bluuebunny/crossref_metadata_2025 huggingface dataset:
Variability of Ventricular Premature Complexes and Mortality Risk
Authors: Malik Marek , Mercando Anthony D. , SCHMIDT GEORG , MORFILL GREGOR E. , BARTHEL PETRA , HADAMITZKY MARTIN , KREUZBERG HEINZ , DEMMEL VALENTIN , SCHNEIDER RAPHAEL , ULM KURT , SCHÖMIG ALBERT
Published: July 2006

A method using a parameter from the field of nonlinear dynamics to quantify the variability of ventricular premature complexes (VPCs) is presented. One hundred patients with coronary artery disease and ≥ 10 VPCs/hour were included in the studv. The RR intervals were plotted in a three‐dimensional artificial phase space, and the structures in phase space were quantified by the local scaling indices, a. In the frequency distribution histogram, n(α), for each patient, the maximum of the ventricular ectopies αvpc, adjusted to the VPC frequency, was assessed; αvpc, was used as the risk indicator. Endpoints were total mortality and sudden cardiac death. During follow‐up (mean 3.1 years), 28 out of 100 patients died, 16 suddenly; αvpc had a significant prognostic impact end was independent from other risk indicators, such as left ventricular ejection fraction (LVEF). Patients who died during follow‐up were characterized by a high αvpc. The optimal discrimination of high risk patients and low risk patients occurred at αvpc — 3.0. After 4 years, the survival rate of patients with a αvpc > 3.0 was 59%, in contrast to 97% in patients with αvpc ≤ 0.3. As to the sudden death mortality, the survival rates were 74% and 97%, respectively. The difference between the groups were significant for both endpoints. Patients with an increased VPC variability (i.e., αvpc > 3.0) were at enhanced risk of sudden death and total mortality risk; αvpc was independent from other risk indicators such as the LVEF or heart rate variability parameters.
Radiofrequency Catheter Ablation of Atrial Tachycardia with Unusual Left Atrial Sites of Origin: Report of Two Cases
Authors: MALLAVARAPU CHRISTOPHER , SCHWARTZMAN DAVID , CALLANS DAVID J. , GOTTLIEB CHARLES D. , MARCHLINSKI FRANCIS E.
Published: July 2006

Two cases of successful radiofrequency catheter ablation of adult‐onset atrial tachycardia originating from the left atrium adjacent to the mitral annulus are presented. Endocardial catheter activation mapping performed by retrograde or atrial transseptal approach revealed presystolic activation at the successful ablation site in both patients, and fractionation during sinus rhythm and tachycardia in one. The 12 lead electrocardiogrnphic P wave appearance was suggestive of a left atrial tachycardia origin in both cases.
Radiofrequency Catheter Ablation of an Incessant Supraventricular Tachycardia Initiated by a Hisian Parasystole
Authors: CRUZ FERNANDO E.S. , FAGUNDES MARCIO , BOGHOSSIAN SILVIA , RIBEIRO JOSE CARLOS , VANHEUSDEN LUTGARDE , MAIA IVAN G.
Published: July 2006

The coexistence of a pamsystolic focus, tachycardia dependent right bundle branch aberrancy, and an AV accessory pathway is reported here. This condition was present in a 40‐year‐old man, which led to an incessant AV reciprocating tachycardia. Further electrophysiological study revealed that the parasystolic focus was located somewhere in the His bundle; endocardial mapping disclosed a right posterior accessory pathway. Radiofrequency current was delivered at the atrial level of the right posterolateral AV groove and successfully ablated the accessory pathway, leading to a dramatic improvement in cardiac function. In conclusion, the recognition of the electrophysiological mechanism of incessant Supraventricular tachycardia was of crucial importance for the therapy decision. A definitive intervention using radiofrequency catheter ablation should be considered early and not postponed in patients with tachycardia‐induced cardiomyopathy.
Treatment of Refractory Ventricular Fibrillation by Combined Internal (Epicardial) and External (Transthoracic) Defibrillation
Authors: FREDMAN CAREY S. , BIERMANN KURT M. , BAROLD S. SERGE , DOLAN PATRICK H. , MARBARGER JOHN P. , GARRETT TED E.
Published: July 2006

This report describes a modified defibrillation technique used successfully in a patient with an implanted epicardial cardioverter defibrillator who developed refractory ventricular fibrillation. During operative testing at the time of generator replacement, two episodes of intractable ventricular fibrillation were terminated by using a combined internal (epicardial)‐external (transthoracic) defibrillation system that delivered a 360‐J shock between the anterior epicardial patch and a large posterior skin electrode.
Beta Adrenergic Blockade in the Treatment of Sustained Ventricular Tachycardia or Ventricular Fibrillation
Authors: WIESFELD ANS C.P. , CRIJNS HARRY J.G.M. , TUININGA YPE S. , LIE KONG I.
Published: July 2006

The value of β‐blockers as antiarrhythmic drugs in patients with sustained VT or VF has received only little attention. This article summarizes the current state of knowledge regarding the identification of patients with sustained VT or VF with the highest benefit of β‐blockade. The antiarrhythmic mechanisms of β‐blockade and its efficacy as single or adjuvant therapy in patients with sustained VT or VF are reviewed. Current insights into the effects of β‐blockade in patients suffering from VT, in particular in the setting of heart failure, are discussed and future directions are considered.
Activity Controlled Cardiac Pacemakers During Stairwalking: A Comparison of Accelerometer with Vibration Guided Devices and with Sinus Rate
Authors: MATULA MARKUS , SCHLEGL MICHAEL , ALT ECKHARD
Published: July 2006

