bluuebunny/crossref_metadata_2025 huggingface dataset:
Wavelength and Atrial Vulnerability: an Endocavitary Approach in Humans
Authors: GRAUX PIERRE , CARLIOZ ROLAND , RIVAT PHILIPPE , BERA JÉROME , GUYOMAR YVES , DUTOIT ALBERT
Published: July 2006

If atrial vulnerability parameters are well defined, wavelength (WL) measurement (conduction velocity x refractory period), has never been assessed through an endocavitary electrophysiological exam.

We investigated 30 patients (14 female, mean age 63.4 ± 13 y.o.), 10 with paroxysmal atrial fibrillation (PAF group), 10 with ischemic cerebral injury (ICI group) by comparison with 10 controls (C group).

The upper to lower right atrium conduction time and velocity were measured in the right atrium with a decapolar electrode catheter applied along the free wall. Others parameters correlated to atrial excitability were also taken into account: effective (ERP) and functional refractory periods (FRP); spontaneous or paced atrial electrogram (AI) or extrastimulated atrial electrogram (A2) widths, ERP/ A2 ratio, provocative atrial testing. Measurements were taken in sinus rhythm and in 600 – 460 ms paced cycle lengths. If ERP, FRP, Al widths are the same in the 3 groups, PAF and ICI groups have a significant increased conduction time and lower conduction velocity, leading to a shorter A1 WL during 600 and 460 ms paced rhythms (p 0.05) and A 2 WL during 460 ms paced rhythm. The provocative testing was positive in 60% of PAF and ICI groups, and there is a significant correlation between arrhythmia induction and 600 ms A1 WL or 460 ms A2 WL.

This electrophysiological study suggests the possibility of an approach in humans of wavelength concept and proves the presence of correlation between a short wavelength and atrial spontaneous or induced arrhythmias. A no‐arrhythmia band (A1 WL > 17 cm during 600 ms paced rhythm, Al WL > 16 cm or A2 WL > 12cm during 460 ms paced rhythm) and a fibrillation‐band (A1 WL < 12 cm during 600 and 460 ms pacing, A 2 WL < 7 cm during 460 ms pacing) can be defined. Therefore, the ICI group has the same atrial pattern as the AF group.
New Method of Atrial and Ventricular Capture Detection
Authors: VONK BEN F.M. , VAN OORT GEESKE
Published: July 2006

Polarization as a result of the pacing stimulus has always been the main factor for complicating evoked response detection. Tri‐phasic pulse schemes have been developed and used for a long time to solve the polarization issue and are used in commercial products today to enable evoked T‐wave detection. For measurement of the evoked R wave in the ventricle and the evoked P wave in the atrium a further optimization step had to be taken. The results presented in this paper show that by individual optimization of the lead system in all cases the evoked P‐ or R wave could be detected. One aspect of the tri‐phasic pulse scheme is the dynamic behavior of the polarization to a change in amplitude or pulse width of the pacing pulse. The time to rebalance the electrode tissue interface and the non‐linear behavior of this system can lead to incorrect detections of evoked potentials. The response time of this phenomenon was investigated. A possibility to solve this problem is described with the introduction of a double pulse scheme where a test pulse is placed in front of the regular output pulse. Changes in this double pulse balanced system never lead to a loss of capture situation and the system is given time to re‐balance before it can be decided which of the two pulses was responsible for a depolarization of the myocardium.
A Sensor‐based Evaluation of Heart Contractility in Patients with Head‐up Tilt‐induced Syncope
Authors: DEHARO J.C. , PEYRE J.P. , RITTER P.H. , CHALVIDAN T. , BERLAND Y. , DJIANE P.
Published: July 2006

Studies using the head‐up tilt test (HUT) suggest that a reflex increase in sympathetic activity resulting in vigorous myocardial contractions precedes neurally‐mediated syncope (NMS), The aim of this study wax to evaluate heart contractility changes during positive HUT. Ten patients with recurrent NMS and positive HUT were investigated. Before HUT we temporarily placed a standard right ventricular pacing electrode incorporating in its tip a recently developed microaccelerometer (Sorin Biomedica, Italy) that measures the peak endocardial acceleration (PEA) during the isovolumetric phase as an index of heart contractility. PEA potential amplitude, heart rate and mean blood pressure were continuously studied during HUT. Syncope occurred 16.7 ± 10.3 min after 60° till, either at baseline (8 patients) or after sublingual nitrate administration (2 patients). PEA value was stable at 0.62 ± 0.34 (1G = 9.8 m/sec2) during the supine phase. It slightly increased to 0.72 ± 0.44 G (p = NS) during the first minutes of 60° tilt and then remained unchanged until a further increase of 71 ± 79% (range 10 to 266 %) as compared to tilt value (p = 0.004) at 2.8 ± 2.4 min (range 0.25 to 6.5 min) before the syncope in 9 patients. The latter increase was not observed in the patient with dilated cardiomyopathy. In conclusion, a significant increase in heart contractility was observed in 9 patients in the minutes preceding HUT‐induced NMS. These changes might be used for driving a rate adaptive pacemaker when cardiac pacing is indicated to prevent NMS.
Simultaneous Recordings of the Monophasic Action Potential with Silver Chloride‐ and Ir‐Coated Electrodes
Authors: MERKELY BÉLA , LANG VOLKER , GELLÉR LÁSZLÓ , STRÖBEL JÖRG P. , KISS ORSOLYA , FAZEKAS LEVENTE , VECSEY TIBOR , HORKAY FERENC , JUHÁSZ‐NAGY ALEXANDER , SCHALDACH MAX
Published: July 2006

