bluuebunny/crossref_metadata_2025 huggingface dataset:
Transatrial Implantation of Transvenous Pacing Leads is an Alternative to Implantation of Epicardial Leads
Authors: BYRD CHARLES L. , SCHWARTZ SUSAN J.
Published: October 2007

BYRD, C.L.: Transatrial Implantation of Transvenous Pacing Leads as an Alternative to Implantation of Epicardial Leads. State‐of‐the‐art pacing modalities are not readily utilized with conventional epicardial pacing lead implantation techniques. A transatrial implantation technique was developed combining a limited surgical approach with transvenous leads. Six patients who were poor candidates for transvenous implants have received DDD or DDDR pacemakers by this approach. The limited surgical approach includes resection of the third or fourth costal cartilage through a small skin incision, reflection of the pleura, and opening of the pericardium. The introducer and transvenous leads are inserted through a right atrial pursestring suture. The leads are positioned in the right ventricle and right atrium using standard fluoroscopic techniques. Through the incision, the subcutaneous tissue pocket is constructed on the right anterior chest wall. The leads are connected to the pacemaker without the need for adaptors or tunneling. There were no procedure‐related complications. The magnitude of the surgery and postoperative morbidity are significantly less than for a standard thoracotomy, median sternotomy, and transdiaphragmatic epigastric or subcostal approach. The utility of the transatrial implantation technique is that it allows the use of state‐of‐the‐ art bipolar dual chamber pacemakers restoring access to all pacing modalities for those patients not candidates for transvenous implantation.
A Method for Estimating Endocardial Electrode Stability
Authors: STIRBYS PETRAS , SKUCAS JONAS , ANDZIUKEVICIUS GIEDRIUS
Published: October 2007

STIRBYS, P., ET AL.: A Method for Estimating Endocardial Electrode Stability. Assessment of cardiac pacing electrode stability following implantation is of major importance. We describe a method of testing electrode stability using a provocative test. The method includes synchronized electrical pacing of the left phrenic nerve by an especially designed external pacemaker. A positive response is abrupt, a diaphragmatic contraction, which in turn induces an abrupt heart movement in its diastole, its relaxation phase. Fifty‐six various endocardial electrodes were tested in this fashion. Seven electrodes, one with flange tip, two tined, and four had no fixation dislodged after this pacing test. Insignificant elevation of acute ventricular pacing threshold was observed. While this method appears to be advantageous, additional clinical data is necessary.
Intravascular Lead Extraction Using Locking Stylets, Sheaths, and Other Techniques
Authors: FEARNOT NEAL E. , SMITH HEIDI J. , GOODE LOUIS B. , BYRD CHARLES L. , WILKOFF BRUCE L. , SELLERS T. DUNCAN
Published: October 2007

FEARNOT, N.E., ET AL.: Intravascular Lead Extraction Using Locking Stylets, Sheaths, and Other Techniques. Septicemia necessitates extraction of chronic pacemaker leads. Using locking stylets and sheaths to extract leads via the implantation vein (subclavian, cephalic, or jugular) and maneuvering devices, sheaths, and retrieval baskets via the femoral approach, extraction of 228 leads implanted 5 days to 240 months (mean 55 months) was attempted in 136 patients (mean 62 years) at 34 institutions. In addition to septicemia (9%) and infection (39Y0), total 48%, indications included prophylaxis/replacement (40%), and other (12%). Seventy‐seven leads were atrial, 151 ventricular; 147 were unipolar, 81 bipolar; 96 had silicone insulation, 127 polyurethane, 1 poly/silicone, and 2 undetermined. Fixation included tines or fins (1601, screw (401, flange (12), and other (16). One hundred and ninety‐four leads were completely extracted, 19 partly extracted, and 15 not extracted. Procedural complications were: torn atrium requiring open heart repair (1), hemothorax requiring a chest tube and blood transfusions (1), subacute hemothorax requiring drainage 18 days after discharge (1), thrombosis treated by drugs (1), and myocardial avulsion without sequela (1). Important observations included the significant training required due to the large number of possible clinical variables, and the need to be prepared for life‐threatening cardiovascular complications. With training, procedures done at higher volume and lower volume institutions met with similar success. Conclusion: Intravascular lead extraction is a viable technique whose benefits outweigh the risks, given the proper intensive training and open heart surgical backup, and may obviate the need for open heart surgery for lead extraction.
Drug‐Eluting Collar—A New Approach to Reducing Threshold
Authors: WILSON ANTHONY , COWLING RAY , MATHIVANAR RANJI , BREWER GREGORY , ANDERSON NEIL , SKALSKY MICHAEL
Published: October 2007

WILSON, A., ET AL.: Drug‐Eluting Collar—A New Approach to Reducing Threshold. This study evaluated the clinical performance of leads with a drug‐eluting (< 0.5 mg of dexamethasone sodium phosphate) collar (DEC) placed adjacent to a 4‐mm2 Pt/Ir coated electrode (Telectronics model 030–368). Ten trailing tined ventricular silicone DEC leads and ten control leads (model 030–359) were implanted transvenously in patients of comparable age, sex, and indication for pacing. Early threshold rise, chronic thresholds (Vario), and lead impedances were monitored by pacer telemetry. The DEC lead had substantially lower thresholds in the first few weeks (p < 0.0005) as well as chronically (p < 0.025). The study has shown that a drug dose of < 0.5 mg, released from a drug‐eluting collar (DEC), is effective in reducing thresholds.
Chronic Animal Testing of New Cardiac Pacing Electrodes
Authors: ADLER STEVEN , SPEHR PAUL , ALLEN JOHN , BLOCK WARREN
Published: October 2007

