bluuebunny/crossref_metadata_2025 huggingface dataset:
Delayed Restoration of Atrioventricular Synchrony with Beat‐to‐Beat Mode Switch
Authors: BODE FRANK , WIEGAND UWE K.H. , PETERS WERNER , KATUS HUGO A.
Published: July 2003

BODE, F., et al.: Delayed Restoration of Atrioventricular Synchrony with Beat‐to‐Beat Mode Switch. This case report describes a patient with complete AV block and a VDD pacemaker who experienced repetitive episodes of symptomatic bradycardia. Episodes occurred due to activation of an automatic beat‐to‐beat mode switch algorithm. After mode switch to VDI operation, the pacemaker failed to immediately switch back to AV synchronous pacing when regular sinus rhythm (≥ 100 beats per minute) resumed despite adequate P wave sensing. Dizziness was felt for up to several minutes of asynchronous pacing at the lower rate limit until VDD mode was restored. Episodes were completely eliminated by programming the mode switch function from an automatic beat‐to‐beat algorithm to a fixed rate algorithm.
Lead Configuration for Defibrillator Implantation in a Patient with Congenital Heart Disease and a Mechanical Prosthetic Tricuspid Valve
Authors: LENG CHARLES T. , CROSSON JANE E. , CALKINS HUGH , BERGER RONALD D.
Published: July 2003

LENG, C.T., et al.: Lead Configuration for Defibrillator Implantation in a Patient with Congenital Heart Disease and a Mechanical Prosthetic Tricuspid Valve. The authors devised a nonthoracotomy defibrillation system for a patient with a prosthetic tricuspid valve using existing technology and previously established implantation techniques. Their lead configuration deviates substantially from existing designs in its primary use of a coronary sinus defibrillation coil and a left‐sided subcutaneous array to distribute current across the ventricular myocardium.
Sinus Node Recovery After 25 Years of Atrial Flutter
Authors: PALMA EUGEN C. , VIJAYARAMAN PUGAZHENDI , FERRICK KEVIN J. , GROSS JAY N. , KIM SOO G. , FISHER JOHN D.
Published: July 2003

PALMA, E.C., et al.: Sinus Node Recovery After 25 Years of Atrial Flutter. This case report demonstrates that the sinus node can recover relatively quickly even after being suppressed by atrial flutter for 25 years, and that a permanent pacemaker may not always be necessary in all patients with sinus arrest after a successful atrial flutter ablation.
Radiofrequency Energy Modification of the Atrioventricular Junction in Patients with Atrial Fibrillation: Modes of Ventricular Response Under Autonomic Blockade and Long‐Term Effect
Authors: KRIATSELIS HARALAMPOS D. , GOEHL KONRAD , RICHTER PETER , HELBIG SEBASTIAN , SINDERMANN JÜRGEN , GOTTWIK MARTIN
Published: July 2003

KRIATSELIS, H.D., et al.: Radiofrequency Energy Modification of the Atrioventricular Junction in Patients with Atrial Fibrillation: Modes of Ventricular Response Under Autonomic Blockade and Long‐Term Effect. The short‐ and long‐term effect of radiofrequency (RF) modification of the AV junction on ventricular rate and left ventricular function and the different types of ventricular response during energy application under autonomic nervous blockade were assessed in 28 patients with medically refractory atrial fibrillation. During the successful RF application, ventricular rate slowed progressively (type I response, ten patients) or accelerated at first and then slowed (type II response, 11 patients). Type II response was associated with a more anterior ablation site compared to Type I response. A primary successful outcome was achieved in 21 patients. Inadvertent complete AV block developed in three patients, while in four patients AV nodal ablation was performed after an unsuccessful modification attempt. During 6‐month follow‐up, the ventricular rate was adequately controlled in only four patients. Among the 16 patients with a recurrence of uncontrolled AF were all 10 patients with type I response and 6 of 11 patients with type II response. One patient died suddenly 10 weeks after the procedure.
Enhanced Detection Criteria in Implantable Cardioverter Defibrillators: Sensitivity and Specificity of the Stability Algorithm at Different Heart Rates
Authors: KETTERING KLAUS , DÖRNBERGER VOLKER , LANG REINHARD , VONTHEIN REINHARD , SUCHALLA RALF , BOSCH RALPH F. , MEWIS CHRISTIAN , EIGENBERGER BERND , KÜHLKAMP VOLKER
Published: July 2003

KETTERING, K., et al.: Enhanced Detection Criteria in Implantable Cardioverter Defibrillators: Sensitivity and Specificity of the Stability Algorithm at Different Heart Rates. Sensitivity and Specificity of the Stability Algorithm at Different Heart Rates. The lack of specificity in the detection of ventricular tachyarrhythmias remains a major clinical problem in the therapy with ICDs. The stability criterion has been shown to be useful in discriminating ventricular tachyarrhythmias characterized by a small variation in cycle lengths from AF with rapid ventricular response presenting a higher degree of variability of RR intervals. But RR variability decreases with increasing heart rate during AF. Therefore, the aim of the study was to determine if the sensitivity and specificity of the STABILITY algorithm for spontaneous tachyarrhythmias is related to ventricular rate. Forty‐two patients who had received an ICD (CPI Ventak Mini I, II, III or Ventak AV) were enrolled in the study. Two hundred ninety‐eight episodes of AF with rapid ventricular response and 817 episodes of ventricular tachyarrhythmias were analyzed. Sensitivity and specificity in the detection of ventricular tachyarrhythmias were calculated at different heart rates. When a stability value of 30 ms was programmed the result was a sensitivity of 82.7% and a specificity of 91.4% in the detection of slow ventricular tachyarrhythmias (heart rate < 150 beats/min). When faster ventricular tachyarrhythmias with rates between 150 and 169 beats/min (170–189 beats/min) were analyzed, a stability value of 30 ms provided a sensitivity of 94.5% (94.7%) and a specificity of 76.5% (54.0%). For arrhythmia episodes ≥ 190 beats/min, the same stability value resulted in a sensitivity of 78.2% and a specificity of 41.0%. Even when other stability values were taken into consideration, no acceptable sensitivity/specificity values could be obtained in this subgroup. RR variability decreases with increasing heart rate during AF while RR variability remains almost constant at different cycle lengths during ventricular tachyarrhythmias. Thus, acceptable performance of the STABILITY algorithm appears to be limited to ventricular rate zones < 170 beats/min.
Combined Cardiomyopathy and Skeletal Myopathy: A Variant with Atrial Fibrillation and Ventricular Tachycardia
Authors: VLAY STEPHEN C. , VLAY LINDA C. , COYLE P. K.
Published: July 2003