Ag AgCI and Ir‐coated electrodes allow the recording of the monophasic action potential (MAP) due to their electrical properties like non‐polarisability. This study investigates the correlation of MAP recorded with both types of electrodes. In 20 mongrel dogs (18 ± 6 kg) an Ag/AgCI and an Ir‐coated catheter (Ir) were placed endo‐cardially in the apex of the right ventricle. The effects of isoproterenol and verapamil were investigated during spontaneous rhythm and stimulation simultaneously recorded with both types of electrodes in 10 dogs without AV‐node ablation. The correlation at different heart rates were investigated in 10 other dogs with complete AV‐block. The morphology and amplitudes of MAP were comparable (AgCl: 15±7 mV; Ir: 13±8 mV). Following an i.v. bolus of 2μg/kg isoproterenol the spontaneous rate increased (175±18 to 245±25 bpm). During stimulation with 250 ms cycle length the duration shortened (MAPd90: AgCl: 160 ± 11 to 130 ± 12 ms; Ir: 154 ± 18 to 128±15 ms). The alterations reversed after 20 mm. An i.v. bolus of 0.2 mg/kg verapamil decreased the spontaneous rate (167±11 to 104 ± 23 bpm) and lengthened the MAPd90 (AgCl: 182 ± 14 to 220±13 ms; Ir: 174 ± 16 to 216, 21 ms) at 300 ms stimulation. The correlation between the MAPd90 of both lead types was r=0.98 during all measurements. Under the effect of beta‐agonist and Ca2+ ‐antagonist medication MAP showed a strong correlation recorded with both types of electrodes. Thus, both leads allow the recording of MAP but only the Ir‐electrodes with their long‐term stability are implantable and allows us to control the effects of drugs with implantable devices.
Intraoperative Recordings of Monophasic Action Potentials with Chronically Implantable Pacemaker Leads
Authors: ZRENNER BERNHARD , MÜSSIG DIRK , SCHREIECK JÜRGEN , WEYERBROCK SONJA , SCHNEIDER MICHAEL , SCHALDACH MAX , SCHÖMIG ALBERT , SCHMITT CLAUS
Published: July 2006

Since the development of fracially coaled Iridium electrodes recordings of monophasic action potentials are possible. Intraoperative recordings of MAP from 15 pacemaker implantations were done after positioning the chronically implantabie pacemaker leads (Biotronik, Berlin, Germany) in the right ventricle by using five screw‐in electrodes and ten anchor electrodes. Intraoperative recordings of MAP are possible with all implanted pacemaker leads. The recordings of typical MAP signals were always accompanied with stable electrode positions and good sensing and pacing characteristics.
Clinical Observations with Long‐term Atrial Pacing
Authors: BÖHM ÁDÁM , PINTÉR ARNOLD , SZÉKELY ÁDÁM , PRÉDA ISTVÁN
Published: July 2006

Atrial pacing (AP), despite its beneficial hemodynamic and antiarrhythmic effect, is still an underused mode of stimulation. The main purpose of this study was to evaluate the long‐term results of AP. Sixty four patients (pts) with sinus node disease (28 male and 36 female: mean age 54,2; range:44–88 years), 3,2% of the total implantation at our clinic were treated with AP between 1982–96. Criteria for atrial pacing were: no AV block in the history, no AV‐block during carotid sinus massage, Wenckebach point > 130/min, left atrium <50mm, left ventricular EF >40%. The indication for pacing was predominant sinus bradycardia (SB) in 34 pts and tachycardia‐bradycardia syndrome (TBS) in 30 pts. Pts with TBS were on antiarrhythmic treatment, while most pts with SB received no antiarrhythmic drugs. All the pts were checked up at every 3–6 month. Sixty‐two pts were followed for 3–154 (mean: 67) months, two pts were lost for follow‐up. Repeated lead dislodgment occurred in two pts, which made a pacing mode change necessary. Four pts died during the follow‐up period for non‐cardiac reasons. At the end of the follow‐up period the data of 60 pts were available for evaluation (33 pts with SB, 27 pts with TBS). All the pts with SB were in sinus rhythm, and no patient developed AV block by the end of the follow‐up period Seven out of 27 pts with TBS developed chronic atrial fibrillation, 3 out of them suffered a cerebral embolism; the remaining 20 pts were in sinus rhythm, and the number of paroxysmal attacks decreased significantly, which improved their quality of life significantly. Three pts in this group developed a temporary complete AV block, which regressed with decreasing the dosage of antiarrhythmic drugs. Atrial pacing is proved to be a safe and reliable treatment for sick sinus syndrome. Proper patient selection is crucial in preventing the development of AV conduction disturbance. Atrial stimulation had a satisfactory long‐term antiarrhythmic effect in pts with sick sinus syndrome (SSS).
Prevalence of supraventricular arrhythmias from the automated analysis of data stored in the DDD pacemakers of 617 patients: the AIDA study
Authors: DEFAYE P. , DOURNAUX F. , MOUTON E. ,   for the AIDA MULTICHNTER STUDY GROUP.
Published: July 2006