ADLER, S., ET AL.: Chronic Animal Testing of New Cardiac Pacing Electrodes. To evaluate the electrical performance of new electrode technologies, 24 leads containing either carbon coated porous titanium (BIOPORE, (Intermedics, Inc., Freeport, TX)), iridium oxide (IROX), or iridium oxide coated with polyethylene glycol (IROX‐PEG) electrodes (eight of each) were implanted into the ventricles of 12 canines. Stimulation threshold data was measured at regular intervals for 24 weeks. Low acute values were observed for all leads (0.32 ± 13 V at 0.6 msec pulse width), but the IROX‐PEG electrode demonstrated lower subchronic, peak, and chronic values. Compared to implant, the IROX‐PEG electrodes' stimulation thresholds rose only 0.23 V when chronic conditions occurred. There were no significant differences between the electrodes in pacing impedance or R wave amplitude measurements. We conclude that both IROX and IROX‐PEG technologies represent a promising approach to the design of more efficient cardiac pacing leads.
A New Single Lead VDD Pacing System
Authors: PERCOCO G.F. , ANSANI L. , BARBIERI D. , GUARDIGLI G. , TOSELLI T. , AUDOGLIO R. , ANTONIOLI G.E.
Published: October 2007

PERCOCO, G.F., ET AL.: A New Single Lead VDD Pacing System. In 24 patients with advanced heart block and normal sinus node function, a new single lead VDD pacing system was implanted. At implantation, the endoatrial, bipolar electrogram was recorded in all patients. The lead position was checked by means of chest X‐ray. At discharge and after 1, 3, and 6 months, testing for myopotential inhibition, telemetric evaluation of the endoatrial potential, and Holter recordings were made. After discharge, 18 patients performed two cardiopulmonary exercise tests at two different rate‐matched AV intervals. All investigations showed good AV synchrony and a lack of interferences by myopotentials. The maximum rate‐matched AV interval provided a significantly improved exercise capacity, which was more evident in patients with signs of myocardial failure.
Survival of Implantable Pacemaker Leads
Authors: FURMAN SEYMOUR , BENEDEK Z. MICHAEL
Published: October 2007

FURMAN, S., ET AL.: Survival of Implantable Pacemaker Leads. Early polyurethane leads were reported to have a high incidence of materials failure. In 1979 a six‐center registry was begun. By October 31, 1989, 7, 311 leads had been registered and lead longevity was calculated by individual manufacturer, cumulatively for all manufacturers and for individual leads. Each lead was registered at implant and at removal from service as having been removed for materials failure or for unrelated reasons. Calculations were made for 23 models and for a total of three manufacturers with more than 100 leads implanted. Four thousand seven hundred and sixty three leads (65.1%) were from Medtronic; 2, 177 (29.8%) from Cordis; 297 (4.1%) from Intermedics; and 77 (1.0%) were from all others. The 10‐year cumulative survival of Medtronic leads was 96.6 ± 0.4%; for Cordis leads it was 99.9 ± 0.1% and for Intermedics leads 97.7 ± 0.9%. Three lead models registered over 100 units and had poorer survival at 5 years than the remainder of all manufacturers' experience. They were #6972 (n = 107) with 78.6 ± 4.5%; #6991U (n = 294) with 90.6 ± 1.9%; and #4012 (n = 288) with 97.3 ± 1.5%. Other possibly failed models did not achieve statistical significance. It can be anticipated that a lead which survives to the seventh year will have prolonged longevity as thereafter additional failures are uncommon.
Stiffness of the Distal Tip of Bipolar Pacing Leads
Authors: CAMERON JIM , MOND HARRY , CIDDOR GARY , HARPER KEITH , MCKIE JENNIFER
Published: October 2007

CAMERON, J., ET AL.: Stiffness of the Distal Tip of Bipolar Pacing Leads. The stiffness of a bipolar pacing lead, particularly between anode and cathode, may be responsible for myocardial penetration and perforation. Following an unprecedented 7% incidence of high threshold exit block with a single model bipolar ventricular endocardial lead, a study was undertaken to compare pacing lead stiffness between anode and cathode of six models of bipolar leads from two manufacturers; Telectronics (T) and Medtronics (M). Four leads had polyurethane insulation; T 030–284 (Laser Dish), T 329–259 (Cordis, Encor), M4012 (Target Tip), and M 4004 (Capsure). Two leads had silicone rubber insulation; M 5026 (Capsure) and M 5024 (Capsure SP). All leads were subjected to two stiffness tests. The Tip Deflection Test involved securing the lead at 45° at the indifferent electrode and applying a force to deflect the tip 5 mm. The three point bending test involved placing the lead over two fixed bars in contact with the anode and cathode. Midway a third bar was pushed onto the lead and the force to deflect the lead 2 mm was recorded. The results showed that pacing leads with polyurethane insulation were much stiffer than those with silicone rubber insulation. The T 030–284 because of its construction was found to be the stiffest. The next stiffest was the M 4012. Both these leads had an unacceptable incidence of high threshold exit block; 7% with the T 030–284 (89 implants) and 3% with the M 4012 (102 implants). No cases of high threshold exit block were documented with the other four pacing leads and in particular the silicone rubber M 5026 (344 implants). It is recommended that bipolar pacing leads with low stiffness between anode and cathode be used and that all new pacing leads be tested for stiffness prior to human implants.
Variability of the Intracardiac Electrogram: Effect on Specificity of Tachycardia Detection
Authors: PAUL V.E. , BASHIR Y. , MURPHY T. , MALIK M. , SAUMUREZ R. , CAMM A.J.
Published: October 2007