VLAY, S., et al.: Combined Cardiomyopathy and Skeletal Myopathy: A Variant with Atrial Fibrillation and Ventricular Tachycardia. This article describes a family characterized by combined cardiomyopathy and nonspecific skeletal myopathy who present in the third to fifth decades with cardiac manifestations but earlier have evidence of subtle skeletal muscle dysfunction. They differ from previously defined syndromes and potentially represent a different genetic expression or mutation. Cardiomyopathy presents with atrial arrhythmias including AF and atrial flutter. Life‐threatening ventricular tachyarrhythmias occur next with onset of ventricular dysfunction. Electrophysiological study revealed sustained monomorphic VT. Affected family members benefitted from an ICD and progression to congestive heart failure (CHF) occurred late. Skeletal myopathy continues with marked progressive muscle weakness and inability to ambulate without assistance. Genetic analysis is currently ongoing. Neurological evaluation in all three family members revealed nonspecific myopathy affecting the psoas and iliopsoas muscles. Atrophy and wasting of the facial and temporalis muscles were common. Skeletal muscle biopsy revealed myofiber atrophy consistent with myopathy.
Ibutilide Induced Intraatrial Wenckebach Periodicity in the Neonatal Canine Heart
Authors: PICKOFF ARTHUR S. , STOLFI ADRIENNE
Published: July 2003

PICKOFF, A.S., et al.: Ibutilide Induced Intraatrial Wenckebach Periodicity in the Neonatal Canine Heart. In nine anesthetized canine neonates, the high right atrium was paced at progressively shorter cycle lengths while recording high right atrial electrograms and left atrial appendage monophasic action potentials before and after the administration of the new Class III agent, ibutilide. Prior to ibutilide administration, 1:1 conduction was maintained from the high right atrium to the left atrial appendage at all paced cycle lengths, down to 160 ms. Following ibutilide, a pattern of intraatrial conduction was observed in two of nine neonates at a cycle length of 160 ms that was consistent with the development of intraatrial Wenckebach periodicity. This represents one of the only demonstrations of drug induced intraatrial Wenckebach periodicity in vivo and suggests that this rarely reported form of atrial conduction block might play a role in ibutilide's clinical efficacy against atrial arrhythmias.
Quinidine Induced Electrocardiographic Normalization in Two Patients with Brugada Syndrome
Authors: ALINGS MARCO , DEKKER LUKAS , SADÉE ARTHUR , WILDE ARTHUR
Published: July 2003

ALINGS, M., et al.: Quinidine Induced Electrocardiographic Normalization in Two Patients with Bru‐gada Syndrome. Two patients with Brugada syndrome are presented. The ECGs showed right precordial J waves and ST‐segment elevation. Patient 1 was resuscitated from nocturnal ventricular fibrillation, patient 2 was asymptomatic. In only patient 1, flecainide was infused causing monomorphic “malignant” ventricular extrasystoles (R on T), demonstrating the deleterious effect of Class IC antiarrhythmic drugs in Brugada syndrome. However, administration of the Class Ia antiarrhythmic drug quinidine caused normalization of the ECG in both patients. Based on in vitro experiments, agents that reduce the magnitude of Ito‐mediated phase 1 have been suggested to normalize ST‐segment elevation in Brugada syndrome. This is the first clinical report of such a quinidine induced ECG normalization.
Hyperkalemia Induced Pacemaker Far‐Field Endless Loop Tachycardia
Authors: BAROLD S. SERGE
Published: July 2003

BAROLD, S.: Hyperkalemia Induced Pacemaker Far‐Field Endless Loop Tachycardia. This report describes the induction of a far‐field endless loop tachycardia by hyperkalemia in a patient with severe heart disease. Ventricular activation was so prolonged that the atrial channel sensed the far‐field ventricular deflection within the atrial electrogram beyond the 300 ms postventricular atrial refractory period.
Catheter Ablation of a Right Atrial Appendage to the Right Ventricle Connection in a Neonate
Authors: SHAH MAULLY J. , GARABEDIAN HRAIR , GAROUTTE MARY C. , CECCHIN FRANK
Published: July 2003

SHAH, M.J., et al.: Catheter Ablation of a Right Atrial Appendage to the Right Ventricle Connection in a Neonate. A neonate with incessant supraventricular tachycardia refractory to multiple antiarrhythmic medications was referred to our institution for radiofrequency ablation. An unusual accessory pathway between the right atrial appendage and right ventricle was successfully ablated. This case also emphasizes the congenital origin of such an accessory pathway.
Postpericardiotomy Syndrome and Cardiac Tamponade as a Late Complication After Pacemaker Implantation
Authors: SPINDLER MATTHIAS , BURROWS GABRIEL , KOWALLIK PETER , ERTL GEORG , VOELKER WOLFRAM
Published: July 2003