Activity controlled pacemakers are the most widely used rate adaptive systems. We studied second‐generation activity controlled systems (accelerometer) in 21 patients with such an accelerometer controlled system implanted during walking level and stairs. We compared them to the rate of vibration controlled, first‐generation activity pacemakers and to the sinus rate of a healthy control group. A metronome directed the speed during walking and climbing stairs at 92, 108, and 120 steps/min. At 92 steps/min, the new accelerometer controlled systems showed a significant (P ≤ 0.001) pacing rate increase from 107 ± 8 beats/mm during walking level to 124 ± 8 beats/min during climbing stairs, and a significant decrease to 105 ± 12 beats/mm during walking downstairs. In contrast, first‐generation activity controlled pacemakers showed a less physiological rate behavior with higher pacing rate (113 ± 7 beats/min) walking downstairs than walking upstairs (97 ± 9), For everyday activities at normal walking speed, accelerometer controlled pacemakers show a more physiological rate behavior than first‐generation pacemakers, hut they lose this physiological response with faster walking.
Simultaneous Multipolar Radiofrequency Ablation in the Monopolar Mode Increases Lesion Size
Authors: MACKEY SEAN , THORNTON LARA , HE DING SHENG , MARCUS FRANK I. , LAMPE LOUIS F.
Published: July 2006

Delivery of radiofrequency (RF) energy from the distal tip of electrophysiology catheters produces lesions that may be too small to ablate arrhythmogenic sites during a single application of RF energy. To produce larger lesions, we delivered RF energy via a quadripolar catheter in which all four electrodes were connected in unipolar fashion. The catheter (Webster Labs) had a 4‐mm tip, 2‐mm ring electrodes, and 2‐mm intereiectrode distance. Lesion size was compared using RF energy delivered in a multipolar configuration with that delivered only to the distal tip using fresh bovine ventricular tissue. In vivo, RF lesions were made in dogs using the distal tip as well as all four poles of the same catheter inserted percutaneously. RF energy was delivered using a constant voltage at a frequency of 400 kHz. Preliminary experiments were conducted to determine the maximum power deliverable without coagulation using each electrode configuration. The use of simultaneous muitipolar RF ablation produced significantly larger lesions both in vitro and in vivo. The length of the lesion was increased by a factor of approximately 2 in both the in vitro and in vivo experiments. There was a trend toward an increasing depth of the lesion by simultaneously applying RF energy to all four electrodes. Lesion width was significantly increased in the in vivo studies. We concluded that simultaneous muitipolar delivery of RF energy produces larger lesions than can be obtained with delivery of RF energy to the distal tip alone. This technique may offer a means of increasing lesion size, leading to a decrease in the number of applications of RF energy necessary for ablation of arrhythmias.
High Energy Transcatheter Cardioversion for Chronic, Poorly Tolerated Atrial Fibrillation
Authors: FORGIONE NICOLA FORTUNATO , ACQUATI FIORENZO , CAICO SALVATORE IVAN , SAVERI CECELIA , VERNA EDOARDO , TAGLIAGAMBE LUCA , REPETTO SERGIO
Published: July 2006

Between August 1991 and May 1993, 14 patients affected by chronic, poorly tolerated atrial fibrillation (AF) were submitted to high energy transcatheter Cardioversion. Mean duration of AF was 27.4 ± 45.1 months. In nine patients (56%), AF lasted for > 1 year. All patients had underlying heart disease, with a mean LVEF of 45.2%± 11.8% and a NYHA Class ≥ II. Previously, a mean of 2.9 ± 1.3 patients failed external electrical Cardioversion, with and without antiarrhythmics, have been attempted. Transcatheter conversion was performed by pulling the His‐bundle catheter back in the right atrial cavity until no His bundle activity was recorded on distal poles, and then delivering the shock between a proximal electrode (cathode) and a back plate (anode). In all patients, transcatheter conversion restored sinus rhythm. Transient complete atrioventricular (AV) block was observed in four patients (28%), and treated by prophylactic temporary pacing. At 1 year, seven patients (50%) were still in sinus rhythm. In this series, only younger age could be related to AF recurrence (46.1 ± 10.8 vs 63.4 ± 6.8 years, P ≤ 0.004), even if prophylaxis with amiodarone showed a positive trend versus sinus rhythm maintenance (71 % vs 14%, P = NS). In conclusion, high energy transcatheter Cardioversion is a safe and effective method of restoring sinus rhythm in patients with chronic, poorly tolerated AF. In these patients, high energy transcatheter Cardioversion could be considered as an alternative to AV node ablation techniques, avoiding pacemaker implant and embolic risk. Larger studies are needed to determine better patient selection and delineate drug strategy after the procedure.
Comparison of Three Cardioverter Defibrillator Implantation Techniques: Initial Results with Transvenous Pectoral Implantation
Authors: ANVARI ANAHIT , STIX GÜNTER , GRABENWÖGER MARTIN , SCHNEIDER BARBARA , TUREL ZEYNEP , SCHMIDINGER HERWIG
Published: July 2006

