Bipolar Lead Research Articles

A33-2 Optimization of the design of a novel far field signal reduction bipolar lead

A33-2 Optimization of the design of a novel far field signal reduction bipolar lead

Induction ovens and electromagnetic interference: what is the risk for patients with implanted pacemakers?

Electromagnetic fields may interfere with normal pacemaker function. Despite the introduction of modern pacemakers and bipolar lead systems, electromagnetic interference (EMI) still remains to be a concern during daily lives when patients are exposed to cellular phones, electronic security systems, and several household appliances. The aim of this study was to evaluate potential EMI risk of induction ovens, which are increasingly used in private households. The study included 40 consecutive patients (22 men, 18 women; age 73 +/- 11 years) with implanted DDD, VVI, VDD, and AAI pacemaker systems. The pacemakers were programmed to unipolar sensing and pacing. Sensitivity remained unchanged, if the measured sensing threshold was more than twice the programmed value; otherwise, it was set at half of the measured sensing threshold. Patients were placed in a sitting position at the closest possible distance of about 20 cm between two cooking pots and pacemaker bending the upper part of the body slightly over the induction oven. The energy was increased stepwise to the maximum. One pot was removed and placed again at the highest oven level. Potential interference was monitored continuously. The study showed no incidence of pacemaker malfunction during the entire test while the patients with intrinsic cardiac rhythms were exposed to the induction oven at varying energy strengths. Likewise, there was no external interference when the patients were paced at heart rates of 10-15 beats/min above their heart rates. The programmed parameters remained unchanged after the study. In conclusion, this study shows no EMI risk of an induction oven in patients with bipolar or right-sided unipolar pacemakers.

Autocapture Enhancements: Unipolar and Bipolar Lead Compatibility and Bipolar Pacing Capability on Bipolar Leads

Beat-by-beat Autocapture maximizes device longevity by minimizing stimulus amplitude while assuring patient safety. Currently, Autocapture permits use of only bipolar leads. The authors have devised a detection method that operates with unipolar and bipolar leads and covers all pacing and sensing combinations (but bipolar pace and sense simultaneously). This new detection method for unipolar sensing uses the integral of the negative portion of the unipolar evoked response as a robust capture detection feature. When using bipolar leads, the method provides the flexibility of bipolar or unipolar pacing. In this study, unipolar ventricular intracardiac electrograms (EGMs) were recorded in 71 patients, 73.7 +/- 9.9 years of age; 9 with high polarization, 62 with low polarization. High polarization had polished platinum or activated carbon electrodes. Low polarization had TiN, platinized platinum, or IrOx electrodes. The intracardiac EGMs were recorded 544 +/- 796 days after implant. The pacemakers performed an automatic capture threshold test while the intracardiac EGM signals were recorded in a programmer. These digitized signals were saved for off-line analysis. The unipolar evoked response was calculated at up to six (depending on capture threshold) pacing voltages and the polarization integral at 4.5 V and at loss of capture. An automatic calibration algorithm determined if the signal-to-noise ratio was adequate for Autocapture operation. Autocapture was possible with 60 of 62 of the low polarizations, and with 6 of 9 of the high polarizations. The average values form the data collected were: average unipolar evoked response--4.1 +/- 2.1 mV, average peak negative voltage--10.0 +/- 3.7 mV, average polarization 0.3 +/- 0.34 mV, and average signal-to-noise ratio (unipolar evoked response/ polarization) 38 +/- 71. In all cases the algorithm correctly determined the appropriateness of using Autocapture with the electrodes tested and the unipolar evoked response threshold to be used.

Unexpected late clinical problems associated with a ventricular bipolar pacing lead

Unexpected late clinical problems associated with a ventricular bipolar pacing lead