PAUL, V.E., ET AL.: Variability of the Intracardiac Electrogram: Effect on Specificity of Tachycardia Detection. Correlation has been described as a method of high sensitivity to distinguish ventricular arrhythmias from sinus rhythm but the specificity of this algorithm has not been assessed. Ten patients with a history of chronic ventricular tachycardia were studied. The ventricular endocardial electrogram was recorded during sinus rhythm at rest immediately following exercise and during their clinical ventricular tachycardia. Each complex recorded during these sample periods was correlated with a template constructed during sinus rhythm at rest. Although for each patient the range of correlation values obtained at rest were clearly separated from those obtained during ventricular tachycardia, in 69% of cases there was overlap of the range in sinus tachycardia and ventricular tachycardia.
Detection of Ventricular Tachycardia Using Scanning Correlation Analysis
Authors: STEINHAUS BRUCE M. , WELLS RANDY T. , GREENHUT SAUL E. , MAAS STEVE M. , NAPPHOLZ TIBOR A. , JENKINS JANICE M. , DICARLO LORENZO A.
Published: October 2007

STEINHAUS, B.M., ET AL.: Detection of Ventricular Tachycardia Using Scanning Correlation Analysis. Cross correlation is an accurate method for distinguishing normal sinus rhythm (NSR) from ventricular arrhythmias. The computational demands of the method, however, have prohibited development of an implantable device using correlation. In this study, temporal data compression prior to correlation analysis was used to reduce the total number of computations. Unipolar and bipolar intracardiac electrograms of NSR and 23 episodes of ventricular tachycardia (VT) from 23 patients were obtained from a right ventricular apex electrode catheter during routine electrophysiology studies. The data were filtered (111 Hz), digitized (250 samples/sec) and temporally compressed to 50 samples/sec. Data compression removed four out of every five samples by only saving the sample with the maximum excursion from the last saved sample. The average squared correlation coefficient (r2) was computed for the NSR and VT episodes using each patient's NSR waveform as a template. In all 23 patients, the r2 values showed large separation between NSR versus VT in both unipolar (0.93 ± 0.05 vs 0.20 ± 0.16, p < 0.005) and bipolar (0.91 ± 0.07 vs 0.17 ± 0.11, p < 0.005) electrode configurations using template lengths of 80% the intrinsic interval (avg ± SD). Narrow templates 40% intrinsic interval or less) often resulted in multiple r2 peaks during each heart cycle and degraded the r2 separation (n = 10, p < 0.005). High pass filtering at 3 Hz also degraded the r2 separation (n = 10, p < 0.05). Standard noncompressed correlations indicated that data compression had negligible effects on the results. Thus, a computationally efficient cross correlation method was found to be a reliable detector of VT. The results suggest that the T wave, as well as the QRS complex, is useful in VT recognition.
Nonhomogeneous Local Atrial Activity During Acute Atrial Fibrillation: Spectral and Dynamic Analysis
Authors: KARAGUEUZIAN HRAYR S. , KHAN STEVEN S. , PETERS WERNER , MANDEL WILLIAM J. , DIAMOND GEORGE A.
Published: October 2007

KARAGUEUZIAN, H.S., ET AL.: Nonhomogeneous Local Atrial Activity During Acute Atrial Fibrillation: Spectral and Dynamic Analysis. Atrial fibrillation (A Fib) has been categorized into four different types (I‐IV) based on the morphology of the epicardial bipolar electrogram. In the present study, we hypothesized that these same types of A Fib also exist at endocardial sites. Simultaneous high, mid, and low right atrial endocardial bipolar electrograms were analyzed during acute A Fib induced by a rapid train of stimuli (20–40 Hz] for 1–3 seconds in anesthetized closed‐chest dogs (N = 7, total of 72 episodes). A Fib lasted between 3 seconds and a few minutes (22.3 ± 22.8 sec). During A Fib, bipolar electrograms (0.5–500 Hz) were both discrete (types I and II) on electrograms recorded at one site and at the same time irregular (type III) on electrograms recorded at another site. The three simultaneously recorded electrograms encompassed all combinations of the four types of A Fib. When A Fib had a discrete electrogram morphology (types I andlor II), the mean rate of the A Fib was 494 ± 93 beats/min. At a given site, electrogram morphology also changed type over time. Fast Fourier transform (FFT) of the digitized electrograms (8–10 sec, 800 Hz digitization) showed peaks mostly below 15 Hz [range 0–30 Hz), that were either discrete (narrow band) with clear harmonic components, or had continuous (broad band) spectra, that changed in a time and site dependent manner. Phase plane plots (PPP), a plot of voltage versus rate of change of voltage, varied with respect to time and location. However, the morphology of these PPP often inscribed well defined structure suggesting dynamics compatible with deterministic chaos, rather than random dynamics. We conclude that A Fib is both temporally and spatially heterogeneous and that all combinations of the four different types of A Fib occur simultaneously. These findings may be helpful in developing robust algorithms for A Fib recognition for antitachycardia devices.
Computerized Methods of Pace‐Mapping for Topical Diagnosis of Ventricular Arrhythmias
Authors: BOCKERIA L.A. , MIRSKY G.V. , MAKAROVA L.K.
Published: October 2007

BOCKERIA, L.A., ET AL.: Computerized Methods of Pace‐Mapping for Topical Diagnosis of Ventricular Arrhythmias. Surgical treatment of ventricular arrhythmias (VAs) is an effective method of solving sudden cardiac death. The important problem of surgical treatment of VAs is the topical diagnosis of the origin of arrhythmia. The precise localization of this area is extremely important for effectiveness of operation. The method of epicardial mapping of the heart during the induced paroxysm of VA is widely used for solving this problem. This problem is difficult when it is impossible to induce tachycardia during the operation. The method of pace‐mapping was developed for such cases. This method includes sequential electrical stimulation of ventricles with ECG recording and comparison between intraoperative and preoperative ECG. The goal is the identification of the area of ventricles closed to preoperative ECG with VA. Manual processing of these data is difficult and takes time. The results of such processing have a low precision. That is why we propose using computerized methods. The goal of this investigation is to develop computerized methods of topical ECG diagnosis of VA. We propose a method of computer comparative analysis of ECG morphology for spontaneous and stimulated ECG. The goal is the determination with stimulated ECG the point of ventricles with ECG closest to spontaneous ECG during ventricular tachycardia. Nine patients (15–57 years old) with VA were studied. The main result of this investigation is that computerized pace‐mapping method is an effective tool for topical diagnostics of different forms of VAs, which is impossible to induce by electrical programmed stimulation.
Perioperative Mapping of Parahisian Accessory Pathways
Authors: VERBEET THIERRY W. , VAN‐NOOTEN GUIDO , MASSAUT JACQUES J. , KACENELENBOGEN RAYMOND H. , DEUVAERT FRANK E. , TELERMAN MICHEL
Published: October 2007