A total of 121 patients underwent epicardial (n = 32), transvenous abdominal (n = 30), and transvenous pectoral (n = 59) ICD implants. Perioperative complications were defined as those occurring within 30 days after surgery. Hospital costs were calculated with $750 per day as a fixed charge. Duration of surgery was the time between the first skin incision and the last skin suture. Severe perioperative complications that were life‐threatening or required surgical intervention occurred in the epicardial (6%) and transvenous (10%) abdominal groups, but not in the pectoral group. Perioperative mortality occurred only in the epicardial abdominal group, predominantly in patients with concomitant surgery (18%), and in 5% of patients without concomitant surgery. The duration of surgery was significantly shorter for transvenous pectoral implantation (58 ± 15 rain, P < 0.05) compared to transvenous abdominal implantation (115 ± 38 min). Epicardial abdominal ICD implantation had the longest procedure time (154 ± 31 min). The postimplant hospital length of stay was significantly shorter for pectoral implantation (5 ± 3 days, P < 0.05) compared to transvenous (13 ± 5) and epicardial (19 ± 5) abdominal implantation. Total hospitalization costs significantly decreased in the pectoral implantation group ($4,068 ±$2,099 for the pectoral group vs $14,887 ±$4,415 and $9,975 ±$3,657 for the epicardial and the transvenous abdominal group, respectively, P < 0.05). These initial results demonstrate the advantage of transvenous pectoral ICD implantation in terms of perioperative complications, procedure time, hospital length of stay, and hospitalization costs.
Direct Angiography of the Coronary Sinus: Impact on Left Posteroseptal Accessory Pathway Ablation
Authors: TEBBENJOHANNS JÜRGEN , PFEIFFER DIETRICH , SCHUMACHER BURGHARD , JUNG WERNER , MANZ MATTHIAS , LÜDERITZ BERNDT
Published: July 2006

The purpose of this study was to determine the incidence and types of venous branches and anomalies in posteroseptal accessory pathways (APs) and whether these findings are indicative for successful ablation sites. Some posteroseptal APs may be located epicardially, or may be associated with venous anomalies or related to the middle cardiac vein. These APs account for many of the failures encountered during endocardial ablation. Direct coronary sinus (CS) angiography was performed in 43 consecutive patients with left posteroseptal APs (n ‐ 23) and in 20 patients with A V nodal reentrant tachycardia prior to catheter ablation. In 14 (61%) of 23 APs, a venous branch or an anomaly of the CS was found in the posteroseptal region (6 with middle cardiac vein, 2 with other ventricular venous branches, and 6 had a diverticulum). Eleven (48%) of 23 APs were successfully abolished from within that demonstrated venous system, with a median of four radio frequency impulses. In the remaining 12 (52%) patients, ablation was attempted from the endocardial site of the mitral annulus. Repeat angiography after energy delivery revealed no major complications in any patient. One (5%) patient with AV nodal reentrant tachycardia had evidence of a CS anomaly (P < 0.01). Various types of venous branches and anomalies are associated with the majority of patients with left posteroseptal APs. The APs are directly related to these complex findings, and AP conduction can easily be eliminated from within the venous branches. CS angiography is suggested prior to catheter ablation of left posteroseptal APs to facilitate the ablation procedure.
Effects of Isoflurane on Electrophysiological Measurements in Children with the Wolff‐Parkinson‐White Syndrome
Authors: CHANG RUEY‐KANG R. , STEVENSON WILLIAM G. , WETZEL GLENN T. , SHANNON KEVIN , BAUM VICTOR C. , KLITZNER THOMAS S.
Published: July 2006

This study was designed to assess the effects of isoflurane (ISO) on the electrophysiological properties of the accessory pathway, atrium, ventricle, and AV node in children with the Wolff‐Parkinson‐White (WPW) syndrome. The results of programmed electrical stimulation were analyzed in 51 patients (4 months to 17 years of age) with WPW. The study population was divided into two groups. Twenty‐seven patients received local anesthesia and intramuscular injection of meperidine, promethazine, and chlorpromazine (MPC group). Twenty‐four patients received general anesthesia with ISO inhalation (ISO group). We compared the antegrade effective refractory period of the accessory pathway (antegrade APERP), ventricular effective refractory period (VERP), atrial effective refractory period (AERP), AH interval, and cycle length of circus movement tachycardia (CMT‐CL) in 12 pairs of age and sex matched patients selected from the MPC and ISO groups. Of the 12 pairs of age and sex matched patients, antegrade APERP in patients who received ISO (299 ± 17 ms, mean ± SEM) was significantly longer as compared with matched patients in the MPC group (262 ± 5 ms, P < 0.025). The VERP and AERP in patients from the ISO group were significantly prolonged compared with the MPC patients (239 ± 7 vs 210 ± 8 ms, P < 0.025, and 228 ± 11 vs 180 ± 6 ms, P < 0.01, respectively). There was no significant difference in the AH interval or CMT‐CL between the two subgroups. Thus, ISO prolongs the antegrade APERPs as well as the effective refractory periods of atrial and ventricular muscle in children with WPW, while the AH interval and CMT‐CL appear to be unaffected. Care must be taken in interpreting measurements of the antegrade APERP made in patients under general anesthesia for RF ablation of accessory pathways.
Lead Fracture in Cephalic Versus Subclavian Approach with Transvenous Implantable Cardioverter Defibrillator Systems
Authors: GALLIK DONNA M. , BEN‐ZUR URI M. , GROSS JAY N. , FURMAN SEYMOUR
Published: July 2006