磁気刺激による顔面神経伝導速度分布の検討

Objective: The purpose of this study was to evaluate by the collision method the distribution of nerve conduction velocities (DNCVs) of the facial nerve under transcranial magnetic stimulation (TMS), to better understand its neurophysiological characteristics.Materials and Methods: The subjects were 13 normal volunteers and 3 patients with Bell's palsy. The experiments were carried out using Magstim model 200, a large coil measuring 90mm in diameter with a maximal output of 2.0 tesla (T), and a Neuropack 8 (Nikon Kohden, Japan) to control the stimulation and record the electromyographical findings. The labyrinthine segment of the facial nerve within the temporal bone was selected as the site for transcranial magnetic stimulation, and the main trunk of the facial nerve that runs subcutaneously in the parotid region was selected as the site for electric stimulation. The reference electrode of the bipolar lead was placed over the mentalis muscle. The amplitude of compound muscle action potentials (CMAP) to the mentalis muscle was studied by the collision method.Measurement and Results: The peak of DNCV was detected at 22 to 24m/sec in 13 normal volunteers. The data showed a decrease in the number of thicker fibers, which tended to show faster conduction velocities, in Bell's palsy patients.Conclusions: We were able to investigate the DNCVs of the facial nerve by TMS. Thicker myelinated fibers may be more susceptible to compression damage. From this finding it can be said that the compression of the nerve results in a state comparable with Bell's palsy.

Compatibility of automatic threshold tracking pacemakers with previously implanted pacing leads in children.

The Autocapture function controls and optimizes the amplitude of the pacing pulse and saves energy. The manufacturer recommends using a special low polarization, low threshold bipolar Pacesetter lead for the Autocapture function. The purpose of this study was to evaluate the compatibility of Autocapture with previously implanted pacing leads. The study included 15 patients (mean age 13.6 +/- 3.4 years) who needed pulse generator replacement and received the VVIR pacemaker Regency SR+ or the DDDR pacemakers Affinity DR or Integrity DR with the Autocapture function. The new pulse generators connected to previously implanted ventricular leads. At the time of implantation the pacing threshold was 1.0 +/- 0.35 V at 0.5 ms, the lead impedance was 580 +/- 80 omega, and the spontaneous R wave amplitude was 7.89 +/- 4.89 mV. The polarization signal (PS) was 3.8 +/- 3.04 mV, and evoked response (ER) was 8.15 +/- 4.57 mV at the predischarge testing. Follow-up telemetry was done at months 1, 3, 6, 12, and 18. The follow-up duration was 9.4 +/- 5 months (range 1-18 months). If the results of PS and ER measurements were acceptable for autocapture, it turned on at the 1-month visit. In six (40%) patients the results were found acceptable for autocapture function. Age, lead impedance, pacing threshold, intrinsic R wave measurement, lead age, fixation mechanism, and ER measurements were not statistically different in Autocapture suitable and not suitable groups. The main reason not to activate Autocapture had been increased PS. Any significant fluctuations were not observed in pacing threshold, lead impedance, ER, and PS during follow-up. In conclusion, previously implanted pacing leads may be compatible with the Autocapture function.

Unexpected loss of bipolar lead function associated with lead connection design in dual chamber pacemakers.

Unexpected loss of bipolar pacing function can occur in Guidant VIGOR dual chamber pacemakers with QC2 (Quick Connect) headers. In a retrospective review of 305 implanted patients, 23 exhibited unexpected loss of bipolar pacing lead function from < 1 to 51 months postimplant. Atrial lead problems were seen in 17 patients and ventricular lead problems in 6 (P < 0.05 atrial vs ventricular). Significant symptoms developed in six patients including two with syncope as a result of noncapture. No significant change in bipolar sensing function was seen. Reprogramming devices to the unipolar mode restored appropriate pacing thresholds and lead impedance. The changes in bipolar lead function are likely caused by failure of the QC2 header lead connection system over time.

Implantable electrical gastric stimulation to treat morbid obesity in the human: operative technique.

The surgery to place the implantable gastric stimulator (IGS) is described. There are two implantable components to the IGS. One is the electrical stimulator itself, which is placed in the anterior abdominal wall. It is connected to a bipolar lead that is positioned in the muscle wall of the stomach. We describe the procedure that is necessary to safely place the components. 4 patients have been implanted using techniques that were developed and refined around the world. There were no operative deaths. All procedures were successfully completed laparoscopically. Two (2/4) connections required revision because the leads were not fully inserted into the header of the generator. The operation to implant the IGS is safe and simple to perform. Attention to technical details is essential.

Far-field P-wave sensing by the right ventricular lead of conventional dual chamber pacemakers.