VERBEET, T.W., ET AL.: Perioperative Mapping of Parahisian Accessory Pathways. In 1989, two patients were operated for deep septal “parahisian” pathways in our institution. Three different mapping techniques were used. (1) Epicardial activation mapping with a belt of 21 bipolar electrodes positioned around the heart. This belt was positioned either on the atrial or on the ventricular side of the atrio‐ventricular annulus in order to localize both the atrial and the ventricular insertion of the bypass tract. (2) Right intra‐atrial activation mapping on the normothermic beating heart with a bipolar hand‐held probe. (3) Right intra‐atrial cryomapping at 0°C. The “parahisian” pathways are remote from the epicardium and the pattern of epicardial activation is different from that of the free‐wall pathways. Case 1: The electrophysiological study showed a concealed anteroseptal bypass tract. The peroperative atrial epicardial mapping during orthodromic tachycardia (OT) showed simultaneous activation of the posteroseptal area and of the basis of the right appendage. Right intra‐atrial mapping during OT showed an anteroseptal “parahisian” pathway. Case 2: The ECG and electrophysiological study showed a right posterior pathway. The first site of epicardial ventricular activation during atrial stimulation was the right posterior area, 30 ms after the onset of the delta wave. The first site of epicardial atrial activation during OT was the posteroseptal area. The right intra‐atrial mapping showed a posteroseptal “parahisian” bypass tract. This localization was confirmed with cryomapping. Conclusions: Some patterns of epicardial mapping may suggest the presence of a deep septal “parahisian” bypass tract: retrograde atrial activation at different sites (mimicking activation among multiple pathways); delay between the delta wave and the first epicardial electrogram. Right intra‐atrial activation and cryomapping are useful to confirm the diagnosis.
Better Predictors of Successful His‐Bundle Ablation Analysis of First Shocks
Authors: IWA TORU , TONET JOELCI , EVANS STEVEN , FRANK ROBERT , LASCAULT GILLES , BRITO MITERMAYER , ADRAGAO PEDRO , ROUGIER ISABELLE , FONTAINE GUY , GROSGOGEAT YVES
Published: October 2007

IWA, T., ET AL.: Better Predictors of Successful His‐Bundle Ablation Analysis of First Shocks. We have reported here that a longer HV interval in asssociation with a larger His amplitude yields a high rate of success when used to position the ablating catheter for His‐bundle ablation. Additionally, we have shown that double discharge shocks are more effective than single discharge shocks, and that negative polarity is more effective than positive polarity. The use of bipolar or tripolar, and not quadripolar catheters, was also associated with a higher success rate. In our institution, using a bipolar catheter, we attempt to record an HV interval > 55 msec and a His amplitude > 0.35 mV. When both of these criteria are fulfilled, we use 3 to 4 joules per kg, and a single discharge shock. When one or the other of these criteria are not fulfilled, we use the double discharge shock method. Using these techniques, we have achieved successful His‐bundle ablation with only one shock in all but one of the most recent 21 consecutive patients.
Transcutaneous Cardiac Pacing: Evaluation of Cardiac Activation
Authors: ALTAMURA GIULIANO , TOSCANO SALVATORE , BIANCONI LEOPOLDO , BIANCO FRANCESCO LO , MONTEFOSCHI NICOLA , PISTOLESE MICHELE
Published: October 2007

ALTAMURA, G., ET AL.: Transcutaneous Cardiac Pacing: Evaluation of Cardiac Activation. The effects of transcutaneous cardiac pacing (TCP) on cardiac activation were evaluated by endocavitary recording (HRA, RVA) in eight patients, in order to test the possibility to obtain a simultaneous atrial and ventricular stimulation. The transcutaneous pacemaker used was the Pace Aid 52 (pacing rate 50–160 ppm, current output 10–150 mA, pulse width 20 sec). The two skin electrodes [surface area 50 cm2) were placed on the chest in anteroposterior position. Ventricular capture was observed in all patients [threshold = 74 ± 14 mA), simultaneous atrial capture was obtained in only four cases (threshold = 138 ± 25 mA). In conclusion, our data show that four‐chamber simultaneous stimulation by TCP is possible, but only with pacing energies much higher than those usually required to capture the ventricle. The ability of TCP to simultaneously pace the atria and ventricles, though not relevant in the emergency cardiac stimulation for symptomatic severe bradyarrhythmias, could be useful in the treatment of reentrant supraventricular tachycardias.
Description of the Strength‐Interval Relation with External Noninvasive Pacing
Authors: LUCK JERRY C. , GRUBB BLAIR P. , MARKEL MICHAEL L.
Published: October 2007