Lead fracture, occurring in approximately 1%–4% of patients, is an infrequent, but potentially catastrophic complication of permanent pacing systems. Its incidence in transvenous defibrillator systems has not been established. We analyzed data from 757 patients undergoing implantation of transvenous Cardioverter defibrillator systems using the Medtronic Transvene Lead® system between October 20, 1989 and June 25, 1992 to determine if site of venous approach influenced incidence of lead fracture. All patients received a 3‐lead system in 1 of 3 configurations: (1) right ventricle/superior vena cava/subcutaneous patch; (2) right ventricle/coronary sinus/subcutaneous patch; or (3) right ventricle/superior vena cava/coronary sinus. Of 767 right ventricular leads placed, 523 were placed via the subclavian vein, 221 via cephalic vein, and 18 via the internal jugular (5 leads were implanted using another vein). The total number of leads is greater than the total number of patients, as five patients received a second defibrillator system if the initial system was explanted and reimplanted for any reason. Seven patients (0.9%) had right ventricular lead fracture, presenting with inappropriate defibrillator shocks (1), loss of pacing ability (3), both loss of pacing ability and inappropriate shocks (1), or increased pacing threshold (2). All patients required reoperation. AH had leads placed by the subclavian venous approach, with chest X ray confirming fracture at the clavicle‐first rib junction in 6 of 7 cases. Using Fisher's Exact test, the difference in lead fracture between subclavian and cephalic vein implant approached statistical significance (P = 0.08). The trend toward increased lead fracture incidence with leads placed via subclavian vein suggests that cephalic vein approach may be preferable to avoid this complication.
The Treatment of Septicemia in Pacemaker Patients
Authors: BÖHM ÁDÁM , BÁNYAI FERENC , PRÉDA ISTVÁN , ZÁMOLYI KÁROLY
Published: July 2006

The authors analyzed the data of seven patients who had undergone open heart surgery because of pacemaker endocarditis in the past 4 years. Repeated surgical interventions on the pacemaker system were found to be the most common predisposing factors. Staphylococcus aureus and Staphylococcus epidermidis were the most common causative organisms. Two‐dimensional echocardiography was important in the diagnosis of cases with atypical clinical picture and negative blood cultures. We concluded that: (1) any pacemaker patient with fever should be considered to have a pacemaker endocarditis; (2) all of these patients should be examined by two‐dimenensional echocardiography; and (3) the total removal of the infected hardware seems to be the only way to achieve complete recovery.
The Health Insurance System in Japan
Authors: WATANABE YOSHIO
Published: July 2006

The steadily increasing cost of medical care associated with advancing medical technology as well as the rapid progression of generalized aging of the society has become a major socioeconomical issue confronting most developed countries. Although Japan is no exception in this regard, and a drastic modification of the health care system is now being discussed, it is also clear that its postwar health insurance system has played a major role for the Japanese achieving the longest life expectancy in the world (over 82 years for female and 76 years for male) in the past decade. It is thus my understanding that the invitation for this brief review reflects the need for reference information regarding the current debate in the North American continent.
Pacemaker Upgrade for Recurrent Pacemaker Syndrome Using a Redundant Contralateral Electrode in a Patient with Bilateral Venous Stenoses
Authors: SULKE NEIL , TAN KIM , BOSTOCK JULIAN
Published: July 2006

Following His‐bundle ablation and VVIR pacemaker implantation, severe Pacemaker syndrome developed and was treated with DDDR pacing in a 70‐year‐old woman. Due to bilateral subclavian vein stenosis, DDDR pacing could not be maintained and an unusual method of restoring atrioventricular synchrony is described using the contralateral redundant atrial electrode connected to the ipsilateral dual chamber pacemaker and ventricular electrode.
Transient Entrainment: The Evolution of a Medical Concept from Description to Prescription
Authors: COOPER M. WAYNE
Published: July 2006

Entrainment is a phenomenon that has come to have considerable utility in cardiac electrophysiology diagnosis and treatment; specifically, to identify a zone of slow conduction in a reentrant circuit, a zone hypothetically vulnerable to intervention from the application of RF energy. The observation of entrainment has gone through an evolutionary sequence in the literature, from the initial simple observations of the phenomenon to the present stage of relatively fixed criteria of identification. This article follows the evolution of the specific features of the criteria of entrainment to their current crystallization into features that are suggested to prescribe sites for attempted ablation. This examination of the evolutionary course of the development of the conception of entrainment is of interest not only to cardiac electrophysiology, but also to philosophers of science, by illustrating how scientists emphasize and develop certain observations with the ultimate aim of applying the observations for successful intervention in pathological entities.
A Conceptual Basis for Pacing Waveforms
Authors: CLELAND BRIAN G.
Published: July 2006

A model is developed that allows evaluation of the pacing efficacy of different stimulus waveforms. It treats the heart as having a first order time constant and enables ready visualization of the time course of the effective voltage within the heart. For pacemakers, where the stimulus pulse is produced by the discharge of a capacitor, the voltage within the heart rapidly rises to a peak and then more slowlv decays to zero. The time interval at which the peak occurs defines the optimal duration, i.e., the shortest duration with minimal pacing voltage. Characteristics are developed that show the changes in optimal duration and pacing threshold for changes in the pacemaker's output capacitor and for differences in lead impedance and time constant of the heart.
A Conceptual Basis for Defibrillation Waveforms
Authors: CLELAND BRIAN G.
Published: July 2006

A model is developed for defibrillation that treats the heart as a first order time constant. Such a model allows ready evaluation of different monophasic waveforms. For implantabls devices where the voltage is provided by the discharge of a capacitor, it can be seen that the effective voltage within the heart rises rapidly to a peak and then decays to zero. The time interval at which this peak occurs is defined as the optimal duration, and there is no advantage in extending the pulse beyond this point. Characteristics are presented that show how the time course of this voltage within the heart changes with different device capacitors and load impedances. The effect of different heart time constant are also examined. Forbiphasic waveforms, a contour plot of threshold voltage is presented with phase 1 and phase 2 durations on the two axes. It is seen that there is a region of reliable low threshold defibrillation from 3.5/1.5 ms to 9/6 ms.
A Comparison of Unipolar and Bipolar Electrodes During Cardiac Mapping Studies
Authors: KIMBER S. , DOWNAR EUGENE , MASSE S. , SEVAPTSIDIS ELIAS , CHEN THOMAS , MICKLEBOROUGH LYNDA , PARSONS IAN
Published: July 2006