The confirmation of the occurrence of supraventricular arrhythmias (SVAs) is possible only if a surface electrocardiogram (ECG) is recorded during an episode, or if SVAs occur during 24 h ambulatory monitoring (Holter). The automatic interpretation of memory functions in DDD pacemakers may be useful in this diagnostic task over longer periods of follow up. This hypothesis was tested in 384 men and 233 women (mean age = 70 ± 11 years) who had received Chorus 6034/6035, 6234 or 7034 pacemakers (ELA Medical, Montrouge, France) with fall‐back function in case of sustained SVAs. The Automatic Interpretation for Diagnostic Assistance (AIDA) algorithm included in these pacemakers was compared with 24 h Holters recorded simultaneously (DI) and with the clinical history of symptoms consistent with SVAs up to 28 days of follow up (D28). Indications for pacing were atrioventricular block (AVB) in 269 patients, sinus node dysfunction (SND) in 248, and AVB + SND in 100. SVAs were documented before implant in 199 patients (32%). Among the 617 patients included at D1. 76 (12.4%) developed at least one SVA episode, lasting between 1 min and 24 hours, simultaneously recorded on Holter and by AIDA with a 93.8% sensitivity and 94.2% specificity. Data from 354 patients were available for analysis at D28. AIDA diagnosed SVAs in 179 patients (50.6%), 104 of whom (65%) had remained asymptomatic and 117 of whom (65%) had had no SVA documented before implant. Among the 354 patients, AIDA diagnosed SVAs in 76 (21%) asymptomatic patients who had no known SVA before implant. The prevalence of SVA in our AVB population was higher than reported in previous studies: 89 patients (56.3%) with AVB had SVAs versus 90 patients (45.9%) with other diagnoses (p=0.55). Furthermore atrial pacing was associated with fewer SVAs. These first clinical results of the AIDA study demonstrate that the memory functions of Chorus pacemakers and the AIDA software are reliable to analyze the prevalence of SVA at 1 month of follow‐up. From a clinical point of view, AIDA is a valuable tool to evaluate the efficacy of antiarrhythmic therapy, particularly as it pertains to the prevention of stroke due to atrial fibrillation.
What Range of Programmable AV Delays is Necessary in Antibradycardia DDD Stimulation?
Authors: VON KNORRE GEORG H. , ISMER BRUNO , VOSS WOLFGANG , PETZSCH MICHAEL , PULYA KAMESH
Published: July 2006

DDD pacemakers differ considerably in device specific extents of AV delay (AVD) programmability. To demonstrate the requirements of a mean DDD pacemaker patient population optimal AVDs in 200 DDD pacemaker patients (age 8 to 91 years) were estimated by left atrial electrography. The results should help to define an AVD programmability standard. Left atrial electrograms were recorded via a bipolar filtered esophageal lead. The method aims on adjusting the left atrial electrogram to 70 ms prior to the ventricular spike, both during VDD and DDD operation of the pacemaker. In atrial sensed stimulation the optimal AVD varied from 40 to 205 ms (100.5 ± 24.5 ms) and in atrial paced stimulation from 85 to 245 ms (169.1 ±24.5 ms). The difference of the mean values is statistically significant (p < 0.001). The difference between both values in the individual patient, the individual AVD correction time, varied from 0 to 170 ms (68.7 ± 26.6 ms). Thus, from our findings requirements on AV delay programmability standard can be derived: AVDs (1) should have a range from 40 to 250 ms, (2) should be independently programmable during atrial sensed and atrial paced operation, ami (3) should provide as nominal settings 100 ms for atrial sensed and 170 ms for atrial paced stimulation.
First European Experience Using Excimer Laser for the Extraction of Permanent Pacemaker Leads
Authors: KENNERGREN CHARLES
Published: July 2006

An Excimer Laser system for the extraction of permanent pacemaker leads has been developed by Spectranetics Inc. and Dr. Charles L. Byrd. The laser energy is emitted at the tip of a flexible, fiberoptic 12F sheath that permits the removal of leads with a max outer diameter of 7.1F. The CVX‐300 Excimer Laser source is a xenon chloride laser with an output of 308 nm not visible to the human eye. This cool cutting laser has an absorption depth of 0.06 mm, the energy being absorbed by proteins and lipids. In clinical practice this means that the fibrotic sheaths usually surrotinding the leads can be cut without damaging the endothelial wall or the insulation of leads, due to these characteristics the sheath can, however, not pass over tines. For the freeing of lead tips, locking stylets and outer sheaths are combined to perform counter traction. Results: From 8/96 to 5/97 50 leads (38 atrial, 12 ventricular) from 45 patients (22 females, 23 males, mean age 65.1 years, range 32–94) were extracted using the Excimer Laser at our institution. Mean lead implantation time was 47.7 months (range 10.5–351.7). Indication for extraction was suspected J‐wire fracture in 16 leads, prophylactic in 8 leads, infection in 12 leads, exit block in 4 leads and other reasons in 10 leads. Mean extraction time, excluding reimplantation, was 10 minutes (range 1–50). The objective of the procedure (normally complete lead removal) was accomplished in all cases but three. All intended lead replacements were successful. No complications occurred. All patients left the hospital in good condition, one patient died, within 30 days due to progressive heart failure. Conclusions: Lead extraction with Excimer Laser seems to be a safe and efficacious procedure. However, due to the inherent risks appropriate training and experience are essential. If the initial promising results can be maintained, indications for the removal of permanent pacing leads may widen considerably.
Comparison of Right Atrial and Peripheral Procainamide Infusion Levels in Patients with Spontaneous or Induced Atrial Fibrillation
Authors: LURIE KEITH G. , BUSCEMI PAUL J. , ISKOS DEMOS , ADKISSON WAYNE , FAHY GERARD J. , SAKAGUCHI SCOTT , HOFF JULIE , BENDITT DAVID G.
Published: July 2006