LUCK, J.C., ET AL.: Description of the Strength‐Interval Relation with External Noninvasive Pacing. The strength‐interval relationship obtained by external pacing (EXP) was compared to curves obtained by endocardial pacing from a right ventricular site. There were 17 patients, age 45 ± 17 years. Effective and functional ventricular refractory periods (ERP, FRP) were determined during a ventricular drive train of 8 stimuli at a cycle length 500 msec. Endocardial pacing threshold current averaged 0.5 ± 0.3 mA (range 0.2‐1.0 mA) and EXP threshold current averaged 64 ± 14 mA [range 40–80 mA]. At twice threshold, endocardial ventricular ERP was 235 ± 32 msec and FRP was 262 ± 29 msec. At 10 mA above threshold, EXP ventricular ERP was 276 ± 29 msec and was significantly longer than endocardial ERP at twice threshold (p < 0.001). EXP ventricular FRP shortened to 237 ± 39 msec at twice threshold and was similar to endocardial ERP (P = 0.55). EXP ventricular FRP was significantly longer than endocardial ERP (280 ± 29 vs 262 k 29 msec, p < 0.001) at twice threshold. EXP strength‐interval curves were similar to endocardial curves in 14 of 17 (82%) patients. We conclude, that at twice threshold, similar coupling intervals can be obtained with both endocardial and EXP. Therefore, EXP can provide critically coupled extrastimuli for programmed ventricular stimulation.
Emergency Cardiac Pacing for Severe Bradycardia
Authors: ALTAMURA GIULIANO , TOSCANO SALVATORE , BIANCO FRANCESCO LO , CATALANO FRANCESCO , PISTOLESE MICHELE
Published: October 2007

ALTAMURA, G., ET AL.: Emergency Cardiac Pacing for Severe Bradycardia. Our study included the treatment of transcutaneous cardiac pacing (TCP) in 32 patients: (A) 19 patients were treated in the emergency area for complete symptomatic AV block before endocavitary pacing; (B) five patients were in asystole following DC shock or out‐of‐hospital cardiac arrest; and (C) eight patients were affected by bifascicular block undergoing emergency surgery and were treated in order to prevent complete AV block. Two transcutaneous stimulators were used. PaceAid‐CRC model 50/52 with 20‐msec pulse width; the electrodes were positioned on the V, ECG position and on the back. Results: in all but two patients, it was possible to obtain stable cardiac capture; in one patient arrived in hospital in asystole after prolonged cardiac arrest and in the other one was affected by complete AV block, TCP was ineffective. In groups A and B, TCP was maintained for a mean time of 15 minutes; in group C, TCP was tested in all patients, but performed in only one patient during surgery. Mean threshold was 81 mA. Stimulation was well tolerated in all but five patients. TCP is a reliable, noninvasive method that offers the possibility to initiate pacing within seconds and can be used by medical staff. In our opinion, it should be considered as the first choice emergency treatment of severe symptomatic bradycardia. In asystole, beneficial effects can be obtained only if TCP is performed early enough after the onset of arrhythmia.
Electrophysiological Evaluation of Tachycardias Using Transesophageal Pacing and Recording
Authors: VOLKMANN H. , KÜHNERT H. , DANNBERG G.
Published: October 2007

VOLKMANN, H., ET AL: Electrophysiological Evaluation of Tachycardias Using Transesophageal Pacing and Recording. Programmed electrical stimulation of the heart to initiate and terminate tachycardia has been useful in the evaluation of supraventricular and ventricular tachyarrhythmias. A wide use of these procedures, however, failed because of the expense of the invasive approach as well as the lack of physician experience in smaller hospitals. These disadvantages of the invasive proceeding can be abolished by transesophageal pacing. In our study, supraventricular tachycardias were initiated by programmed transesophageal atrial stimulation in 251 patients [AV node reentry in 75 patients, orthodromic AV reciprocating tachycardia using accessory pathway in 97 patients, antidromic AV reciprocating tachycardia in 11 patients, and atrial reentry in 39 patients). The stimulation protocol included one and two extrastimuli during sinus rhythm and after a pacing drive at different cycle lengths. The electrophysiological mechanism of tachycardias was determined by surface ECG, VA interval (esophageal lead), initiation mode at programmed transesophageal stimulation and by behavior of AV conduction and refractoriness. In 29 patients the mechanism of tachycardia was not clear. Invasive electraphysiological study was done in 219 of these 251 patients. In only nine patients, the supported mechanism of tachycardia was not confirmed by invasive investigation. In 11 patients, the etectrophysiological mechanism remained uncertain. In conclusion, the noninvasive transesophageal pacing is an appropriate method for evaluation of supraventricular tachycardia. It allows serial drug testing in a simple manner for finding an effective antiarrhythmic treatment.
Pacing for Carotid Sinus Syndrome and Sick Sinus Syndrome
Authors: BRIGNOLE MICHELE , MENOZZI CARLO , LOLLI GINO , ODDONE DANIELE , GIANFRANCHI LORELLA , BERTULLA ANTONIO
Published: October 2007

BRIGNOLE, M., ET AL: Pacing for Carotid Sinus Syndrome and Sick Sinus Syndrome.The real incidence of pacemaker implants for carotid sinus syndrome (CSS) and the relation between CSS and sick sinus syndrome (SSS) is not precisely known. Patients who needed pacing therapy because of atrial bradyarrhythmias were investigated by means of carotid sinus massage, dynamic ECG, and invasive electrophysiological sinus node evaluation. Of 298 consecutive patients receiving a pacemaker implant, 36 (12%) had a severe cardioinhibitory carotid sinus reflex with reproducible spontaneous symptoms (CSS), 33 (11%) had sinus bradycardia < 50 beat/min or an abnormal electrophysiological evaluation (SSS) and 24 (8%) had both (CSS + SSS). The annual incidence was 40, 37, and 26, respectively, implants per year/million of inhabitants (total incidence 325). Patients affected by CSS, if compared with those affected by SSS, showed: a higher prevalence of syncope (97% vs 42%); more syncopal, episodes per patient (2.9 ± 2 vs 1.8 ± 0.9); a lower prevalence of associated cardiac diseases (53% vs 100%); cardiac enlargement (36% vs 88%); heart failure (6% vs 36%) and paroxysmal atrial fibrillation (0% vs 42%); and a more frequent indication for VVI pacing (75% vs 3%). In patients with CSS + SSS, intermediate characteristics were present. In conclusion, CSS is as frequent an indication to cardiac pacing as SSS; clinical differences justify a distinction between them, even if they are associated in 26% of cases.
Morbidity and Mortality of Patients with Sinus Node Disease: Comparative Effects of Atrial and Ventricular Pacing
Authors: ZANINI ROBERTO , FACCHINETTI ADELE I. , GALLO GIOVANNI , CAZZAMALLI LIVIO , BONANDI LEONARDO , CAS LIVIO DEI
Published: October 2007