Controversy exists as to whether the unipolar or bipolar electrode configuration is superior in detecting local activations during cardiac mapping studies. However, the strengths and weaknesses of each mode suggest that they may provide complementary information. To examine therelative merits of unipolar and bipolar electrode configurations, recordings by each were simultaneously acquired during episodes of ventricular tachycardia in eight consecutive patients undergoing map guided arrhythmia surgery. Unipolar electrograms were classified as either unambiguous or ambiguous according to whether or not they were polyphasic in nature. The activation times from the unambiguous electrograms were compared with activation times from the corresponding bipolar signals where local activation was measured both at the signal's peak amplitude (BI‐PK), and at the point at which the waveform's first major, rapid transient crossed baseline (BI‐TRN). Occurrences of discrete diastolic activations were also quantified from the unipolar and bipolar tracings. From a total of 415 unipolar electrograms, 301 unambiguous signals were identified as suitable for comparison with the bipolar signals. Both BI‐PK and BI‐TRN criteria for the determination of local activation were highly correlated with and not significantly different from the local activation from the unipolar electrogram. From 85 ambiguous unipolar electrograms, it was possible to determine local activation from the corresponding bipolar signal in 33% of the occurrences. From the eight patients, 64 diastolic potentials were recorded of which 42 were seen only in bipolar mode, 7 in only unipolar mode, and 15 were evident in both tracings. The prevalence of diastolic potentials was significantly greater in recordings made using bipolar mode. The results demonstrate that complementary information regarding local activations and diastolic potentials can be derived from unipolar and bipolar recordings and suggest that both electrode configurations should be used in multichannel cardiac mapping systems.
Electrostimulated Cardiomyoplasty: From Experimental to Clinical Studies
Authors: DUMCIUS ARIMANTAS , SALCIUS KESTUTIS , RALIENE LAIMA , VASKELYTE JOLANTA , GIEDRAITIS SAULIUS , SIRVINSKAS EDMUNDAS , MARCINKEVICIENE JOLANTA , SKUCAS JONAS
Published: July 2006

Cardiomyoplasty is a method for managing patients with dilated cardiomyopathy. We evaluated the means of carbon fiber electrode stimulation of the nerve to the latissimus dorsi muscle (LDM) in dogs to increase skeletal muscle contractility. Histochemical examination of biopsies of muscle electrically conditioned by a single pulse stimulator via the thoracodorsal nerve demonstrated transformation of muscle into fatigue resistant slow fibers without damage to muscle or nerve tissue. Canine experiments confirmed that carbon fibers are one of the best electrodes for chronic LDM stimulation. Between 1988 and 1992, we operated on ten patients, New York Heart Association (NYHA) Class III (4 patients) and Class IV (6 patients), with a mean left ventricular ejection fraction (LVEF) of 23%. The indications for Cardiomyoplasty were idiopathic (7 patients) and ischemic (3 patients) cardiomyopathy refractory to maximum medical therapy. The operative procedure was performed via median sternotomy (5 patients) and left thoracotomy (5 patients). There was one operative mortality and two additional deaths during the late follow‐up period. The mean postoperative LVEF increased to 27%. Functional class, quality‐of‐life, and ventricular performance were improved after Cardiomyoplasty. Two of the surviving patients are in NYHA Class I, four in Class II, and one in Class III.
Improved Sensing Signals After Endocardial Defibrillation with a Redesigned Integrated Sense Pace Defibrillation Lead
Authors: ISBRUCH FRANK M. , BLOCK MICHAEL , BÖCKER DIRK , DEES HEIKE , HAMMEL DIETER , BORGGREFE MARTIN , SCHELD HANS H. , BREITHARDT GÜNTER
Published: July 2006

Adequate sensing is a basic requirement for appropriate therapy with ICDs. Integrated sense pace defibrillation leads, which facilitate ICD implantation, show a close proximity of sensing and defibrillation electrodes that might affect the sensing signal amplitude by the high currents of internal defibrillation. In 99 patients, we retrospectively examined two integrated sense pace defibrillation leads, eitherboth with a distance of 6 mm between the tip of the lead (sensing cathode) and the right ventricular defibrillation electrode (sensing anode) or one with a distance of 12 mm. Three seconds after a shock of 20 J, mean sensing signal amplitude during sinus rhythm (SR) decreased from 10.5 ± 4.3 mVto 5.1 ± 3.7 mV (P < 0.001) for the 6‐mm lead, but showed no significant decrease for the 12‐mm lead. The degree of signal reduction was inversely related to the time passed since defibrillation. Significant differences in reduction of sensing signal amplitude concerning monophasic and biphasic shocks could not be observed. Mean sensing signal amplitude of VF after shocks that failed to terminate it decreased in the same order as during SR (from 8.3 ± 4.1 mV to 4.1 ± 3.2 mV), but resulted in no failure of redetection during ongoing VF. DFTs did not differ for the 6‐mm and the 12‐mm lead. In conclusion, close proximity of the right ventricular defibrillation coil to the sensing tip of an integrated sense pace defibrillation lead causes energy and time related reductions in sensing signal amplitude after defibrillation, and might cause undersensing in the postshock period. A new lead design with a more proximal position of the right ventricular defibrillation coil avoids these problems without impairing DFTs.
Improved Recovery of High Frequency P Wave Energy by Selective P Wave Averaging
Authors: STAFFORD PETER J. , COOPER JOANNE , GARRATT CLIFFORD J.
Published: July 2006