This report describes two cases of far-field sensing of the P wave by the ventricular channel of conventional DDD pacemakers programmed to a relatively high sensitivity to promote sensing of ventricular extrasystoles. Ventricular pacing was maintained in both cases when the ventricular channel was not inhibited. One case was caused by displacement of a bipolar ventricular lead towards the right ventricular inflow tract. The other case occurred only in relation to an atrial extrasystole in the absence of ventricular lead displacement.

Standard electrocardiographic values in Holstein calves

This paper presents electrocardiographic values in 25 Holstein calves using the standard bipolar limbs leads (I, II and III), augmented unipolar limb leads (avL, avR and avF) and a bipolar chest lead (V10). Two groups with different ages were compared (newborn - 18 to 72 hours and calves - 27 to 33 days old). It was concluded that no differences between age groups in P, Q, R, S and T waves, in the PR, QRS, QT and ST intervals and in axis orientation were observed.

Thin co-radial bipolar leads: technology and clinical performance.

While bipolar leads offer advantages such as better sensing performance than unipolar leads, their use has been limited by a larger lead diameter and reports about a high failure rate of several bipolar lead models. This has led to the development of thin bipolar leads using a special technology which aims at improving lead safety. Leads with monofilar thin conductors (drawn filled tube) which are individually coated with a very resistant material (ETFE) have been developed. Using a co-radial instead of co-axial bipolar conductor design, the lead diameter could be reduced to 4.5 F compared to 6-7 F of conventional bipolar leads. Bench testing demonstrated a significant improvement of this lead technology with respect to degradation of insulation material by biochemically reactive solutions. Also mechanical characteristics such as resistance to tearing forces and compression showed a high lead durability. From our own experience, co-radial bipolar leads show a favorable electrical performance with the exception of a relatively low pacing impedance. Also during long-term follow-up, the rate of lead failure was very low. These findings are corroborated by other clinical studies which also demonstrated good handling characteristics of thin bipolar leads during implantation.

Alternative to the transvenous approach in pediatric pacing - long-term experiences with bipolar epicardial pacing leads.

Cardiovascular anatomy and limited venous access may preclude the implantation of endocardial pacing systems in children as well as adults with congenital heart disease. Thus, the implantation of myo/epicardial pacing leads is required in these patients. The less favorable long-term results experienced in the past with myocardial screw-in leads are often used to justify the transvenous approach whenever possible, even in infants. However, encouraging preliminary results were reported from modern bipolar steroid eluting epicardial pacing leads. Further follow-up data are now warranted to obtain arguments for the dispute regarding the preferable or optimal pacing approach in infants and small children. Methods From January 1994 to November 2000 a total of 64 bipolar steroid-eluting epicardial pacing leads (Medtronic CapSure Epi 10366 and 4968, Medtronic, Inc, Minneapolis, MN, USA) were implanted in 52 children at our institutions (52 electrodes in ventricular and 12 in atrial position). The median age of the children was 25.5 months (range 0.03 to 193 months). As part of a prospective multicenter study these leads were continuously followed in combination with AutoCapture devices since December 1996. Results Telemetry data demonstrated at discharge low pacing thresholds both for the ventricular (0.8±0.37Volt @ 0.5ms) and the atrial leads (0.8±0.4Volt @ 0.5ms) as well as excellent sensing signals (P wave 2.9±1.4mV and R wave 10.6±5.5mV) without significant changes during follow-up up to 24 months. AutoCapture controlled pacing could be applied in 46/52 (88%) children rendering a calculated battery service life of 14.8±2.9 years with a VVIR device (Regency SR 5130, St. Jude Medical, Sylmar, CA, USA) and 10.8±1.1 years with a dual chamber device (Affinity DR 5330, St. Jude Medical, Sylmar, CA, USA). Apart from the necessity to reposition three leads in the immediate postoperative period no late lead related complications have been experienced during follow-up. Conclusions The new steroid-eluting bipolar epicardial pacing lead demonstrates a high reliability and consistent extraordinary pacing as well as sensing thresholds. AutoCapture controlled pacing is feasible in most patients and may result in marked battery service life extension. Hence epicardial pacing can now be highly recommended as the first choice for permanent pacing in infants and children.

Cisapride plasma levels and corrected QT interval in infants undergoing routine polysomnography.