ZANINI, R., ET AL.: Morbidity and Mortality of Patients with Sinus Node Disease: Comparative Effects of Atrial and Ventricular Pacing. In patients with sinus node disease (SND), VVI pacing seems an inappropriate method of cardiac stimulation because of its potential adverse hemodynamic and arrhythmic effects. AAI‐DDD pacing, preferred because of lower morbidity, may also determine a higher survival rate. We examined retrospectively two groups of patients with SND. Stimulated respectively with VVI pacing (group 1 = 57 patients) and AAI pacing (group 2 = 53 patients). The mean duration of the follow‐up interval was 40.1 months for group 1 and 45 months for group 2. Ten patients (17.5%) in the VVI group and five (9.4%) in the AAI died. During the follow‐up, in the VVI group three patients developed congestive heart failure and ten developed chronic atrial fibrillation, whereas only one case of heart failure and two with atrial fibrillation have been recorded in the AAI group. Moreover, four patients had embolic complications in group 1. Five patients (9.4%) with AAI pacing were converted to sequential pacing due to the occurrence of second‐degree heart block. The statistical analysis was developed by the X2 test for the comparison of the proportion of the events (atrial fibrillation, congestive heart failure, embolic accidents) in the two groups: a significantly higher morbidity (p < 0.01) was recorded in the AAI group. Survival is also higher in AAI patients, but the survival rate difference, calculated using the Mantel‐Cox method, is not statistically significant. The findings of our study show that in SND the superiority of AAI pacing over VVI is statistically significant as far as morbidity is concerned, and we have also noticed an evident but not statistically significant superiority regarding mortality.
Evolution of P Wave Characteristics After Pacemaker Implantation
Authors: SNOECK J. , DECOSTER H. , VERHERSTRAETEN M. , BERKHOF M. , VORLAT A. , HEUTEN H. , VRINTS C. , KAHN J.C. , MARCHAND X.
Published: October 2007

SNOECK, J., ET AL.: Evolution of P Wave Characteristics After Pacemaker Implantation. This study is an investigation of the long‐term effects of VVI pacing on the atrium as derived from the evolution of P wave characteristics of 285 patients. The occurrence of left and right atrial disease is demonstrated as well as the evolution of left atrial hypertrophy in some cases. A comparison is made with DDD pacing and special attention is given to the progression to atrial fibrillation.
Permanent Transvenous Pacing After a Mustard Procedure
Authors: HANDLER CLIVE E. , WALKER J. MALCOLM
Published: October 2007

HANDLER, C.E., ET AL.: Permanent Transvenous Pacing After a Mustard Procedure. We report the case of a 20‐year‐old man born with transposition of the great arteries who underwent emergency balloon septostomy and subsequently a Mustard procedure. When aged 20 years, he had several syncopal attacks due to sinoatrial disease for which he was simply and successfully paced transvenously in VVI mode.
Is Activity Sensored Pacing in Children and Young Adults a Feasible Option?
Authors: ZEIGLER VICKI L. , GILLETTE PAUL C. , KRATZ JOHN
Published: October 2007

ZEIGLER, V., ET AL.: Is Activity Sensored Pacing in Children and Young Adults a Feasible Option? Activity sensing pacemakers are being utilized with increasing frequency in adults, but less frequently in the pediatric and young adult age group. We evaluated 12 young patients with activity sensing devices. Seven of the implanted devices were VVIRO, four were DDDRO and one was AAIRO. Patients ranged in age from 1–21 years, mean 9.3 years, median 8 years. Weights ranged from 8.25 to 80 kgs, mean 35 kgs, median 27.6 kgs. Anatomical diagnoses revealed six normal hearts, two P/O tetralogy, one P/O transposition, two P/O ablations, and one P/O Fontan. Rhythm diagnoses included congenital complete atrioventricular block in five, acquired complete atrioventricular block in three, sinus bradycardia in two, and His‐bundle catheter ablation in one patient. Rate responsive settings of medium and 7 were used in 10 out of 12 patients. Treadmill exercise testing showed that 5 out of 7 patients' rates were controlled by the activity sensor at peak exercise while two were tracking sinus rhythm (average rate increase was 76.8 ppm in the five patients). Ambulatory monitoring revealed that 10 out of 12 patients used their activity sensor to control their heart rate (average rate increase was 54 ppm). Follow‐up has ranged from 1–26 months, mean 6.8 months, median 5.5 months. There was one death. Effective rate modulated, activity sensing pacing was achieved in 7 out of 9 young patients. It should be considered when the atrium itself is not a feasible sensor.
Rate‐Adaptive Cardiac Pacing in Children Using a Minute Ventilation Biosensor
Authors: YABEK STEVEN M. , WERNLY JORGE , CHICK THOMAS W. , BERMAN WILLIAM , McWILLIAMS BENNIE
Published: October 2007