Most signal averaging processes used for cardiac signals align successive waveforms using a template matching process. In addition to achieving accurate temporal alignment of the signals, this operation m ust also ensure that the signal average comprises signals of the same morphology. For P wave signal averaging, systems designed for QRS complex averaging are often used, with the template acquisition window shifted to include the P wave. Theoretically, with this technique, variations in P wave morphology could reduce the high frequency content of the signal. We tested this hypothesis by comparing the performance of a selective P wave averaging system with a conventional system, based on template matching by cross‐correlation over a fixed acquisition window, on identical P wave recordings from 15 subjects. The selective system identifies variations in P wave morphology and generates up to five candidate templates for averaging. Subsequently, the most frequently matched template over a 100‐beat sample is used for averaging. Only P waves with the same morphology as this template are averaged. Selective averaging mainly increased the measured high frequency P wave energy, without affecting P wave duration after high pass filtering at 40 Hz, (Duration: 157(4)ms selective vs 155(4) nonselective. Energy 80–150 Hz: 1.77(0.28)μV2.s selective vs 1.61(0.3)μV2.s non selective, P < 0.01). These observations confirm that non‐selective P wave averaging can reduce apparent P wave energy, especially at high frequency. Before meaningful studies of the value of frequency domain analysis of the P wave can be performed, it is important that signal averaging systems of sufficient fidelity are utilized.
Diagnosis of Retrograde Ventriculoatrial Conduction by Left Atrial Appendage Doppler Flow Analysis
Authors: BHAGWAT AJIT R. , HOIT BRIAN D.
Published: July 2006

We report a case of pacemaker syndrome where the diagnosis of retrograde ventriculoatrial conduction was made by Doppler analysis of left atrial appendage flow. Doppler analysis of left atrial appendage flow provides another noninvasive parameter to diagnose retrograde Ventriculoatrial conduction.
Implantable Cardioverter Defibrillator Therapy in a Patient with the Idiopathic Long QT Syndrome
Authors: GRÖNEFELD GERIAN , HÖLTGEN REINHARD , HOHNLOSER STEFAN H.
Published: July 2006

The idiopathic long QT syndrome (LQTS) carries a high mortality in untreated patients. Administration of beta‐receptor antagonists is considered the treatment of choice. Data concerning the usefulness of implantable cardioverter‐defibrillator (ICD) therapy in this condition are sparse. We report on a 29‐year‐old female with LQTS who was treated with propranolol, but also underwent implantation of an ICD as a fail‐safe therapy. During the next 17 months, the patient was asymptomatic. However, after skipping her propranolol for 3 days, she had several syncopal spells with concomitant device therapy. ICD interrogation revealed a total of 55 nonsustained runs of ventricular tachycardia and 16 sustained episodes that were correctly identified by the device and respectively terminated by the first shock. This case report demonstrates that in selected patients with the LQTS, using ICD therapy as a fail‐safe treatment may be life‐saving, particularly when compliance to medical therapy is uncertain.
The Effect of Ventricular Activation Sequence on Cardiac Performance During Pacing
Authors: ROSENQVIST M. , BERGFELDT L. , HAGA Y. , RYDÉN J. , RYDÉN L. , ÖWALL A.
Published: July 2006

The aim of this study was to evaluate the importance of a normal ventricular activation pattern for cardiac performance. In nine mongrel clogs, atrial pacing was compared to AV synchronous pacing at three different A V delays (150, 100, and 60 nis). In six dogs, proximal septal AV synchronous pacing was compared to apical A V synchronous pacing at three different A V delays. AV synchronous pacing was performed after RF induced complete heart block. Hemodynarnics were evaluated by assessment of positive and negative dP/dt, cardiac output, and left ventricular and pulmonary pressures. Atrial pacing was superior to AV synchronous pacing with respect to positive and negative dP/dt and cardiac output. This difference was present at all AV delays. Proximal septal pacing was associated with a higher positive and negative dP/dl compared to apical pacing at all AV delays. Left ventricular activation time was significantly shorter during proximal septal pacing than during apical pacing (88 ± 4 vs 115 ± 4 ms, P < 0.001). We conclude that atrial and proximal septal pacing improves cardiac function and shortens the ventricular activation time compared to apical AV synchronous pacing independent of the AV interval.
Acute Effects of Radiofrequency Ablation of Atrial Arrhythmias on Implanted Permanent Pacing Systems
Authors: ELLENBOGEN KENNETH A. , WOOD MARK A. , STAMBLER BRUCE S. ,   CO‐INVESTIGATORS
Published: July 2006

We studied the safety of performing RF catheter ablation in patients with implanted permanent pacemakers by monitoring the function of implanted pacing systems before, during, and immediately after exposure to RF energy. Patients with implanted pacing systems may require RF ablation for treatment of a variety of tachyarrhythmias. High frequency electromagnetic fields, such as RF energy, may affect implanted pacing systems, causing temporary or permanent loss of output, under‐ sensing, oversensing, asynchronous pacing, or reversion to “reset” (Recommended Replacement Time or Power On Reset) parameters. Thirty‐five patients with implanted pacing systems (23 DDDR, 6 VVIR, 5 DDD, 1 VVI, 31 bipolar and 4 unipolar) underwent RF catheter ablation. Prior to ablation, each pacing system underwent measurements of pacing and sensing thresholds, telemetry of intracardiac electrograms and measurement of battery voltage and lead impedance(s). During ablation, pacemaker function was monitored by real‐time telemetry, intracardiac electrograms, and surface ECG. Immediately after ablation, each pacing system was reevaluated. Telemetry during RF ablation revealed normal pacing and sensing in 14 (40%) of 35 patients. Refractory period extension with asynchronous pacing and noise mode reversion were seen in 16 (46%) of 35 patients. Rare under‐ and/or oversensing, reversion to reset parameters, and telemetry “lock up” with inhibition of pacing output was seen in a few patients. After ablation, there were no significant changes in atrial or ventricular pacing or sensing thresholds or measurements of atrial and ventricular lead impedances. We conclude that most permanent pacemakers are not adversely affected by exposure to RF energy during catheter ablation. A variety of pacemaker behaviors may be seen during RF ablation, and a thorough understanding of each pulse generator's potential response(s) to electromagnetic interference is important before undertaking catheter ablation in patients with permanent pacemakers. Careful revaluation of the patient's pacing system following the procedure is mandatory.
A Second Defibrillator Chest Patch Electrode Will Increase Implantation Rates for Nonthoracotomy Defibrillators
Authors: SOLOMON ALLEN J. , SWARTZ JOHN F. , KODAK DAVID J. , MOORE HANS J. , HANNAN ROBERT L. , TRACY CYNTHIA M. , FLETCHER ROSS D.
Published: July 2006