SPINDLER, M., et al.: Postpericardiotomy Syndrome and Cardiac. Tamponade as a Late Complication After Pacemaker Implantation. In a 78‐year old woman, pacemaker implantation was complicated by a transient perforation of the endocardial lead. The patient was in stable condition for up to 7 weeks after implantation, after which pericardial effusion and subacute cardiac tamponade developed and pericardiocentesis became necessary. This case illustrates that even after initially uneventful pacemaker lead perforation, careful, long‐term follow‐up is necessary to recognize the potential development of late postpericardiotomy syndrome.
Multicenter Experiences with a Single Lead Electrode for Dual Chamber ICD Systems
Authors: NIEHAUS MICHAEL , SCHUCHERT ANDREAS , THAMASETT STEFAN , PFEIFFER DIETRICH , KORTE THOMAS , PICHLMAIER MAX , PANNING BERNHARD , BELKE ROBERTO , TEBBENJOHANNS JÜRGEN
Published: July 2003

NIEHAUS, M., et al.: Multicenter Experiences with a Single Lead Electrode for Dual Chamber ICD Systems. Monitoring of atrial signals improves the accuracy in identifying supraventricular tachyarrhythmias to prevent inappropriate therapies in patients with implantable ICDs. Since difficulties due to the additional atrial lead were found in dual chamber ICD systems with two leads, the authors designed a single pass VDD lead for use with dual chamber ICDs. After a successful animal study, the prototype VDD lead (single coil defibrillation lead with two additional fractally coated rings for bipolar sensing in the atrium) was temporarily used in 30 patients during a German multicenter study. Atrial and ventricular signals were recorded during sinus rhythm (SR), atrial flutter, AF, and VT or VF. The implantation of the lead was successful in 27 of 30 patients. Mean atrial pacing threshold was 2.5 ± 0.9 V/0.5 ms, mean atrial impedance was 213 ± 31Ω. Atrial amplitudes were greater during SR (2.7 ± 1.6 mV) than during atrial flutter (1.46 ± 0.3 mV, P < 0.05) or AF (0.93 ± 0.37 mV, P < 0.01). During VF atrial “sinus” signals had significantly (P < 0.01) lower amplitudes (1.4 ± 0.52 mV) than during SR. The mean ventricular sensing was 13.3 ± 7.9 mV and mean ventricular impedance was 577 ± 64Ω. Defibrillation was successful with a 20‐J shock in all patients. In addition, 99.6% of P waves could be detected in SR and 84.4% of flutter waves during atrial flutter. During AF, 56.6% of atrial signals could be detected without modification of the signal amplifier. In conclusion, a new designed VDD dual chamber lead provides stable detection of atrial and ventricular signals during SR and atrial flutter. Reliable detection of atrial signals is possible without modification of the ICD amplifier.
Echocardiographic Assessment of the Interventricular Delay of Activation and Correlation to the QRS Width in Dilated Cardiomyopathy
Authors: ROULEAU FRÉDÉRIC , MERHEB MICHEL , GEFFROY SYLVIE , BERTHELOT JEAN , CHALEIL DENIS , DUPUIS JEAN MARC , VICTOR JACQUES , GESLIN PHILIPPE
Published: July 2003

ROULEAU, F., et al.: Echocardiographic Assessment of the Interventricular Delay of Activation and Correlation to the QRS Width in Dilated Cardiomyopathy. The aim of the study was to define criteria for left ventricular pacing in dilated cardiomyopathy (DCM) using an echocardiographic evaluation of interventricular electromechanical delay (IMD) and a correlation of IMD to QRS duration. Standard 12‐lead ECG and echocardiography with pulsed Doppler tissue imaging (DTI) were recorded in 35 DCM patients (mean age 58 ± 11 years) with QRS duration from narrow (80 ms) to broad (222 ms) patterns. The time for left ventricular activation was evaluated from the onset of QRS to the onset of aortic flow (Q‐Ao) by standard pulsed Doppler (SP) or to the onset of mitral annulus systolic wave (Q‐Mit) (DTI). The time for right ventricular activation was determined from the onset of QRS to the onset of pulmonary flow (Q‐Pulm) (SP) or to the onset of tricuspid annulus systolic wave (Q‐Tri) (DTI). (Q‐Ao)–(Q‐Pulm) and (Q‐Mit)–(Q‐Tri) determined IMD for each method, respectively. QRS width and IMD showed correlation coefficients of r = 0.86 ([Q‐Ao]‐[Q‐Pulm]) and r = 0.82 ([Q‐Mit]‐[Q‐Tri]) (P ≤ 0.001). Mean IMD of 77 ± 15 ms (SP) and 88 ± 26 ms (DTI) were noted for QRS width above 150 ms. Left ventricle delayed activation was positively correlated to QRS widening with both methods, (r = 0.90, [Q‐Ao]), (r = 0.83, [Q‐Mit]) (P ≤ 0.001). In conclusion, QRS duration is a good marker of an interventricular mechanical asynchrony. According to IMD correction, left ventricular pacing may be mainly proposed to symptomatic DCM patients with QRS duration > 150 ms.
Electroanatomically Guided Catheter Ablation of Ventricular Tachycardias Causing Multiple Defibrillator Shocks
Authors: SRA JASBIR , BHATIA ATUL , DHALA ANWER , BLANCK ZALMEN , DESHPANDE SANJAY , COOLEY RYAN , AKHTAR MASOOD
Published: July 2003