As part of a new effort to develop an implantable drug infusion pacing system to treat atrial fibrillation, this study examined the effects of rapid intracardiac procainamide infusion in humans with pacing‐induced atrial fibrillation. Twenty patients with atrial fibrillation for >5 minutes during an EP study received 500mg of procainamide either via a peripheral venotis infusion (n=5) or directly in the right atrium (n=15). Peak coronary simis and femoral vein procainamide blood levels (mean ± SEM) during 10, 5, and 3.3 minute central infusions were 17.0 ± 4.1, 25.1 ± 4.5, 45.6 ± 5.1 and 11.3 ± 3.2, 17.1 ± 6.4, 18.7 ± 5.0, respectively. In contrast, peak coronary sinus and femoral procainamide levels following the 5 minute intravenous infusion were 17.7 ± 5.1 and 9.3 ± 2.1. Changes in QT, QTc, QRS, and RI intervals were similar at each infiision rate. Systolic blood pressures (BP) decreased more with higher procainamide infusion rates but similar when comparing intravenous versus central drug administration at the same rate. The mean ± SEM decreases in blood pressure with the 10, 5, and 3.3 min procainamide infusions were 12f5, 20f11, and 39f14, respectively. Conversion to sinus rhythm was not a primary endpoint given the often transient nature of acute atrial fibrillation in this setting. We conclude that significantly higher femoral vein and coronary sinus procainamide levels can be achieved by central rather than peripheral drug infusion. These data support that concept that rapid central infitsion of anti‐arrhythmic therapy can result in high intracardiac levels of antifibrillatory agents for the treatment of paroxysmal atrial fibrillation.
Rapid Drug Infusion for Termination of Atrial Fibrillation in an Experimental Model
Authors: ARZBAECHER ROBERT , GEMPERLINE JUDITH , HAKLIN MICHAEL , BUSCEMI PAUL
Published: July 2006

Episodes of paroxysmal atrial fibrillation (PAF) in the ambulatory patient might be terminated promptly by intravenous infusion from an implanted drug delivery system. We have explored this concept in a series of experiments using rapid intra‐atrial infusions in dogs. In the acute studies, rapid intra‐atrial infusions of procainamide were delivered during continual measurements of epicardial monophasic action potentials (MAP), atrial effective refractory periods (ERP), and right to left atrial conduction times (CT) in 9 dogs. In the chronic studies, 20 episodes of sustained PAF were induced in 4 dogs after six weeks of rapid or burst atrial pacing from a specially programmed implanted pacemaker. Rapid infusions of procainamide were then delivered to the right atrium through a previously implanted catheter connected to a subcutaneous access port. Procainamide significantly increased the duration of the atrial MAP. ERP and CT in the acute experiments. It also terminated induced PAF within five minutes of the end of infusion in all twenty of the chronic experiments. We conclude that rapid intra‐atrial infusion of procainamide is very effective in this animal model of PAF, and that such infusion prolongs atrial MAP, ERP and CT.
New ICD‐Technologies: First Clinical Experience with Dual‐Chamber Sensing for Differentiation of Supraventricular Tachyarrhythmias
Authors: OSSWALD S. , CRON T. A. , STERNS L. , ALT E. , STOTTS L. , COENEN M.
Published: July 2006

Inappropriate ICD therapy for supraventricular arrhythmias remains an unsolved problem and may lead to serious clinical situations. Current algorithms for differentiation of supraventricular and ventricular arrhythmias are based on ventricular sensing solely and, therefore, lack semitivity and specificity. This preliminary analysis from a multicenter trial comprises data from the first 26 patients who received a Res‐Q™ Micron active‐can ICD (Stdzer Intermedics) with a ventricular defibrillation lead and an additional bipolar lead for atrial sensing. Digitized atrial and ventricular waveform storage as well as interval charts from 102 induced and 30 spontaneous arrhythmia episodes were prospectively collected and analyzed with regard to appropriateness of ICD therapy. From all 132 arrhythmia episodes, high‐quality stored dual‐chamber intracardiac electrograms (JFXJM) could be retrieved for further analysis: in 40 (30%) episodes, atrial fibrillation (AF with rapid ventricular response 22, AF with VT9, AF with VF 9) was identified as the underlying intrinsic rhythm, and inappropriate ICD therapy was delivered in 4/22 (18%) episodes of AF with rapid ventricular response. In the remaining 92 (70%) episodes, sinus rhythm was the underlying atrial rhythm (SR with VT 13, SR with VF 79), and no inappropriate therapy was observed. Three of 22 (15%) high‐energy shocks delivered for ventricular arrhythmias (VT 9, VF 9, rapid AF 4) terminated AF at the same time. In total, there were 3 complications (2 atrial lead dislodgments, I revision for bleeding). Both atrial lead dislodgments occurred in the 2 patients with passive‐fixation leads compared to none in the 24 patients with active‐fixation leads (p ‐ 0.003). In conclusion, dual‐chamber sensing and waveform storage of the new Res‐Q™ Micron offer very helpful diagnostic tools for the detection of inappropriate ICD‐therapy. Placement of an additional atrial lead is safe and does not interfere with proper ICD function. However, for avoidance of atrial lead dislodgment, active fixation leads are recommended With the tested active‐can lead configuration, the efficacy of successful atrial cardioversion by high‐energy shocks delivered for ventricular arrhythmias seems to be low.
Post‐mortem Changes After Lead Extraction From the Ovine Coronary Sinus and Great Cardiac Vein
Authors: TACKER WILLIS A. , VANVLEET JOHN F. , SCHOENLEIN WILLIAM E. , JANAS WOLFGANG , AYERS GREGORY M. , BYRD CHARLES L.
Published: July 2006

We investigated in sheep, non‐thoracotomy extraction of leads which had been chronically implanted in the right atrium (RA), coronary sinus/great cardiac vein (CS / GCV) and right ventricle (RV) for atrial implantable defibrillation. Clinical success of extraction as well as gross and histologic findings in the heart are reported. Six of nine sheep had successful extractions. The major complication was laceration of the wall of the great coronary vein with hemorrhage into the pericardial space and cardiac tamponade. Tissue damage included several reversible changes: intra‐tissue hemorrhage, thrombosis in the veins, and some necrosis of fat, vascular wall and myocardium. Myocyte necrosis was estimated as 0.03 to 0.3 grams of tissue. Osseous and cartilaginous metaplasia was more common around the RA lead than the CS/GCV lead. In cases where the lead must be removed, removal from the venous insertion site using lead extraction equipment should only be attempted with surgical back‐up for emergency thora‐cotomy to control hemorrhage in the event of vessel laceration. Safer explantation of these leads from the vein entry site will require the development of new extraction procedures.
The Value of Electrophysiology Study and Prophylactic Implantation of Cardioverter Defibrillator in Patients with Hypertrophic Cardiomyopathy
Authors: ZHU DENNIS W.X. , SUN HUABIN , HILL RITA , ROBERTS ROBERT
Published: July 2006

