to initiate the urgency and fecal incontinence of URDS. It is suggested that a disordered rectosigmoid pacemaker causes the dysrhythmic waves.     

Study of the Rectal Electric Activity of the Uninhibited Rectal Detrusor (Overactive Rectum): A New Concept of Pathogenesis

Abstract

Background/Objective: One of the causes of fecal incontinence is uninhibited rectal detrusor syndrome (URDS). Patients with this condition either perceived the first rectal sensation after the onset of involuntary rectal contraction or not at all. We investigated the hypothesis that the abnormal rectal contractility in URDS may be caused by deranged rectal electric activity.

Methods: Twenty-five patients with URD (14 women and 11 men; age, 44.7 ± 10.3 years) and 10 healthy volunteers (6 women and 4 men; age, 42.8 ± 8.7 years) were studied. URDS was diagnosed by rectometry and provocative test. A transcutaneous EMG was performed with one electrode placed lateral to each sacroiliac joint and the third one midway between the greater trochanter and the ischial tuberosity. Two 20- minute recording sessions were performed for each subject.

Results: Slow waves (SWs) with regular rhythm and similar parameters (frequency, amplitude, conduction velocity) from the 3 electrodes were recorded from the healthy volunteers. They showed a significant increase in the parameters on saline filling of the rectum. The SWs of patients with URDS exhibited a “dysrhythmic” pattern with irregular parameters, which were different in the 3 electrodes and inconsistent during recording. They showed areas of tachyrhythmia, bradyrhythmia, and arrhythmia. On provoking rectal overactivity, the SWs showed an increased dysrhythmic activity.

Conclusions: The patients with URD exhibited a “dysrhythmic” electric pattern with areas of variable electric activity. The tachyrhythmic areas seem to initiate the urgency and fecal incontinence of URDS. It is suggested that a disordered rectosigmoid pacemaker causes the dysrhythmic waves.     

Rectal pacing: pacing parameters required for rectal evacuation of normal and constipated subjects

BACKGROUND AND PURPOSE: Our previous studies have demonstrated that rectal electric waves start at the rectosigmoid junction (RSJ) and spread caudad along the rectum. A rectosigmoid pacemaker was postulated to exist at the RSJ. We also demonstrated that electric waves in rectal inertia are so scarce that a "silent" electrorectogram is recorded; the myoelectric activity in such cases was stimulated by an artificial pacemaker placed at the RSJ. For this article we investigated the pacing parameters necessary for rectal evacuation in rectal inertia patients. METHODS: The study comprised 24 patients with rectal inertia divided into two groups: study group (10 women, 6 men; mean age, 38.9 +/- 10.6 years) and control group (6 women, 2 men; mean age, 36.3 +/- 9.8 years). The main complaint was infrequent defecation and straining at stools. Eight healthy volunteers (6 women, 2 men; mean age, 37.2 +/- 9.4 years) with normal stool frequency were included in the study. Through a sigmoidoscope, an electrode was hooked to the RSJ (stimulating) and two electrodes were hooked to the rectal mucosa (recording). Rectal electric activity was recorded before (basal activity) and during electric stimulation of the RSJ electrode with an electrical stimulator delivering constant electric current of 5-mA amplitude and 200-ms pulse width. RESULTS: In the healthy volunteers, rectal pacing effected increases in frequency, amplitude, and velocity from a mean of 2.3 +/- 0.9 to 6.2 +/- 1.8 cycles/min (P < 0.01), 1.2 +/- 0.6 to 1.7 +/- 0.8 mV (P < 0.05), and 4.1 +/- 1. 2 to 6.3 +/- 1.7 cm/s (P < 0.05), respectively. No waves were recorded from rectal inertia patients at rest. Rectal pacing of the study group showed pacesetter potentials with a mean frequency of 2. 1 +/- 1.2 cycles/min, amplitude of 0.9 +/- 0.1 mV, and velocity of 3. 3 +/- 1.6 ms. The control group, in whom the pacemaker was not activated, showed no electric activity. CONCLUSIONS: Rectal pacing succeeded in producing myoelectric activity in patients with rectal inertia. It is therefore suggested that this method be applied for rectal evacuation in patients with inertia constipation.     