Reported QTc prolongation associated with cardiac arrhythmia in a small number of children undergoing cisapride therapy and lack of pharmacokinetic correlation provided the impetus for this prospective study. The authors evaluated the relation between cisapride plasma concentrations, the electrocardiographic QT interval, and cardiac rhythm in infants undergoing routine 8-hour polysomnography. A total of 211 infants were enrolled: 84 (17 born prematurely) undergoing cisapride therapy for at least 4 days for suspected gastroesophageal reflux and 127 controls (10 born prematurely), aged between 1 week and 13.5 months. Infants underwent continuous bipolar limb lead I recording during routine 8-hour polysomnography. QT intervals and heart rate were measured at hourly intervals. The morning after polysomnography, 12-lead electrocardiography was performed (1 hour after cisapride administration). Cisapride plasma concentrations were determined immediately before and 1 to 2 hours after administration. Serum electrolyte concentrations were measured. The administered cisapride dose ranged from 0.35 to 1.55 (mean, 0.81, median 0.79) mg. kg-1. d-1. Cisapride plasma concentrations were significantly higher in infants younger than 3 months of age. Cisapride-treated infants younger than 3 months of age had longer QTc intervals compared with age-matched controls. Heart rate was similar for cisapride-treated and control infants. No arrhythmia or atrioventricular conduction abnormalities were observed. At comparable doses of cisapride and comparable plasma concentrations, the QTc was significantly higher in infants younger than 3 months of age. This confirms age-dependent cisapride pharmacokinetics in the first 10 to 12 weeks strongly correlated with changes in body weight and may also suggest an altered ability of infants younger than 3 months of age to metabolize cisapride. The clinical significance and risk of the increased QTc interval is unclear. Cisapride should be judiciously prescribed in infants younger than the age of 3 months and electrocardiography should be performed before and during therapy.

Cisapride Plasma Levels and Corrected QT Interval in Infants Undergoing Routine Polysomnography

ABSTRACTBackgroundReported QTc prolongation associated with cardiac arrhythmia in a small number of children undergoing cisapride therapy and lack of pharmacokinetic correlation provided the impetus for this prospective study. The authors evaluated the relation between cisapride plasma concentrations, the electrocardiographic QT interval, and cardiac rhythm in infants undergoing routine 8‐hour polysomnography.MethodsA total of 211 infants were enrolled: 84 (17 born prematurely) undergoing cisapride therapy for at least 4 days for suspected gastroesophageal reflux and 127 controls (10 born prematurely), aged between 1 week and 13.5 months. Infants underwent continuous bipolar limb lead I recording during routine 8‐hour polysomnography. QT intervals and heart rate were measured at hourly intervals. The morning after polysomnography, 12‐lead electrocardiography was performed (1 hour after cisapride administration). Cisapride plasma concentrations were determined immediately before and 1 to 2 hours after administration. Serum electrolyte concentrations were measured.ResultsThe administered cisapride dose ranged from 0.35 to 1.55 (mean, 0.81, median 0.79) mg · kg −1 · d −1 . Cisapride plasma concentrations were significantly higher in infants younger than 3 months of age. Cisapride‐treated infants younger than 3 months of age had longer QTc intervals compared with age‐matched controls. Heart rate was similar for cisapride‐treated and control infants. No arrhythmia or atrioventricular conduction abnormalities were observed.ConclusionsAt comparable doses of cisapride and comparable plasma concentrations, the QTc was significantly higher in infants younger than 3 months of age. This confirms age‐dependent cisapride pharmacokinetics in the first 10 to 12 weeks strongly correlated with changes in body weight and may also suggest an altered ability of infants younger than 3 months of age to metabolize cisapride. The clinical significance and risk of the increased QTc interval is unclear. Cisapride should be judiciously prescribed in infants younger than the age of 3 months and electrocardiography should be performed before and during therapy.

Experimental study for single-pass lead DDD pacing

We investigated the possibility of single-pass lead DDD pacing in animal experiments, using an original double balloon bipolar lead with variable dipole spacing. In the present study, P-wave sensing was best with a narrower dipole spacing, a smaller electrode surface area, and with the placement of atrial electrodes in the upper region of the atrium. The pacing threshold was not significantly different in various atrial sites, whereas the threshold energy increased dramatically under conditions of truly floating atrial pacing. Additionally, our simulation analysis revealed that the pacing thresholds were lower with a smaller electrode surface and the optimal dipole spacing was dependent on the distance between the atrial wall and the stimulating electrodes. Since stimulation at a distance from the atrial wall is barely feasible, further studies are required to achieve single-pass lead DDD pacing.