SRA, J., et al.: Electroanatomically Guided Catheter Ablation of Ventricular Tachycardias Causing Multiple Defibrillator Shocks. With conventional techniques, RF catheter ablation is difficult in patients with unstable VT or with multiple VTs. The feasibility of RF catheter ablation guided by three‐dimensional electroanatomic mapping technique in patients whose implanted ICD continued to deliver multiple shocks due to VT despite use of antiarrhythmic medications was assessed in 19 patients (15 men, 4 women; mean age [± SD] 70 ± 7 years). All had a prior history of MI and subsequently had received an ICD due to VT. During the 12‐week preablation period, these patients received 31 ± 15 shocks (range 4–62 shocks) due to refractory monomorphic VTs. An electroanatomic mapping technique using the CARTO system was performed to delineate scar tissue. RF catheter ablation was then performed at appropriate sites identified by pacemapping and by substrate mapping. Seventeen patients were on amiodarone at the time of ablation. Twenty‐seven VTs were documented clinically, and 45 were induced during electrophysiological evaluation. Of the 45 tachycardias induced, 38 VTs were targeted for ablation. Catheter ablation was performed during sinus rhythm in 31 episodes and during VT in 7 episodes. During a mean follow‐up of 26 ± 8 weeks (range 18–48 weeks), 13 (66%) patients had no recurrence of VT (P < 0.0001) and antiarrhythmic drugs were discontinued or the number of medications reduced in 17 patients (P < 0.0001). Electroanatomic mapping is helpful in identifying sites for catheter ablation in highly symptomatic patients with refractory VT associated with myocardial scarring.
Doppler Index and Plasma Level of Atrial Natriuretic Hormone Are Improved by Optimizing Atrioventricular Delay in Atrioventricular Block Patients with Implanted DDD Pacemakers
Authors: TODA NORITAKA , ISHIKAWA TOSHIYUKI , NOZAWA NAOKI , KOBAYASHI IZUMI , OCHIAI HISAO , MIYAMOTO KAZUYUKI , SUMITA SHINICHI , KIMURA KAZUO , UMEMURA SATOSHI
Published: July 2003

TODA, N., et al.: Doppler Index and Plasma Level of Atrial Natriuretic Hormone Are Improved by Optimizing Atrioventricular Delay in Atrioventricular Block Patients with Implanted DDD Pacemakers. Doppler index is the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and has clinical value as an index of combined systolic and diastolic myocardial performance. This crossover study compared the Doppler index and atrial natriuretic hormone (atrial natriuretic peptide) [ANP] between optimal (AV) delay and prolonged AV delay in patients with DDD pacemakers. The study included 14 patients (6 men, 8 women, age 78.4 ± 9.3 [SD] years) with AV block with an implanted DDD pacemaker. AV delay was prolonged in a 25‐ms, stepwise fashion starting from 125 ms to 250 ms. Pacing rate was set at 70 beats/min. Cardiac output (CO) was assessed by pulsed Doppler echocardiography, and optimal AV delay was defined as the AV delay at which CO was maximum, and an AV delay setting of 250 ms as prolonged AV delay. Plasma level of ANP and Doppler index determined by echocardiography were measured 1 week after programming. AV delay was switched to another AV delay and measurements were repeated after 1 week. Optimal AV delay was 159 ± 19 ms. Doppler index was significantly lower at optimal AV delay than at prolonged AV delay (0.68 ± 0.26 vs 0.92 ± 0.30, P < 0.05). The plasma ANP level was significantly lower at optimal AV delay than at prolonged AV delay (29.0 ± 30.7 vs 52.6 ± 44.9 pg/mL, P < 0.05). In conclusion, the Doppler index and the plasma ANP level were significantly lower at optimal AV delay than at prolonged AV delay. This study shows the importance of the optimal AV delay setting in patients with an implanted DDD pacemaker, the Doppler index and plasma ANP levels are good indicators for optimizing AV delay.
Implantable Cardioverter Defibrillator in a 4‐Month‐Old Infant with Cardiac Arrest Associated with a Vascular Heart Tumor
Authors: THØGERSEN ANNA MARGRETHE , HELVIND MORTEN , JENSEN TIM , ANDERSEN HELLE , JACOBSEN JOES RAMSØE , CHEN XU
Published: July 2003

THØGERSEN, A.M., et al.: Implantable Cardioverter Defibrillator in a 4‐Month‐Old Infant with Cardiac Arrest Associated with a Vascular Heart Tumor. A previously healthy male infant was resuscitated after spontaneous ventricular fibrillation at 9 weeks of age. Echocardiography revealed three tumors in the left ventricle not amenable to complete resection. Despite treatment with antiarrhythmic agents the ventricular arrhythmias continued. When the child was 4 months old and weighed 7 kg an ICD system was implanted using epicardial sense‐pacing leads and a superior vena caval lead as a subcutaneous defibrillator coil placed posterior on the left thorax. Shocks were delivered between the subcutaneous coil lead and the intraabdominally placed ICD can. This ICD array system has not been reported previously.
Intermittent Mode Reversion to VOO of a Dual Chamber Pacemaker Model
Authors: ERDOGAN OKAN , ALTUN ARMAGAN , OZBAY GULTAC
Published: July 2003

ERDOGAN, O., et al.: Intermittent Mode Reversion to VOO of a Dual Chamber Pacemaker Model. This report describes an asymptomatic patient with a DDDR pacemaker system (Inos Cls, Biotronik) that showed intermittent mode reversion to VOO and sometimes to VVI without a detectable source of electromagnetic interference and oversensing. Patients with this Biotronik model should be carefully assessed along with a surface ECG before placing the programming head.
Inferior Vena Caval Loop of an Endocardial Pacing Lead Did Not Solve the Growth Problem in a Child
Authors: ANTRETTER HERWIG , HANGLER HERBERT , COLVIN JOSHUA , LAUFER GUENTHER
Published: July 2003

ANTRETTER, H., et al.: Inferior Vena Caval Loop of an Endocardial Pacing Lead Did Not Solve the Growth Problem in a Child. This report describes a transvenous pacemaker lead insertion into a child's right ventricle with a loop formed within the inferior vena cava to allow growth. Five years later emergency revision was necessary because of loss of capture. The expected lead release had not taken place.
Minimally Invasive Cardioverter Defibrillator Implantation for Children: An Animal Model and Pediatric Case Report
Authors: BERUL CHARLES I. , TRIEDMAN JOHN K. , FORBESS JOSEPH , BEVILACQUA LAURA M. , ALEXANDER MARK E. , DAHLBY DANIELLE , GILKERSON JAMES O. , WALSH EDWARD P.
Published: July 2003