The electrovesicogram in the overactive bladder: role in determining pathogenesis and diagnostic significance

We investigated the hypothesis that the abnormal contractility of the smooth musculature of the overactive bladder (OAB) may be due to derangement of its electrical activity. Percutaneous electrovesicography was performed in 22 patients (mean age 46.3 years, 12 men, ten women) with OAB and 14 healthy volunteers (mean age 45.6 years, eight men, six women). Recording was performed with the bladder full and empty. Three electrodes were applied suprapubically and one reference electrode was applied to a lower limb. Reproducible regular triphasic slow waves (SWs) were recorded in the volunteers. The pattern of the full and empty bladder were similar except for the higher amplitude of the waves in the former (P<0.05). The OAB patients showed a dysrhythmic pattern with irregular frequency, amplitude and conduction velocity in both the empty and full bladders. We obtained tachyrhythmic, bradyrhythmic and arrhythmic areas in the same recording. The OAB exhibited a dysrhythmic electrical pattern with areas of different electrical activity in the same recording. The tachyrhythmic, bradyrhythmic and arrhythmic areas are suggested to explain the abnormal vesical contractions and clinical manifestations of OAB. Further studies are required to investigate the cause of the dysrhythmic pattern and the electrovesicogram is suggested as an investigative tool in OAB diagnosis.     

Electrophysiologic identification of the location of the colonic pacemakers in humans: further study.

We recently defined the sites of four colonic pacemakers that appear to generate the electric waves assumed to be responsible for the colonic motility. We hypothesized that a dysfunction of one or more of these pacemakers might interfere with the generation of electric waves and the colonic motility. This hypothesis was investigated in the current communication. The tests were performed during the repair of huge incisional hernia of 8 subjects (5 F, 3 M; mean age 42.8 +/- 3.3 SD years). Two electrodes were applied to each of the terminal ileum (TI), cecum (C), and ascending (AC), transverse (TC), descending (DC), and sigmoid (SC) colon. The electric activity of the TI and the various colonic segments was recorded using surface silver-silver chloride electrodes applied to the colon. The site of change of the wave variables between the TI and the C and between the different other colonic segments was determined by changing the position of the electrodes placed over the segments to be examined. Presumably, the sites where the wave variables changed represent the potential location of the pacemakers. We anesthetized these sites individually by injection of 2% Xylocaine, and then recorded the electric activity after 20 min in all the subjects and after 2 h in only 5 subjects. Electric waves in the form of pacesetter and action potentials were recorded from the TI and the colon. The sites of potential pacemakers could be defined at the ileocecal and cecocolonic junctions, at the mid third of the TC, and at the colosigmoid junction. Anesthetization of the cecal pole resulted in disappearance of the cecal electric waves, with persistence of the waves from the other colon segments. Anesthetization of the cecocolonic junction eliminated the electric waves of the AC and the right half of the TC, while the waves in the rest of the colon persisted. The remaining two pacemaker sites produced similar results when anesthetized. The electric waves reappeared after the anesthetic effect had waned. Thus, the colon possesses at least four pacemakers that appear to mediate the colonic motor activity. Individual pacemaker block by anesthetization effected disappearance of electric waves in the relative colonic segment, which reappeared after waning of the anesthetic effect. The disappearance of these waves upon pacemaker anesthetization supports a relationship between the pacemakers at the anesthetized site and the electric waves. The electric waves seem to be generated by these pacemakers. We suggest that colonic inertia, segmental or total, results from the dysfunction of one or more pacemakers, and that an artificial pacemaker could be applied for the treatment of such conditions. These suggestions need to be further studied.     