Nonthoracotomy defibrillator systems can be implanted with a lower morbidity and mortality, compared to epicardial systems. However, implantation may be unsuccessful in up to 15% of patients, using a monophasic waveform. It was the purpose of this study to prospectively examine the efficacy of a second chest patch electrode in a nonthoracotomy defibrillator system. Fourteen patients (mean age 62 ± 11 years, ejection fraction = 0.29 ± 0.12) with elevated defibrillation thresholds, defined as ≥ 24 J, were studied. The initial lead system consisted of a right ventricular electrode (cathode), a left innominate vein, and subscapular chest patch electrode (anodes). If the initial defibrillation threshold was ≥ 24 J, a second chest patch electrode was added. This was placed subcutaneously in the anterior chest (8 cases), or submuscularly in the subscapular space (6 cases). This resulted in a decrease in the system impedance at the defibrillation threshold, from 72.3 ± 13.3 Ω to 52.2 ± 8.6 Ω. Additionally, the defibrillation threshold decreased from ≥ 24 J, with a single patch, to 16.6 ± 2.8 J with two patches. These changes were associated with successful implantation of a nonthoracotomy defibrillator system in all cases. In conclusion, the addition of a second chest patch electrode (using a subscapular approach) will result in lower defibrillation thresholds in patients with high defibrillation thresholds, and will subsequently increase implantation rates for nonthoracotomy defibrillators.
Appraisal of Pacing Lead Performance from the Danish Pacemaker Register
Authors: MØLLER MOGENS , ARNSBO PER ,   for the DANISH PACEMAKER REGISTER
Published: July 2006

The Danish Pacemaker Register was established in January 1982, and the 11 implanting centers in Denmark report to the Register on a continuous basis by use of the European Pacemaker Patient Identification Card proposed by the European Working Group on Cardiac Pacing. As of May 1994, the Register contained data on 18,053 lead implants performed in Denmark, i.e., 1,253 (7%) lead implants before 1982, and all the 16,800 initial lead implants since 1982 on 17,020 generators in 15,366 patients for a total of 12,188 (67,5%) ventricular unipolar, 3,178 (17.6%) ventricular bipolar, 1,316 (7.3%) atrial unipolar, and 1,371 (7.6%) atrial bipolar leads. Preformed J shaped leads were used in 3.5% of the atrial implants and active fixation in < 8%. Lead failure was defined as need for replacement or abandonment of the lead due to pacing or sensing problems with the exception of lead displacement. The 10‐year survival rate for unipolar atrial and ventricular leads was 95.8%± 2.1% (2 standard errors) and 97.1 %± 0.6%, respectively, as compared to a 4‐year survival rate of 91.5%± 4.6% and 91.6%± 1.7% for bipolar atrial and ventricular leads, and an 8‐year survival rate for bipolar ventricular leads of 75.1%± 5.0%. The 5‐year survival rate for the bipolar Medtronic model 4012 lead was 85.8%± 8.1% and 67.4%± 7.3% for the bipolar Siemens model 1010T lead, indicating a poor performance. The Siemens lead models 105T and 1050T seem to be performing like the model 101OT. The 5‐year survival rate for the bipolar Telectronics model 284 lead was 88.4%± 6.2%. The data from the Danish Pacemaker Register confirm the previous reported good survival of unipolar pacing leads irrespective of the chamber paced, and demonstrate that the bipolar Medtronic 4012 lead, the bipolar Telectronics 284 lead, and especially the bipolar Siemens 1010T, 105T, and 1050T models are unreliable leads that need careful monitoring and appropriate replacement.
A Simple Method for Preoperative Assessment of the Best Fitting Electrode Length in Single Lead VDD Pacing
Authors: NOWAK BERND , VOIGTLÄNDER THOMAS , LIEBRICH ANDREAS , HIMMRICH EWALD , MÖLLER BERNHARD , MEYER JÜRGEN
Published: July 2006