2:1 Tracking of Sinus Rhythm in a Patient with a Dual‐Chamber Implantable Cardioverter Defibrillator: What is the Mechanism?

A 49-year-old woman with hypertrophic obstructive cardiomyopathy received a dual-chamber pacemaker in 1995. It resulted in signiŽ cant reduction in the intraventricular pressure gradient and signiŽ cant improvement in symptoms. She developed ventricular tachycardia, and the pacemaker was replaced with a dual-chamber implantable cardioverter deŽ brillator (ICD). The ventricular pacing lead was extracted, and the preexistent atrial lead (P wave: 3 mV) and a new active-Ž xation, “integrated” bipolar deŽ brillation lead (Sprint SVC 6945; Medtronic Inc., Minneapolis, MN, USA) were connected to a GEM DR 7271 (Medtronic) generator. Programming was as follows: pacing mode DDD, lower rate 60 beats/min, upper rate 120 beats/min, sensed AV delay 100 msec, ventricular output 4 V at 0.4 msec, maximum atrial sensing 0.3 mV, maximum ventricular sensitivity 0.3 mV, postventricular atrial refractory period (PVARP) 310 msec, postpace ventricular blanking 240 msec, premature ventricular complex (PVC) response ON. Immediately after lead connection, an unusual pattern of pacemaker alternans was seen (Fig. 1). Only every other sinus beat was tracked as expected. The other beats presented intrinsic conduction with a PR interval longer than the programmed AV delay. What is the mechanism for the alternans?

A convenient method to reduce crosstalk in surface EMG

Objectives: Crosstalk in surface EMG can be reduced by the use of spatial filters. We compared a variety of spatial filters to establish the most effective and the least complex method to reduce crosstalk. Methods: Six different spatial filters described in the literature were tested in 8 healthy volunteers. Electrode arrays were placed over the anterior tibial and triceps surae muscles. Selective muscle activation was achieved both by supramaximal nerve stimulation and by maximal voluntary contraction. Selectivity of activation was guaranteed by using intramuscular wire electrodes. Crosstalk was quantified by dividing the amount of EMG activity recorded during pure agonist activation (i.e. the muscle directly under the electrode array) by the EMG activity recorded during pure antagonist activation. This was done for both compound muscle action potentials and voluntary muscle activation. The amount of crosstalk recorded with the different spatial filters was compared with that recorded with a standard bipolar lead. Results: Crosstalk was most reduced by the ‘double-differential’ (DD) filter, yielding an up to 6-fold improvement of EMG selectivity. We then compared signals recorded with this DD filter with those recorded with the less complex ‘branched electrode’. As expected on theoretical grounds, signals from both filter types were identical. Conclusions: Crosstalk is best reduced using a ‘double-differentiating’ recording technique, which can be achieved easily using a branched electrode instead of a standard bipolar lead. This technique can be used with all conventional EMG equipment.

Advanced bipolar lead–acid battery for hybrid electric vehicles

A large size 80 V bipolar lead acid battery was constructed and tested successfully with a drive cycle especially developed for a HEV. The bipolar battery was made using the bipolar plate developed at TNO and an optimised paste developed by Centurion. An empirical model was derived for calculating the Ragone plot from the results from a small size 12 V bipolar lead–acid battery. This resulted in a specific power of 340 W/kg for the 80 V module. The Ragone plot was calculated at t=5 and t=10 s after the discharge started for current densities varying from 0.02 to 1.2 A/cm 2. A further development of the bipolar lead–acid battery will result in a specific power of 500 W/kg or more. From the economic analysis we estimate that the price of this high power battery will be in the order of 500 US$/kWh. This price is substantially lower than for comparable high power battery systems. This makes it an acceptable candidate future for HEV.