YABEK, S.M., ET AL.: Rate‐Adaptive Cardiac Pacing in Children Using a Minute Ventilation Biosensor.Chronotropic integrity is required for a normal cardiac output response to exercise. We evaluated a rate‐adaptive ventricular demand pacemaker (Telectronics, META‐MV) which uses minute ventilation as the sensed physiological variable for adjusting pacing rate, in seven young patients with a mean age of 11.4 years. All patients had clinically significant bradycardia related to complete heart block (n = 4) or sinus node dysfunction (n = 3). For the entire group, paced heart rates increased from 70 ± 10 beats/min to 151 ± 19 beats/min with exercise testing. The onset of rate adaptation took < 30 seconds. Changes in paced rate were linearly related to workload, VO2 (5.9 to 20.7 mL/min/kg) and minute ventilation (8–65 L/min). The decline in pacing rate after exercise was related directly to the gradual decrease in minute ventilation and VO2. Our data show that minute ventilation closely and accurately reflects the metabolic demands of varying workloads in children and can be used to achieve physiological, rate‐adaptive pacing.
Nonlinear Dynamic Analysis of Temporally Heterogenous Action Potential Characteristics
Authors: KARAGUEUZIAN HRAYR S. , KHAN STEVEN S. , MANDEL WILLIAM J. , HONG KICHOL , DIAMOND GEORGE A.
Published: October 2007

KARAGUEUZIAN, H.S., ET AL.: Nonlinear Dynamic Analysis of Temporally Heterogenous Action Potential Characteristics.Rate‐dependent bifurcations and aperiodic changes in action potential duration and amplitude were observed in periodically stimulated cardiac Purkinje and ventricular muscle cells isolated from dogs with quinidine‐induced ventricular fibrillation and ventricular tachycardia. The slope of the action potential duration restitution curve was higher in the quinidine intoxicated fibers than in normal untreated fibers. Aperiodicity and bifurcations in action potential duration (APD) could not be observed in normal untreated cardiac fibers. The data suggest that induction of reentrant ventricular fibrillation and ventricular tachycardia could be brought about not by fixed but rather by changing alterations in cellular electrical activity. Theory based on nonlinear dynamics seems to provide a quantitative basis for such an analysis. This could have important implications in the issue of sudden cardiac death, a major problem in cardiology.
The Signal Averaged Electrocardiogram and Programmed Stimulation in Patients with Complex Ventricular Arrhythmias
Authors: TURITTO GIOIA , EL‐SHERIF NABIL
Published: October 2007

TURITO, G., ET AL.: The Signal Averaged Electrocardiogram and Programmed Stimulation in Patients with Complex Ventricular Arrhythmias.The signal averaged electrocardiogram (SA‐ECG), programmed electrical stimulation (PES), and left ventricular ejection fraction (EF) studies were utilized for risk stratification and management of patients with complex ventricular arrhythmias and nonsustained ventricular tachycardia (VT). The study population included 90 patients (63 with coronary artery disease and 27 with dilated cardiomyopathy). Sustained monomorphic VT was induced in 22 cases (24%), ventricular fibrillation (VF) in 10 (11%), and no sustained VT/VF in 58 (64%). An abnormal SA‐ECG was recorded in 23 patients (26%) and was more common in patients with than in those without induced sustained VT (68% vs 12%, p < 0.0001). None of 33 patients with normal SA‐ECG and EF ≥ 40% had induced VT. Patients were followed‐up for 2.5 ± 0.8 years off antiarrhythmic therapy, unless they had induced sustained VT. The 3‐year sudden death rate was 19% in the group with induced sustained VT, 0 in that with induced VF, and 9% in that without induced VT/VF (P = NS). The 3‐year total cardiac mortality was higher in patients with than in those without EF < 40% (27% vs 7%, p < 0.05). It is concluded that patients with organic heart disease and spontaneous nonsustained VT may not need PES or antiarrhythmic therapy if SA‐ECG is normal and EF is ≥ 40%, since their risk of induced VT and sudden death is low. On the other hand, patients with abnormal SA‐ECG and/or EF < 40% may require PES, since their risk for induced VT is high. Antiarrhythmic therapy may also be considered in these patients. (PACE, Vol. 13, December, Part II 1990)
Review of the Reviewer
Authors: ECTOR HUGO , AUBERT ANDRÉ , STROOBANDT ROLAND
Published: October 2007

ECTOR, H., et al.: Review of the Reviewer. Reviewers can disagree substantially when evaluating the same materials. For papers submitted to an editorial board, the Editor‐in‐Chief can suggest compromises. However, this is not the case in the normal abstract grading procedures for large meetings. If important discrepancies arise between reviewers, a review committee may propose corrective measures. However, this is only feasible for smaller meetings with a limited number of abstract submissions. In this study, when reviewing the same abstracts, a statistically significant correlation between reviewers was present in 15 instances and absent in 13 others. It would appear that some review of the reviewer is highly desirable and may prevent publication bias
High Voltage Shock Induced Cellular Electrophysiological Effects: Transient Refractoriness and Bimodal Changes in Action Potential Duration
Authors: LI HUAGUI G. , JONES DOUGLAS L. , YEE RAYMOND , KLEIN GEORGE J.
Published: October 2007

LI, H.G., et al.: High Voltage Shock Induced Cellular Electrophysiological Effects: Transient Refractoriness and Bimodal Changes in Action Potential Duration. The cellular electrophysiological effects of defibrillation shocks on the myocardium during ventricular fibrillation are not clear. The present study investigated the effects of high voltage shocks on membrane potentials of isolated guinea pig and pig papillary muscles during rapid activations simulating ventricular fibrillation. High voltage shocks induced an action potential with a prolonged duration, followed by a transient refractory state. Subsequent action potentials following this refractory state had shortened durations. The duration of the transient refractory state varied in proportion to shock intensity and stimulation rate, whether the shock was biphasic or monophasic. Shock induced prolonged depolarization was not a consistent finding and mainly observed with slow stimulation rates. In conclusion, high voltage shocks induce bimodal changes of the action potential duration associated with a transient refractory state during rapid activation. The rate dependency of this refractory state suggests that the duration of the shock induced refractory state may be longer in the fibrillating than the normal beating heart, and may contribute to successful defibrillation.
Clinical and Electrophysiological Characteristics of Atrial Standstill
Authors: NAKAZATO YUJI , NAKATA YASURO , HISAOKA TERUHIKOA , SUMIYOSHI MASATAKA , OGURA SHUNSUKE , YAMAGUCHI HIROSHI
Published: October 2007