For single lead VDD pacing, electrodes with various distances between the lead tip and the floating atrial dipole (AV distance) are available. Using different AV distances allows positioning of the atrial dipole in the mid‐ to high right atrium, regardless of the size of the right heart. In this position, reliable atrial sensing and rejection of ventricular far‐field potentials can be expected. A simple test for the preoperative assessment of the best fitting AV distance in the individual patient was tested. We studied 24 consecutive patients prior to implantation of AVDD pacemaker. With the patient in supine position, a test electrode with an AV distance of 13 cm was taped onto the thorax. Under fluoroscopic control, it was moved until its course and projection onto the heart was equal to that of a ventricular lead. If fluoroscopy then showed a projection of the atrial dipole onto the mid‐ to high right atrium, a lead with a similar AV distance of 13 or 13.5 cm was used for implantation. If the atrial dipole projected itself too high or too low, a shorter or longer lead had to be implanted. The maximum time for the test was 2 minutes, and the maximum fluoroscopy time was 15 seconds. According to the test, a lead with an AV distance of 13 or 13.5 cm was implanted in 18 of 24 patients, and a lead with an AV distance of 15.5 or 16 cm was implanted in 6 of 24 patients. The atrial dipole could easily be positioned in the mid‐ to high right atrium in all patients, demonstrating a correct preoperative assessment of the best fitting AV distance. Intraoperatively, a P wave amplitude of 3.5 ± 3.0 mV was measured. The described test allows a fast and reliable assessment of the best fitting electrode length in single lead VDD pacing.
Transient Complete Heart Block During Radiofrequency Ablation of a Left Lateral Bypass Tract
Authors: STAMATO NICHOLAS J. , EDDY STEVEN L. , WHITING DEBRA J.
Published: July 2006

RF catheter ablation of accessory bypass tracts associated with the Wolff‐Parkinson‐White: syndrome has become an accepted and widespread therapy. When bypass tracts are located in the free wall of the left ventricle, a single catheter technique may be utilized. A single catheter is placed via the femoral artery, across the aortic valve into the left ventricle. Mapping is performed during sinus rhythm, and ablation performed at the site of recording of Kent bundle activation. We describe a case of a patient with Wolff‐Parkinson‐White syndrome presenting with rapid atrial fibrillation requiring cardioversion. This patient subsequently underwent catheter ablation of a left free‐wall bypass tract using the single catheter technique. At baseline, preexcitation and right bundle branch block (RBBB) were present on the ECG. During catheter ablation of the accessory pathway, transient complete AV block was seen. This was felt likely to be due to trauma to the His bundle, or more likely to the left bundle branch, as the ablation catheter crossed the aortic valve. The bypass tract was successfully ablated after placement of a temporary right ventricular pacemaker. AV conduction resumed with a pattern of RBBB. A temporary right ventricular pacing catheter should be placed prior to RF ablation of left‐sided bypass tracts when the ECG is also suggestive of RBBB.
Risk of Radiation Induced Skin Injuries from Arrhythmia Ablation Procedures
Authors: PARK THOMAS H. , EICHLING JOHN O. , SCHECHTMAN KENNETH B. , BROMBERG BURT I. , SMITH JOSEPH M. , LINDSAY BRUCE D.
Published: July 2006

Catheter guided ablation of cardiac arrhythmias is an effective and safe procedure for the treatment of most supraventricular and selected ventricular tachycardias. Because catheter manipulation is fluoroscopically guided, there is risk of radiation induced injury, especially during prolonged procedures. The Food and Drug Administration has recently issued a bulletin warning of the risks of acute skin injury occurring during fluoroscopically guided procedures that result in an exposure level exceeding 2 Gray units (Gy). This study was performed as an investigation into the risk of radiation induced skin injury during arrhythmia ablation procedures. The amount of radiation exposure for 500 patients who underwent ablation was calculated based upon fluoroscopy times and the entrance dose of radiation (0.02 Gy/min). The mean radiation exposure was 0.93 ± 0.62 Gy. Although 5.6% of patients (n = 28) received enough radiation exposure to reach the threshold dose (2 Gy) for early transient erythema, no clinical manifestations of acute radiation induced skin injury were observed. No patients achieved the threshold dose for irreversible skin injury. Patients undergoing AV node ablation or modification received significantly less radiation (0.39 ± 0.40 Gy and 0.79 ± 0.44 Gy, respectively) than patients undergoing other ablation procedures (0.94–1.45 Gy, P < 0.05). There was no association between the magnitude of radiation exposure and the presence of underlying heart disease. Patients undergoing ablation of accessory pathways were exposed to more radiation if there was a right‐sided pathway (1.69 ± 0.93 Gy) compared to other sites (0.87–1.24 Gy, P < 0.05). This study demonstrates that the risk of significant radiation induced skin injury during arrhythmia ablation procedures is low provided that precautions are taken to minimize radiation exposure.
Implantable Cardioverter Defibrillator Detection During Radiofrequency Catheter Ablation of Ventricular Tachycardia
Authors: HAMMERSCHMIDT STEFAN , CAO KEJIANG , SCHAUMANN ANSELM , KRIEGLSTEIN HOLGER , GONSKA BERND‐DIETER
Published: July 2006

Right ventricular radiofrequency catheter ablation was performed in an ICD patient with frequent ventricular tachycardia without prior inactivation of the device. The registrations of inlracardiac ECG and marker channel were excellent during energy delivery: the surface ECG was affected. The device did not show dysfunction during and after energy delivery.
Permanent Mechanical Catheter Ablation of an Accessory Pathway in a Child
Authors: MANGIERI ENRICO , BARILLÀ FRANCESCO , BOSCO GIOVANNA , PAPALIA UGO , COLLORIDI VINCENZO , CRITELLI GIUSEPPE
Published: July 2006

Permanent mechanical ablation of an accessory atrioventricular pathway was observed in an infant during intracavitary electrophysiological mapping. The persistent lack of preexcitation was confirmed during a 15‐month follow‐up period.
The Shocking Lung Mass: A Case Report
Authors: MAHAJAN SANJIV , PORTERFIELD JAMES G. , PORTERFIELD LINDA M. , WELLS VAN E. , CRUMP CHARLES A.
Published: July 2006

Two years after implantation of an ICD with epicardial patch leads, a patient presented with hemoptysis. The posterior left ventricular patch was found to have eroded into lingular segmental bronchus. During thomcotomy, the hardware was removed and the bronchus successfully repaired.