BERUL, C.I., et al.: Minimally Invasive Cardioverter Defibrillator Implantation for Children: An Animal Model and Pediatric Case Report. The smaller venous capacitance in infants and small children may hamper transvenous ICD lead implantation, and epicardial approaches require thoracotomy and have associated complications. The study evaluated the feasibility and performance of subcutaneous arrays and active can ICDs without transvenous shocking coils or epicardial patches. An immature and mature pig were anesthetized and ventilated. A pacing lead was inserted in the right ventricle for fibrillation induction and rate sensing. Subcutaneous arrays were positioned in the right and left chest walls. An ICD emulator was placed in abdominal and prepectoral pockets. Fluoroscopic images were acquired for each electrical vector configuration (array → can, can → array, array → array, array + array → can). Ventricular fibrillation was induced and DFT testing performed. Defibrillation was achieved in all ten trials in the immature piglet, with DFT ≤ 9 J, regardless of vector configuration. Using a single subcutaneous array and active can, the shock impedance ranged from 28–36 ohms. With two arrays, shocking impedance fell to 15–22 ohms. In the adult pig, defibrillation was not accomplished with maximum energy of 40 J, using all vector configurations. Using data garnered from these experiments, this technique was then successfully performed in a 2‐year‐old child with VT and repaired congenital heart disease, needing an ICD. This study demonstrates the feasibility of leadless ICD implantation in an immature animal and successful implementation in a small child. A single subcutaneous array and active can resulted in excellent implant characteristics and DFTs with a minimally invasive approach. Defibrillation was not possible in a larger animal, possibly due to maximal available energy. This may be of value for small children requiring ICD implantation.
Cross‐Ventricular Endless Loop Tachycardia During Biventricular Pacing
Authors: BAROLD S. SERGE , BYRD CHARLES L.
Published: July 2003

BAROLD, S.S., et al.: Cross‐Ventricular Endless Loop Tachycardia During Biventricular Pacing. This report describes the development of an unusual pacemaker tachycardia in a patient with a conventional dual chamber pacemaker used for biventricular pacing in the VVIR mode. The atrial channel was connected to the left ventricle and the ventricular channel to the right ventricle. The tachycardia was sustained by sensing of the T wave by the “atrial channel” which triggered pacing by the “ventricular channel.” This “cross‐ventricular” endless loop tachycardia is a reentrant pacemaker tachycardia like classic endless loop tachycardia and can be prevented by appropriate programming of the pacemaker.
Syncope Masquerading as a Panic Disorder: Role of the Subcutaneous Loop Recorder in Eliciting the Appropriate Diagnosis
Authors: KASSOTIS JOHN , YUSUPOVA MARINA , THOBEN DIANNE , STAWIARSKI MAREK , REDDY C.V.R.
Published: July 2003

KASSOTIS, J., et al.: Syncope Masquerading as a Panic Disorder: Role of the Subcutaneous Loop Recorder in Eliciting the Appropriate Diagnosis. The present case describes a 49‐year‐old woman with apparent panic disorder in whom the Reveal Plus, a newly developed subcutaneous loop recorder, was used to show that the panic attacks were secondary to prolonged episodes of ventricular asystole.
Clinical Experience with Electroanatomic Mapping of Ectopic Atrial Tachycardia
Authors: HOFFMANN ELLEN , REITHMANN CHRISTOPHER , NIMMERMANN PETRA , ELSER FLORIAN , DORWARTH UWE , REMP THOMAS , STEINBECK GERHARD
Published: July 2003

HOFFMANN, E., et al.: Clinical Experience with Electroanatomic Mapping of Ectopic Atrial Tachycardia. The aim of this study was to evaluate the clinical use of a new three‐dimensional mapping system as a guide for catheter ablation of ectopic atrial tachycardia. A series of 42 consecutive patients with drug refractory ectopic atrial tachycardia was studied in a prospective observational trial with the electroanatomic mapping system CARTO. The arrhythmogenic focus was found in the right atrium in 30 patients and in the left atrium in 12 patients. The construction of a complete electroanatomic map of the right or left atrium was possible in 37 of 42 consecutive patients with ectopic atrial tachycardia. Mean activation time of the right atrium, including the proximal coronary sinus, was 94 ± 25 ms for right atrial tachycardias; left atrial activation time during left atrial tachycardias was 86 ± 17 ms. Average mapping time was 30 minutes for right atrial tachycardias and 22 minutes for left atrial tachycardias, allowing the collection of 86 ± 50 and 65 ± 28 catheter positions, respectively. The size of the area of earliest atrial activation calculated from the electroanatomic map amounted to 0.6 ± 0.4 cm2 in right atrial tachycardias and 1.0 ± 0.9 cm2 in left atrial tachycardias. In the right atrium the most common locations of the 33 arrhythmogenic foci in 30 patients were the high or mid‐lateral right atrium (n = 10) and the inferoparaseptal region near the coronary sinus ostium (n = 7). Ectopic left atrial foci were most commonly located in an inferior position near the mitral annulus (n = 5) and in proximity to the ostium of the pulmonary veins (n = 4). Biatrial electroanatomic mapping allowed visualization of earliest right atrial activation during left atrial tachycardia at the high interatrial septum or near the coronary sinus ostium. Catheter ablation was successful in 85% of right atrial tachycardias and 82% of left atrial tachycardias. In patients with ectopic atrial tachycardia electroanatomic mapping is a safe and feasible technique that allows three‐dimensional visualization of the automatic focus in a precise anatomic reconstruction of the atria. This novel mapping technology facilitates catheter ablation of complex ectopic atrial tachycardia.
Nonfluoroscopic Magnetic Electroanatomic Mapping to Facilitate Focal Pulmonary Veins Ablation for Paroxysmal Atrial Fibrillation
Authors: TSE HUNG‐FAT , LEE KATHY L.F. , FAN KATHERINE , LAU CHU‐PAK
Published: July 2003