NAKAZATO, Y., et al.: Clinical and Electrophysiological Characteristics of Atrial Standstill. To clarify the clinical and electrophysiological characteristics of atrial standstill (AS) we studied 11 patients (7 males and 4 females), whose average age was 62 years and who were followed over a period of 4–179 months. Underlying heart disease was present in nine patients and two cases were idiopathic. Major clinical symptoms in the 11 cases included Adams‐Stokes attacks, and dyspnea on exertion. In the standard 12‐lead ECGs obtained on admission, the P wave was absent in six cases. Atrial flutter (AF) was noted in 3, atrial fibrillation (Af) in 1, and multifocal atrial tachycardia in 1. In some cases, the ECG initially showed AF or Af, and was transformed after several years into ectopic atrial tachycardia or an ectopic atrial rhythm with a markedly decreased amplitude of the P wave. Finally, the P wave disappeared over a prolonged period. When intracardiac mapping was performed, the atrial electrograms tended to diminish at the site of high, mid‐lateral right atrium (RA). Electrograms were remained present in the vicinity of the tricuspid valve (TV) annulus. A repeated mapping and pacing study conducted in two patients revealed that the “silent” area spread toward the lower site of RA. During the average follow‐up period of 64 months, four patients died. The interval until death in one patient with myocarditis was 6 months, and in another with dilated cardiomyopathy (DCM) it was 8 months. It appears that the atrial muscular lesion starts in the high lateral RA and progresses toward the lower RA, then to the vicinity of the TV annulus. A diffuse and progressive disturbance may occur not only in the atrial muscle, but also in the atrioventricular conduction system in patients with AS who had progressive myocarditis or DCM.
Removal of Infected Dual Chambered Transvenous Pacemaker and Implantation of a New Epicardial Dual Chambered Device with Cardiopulmonary Bypass: Experience with Seven Cases
Authors: ABAD CIPRIANO , MANZANO JUAN J. , QUINTANA JOSÉ , BOLAÑOS JOSÉ , MANZANO JOSÉ L.
Published: October 2007

ABAD, C., et.al.: Removal of Infected Dual Chambered Transvenous Pacemaker and Implantation of a New Epicardial Dual Chambered Device with Cardiopulmonary Bypass: Experience with Seven Cases. Seven patients with infected transvenous dual chambered pacemakers have undergone removal of the device using cardiopulmonary bypass. There were four women and three men with a mean age of 58 years. Six patients had localized infection in the generator pocket (mean of 4.6 previous unsuccessful operations for surgical sterilization). Four infections were due to Staphylococcus epidermidis, two to Staphylococcus aureus, and one patient presented septicemia caused by Staphylococcus epidermidis and Pseudomonas aeruginosa. The atrial and ventricular transvenous electrodes were removed under direct vision using cardiopulmonary bypass. A new dual chambered epicardial pacemaker was implanted. The procedure was well‐tolerated, and all patients are infection free with working pacemakers after a mean follow‐up of 25.4 months.
Effects of the Pacing Site, Procainamide, and Lead Configuration on the Relationship Between the Upper Limit of Vulnerability and the Defibrillation Threshold
Authors: FAN WEI , GOTOH MASAMICHI , CHEN PENG‐SHENG
Published: October 2007

FAN, W., et.al.: Effects of the Pacing Site, Procainamide, and the Lead Configuration on the Relationship Between the Upper Limit of Vulnerability and the Defibrillation Threshold. In six open chest dogs, we determined the upper limit of vulnerability (ULV) and defibrillation threshold (DFT) by an up‐down algorithm when the pacing site was at the right atrium, at the left ventricular apex, and at the left ventricular base. Monophasic shocks (6 ms) were given to epicardial patches at 20 and 40 ms before the peak of the T wave to bracket the mid‐upslope. In an additional six closed‐chest dogs, we determined the ULV and the DFT with transvenous leads with an 8‐ms biphasic waveform. The S1 pacing site was at the right ventricular apex and the right atrium, and the shocks were given at 20 ms and 40 ms before the peak of the T wave, and on the peak of T wave. The same test was repeated after intravenous procainamide infusion (20 mg/Kg loading, then 2 mg/min maintenance). In the first six dogs, the ULV determined when pacing was given to the left ventricular apex, the left ventricular base, and the right atrium was 4.2 ± 1.7 J, 4.4 ± 2.1 J, and 3.9 ± 1.5 J, respectively; values that were not significantly different from the DFT of 4.8 ± 1.9 J, 4.5 ± 1.9 J, and 4.2 ± 1.3 J, respectively. In the latter six dogs, the ULV versus the DFT was 13.5 ± 5.2 J versus 18.2 ± 6.2 J (right ventricular apex) and 12.8 ± 6.0 J versus 15.4 ± 6.0 J (right atrium) at baseline; 14.6 ± 4.6 J versus 19.5 ± 6.7 J (right ventricular apex) and 14.3 ± 5.5 J versus 18.7 ± 6.4 J (right atrium) during procainamide infusion (P = NS for all). We conclude that, when tested with 2–3 shocks on or before the peak of the T wave, the ULV can be used to estimate the DFT with both epicardial patch and transvenous lead configurations. Different S1 pacing sites and procainamide did not change the relationship between the ULV and the DFT.