A novel technique for removal of permanent pacemaker leads

We removed from 4 patients pacemaker leads that had migrated or become infected. Case 1: A 62-year-old man developed uncontrollable infection of the pacing leads. Case 2: A 78-year-old man, whose infected pacemaker was removed, had a second one implanted in the contralateral side; the pacing lead infection from the first procedure, however, was uncontrollable. Case 3: A 56-year-old woman presented with dyspnea and hepatomegaly subsequent to the second implantation of a pacemaker; the pacing leads from the first procedure caused severe stenosis in both the superior and inferior vena cavae. Case 4: A 60-year-old woman had a ruptured and migrated pacing lead in the right ventricle. We operated using a cardiopulmonary bypass and a specially designed plastic tube for removal of the leads. Although Case 2 required reconstruction of the vena cavae, all patients recovered. When removal of pacing leads is necessary, it should be done as soon as possible with cardiopulmonary bypass.     

“Twiddler syndrome” in two patients with deep brain stimulation

Twiddler syndrome occurs when a patient intentionally or unintentionally manipulates an implantable generator (usually a pacemaker) and dislodges the pacing leads, causing malfunction of the device. Though the syndrome has been described in patients with pacemakers, to our knowledge only one spontaneous case has been described in patients undergoing deep brain stimulation for movement disorders. We report the clinical cases of two patients with Parkinson’s disease who had subthalamic bilateral electrodes implanted and presented the twiddler syndrome 2 and 3 years after surgery. We analysed the possible mechanisms of this syndrome and note that twiddler syndrome should be suspected in patients undergoing deep brain stimulation and showing hardware dysfunction.     

Study of the electromechanical activity of the urinary bladder

Summary The electromechanical activity of the urinary bladder (UB) was studied in 16 dogs. With the animals under anesthesia, the UB was exposed and four electrodes were sutured serially to its anterior wall. Electric activity simultaneously with vesical pressure was recorded for periods of 30 min daily on 10 days. Triphasic pacesetter potentials (PP) were registered from electrodes 1–4, having identical frequency and regular rhythm by all electrodes and being consistent in the individual dog on all test days. Action potentials (AP) followed PP randomly and were accompanied by vesical pressure increase; they represented vesical contractile waves. Balloon distension of the UB effected increased PP and AP frequency. Annular vesical myotomy led to PP and AP disappearance distal but not proximal to the myotomy, which would suggest that (a) the waves spread caudally and (b) a pacemaker exists at the upper part of the UB and triggers the PP.     

General anesthesia for a patient with asymptomatic sick sinus syndrome

A 67-year-old man with glioblastoma was scheduled for craniotomy. Before anesthesia induction, asymptomatic bradycardia (40 beats x min(-1)) occurred, and was resistant to atropine 0.4 mg. The surgery was postponed. He was diagnosed as sick sinus syndrome (sinus arrest). He received implantation of a temporary cardiac pacemaker on the day before the rescheduled surgery. Anesthesia was induced with thiopental 400 mg, fentanyl 200 microg, vecuronium 10 mg and isoflurane 5%, and maintained with isoflurane 1-2% in oxygen 3 l x min(-1) and air 3 l x min(-1). Pacing mode was set to fixed rate asynchronous pacing in the ventricle with a rate of 50 beats x min(-1) after anesthesia induction. Surgery was completed in 8 hours and 45 minutes without any complications. The pacing wire was removed the next day. For patients with sick sinus syndrome, implantation of the pacemaker is indicated in case of bradycardia-tachycardia syndrome or with any clinical symptoms. However, a pacemaker should be implanted before general anesthesia even in a patient with no clinical symptoms because of cardiovascular instability induced by anesthesia.     