TSE, H.‐F., et al.: Nonfluoroscopic Magnetic Electroanatomic Mapping to Facilitate Focal Pulmonary Veins Ablation for Paroxysmal Atrial Fibrillation. RF ablation of ectopic foci in the pulmonary veins (PVs) is a promising treatment for patients with paroxysmal AF. The aim of this study was to evaluate the feasibility of using nonfluoroscopic magnetic electroanatomic mapping of PV during spontaneous or induced ectopy to facilitate focal ablation procedure. The study included 35 patients with drug refractory paroxysmal AF who underwent focal RF ablation of the PV. In 10 (29%) patients, mapping and RF ablation procedures were performed using the nonfluoroscopic magnetic electroanatomic mapping system to enable automatic capture of the location and the timing of the ectopy. As a control, 25 patients underwent conventional endocardial activation mapping technique. There were no significant differences in the clinical characteristics between the two groups. Overall procedural duration was similar between them (199 ± 52 vs 221 ± 82 minutes, P > 0.05). However, the mean fluoroscopy time (25 ± 6 vs 52 ± 12 minutes, P = 0.01) and the mean number of RF applications (5 ± 3 vs 12 ± 9, P = 0.02) were significantly less in patients who underwent electroanatomic mapping. There were no significant differences between the two groups in the acute (90 vs 84%) and long‐term success rate (60 vs 56%) after a mean follow‐up of 12 ± 9 months. In conclusion, RF ablation of ectopic foci using nonfluoroscopic magnetic electroanatomic mapping of PVs during spontaneous or induced ectopy is useful even in patients with a limited number of ectopy, and is associated with a similar success rate, but less fluoroscopy time and RF application compared to the conventional approach.
Change in Morphology of Reentrant Atrial Arrhythmias Without Termination Following Radiofrequency Catheter Ablation
Authors: TAKAGI MASAHIKO , SUYAMA KAZUHIRO , TAGUCHI ATSUSHI , SHIMIZU WATARU , KURITA TAKASHI , AIHARA NAOHIKO , KAMAKURA SHIRO
Published: July 2003

TAKAGI, M., et al.: Change in Morphology of Reentrant Atrial Arrhythmias Without Termination Following Radiofrequency Catheter Ablation. A 60‐year‐old woman who had previously undergone an atrial septal defect repair and had type I atrial flutter underwent electrophysiological study. After radiofrequency (RF) ablation to the isthmus between the inferior vena cava and the tricuspid annulus, type I atrial flutter was changed to atrial tachycardia following atriotomy without termination. This atrial tachycardia was eliminated by single‐site RF ablation of a small lesion below the caudal end of the atriotomy scar, where continuous and fragmented potentials were recorded during tachycardia. We experienced a rare case in which RF energy changed tachycardia circuits.
Inappropriate Tachycardia Detection by a Biventricular Implantable Cardioverter Defibrillator
Authors: GARCIA‐MORAN EMILIO , MONT LLUÍS , BRUGADA JOSEP
Published: July 2003

GARCIA‐MORAN, E., et al.: Inappropriate Tachycardia Detection by a Biventricular Implantable Cardioverter Defibrillator. This case describes “double counting” of intrinsic conduction due to the combination of intraventricular conduction delay and the merging of the electrograms from the right and left ventricle (coronary sinus) leads in a biventricular cardioverter defibrillator. This situation prompted asymptomatic antitachycardia pacing. Lengthening of AV conduction by betablocker solved the problem.
Alternans in QRS Amplitude During Ventricular Tachycardia
Authors: MAURY PHILIPPE , METZGER JACQUES
Published: July 2003

MAURY, P., et al.: Alternans in QRS Amplitude During Ventricular Tachycardia. Although the value of T wave alternans as an index of electrical instability has been extensively investigated, little is known about QRS alternans during VT. Intracardiac electrograms of 111 episodes of spontaneous monomorphic regular VT retrieved from implantable defibrillators in 25 patients were retrospectively selected. Three beat series, representing the total amplitudes and amplitudes from baseline to summit and from baseline to lower point of 16 or 32 successive QRS complexes before deliverance of electrical therapy were generated for each episode. Spectral analysis was then performed using the fast Fourrier transform. VT was considered as alternans if the magnitude of the spectral power at the 0.5‐cycle/beat frequency was greater than the mean ± 3 SD of the noise in at least one of the three spectral curves. QRS alternans was present in 23 (20%) of 111 episodes and in 9 (36%) of 25 patients. Alternans was not related to the VT cycle length, QRS duration, QRS amplitude, signal amplification, nor to clinical variables. Alternans was more frequently detected in unipolar configuration and when a higher number of complexes was included in analysis. Failure of antitachycardia pacing was more frequent in case of alternans VT (50% vs 75% success in non‐alternans VT, P = 0.05). Spontaneous termination before deliverance of therapy occurred in 16 nonalternans VT but never in alternans episodes (P = 0.02). Alternans in QRS amplitude is a relatively common finding during VT and could be associated with failure of antitachycardia pacing and lack of spontaneous termination. Lower efficacy of electrical therapies in case of QRS alternans must be confirmed in a way to improve the effectiveness of antitachycardia pacing.
Adjustment of Maximum Automatic Sensitivity (Automatic Gain Control) Reduces Inappropriate Therapies in Patients with Implantable Cardioverter Defibrillators
Authors: NIEHAUS MICHAEL , NEUZNER JÖRG , VOGT JÜRGEN , KORTE THOMAS , TEBBENJOHANNS JÜRGEN
Published: July 2003