Fifty‐three consecutive patients with hypertrophic cardiomyopathy (HCM) and no history of sudden death underwent electrophysiology (EP) study. Sustained polymorphic ventricular tachycardia (VT) or ventricular fibrillation (VF) was induced in 19 patients (35%). Patients with prior syncope or near syncope had a higher incidence of VT/VF inducibility. An implantable cardioverter defibrillator (ICD) was placed in 14 of the 19 patients. Of the remaining 5 patients with inducible VT/VF, three refused ICD implantation, while two underwent septal myectomy and VT/VF was no longer inducible afier the operation. None of the patients received antiarrhythmic drugs. During a mean follow‐up period of 47 ± 31 (2–117) months, no events occurred in the 34 patients with negative EP study. Three events occurred among the 19 patients with inducible VT/VF. One patient died suddenly, one developed wide complex tachycardia which required resuscitation, and one patient received an appropriate ICD shock. In conclusion, sustained polymorphic VT/VF was inducible in about one‐third of patients with HCM. Noninducibility of VT/VF appeared to predict a favorable prognosis. Although the overall event rate was low in patients with inducible VT/VF, prophylactic ICD implantation in patients with multiple risk factors may be appropriate.
An Increase in Sinus Rate Following Radiofrequency Energy Application in the Posteroseptal Space
Authors: GELLER CHRISTOPH , GOETTE ANDREAS , CARLSON MARK D. , ESPERER HANS DIETER , HARTUNG WOLFGANG M. , AURICCHIO ANGELO , KLEIN HELMUT U.
Published: July 2006

An increase in sinus rate has been previously described in patients with AV node reentry (AVNRT) following successful A V node modification. This increase could either be a specific sign of elimination of slow pathway conduction or it could be a consequence of energy application in the posteroseptal area. Thus, we compared the changes in sinus cycle length following successful slow pathway ablation (defined as complete elimination of dual AV node physiology) in patients having AVNRT with those in patients undergoing successful ablation of a posteroseptal atriovetriricular accessory connection. Twenty five patients (16 women and 9 men, mean age 41 ± 4 years) with typical AVNRT (cycle length 378 ± 12 ms and 29 patients (16 women and 13 men, age 34 ± 5 years) with an accessory connection (17 manifest and 12 concealed) were studied. The electrophysiology study was performed during sedation with Fentanyl and Midazolam. The mean number of energy applications was 3 ± 1 for successful slow pathway ablation and 4 ± 1 for successful ablation of the accessory connection (p:NS). Following the successful energy application, the sinus cycle length decreased significantly 776 ms at baseline to 691 ms in patients with AVNRT. Following successful ablation of the posteroseptal AC, sinus cycle length decreased from 755 ms at baseline to 664 ms (p < 0.05 in both groups [difference between groups not significant]). The decrease in sinus cycle length did not correlate with the number ofRF energy applications required for successful ablation or the total energy delivered. In conclusion, ablation of the AV node slow pathway and a posteroseptal accessory connection results in similar increases in the sinus rate. Thus, the increase in sinus rate is probably due to energy application in the posteroseptal space, possibly due to concomitant destruction of vagal inputs, and it is not specific for elimination of slow pathway conduction.
Predictors of Successful Radiofrequency Catheter Ablation of Sinoatrial Tachycardia
Authors: IVANOV MARAT Y. , EVDOKIMOV VLADYMIR P. , VLASENCO VALERY V.
Published: July 2006

Predictors of successful elimination of sinoatrial tachycardia (SAT) using radiofrequency current (RFC) were investigated in this report. Within 1991–1996 fourteen patients with SA T were subjected to electrophysiological study and radiofrequency catheter ablation (RFCA). Ten patients had sinoatrial reentrant tachycardia (SART). and four patients had chronic non‐paroxysmal sinoatrial tachycardia (CNPSAT). The RFC (15–30 W, duration 10–30 sec) were applied during tachycardia in case of CNPSAT, and during sinus rhythm (SR) in case of SART. In 3 patients with SART RFC were delivered during tachycardia due to failing of RFC application, delivered during SR. During successful RFC attempts were noted: I). In case of SART‐transient development (3–6 sec) of SART (if RFC was delivered during SR), and acceleration of tachycardia rate with following termination of tachycardia (if application ofRFC was performed during tachycardia) 2). In case of CNPSAT‐transient development (4–7 sec) of low right atrial (3 patients) or junctional (I patient) rhythm with rapid conversion to SR. All 14 /jatients have been free of tachycardia and have normal sinus node function during follow‐up of 8–60 months. We conclude that predictors of successful elimination of SAT are: 1). In case of SART‐acceleration of tachycardia rate before termination during RFC application (delivered during tachycardia), and transient development of SART during RFC application (delivered during SR): 2). In case of CNPSAT‐transient development of low right atrial or junction rhythm (during application of RFC) with rapid conversion to SR.
A Method for Permanent Transvenous Left Ventricular Pacing
Authors: BLANC JEAN‐JACQUES , BENDITT DAVID G. , GILARD MARTINE , ETIENNE YVES , MANSOURATI JACQUES , LURIE KEITH G.
Published: July 2006