Far field R wave sensing early after implantation-comparison of active and passive fixation leads

With increasing use of Mode Switch algorithms, Far Field R wave Sensing (FFRS) has again become increasingly ImportanL We compared results eady after implantation with a passive and active fixation lead in a dual chamber pacing system allowing the programming of high atrial sensitivities (up to 0.1 mV), in avoiding FFRS. METHODS: 45 patients received a dual chamber pacemaker, Biob'onik Ac~os DR. In 29 patients, an affial bipolar preshaped tined J lead (BiotTonik Synox SX 53 JBP; ring-tip distance 14 mm) was used, 16 patients received an atrial bipolar active fixation lead (Biob'onik Elox 53 BP; dng-tip distance 10 ram). The ventricular lead was a unipolar lead (Biotronik Polymx PX 60-UP) in all cases. P and R wave amplitudes, thresholds and lead impedances ware measured. FFRS threshold was defined as the highest atTial sensitivity setting without Far Field detection of the paced R wave by the atrial sensing amplifier. During FFRS testing, simultaneous recording of atrial and ventricular IEGM, marker channel (A&V) and surface ECG was performed. Measurements ware made within 2 months postimplanL RESULTS: Results are summarized in table 1. Ta~el I E~p. Pwave N d ~ d ~ d NdaJle~:llmp. FFRSunipolm i FFRS / (mv~ (v at 0.4 ms) I (n) I (mV) ~po~ (mV) I ~ 2.89 +/-1.4 0.48 +/0.42 709 +/147 I 0.37 +h 0.22 p.21 .I.h 0.07 I ActhmFtxa0on I 2.33W-1.51 1.11 +/*0.43 378+/-38 I 0.49+1-0.27 p.24+h0.13 I P value ~ 0.2 0.003 <0.001 0.2 / 0.7 (P values = comparison of measumnlents in passive and aclfve fixation lead group) Both leads showed comparable results in terms of atrial sensing, whereas the atrial threshold was significantly higher with the active fixation lead, at least in the early phase after implantation. Lead impedance was higher with the passive (high impedance) lead. Venbicular measurements ware comparable in both groups. FFRS was significantly better in both groups with bipolar sensing compared to unipolar sensing. CONCLUSION: In the early phase after implantation (< 2 months), P wave sensing was comparable with both leads, but anal threshold was higher with the active fixation lead. Far Field R wave sensing was comparable in both leads and better with bipolar compared to unipolar sensing. HIGH IMPEDANCE LATEST GENERATION VENTRICULAR LEADS: COMPARISON BETWEEN TWO STEROID AND ONE NON -STEROID ELUTING LEAD WITH ULTRASMALL PACING SURFACE. D. Cornacchia E. Tampieri, S. Silvani, Cardiology Department, Ravenna, M. Nastasi, Cardiology Department Villabianca Bad, ITALY.

Safe and effective placement of two bipolar silicone leads in the cephalic vein using a hydrophilic guidewire and a split introducer.

The cephalic vein (CV) is preferable to the subclavian vein for implanting permanent pacing leads because of fewer complications. Unfortunately, this access is unusable in a substantial number of patients. This prospective study evaluates a technique to increase CV access for the placement of two silicone bipolar leads used in DDD pulse generator implants. A standard cephalic cutdown was performed under local anesthesia and a hydrophilic guidewire (HGW) threaded in the CV. The first (ventricular) bipolar lead was then introduced and positioned. When possible, introduction of the second (atrial) lead followed the same direct access. A failed introduction led to a modified procedure (MP) relying on a "split" introducer (8-9 Fr Plastimed) advanced with a circular motion over the HGW, then removal of the dilator, removal of the HGW, insertion of the pacing lead into the sheath with placement in the right atrium, followed by sheath withdrawal. Over an 18-month period, 90 consecutive patients had DDD pacemakers implanted. The CV was accessible in 76 (84.5%) of 90 patients and the direct introduction of the ventricular lead was obtained in 74 (97.4%) of these. Atrialization proceeded as follows: direct access CV in 14 (18%) of 76 patients, MP access in 54 (71%) of 76 patients, and MP failure in 8 (11%) of 76 patients. Overall, this approach allowed cephalic dual insertion in 68 (89%) of 76 patients. In conclusion, the modified procedure presented in this study allows a dual catheterization with bipolar leads in 89% of patients when a CV is available. This significantly improves the success rate for dual bipolar lead implants in this configuration.