主动固定电极行右心室流出道间隔部起搏的临床应用研究

目的探讨采用主动固定电极行右心室流出道（RVOT）间隔部起搏的可行性。方法52例需植入心脏起搏器患者,22例采用主动固定电极行RVOT间隔部起搏（主动电极组）,30例应用被动固定电极行右心室心尖部起搏（被动电极组）。记录术中及随访期间两组各项起搏参数。结果RVOT间隔部起搏定位成功率100％,主动电极组的植入时间和曝光时间均长于被动电极组[（56．13±1．18）min比（15．42±1．24）min,（18．77±6．14）min比（10．12±8．14）min,P〈0．0530主动电极组的QRS波时限短于被动电极组[（0．14±0．02）ms比（0．16±0．04）ms,P〈0．05]。术后随访期间两组起搏参数稳定,未见电极脱位等并发症发生。结论主动固定电极行RVOT间隔部起搏是安全可行的。     

Removal of retained transvenous pacemaker electrodes under cardiopulmonary bypass

A case of breakage and removal of a retained transvenous pacemaker electrode is described. A 22-year-old woman with complete A-V block underwent implantation of a transvenous pacemaker system on the left anterior chest wall in 1989. Three years later, a new generator was implanted on the right chest wall because of local infection of the pacemaker pockets. The old electrodes could not be removed and were left in place. Beginning in 1995, the patient complained of anterior chest pain. A chest roentgenogram revealed that one of the pacemaker electrodes had broken at the right costoclavicular ligament and a fragment was floating in the superior vena vava. The retained electrodes were removed under totl cardiopulmonary bypass. These electrodes had become firmly encased with fibrous tissue within the right ventricle and atrium, but they were easily removed under direct vision duting complete cardiac arrest. The postoperative course was uneventful and the patients had no further complaint.     

Extracorporeal shock wave lithotripsy for ureteral stone in patient with implanted cardiac pacemaker: a case report

We report a case of extracorporeal shock wave lithotripsy (SWL) for ureteral stone in patient with implanted cardiac pacemaker. A 68-year-old woman was admitted to our hospital for left back pain due to left single ureteral stone (13 x 7 mm) in 2002. A permanent cardiac pacemaker has been implanted for sick sinus syndrome in 1997. After evaluation for cardiac function and pacemaker function by a cardiologist and a pacemaker technician, SWL (MFL 5000, Dornier) was performed without changing pacemaker mode (DDD mode). Shock waves were incorrectly exposed a few time triggered by arterial pacing amplitude, but no cardiovascular event or malfunction of the pacemaker was occurred during or after SWL. The ureteral stone was successfully fragmented with 2,400 shock waves (24 kV) and the fragments were delivered immediately.     

Clinical experience with nuclear pacemakers.

Approximately 1,400 nuclear pacemakers have been implanted in patients since April, 1970, without a single battery failure; 64 of these have been implanted at the Newark Beth Israel Medical Center. All except four of the 64 pulse generators were attached to transvenous electrodes, 39 to pacing wires already in place. Fifty-nine of the 64 units are in service and continue to function normally in a follow-up period of up to 2 years. In the total worldwide experience, 70 pacemakers are out of service, approximately half because of the patient's death, and the rest for infection or lead problems, and only three or four because of difficulties with components. The first 15 ARCO pacemakers implanted 2 years ago continue to function well. Of the 15 control pacemakers implanted at the same time, one unit has failed. We have concluded that a nuclear pacemaker should not be used in a patient with limited life expectancy or in an infant, but for the otherwise healthy young or middle-age individual, it should be the unit of choice.     

Feasibility of diaphragm pacing in patients after bilateral lung transplantation

Recent animal studies and intraoperative studies in humans suggested that phrenic nerve stimulation could attenuate ventilator‐induced diaphragm dysfunction. The purpose of the present study is to examine the safety and feasibility of diaphragm pacing during the weaning process after bilateral lung transplantation. Four patients, suffering from chronic pulmonary disease, were included, and diaphragm pacing was evaluated after lung transplantation. Implantation of electrodes at the end of the lung transplant procedure was possible in three of the four patients. In all implanted patients, stimulation of the diaphragm could trigger the ventilator. Implanted electrodes were completely removed by percutaneous retraction after up to 7 days of pacing. Adverse events related to pacing included occurrence of pain. Diaphragm pacing with temporary electrodes, inserted during surgery, is feasible and is able to trigger the ventilator in patients after bilateral lung transplantation. The use of intradiaphragmatic electrodes creates the additional opportunity to monitor the evolution of diaphragm electromyography during the postoperative weaning process.     