LV‐based pacing has recently been reported to be of benefit in patients with severe cardiac failure and left bundle branch block. LV permanent pacing has been reported using epicardial leads but the surgical mortality is excessive. A transvenous approach is now favored. In this regard, cannulation of the coronary sinus and of one of its tributaries using only the permanent electrode is feasible but technically challenging. We describe a “long guiding sheath” method using catheterization, and a long radiopaque and peelable sheath. Once the coronaiy sinus is cannulated with the electrophysiological catheter, the long sheath is advanced to the mid‐part of the coronary sinus. The permanent pacing electrode is then placed through the sheath and into a tributary of the coronary sinus. This method has been attempted in 10 patients and was successful in 8, with an average lead insertion time of 21 ± 5.5 minutes and an average fluoroscopic time of 11 ± 5.5 minutes. In conclusion, although transvenous left ventricular pacing remains a challenge, the “long guiding sheath” approach appears to facilitate this procedure with both a high success rate and an acceptable procedure time.
Body Surface Laplacian Mapping in Patients with Left or Right Ventricular Bundle Branch Block
Authors: UMETANI KEN , OKAMOTO YOSHIWO , MASHIMA SABURO , ONO KOHEI , HOSAKA HIDEHIRO , HE BIN
Published: July 2006

Body surface Laplacian maps (BSLMs) have been previously reported to provide enhanced capability in localizing and resolving multiple spatially separate myocardial events. However, only a few studies have been reported on the clinical applications of BSLM. To test the clinical utility of BSLMs, BSLMs and body surface potential maps (BSPMs) during ventricular depolarization for complete right or left ventricular bundle branch block (CRBBB or CLBBB) were studied in ten patients in each group. As a control group, ten healthy subjects were also studied using the same procedure. One hundred and twenty‐eight electrodes were placed uniformly over the entire chest and back of the subjects. BSLMs were computed from recorded potentials, using a numerical algorithm. The BSLMs showed multiple and more localized positive and negative activities compared with the BSPMs. In healthy subjects, the BSLMs showed multiple areas of positive activity overlying the RV, LV, and the RV outflow, and negative activity corresponding to RV free‐wall breakthrough and LV anterolateral breakthrough sites, whereas the BSPMs could not separate RV and LV activities. In the patients with CRRRR, the BSLMs showed more localized areas of activity corresponding to the LV apex breakthrough and LV lateral breakthrough, and separated LV lateral and posterior activation. In the patients with CLBBB, the BSLMs showed multiple RV activation, and propagating activation of LV from lateral to posterior. The BSLMs appear to provide enhanced capability in detecting multiple ventricular electrical events associated with normal and abnormal conduction and a more detailed activation sequence of both ventricles in healthy subjects and in the patients with CRBBB and CLBBB. BSLM may provide an important alternative to other imaging modalities in localizing cardiac electrical activity noninvasively.
Telemetry Guided Pacemaker Programming: Impact of Output Amplitude and the Use of Low Threshold Leads on Projected Pacemaker Longevity
Authors: SCHWAAB BERNHARD , FRÖHLIG GERD , SCHWERDT HOLGER , HEISEL ARMIN , BERG MONIKA , SCHIEFFER HERMANN
Published: July 2006

In a prospective study, a low threshold screw‐in electrode (Medtronic 5078, group I. n = 9) was compared to a conventional active fixation lead (Biotronik Y60BP, group II. n = 9) to investigate whether lower pacing thresholds really translate into longer projected service life of the pacemaker. The leads were implanted in the atrium and were connected to a dual chamber pacing system which included the same ventricular lead (Medtronic 5024) and the same pulse generator model (Intermedics 294–03) in both groups. Eighteen months after implantation, atrial and ventricular pacing thresholds were measured as the charge delivered per pulse [μC] at 0.5, 1.0. 1.5, 2.0, and 3.5 V, respectively. For chronic output programming in both channels, patients capturing at 0.5 V were set to 1.0 V, those capturing at 1.5 V were permanently programmed to 2.0 V with the double of the charge threshold as the safety margin for pacing (“safety charge”). A combination of atrial and ventricular output settings was optimal, if it resulted in minimum battery current drain [μA] as measured by pacemaker telemetry. In both groups, current consumption [μA] decreased significantly as output amplitude was decreased, exhibiting its lowest value at 1.0 V in either channel. All ventricular leads could be programmed to the optimum output amplitude of 1.0 V in groups 1 and 2. As the 2:1 “safety charge” values were almost identical, the ventricular channel essentially contributes the same amount to the battery drain of the pacing system in both groups. In the atrium, all patients of group 1 could be programmed to the optimum output amplitude of 1.0 V with an average pulse duration of 0.42 ± 0.15 ms. In group 2, however, all patients had to be programmed to 2.0 V with a mean pulse width of 0.52 ± 0.15 ms. With the atrial and ventricular output being optimized, the average battery drain of the whole pacing system was 12.19 ± 0.63 μA in group 1 versus 14.42 ± 0.32 μA in group 2 (P < 0.001). As patients were chronically programmed to these output settings, this difference translates into a clinically relevant gain in projected pacemaker longevity of 17 months or 18.3 % (121 ± 4 vs. 104 ± 2 months; P < 0.001). Thus, programming a 2:1 safety margin in terms of charge and optimizing the output parameters by real‐time telemetry of the battery current is a useful approach to reduce battery current drain. Making the most of modern lead technology with a different performance in only one channel of an otherwise identical DDD pacing system translates into a significant prolongation of projected pacemaker service life which is of great importance with the increasing awareness of health care expenditures. The gain in projected longevity is mainly due to the option of reducing the output amplitude which is still significantly beneficial well below the nominal voltage of the power source.
Effects of Procainamide and dl‐Sotalol on the Changes of Atrial Electrophysiology Induced by High Current Stimulation
Authors: YU WEN‐CHUNG , CHEN SHIH‐ANN , TAI CHING‐TAI , WEN ZU‐CHI , FENG AN‐NING , MD YU‐AN DING , CHANG MAU‐SONG
Published: July 2006