NIEHAUS, M., et al.: Adjustment of Maximum Automatic Sensitivity (Automatic Gain Control) Reduces Inappropriate Therapies in Patients with Implantable Cardioverter Defibrillators. Patients with ICDs might experience oversensing associated with inappropriate shock therapy when paced at low bradycardia rates or if they have a low intrinsic rhythm. The amplifier gain of automatic gain control is maximal at long RR intervals and might lead to oversensing of myopotentials. The hypothesis was that an individual adjustment of the sensitivity floor could reduce inappropriate ICD therapies. Fourteen patients implanted with the VENTAK MINI I/II and III in whom oversensing and/or inappropriate shocks had been documented were included in this evaluation based on stored episodes. Sensitivity was modified in all ICDs by means of noninvasive software downloading that allowed reprogramming of the maximum sensitivity from 0.14 mV in two steps to 0.27 mV (“Normal,”“Less,”“Least”). Provocation testing (deep inspiration, sit‐ups, and abdominal pressing) was conducted at “Nominal” settings (0.14 mV) while the intracardiac electrogram with annotated event marker was running continuously and was repeated at 0.22 mV (Less) and 0.27 mV (Least). All patients evaluated had documented spontaneous episodes due to oversensing before the sensitivity floor was reprogrammed. During provocation testing at Nominal settings, oversensing could be documented in 9 of (64.3%) 14 patients. Provocation testing was repeated after the sensitivity selection was reprogrammed and oversensing could not be provoked in any of the 14 implanted devices. Sensitivity was reprogrammed in all 14 patients to a higher value (5 patients Less, 9 patients Least). After sensitivity adjustment, VF was induced in all patients to verify appropriate arrhythmia detection and termination. Sensitivity reprogramming in patients with documented oversensing eliminates the incidence of inappropriate shock therapy without compromising the ability to detect VF appropriately.
The Challenge of Endocardial Right Ventricular Pacing in Patients with a Tricuspid Annuloplasty Ring and Severe Tricuspid Regurgitation
Authors: KISTLER PETER M. , SANDERS PRASHANTHAN , DAVIDSON NEIL C. , MOND HARRY G.
Published: July 2003

KISTLER, P.M., et al.: The Challenge of Endocardial Right Ventricular Pacing in Patients with a Tricuspid Annuloplasty Ring and Severe Tricuspid Regurgitation. On occasion, patients with a tricuspid annuloplasty ring may require permanent cardiac pacing. Although it is technically possible to pass a ventricular transvenous lead through a tricuspid valve with an annuloplasty ring, the procedure is complicated by considerable chamber enlargement and mechanical distortion of the tricuspid valve often with severe residual tricuspid regurgitation. Over a 25‐month period, transvenous ventricular lead placement following insertion of a tricuspid annuloplasty ring was successfully performed in five patients (three women). The patient mean age was 66 years (range 55–77 years). Four cases had slow atrial fibrillation and another paroxysmal atrial fibrillation requiring His‐bundle ablation. Two patients had mitral valve replacement and two aortic and mitral valve replacements. All patients had residual severe to torrential tricuspid regurgitation. Seven ventricular steroid‐eluting screw‐in leads were used. Single leads were used in three cases, whereas in two others, two ventricular leads were attached to a dual chamber pulse generator. Although technically difficult, ventricular lead placement was successful using standard guidewires with broad curvatures. Satisfactory acute and follow‐up stimulation thresholds and sensing were obtained with the only complication being an intraoperative lead dislodgement, prompting a second ventricular lead. Successful transvenous lead placement across a tricuspid annuloplasty ring is possible.
The Imprecision in Heart Rate Correction May Lead to Artificial Observations of Drug Induced QT Interval Changes
Authors: MALIK MAREK
Published: July 2003

MALIK, M.: The Imprecision in Heart Rate Correction May Lead to Artificial Observations of Drug Induced QT Interval Changes. Because of the known limitations of the Bazett and other heart rate correction formulas, it has been proposed that studies of drug induced QT interval changes should use several different heart rate correction formulas and that the consistency of findings by a majority of such formulas should be considered as valid. The aim of this article was to show that such an approach is inappropriate. Using the database of the EMIAT trial, data of QT and RR intervals were taken from electrocardiograms of the first postrandomization visit of 1,402 patients. Of these, 309 were on amiodarone and β‐blockers, 395 on amiodarone and off β‐blockers, 318 on β‐blockers and off amiodarone, and 380 off amiodarone and off β‐blockers. An investigation of drug induced QT interval changes was modeled by evaluating the corrected QT (QTc) interval differences between patients on and off amiodarone, and on and off β‐blockers. A set of 31 previously published heart rate correction formulas was used. In addition to calculating the QTc difference between on and off drug for each formula, the success of heart rate correction was judged by computing correlation coefficients between QTc and RR intervals (ideally corrected QTc values should be independent of heart rate). The difference between on and off drug QT intervals was also evaluated by logarithmic regression models between uncorrected QT and RR intervals in data taken from patients on and off treatment. The QTc interval prolongation on amiodarone was confirmed by all heart rate correction formulas but the extent of the prolongation differed from formula to formula and ranged from 13.6 to 30.9 ms. Of the 31 formulas, 3 reported QTc interval shortening on β‐blockers (up to −11.8 ms) and 28 reported QTc interval prolongation (up to + 16.8 ms). The distribution of the results provided by the different formulas suggested that β‐blocker treatment led to a QTc interval prolongation by approximately 7 ms (e.g., + 7.4 ms by the Fridericia formula, P = 0.002). The on treatment QTc changes obtained by different formulas were closely correlated to their correction success. Formulas that provided QTc intervals almost independent of the RR intervals estimated ≈ 20 ms QTc prolongation on amiodarone and no QTc change on β‐blockers. QT/RR regression analysis confirmed that while amiodarone led to substantial QT prolongation, there was no change of QT interval on β‐blockers beyond the change in heart rate. The study showed that the concept of “majority voting” by different heart rate correction formulas is inappropriate and may lead to erroneous conclusions.
Runaway Pulse Generator Malfunction Resulting from Undetected Battery Depletion
Authors: VIJAYARAMAN PUGAZHENDHI , VAIDYA KEDARNATH , KIM SOO G. , GROSS JAY N. , FERRICK KEVIN J. , PALMA EUGEN , FURMAN SEYMOUR , FISHER JOHN D.
Published: July 2003