Effect of vesical contraction on the non-sphincteric part of the urethra: Recognition of vesicourethral inhibitory reflex

OBJECTIVES: The effect of vesical contraction on the non-sphincteric part of the urethra has been scarcely addressed in the literature. In this study, the hypothesis that detrusor contraction effects dilatation of the non-sphincteric part of the urethra was investigated. METHODS: Non-sphincteric urethral pressure response to vesical balloon distension with normal saline in increments of 50 mL was recorded in 21 healthy volunteers (mean age 40.7 +/- 10.3 years, 13 men) before and after individual anesthetization of the urethra and urinary bladder. Vesical distension was effected by a 10F balloon-ended catheter introduced into bladder per urethram. Urethral and vesical pressures were measured by means of a two-channel microtip catheter. RESULTS: Small-volume vesical distension effected no significant urethral or vesical pressure changes while distension with 350 and 400 mL of saline produced vesical pressure elevation (P < 0.01) and urethral pressure decrease (P < 0.01). Vesical distension after individual vesical and urethral anesthetization effected no change in the urethral pressure. These results were reproducible. CONCLUSIONS: Dilatation of the non-sphincteric part of the urethra upon vesical contraction is suggested to be mediated through a 'vesicourethral inhibitory reflex' and to facilitate passage of urine through the urethra. The reflex may prove to be of diagnostic significance in micturition disorders.     

Electrovesicogram in the Neurogenic Bladder

The vesical electric activiry was studied by electrovesicogram (EVG) in 24 patients with spinal cord injury: 15 with upper (UMNL) and 9 with lower (LMNL) motor neuron lesion. Mean age was 48.3 years; 16 were men and 8 were women. Eight healthy volunteers acted as controls. Transcutaneous recording was done with both a full and empty urinary bladder. Three electrodes were applied supra-pubically and one reference electrode was applied to the lower limb. The normal volunteers recorded regular triphasic pacesetter potentials (PPs), which were reproducible in the individual subject. The electrovesicographic pattern was similar in the full and empty bladder, except that the PPs of the latter had a lower amplitude. The patients with UMNL showed “dysrhythmic” pattern with irregular rhythm, amplitude, and frequency in both the fill and empty urinary bladder. Patients with “LM” exhibited “silent” EVG. The results indicate that electrovesicography could be used as an investigative tool that may help in the diagnosis of such conditions. The technique is simple, easy, noninvasive, and without complications     

Lead fracture--a still frequent cardiac pacemaker complication?

The frequency of pacemaker complications has decreased during later periods of observations. The rate of pacing lead fractures has been reported to amount to 6.2%. According to our experience and data based on 3607 pacemaker implantations for over 15 years this retrospective study examines the following parameters: patient's data, year of implantation, interval till fracture, implantation vena, localisation of the fracture and therapeutic measures. In 1% (36 cases) of our pacemaker patients repeating operations were necessary due to lead fractures. In electrodes implanted after 1977 no break could be observed. Tested material and production methods as well as save implantation modus, avoidance of bending, coiling with a short radius and also a tied fixation ligature, can improve the results.     

Improved silastic sleeve temporary cardiac pacing electrodes

New atrial clip-on and ventricular suture-on temporary pacemaker electrode systems were evaluated in dogs. The ability of these electrodes to sense cardiac electrical activity was evaluated during a 14-day period. At no time did the P-wave potential fall below 3.3 mV and the R-wave potential fall below 6.0 mV. The acute pacing thresholds never exceeded 1.025 V and 1.95 mA. All values are well within acceptable standards for temporary pacing. The lead wires were easily, quickly, and painlessly removed without injury to the myocardium, yet the electrical contact remained tight between the lead wire and electrode preventing premature displacement.