The relation between high current atrial stimulation and antiar‐rhythmic drugs was not clear. We evaluated the effects of procainamide and dl‐sotalol on the electrophysiological changes induced by high current stimulation. Effects of high current atrial stimulation on effective refractory period, dispersion of refractoriness, conduction velocity, and wavelength of the earliest atrial premature beat were evaluated at baseline and after infusion of procainamide (10 patients) and dl‐sotalol (10 patients). High current atrial stimulation shortened effective refractory period locally (−12%± 4.0%, −7.0%± 3.0%, −5.1 ± 3.3%, and −3.0 ± 2.0%, at 0, 7, 14, and 21 mm from the S1 stimulation site, respectively; P < 0.001); increased the dispersion of refractoriness (from 17.8 ± 8.5 to 27.4 ± 12.5 ms, P < 0.001); decreased conduction velocity of the earliest premature beat (from 0.58 ± 0.10 to 0.52 ± 0.09 ms, P = 0.01); and decreased wavelength of the earliest atrial premature beat (from 10.9 ± 2.4 to 8.8 ± 2.1 cm, P < 0.001). These effects of high current stimulation persisted after procainamide infusion. However, after dl‐sotalol infusion, high current atrial stimuli did not change the dispersion of refractoriness (23.1 ± 10 ms vs 26.4 ± 10.4 ms; P > 0.05, twice diastolic threshold vs 10 mA); conduction velocity of the earliest premature beat (0.54 ± 0.06 ms vs 0.50 ± 0.06 ms, P > 0.05); or wavelength of the earliest premature atrial beat (11.5 ± 1.6 m/s vs 10.1 ± 1.7 cm; P > 0.05). Although high current atrial stimulation shortened effective refractory period locally, increased dispersion of refractoriness, and decreased the wavelength of the earliest premature atrial impulse, these effects were abolished by dl‐sotalol but not procainamide.
Transeptal Approach to Ablation of Left‐Sided Arrhythmias Does Not Lead to Persisting Interatrial Shunt: A Transesophageal Echocardiographic Study
Authors: FITCHET A. , TURKIE W. , FITZPATRICK A.P.
Published: July 2006

In experienced hands, antegrade left heart catheterization via a transeptal puncture is a safe and effective method of performing radiofrequency ablation on the left side of the heart. Persistence of atrial septal defect following transeptal puncture for mitral valvuloplasty has been widely reported although hemodynamically significant shunts are rare. To investigate the persistence of interatrial shunt following transeptal puncture in patients undergoing left‐sided electrophysiological procedures using TEE. Fifty‐one adult patients, 20 men, aged 19–82 (mean 42.4) years underwent 55 transeptal punctures. Either an 8 Fr Mullins or 8 Fr Swartz transeptal sheath was deployed in all cases. Of these, 28 consecutive patients were approached and 26 consented to undergo TEE. TEE was performed at least 3 weeks post transeptal puncture using a single‐plane transducer for the first 18 patients, superseded by a multiplane transducer for the later cases. Both color flow Doppler and microcavitation contrast imaging of the interatrial septum were performed. One patient in the single‐plane transducer group was excluded as she failed to swallow the TEE probe. In the remaining 25 patients studied, 9 men aged 21–82 (mean 44.1) years, TEE was performed at a mean of 12.2 (range 3–52) weeks post procedure. No evidence of interatrial shunt was detected by either color flow or contrast studies. Transeptal puncture used in electrophysiological procedures does not result in interatrial shunts persisting > 3 weeks post procedure.
Long‐Term Follow‐Up in Patients with the Permanent Form of Junctional Reciprocating Tachycardia Treated with Radiofrequency Ablation
Authors: AGUINAGA LUIS , PRIMO JOAO , ANGUERA IGNASI , MONT LUIS , VALENTINO MARIANA , BRUGADA PEDRO , BRUGADA JOSEP
Published: July 2006

This study sought to determine the long‐term follow‐up, safety, and efficacy of radiofrequency catheter ablation of patients with the permanent form of junctional reciprocating tachycardia (PJRT). We assessed the reversibility of tachycardia induced LV dysfunction and we detailed the location and electrophysiological characteristics of these retrograde atrioventricular decremental pathways. PJRT is an infrequent form of reciprocating tachycardia, commonly incessant, and usually drug refractory. The ECG hallmarks include an RP interval > PR with inverted P waves in leads II, III, aVF, and V3‐V6. During tachycardia, retrograde VA conduction occurs over an accessory pathway with slow and decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long‐lasting and incessant tachycardia may result in tachycardia induced severe ventricular dysfunction. We included 36 patients (13 men, 23 women, mean ± SD, aged 44 ± 22 years) with the diagnosis of PJRT. Seven patients had tachycardia induced left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during ventricular pacing or during reciprocating tachycardia. All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented with depressed LV function. Radiofrequency ablation was performed in 36 decremental accessory pathways. Earliest retrograde atrial activation was righ t posteroseptal in 32 patients (88%), right mid‐septal in 2 (6%), right posteroiateral in 1 (3%), and left anterolateral in 1 (3%). Thirty‐five accessory pathways were successfully ablated with a mean of 5 ± 3 applications. A mid‐septal accessory pathway could not be ablated. After a mean follow‐up of 21 ± 16 months (range 1–64) 34 patients are asymptomatic. There were recurrences in 8 patients after the initial successful ablation (mean of 1.2 months), 5 were ablated in a second ablation procedure, 2 patients required a third procedure, and 1 patient required four ablation sessions. All patients with LV dysfunction experienced a remarkable improvement after ablation. Mean preablation LV ejection fraction in patients with tachycardiomyopathy was 28%± 6% and rose to 51%± 16% after ablation (P < 0.02). Our study supports the concept that radiofrequency catheter ablation is a safe and effective treatment for patients with PJRT. Radiofrequency ablation should be the treatment of choice in these patients because this arrhythmia is usually drug refractory. The majority of accessory pathways are located in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of LV dysfunction.
Short‐and Long‐Term Performance of a Tripolar Down‐Sized Single Lead for Implantable Cardioverter Defibrillator Treatment: A Randomized Prospective European Multicenter Study
Authors: SANDSTEDT BENGT , KENNERGREN CHARLES , SCHAUMANN ANSELM , HERSE BERNHARD , NEUZNER JÖRG ,   EUROPEAN ENDOTAK DSP INVESTIGATOR GROUP
Published: July 2006