VIJAYARAMAN, P., et al.: Runaway Pulse Generator Malfunction Resulting from Undetected Battery Depletion. Runaway pacemaker is an uncommon, potentially lethal circuit malfunction characterized by sudden onset of erratic pacing at rapid nonphysiological rates. Two patients with a single chamber pacemaker (Medtronic ST 8331 and 8419) presented with episodic dizziness. ECG revealed recurrent decrescendo amplitude episodes of runaway stimuli at 2,400 and 2,600 ppm, approximately 3 seconds in duration, separated by pacing at 62.5 and 65 ppm, respectively. Fortunately the runaway stimuli were subthreshold and did not result in capture of the ventricle. Emergency pulse generator replacement was uneventful. Both leads were normal and both pulse generators had low battery voltages at 1.488 and 1.78 V, respectively.
An Operative Case of Inferior Vena Cava Stenosis Due to Fibrosis Around Permanent Pacemaker Leads
Authors: SHIMADA YASUYUKI , YAKU HITOSHI , KAWATA MASATOSHI , OKA KATSUHIKO , SHUNTOH KEISUKE , OKANO TAKAHISA , TAKAHASHI AKIYUKI , FUKUMOTO ATSUSHI , HAYASHIDA KYOKO , KITAMURA NOBUO
Published: July 2003

SHIMADA, Y., et al.: An Operative Case of Inferior Vena Cava Stenosis Due to Fibrosis Around Permanent Pacemaker Leads. A 56‐year‐old woman presented with general fatigue, dyspnea on exercise, and hepatomegaly subsequent to secondary implantation of a pacemaker. On admission, cardiac echo examination showed tricuspid valve regurgitation due to a migrated looped lead. At surgery, there was evidence of severe stenosis at both orifices of the superior and inferior vena cavae due to fibrous tissue around the leads. We removed the fibrous tissue, pacing leads, and generator. New leads were anchored onto the epicardium and a generator was inserted under the rectus muscle. The postoperative course was satisfactory and the symptoms disappeared.
Alternate Pacing Sites for Patients with Tricuspid Valve Prostheses
Authors: FAERESTRAND SVEIN , OHM OLE‐JØRGEN
Published: July 2003

FAERESTRAND, S., et al.: Alternate Pacing Sites for Patients with Tricuspid Valve Prostheses. The objective of this study was to pace via a coronary vein to avoid interfering with the tricuspid valve prosthesis function. Pacing leads were inserted into the posterior cardiac vein in a 68‐year‐old woman (patient 1), and in the great cardiac vein and the right auricle in a 32‐year‐old woman (patient 2). In patient 1 the stimulation threshold was 1.8 V at implant and stabilized at 3.0 V at the 24‐month follow‐up. In patient 2 the ventricular pacing threshold was 1.2 V at implant and stabilized at 0.7 V at the 24‐month follow‐up. The cardiac output at rest increased 43% during atrioventricular synchronous pacing compared to ventricular pacing. Long‐term stable ventricular pacing via the coronary venous system was obtained.
Utility of Right Precordial Leads at Higher Intercostal Space Positions to Diagnose Brugada Syndrome
Authors: TAKAGI MASAHIKO , TODA IKU , TAKEUCHI KAZUHIDE , YOSHIKAWA JUNICHI
Published: July 2003

TAKAGI, M., et al.: Utility of Right Precordial Leads at Higher Intercostal Space Positions to Diagnose Brugada Syndrome. We encountered a patient with Brugada syndrome whose body surface ECG revealed that the specific ST‐segment elevation was found only at higher positions of leads V1 and V2, above the third intercostal space. Only these right precordial leads at higher intercostal space positions were useful to identify Brugada syndrome in this case.
The Revised NASPE/BPEG Generic Code for Antibradycardia, Adaptive‐Rate, and Multisite Pacing
Authors: BERNSTEIN ALAN D. , DAUBERT JEAN‐CLAUDE , FLETCHER ROSS D. , HAYES DAVID L. , LÜDERITZ BERNDT , REYNOLDS DWIGHT W. , SCHOENFELD MARK H. , SUTTON RICHARD
Published: July 2003

BERNSTEIN, A.D., et al.: The Revised NASPE/BPEG Generic Code for Antibradycardia, Adaptive‐Rate, and Multisite Pacing. In light of evolving pacemaker technology and increasing interest in multisite pacing, the Committee on the Development of Position Statements (CDPS) of the North American Society of Pacing and Electrophysiology (NASPE) created an ad hoc Pacemaker Mode Code Task Force in April 2001 under the chairmanship of David L. Hayes, MD, for the purpose of bringing the NASPE/British Pacing and Electrophysiology Group (BPEG) Generic Pacemaker Code (NBG Code) up to date. The task force, whose members are the authors of this article, designed a revised NBG Code in which three major issues were taken into account. First, it was recognized that all modern pacemaker pulse generators are capable of extensive bidirectional communication with an external programming device, making them “communicating” pulse generators as defined by the current (1987) NBG Code. Second, it was decided that a means of providing basic information regarding the location of multisite pacing would be a useful ingredient of the NBG Code. Third, in view of the extensive antibradycardia pacing capabilities common in modern implantable cardioverter defibrillators and the availability of the NASPE/BPEG Defibrillator Code (NBD Code), it was considered unnecessary for the NBG Code to address the presence or absence of antitachycardia features. The resulting updated version of the NBG Code as described herein was endorsed by the BPEG on September 20, 2001 and adopted by the NASPE Board of Trustees on October 18, 2001. The structure of the revised NBG Code differs from that of the previous version in two respects alone: Position IV specifies only the presence or absence of rate modulation, and Position V specifies only the location or absence of multisite pacing (i.e., biatrial or biventricular pacing with at least two stimulation sites in each case) more than one stimulation site in any single cardiac chamber, or any combination of these. The revised NBG Code is deliberately configured to avoid confusion with earlier mode codes, and it is the authors' hope that it will serve as an enhanced resource for communication among those engaged in every phase of the multidisciplinary practice of cardiac rhythm management.