A new, thinner (10 Fr) and more flexible, single‐pass transvenous endocardial ICD lead, Endotak DSP, was compared with a conventional lead, Endotak C, as a control in a prospective randomized multicenter study in combination with a nonactive can ICD. A total of 123 patients were enrolled, 55 of whom received a down‐sized DSP lead. Lead‐alone configuration was successfully implanted in 95% of the DSP patients vs 88% in the control group. The mean defibrillation threshold (DFT) was determined by means of a step‐down protocol, and was identical in the two groups, 10.5 ± 4.8 J in the DSP group versus 10.5 ± 4.8 J in the control group. At implantation, the DSP mean pacing threshold was lower, 0.51 ± 0.18 V versus 0.62 ± 0.35 V (p < 0.05) in the control group, and the mean pacing impedance higher, 594 ± 110 Ω vs 523 ± 135 Ω (p < 0.05). During the follow‐up period, the statistically significant difference in thresholds disappeared, while the difference in impedance remained. Tachyarrhythmia treatment by shock or antitachycardia pacing (ATP) was delivered in 53% and 41%, respectively, of the patients with a 100% success rate. In the DSP group, all 28 episodes of polymorphic ventricular tachycardia or ventricular fibrillation were converted by the first shock as compared to 57 of 69 episodes (83%) in the control group (p < 0.05). Monomorphic ventricular tachycardias were terminated by ATP alone in 96% versus 94%. Lead related problems were minor and observed in 5% and 7%, respectively. In summary, both leads were safe and efficacious in the detection and treatment of ventricular tachyarrhythmias. There were no differences between the DSP and control groups regarding short‐ or long‐term lead related complications.
Comparison of Normal Sinus Rhythm and Pacing Rate in Children with Minute Ventilation Single Chamber Rate Adaptive Permanent Pacemakers
Authors: ÇELIKER ALPAY , CEVIZ NACI , ALEHAN DURSUN , LENK MUSTAFA K. , ÖZME ŞENCAN
Published: July 2006

Rate adaptive pacemakers are used to achieve a better cardiac performance during exercise by increasing the heart rate and cardiac output. The ideal rate adaptive sensor should be able to mimic sinus node modulation under various degrees of exercise and other metabolic needs. Minute ventilation sensing has proven to be one of the most accurate sensor systems. In this study, alterations in sinus rhythm and pacing rates during daily life conditions in 11 children (median age 11 years, range 6–14 years) with minute ventilation single chamber pacemakers were investigated. Correlation of sinus rhythm with pacing rates was assessed. ECG records were obtained from 24–hour Holter monitoring. Average rates of five consecutive P waves and pace waves were determined every half hour. The average of the two values was then used to determine hourly rates. Correlation coefficients between the sinus rhythm and pacing rates were calculated. In nine patients, pacing rates correlated well to sinus rhythm (range 0.6793–0.9558. P < 0.001 and P < 0.05), whereas in two cases correlation was not sufficient (P > 0.05). Most of the patients, in whom rate response factor (RRF) measurements during peak exercise by treadmill with cnronotropic assessment exercise protocol were performed and pacemakers were programmed to these parameters, had more appropriate ventricular rates compared to spontaneous sinus rates. In these patients mean RRF value was 15.3 ± 2.7 (range 12–20, median 15). This study shows that during daily activities minute ventilation rate adaptive pacemakers can achieve pacing rates well correlated to sinus rhythm that reflects the physiological heart rate in children.
Endocardial Biventricular Pacing
Authors: JAÏS PIERRE , DOUARD HERVÉ , SHAH DIPEN C. , BAROLD SERGE , BARAT JEAN‐LOUIS , CLÉMENTY JACQUES
Published: July 2006

Simultaneous righ t and left ventricular pacing was performed in a 73‐year‐old man with coronary artery disease end‐stage congestive heart failure and a DDD pacemaker implanted for sick sinus syndrome. An endocardial LV lead was introduced transseptally after unsuccessful attempts to enter the coronary sinus. This new approach for multisite pacing offers an alternative to epicardial LV from the coronary sinus or by thoracotomy.
Successful Radiofrequency Catheter Ablation of Congenital Junctional Ectopic Tachycardia with Preservation of Atrioventricular Conduction in a 9‐Month‐Old Infant
Authors: FISHBERGER STEVEN B. , ROSSI ANTHONY F. , MESSINA JOHN J. , SAUL J. PHILIP
Published: July 2006

An infant with congenital junctional ectopic tachyardia required frequent hospitalizations due to tachycardia acceleration despite multiple antiarrhythmic medications. At 9 months of age, he underwent successful radiofrequency catheter ablation of the tachycardia with preservation of AV conduction.
Late Complete Atrioventricular Block Complicating Radiofrequency Catheter Ablation of a Left Posteroseptal Accessory Pathway
Authors: LIU JUNSHI , DOLE LYNN R.
Published: July 2006

A patient with AV reentrant tachycardia underwent radiofrequency catheter ablation for interruption of a left posteroseptal accessory pathway (AP). During the RF current application, he developed transient complete left bundle branch block which lasted for 2 minutes. The following day the patient developed permanent complete AV block. This case indicates that great care should be taken when performing RF ablation for this AP site.