bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrocardiographic Characteristics in Patients with Nonrheumatic Atrial Fibrillation and Their Relation to Echocardiographic Parameters
Authors: BOLLMANN ANDREAS , BINIAS KARL‐HEINZ , SONNE KAI , GROTHUES FRANK , ESPERER HANS‐DIETER , NIKUTTA PETER , KLEIN HELMUT U.
Published: July 2003

BOLLMANN, A., et al.: Electrocardiographic Characteristics in Patients with Nonrheumatic Atrial Fibrillation and their Relation to Echocardiographic Parameters. The aim of this study was to determine the relation between (1) ECG fibrillatory wave amplitude and left atrial diameter and left atrial appendage (LAA) flow velocity using different ECG recording techniques, and (2) ECG fibrillatory frequency and frequency of LAA contractions in patients with nonrheumatic AF. In 36 patients (22 men, 14 women, mean age 61 ± 11 years) with persistent AF, ECG recordings were performed using a standard 12‐lead ECG and an orthogonal ECG lead system using a high gain, high resolution ECG. AF was classified as coarse (fibrillatory amplitude ≥ 1 mm) or fine (fibrillatory amplitude < 1 mm) in leads I, aVF, V1 and corresponding leads X, Y, and Z. Fibrillatory frequency from the ECG was determined by subtracting averaged QRST complexes and applying a Fourier analysis to the resulting signal. Doppler flow was obtained from LAA during transesophageal echocardiography and LAA emptying velocity was determined. Fourier analysis was also applied to the Doppler signal generating the frequency of LAA contractions. Coarse AF was observed in 0, 9, and 18 patients in leads I, aVF, and V, respectively. It was more often (P < 0.05) detected in corresponding leads X (n = 13), Y (n = 31), and Z (n = 23). Fine AF in lead X was associated with a reduced LAA velocity (33 ± 16 cm/s in coarse AF vs 22 ± 13 cm/s in fine AF, P = 0.05). There was neither a relation between AF coarseness in any other ECG lead and LAA flow velocity, left atrial diameter, or echo contrast. In 25 patients with an active LAA flow, the mean frequency of LAA contractions was 6.8 ± 0.8 Hz. The corresponding mean frequency obtained from the ECG was 6.7 ± 0.7 Hz (r = 0.85, P < 0.001). The mean difference between these two measures was 0.04 Hz, and the 95% confidence limits were 0.90 and – 0.82 Hz using the Bland‐Altman method. In conclusion, AF coarseness and its relation to LAA flow velocity depend on the ECG recording technique used. LAA contractions represent one mechanical correlate of the electrical fibrillatory activity in AF.
Influence of Age on the Potential Risk of Sudden Death in Asymptomatic Wolff‐Parkinson‐White Syndrome
Authors: BREMBILLA‐PERROT BÉATRICE , HOLBAN IOANA , HOURIEZ PIERRE , CLAUDON OLIVIER , BEURRIER DANIEL , VANCON ANNE CLAIRE
Published: July 2003

BREMBILLA‐PERROT, B., et al.: Influence of Age on the Potential Risk of Sudden Death in Asymptomatic Wolff‐Parkinson‐White Syndrome. Sudden death might be the first event in patients with asymptomatic WPW. The purpose of the study was to know if the age of the patient modifies the electrophysiological characteristics of asymptomatic WPW. Transesophageal stimulation was performed on 92 asymptomatic WPW patients from the following age groups: 10–69 years (n =14), 20–29 years (n = 33), 30–39 years (n = 15), 40–49 years (n = 17), and 50–69 years (n = 13). The procedure consisted of atrial pacing up to the second AV block, programmed atrial stimulation using one and two extrastimuli delivered on two driven rhythms in the control state, and after infusion of isoproterenol. In the five age groups, paroxysmal junctional tachycardia occurred, respectively, in 1 (7%), 1 (3%), 2 (13%), 2 (12%) patients, and not at all in the oldest group. AF > 1 minute occurred, respectively, in 3 (21%), 9 (27%), 5 (33%), 3 (18%), and 4 (31%) patients. The dangerous form of WPW (rapid conduction in the Kent bundle > 240/min in the control state or > 300/min after isoproterenol + AF induction) occurred, respectively, in 3 (21%), 9 (27%), 4 (27%), 1 (6%), and 3 (23%) patients. In conclusion, electrophysiological data of asymptomatic WPW are not modified by age of the patient. Elderly patients remain at risk of a dangerous form of WPW; systematic evaluation of WPW is recommended in patients with an active life independent of age.
Morphology Discrimination: A Beat‐to‐Beat Algorithm for the Discrimination of Ventricular from Supraventricular Tachycardia by Implantable Cardioverter Defibrillators
Authors: GRÜNEFELD GERIAN C. , SCHULTE BRITTA , HOHNLOSER STEFAN H. , TRAPPE HANS‐JOACHIM , KORTE THOMAS , STELLBRINK CHRISTOPH , JUNG WERNER , MEESMANN MALTE , BÖCKER DIRK , GROSSE‐MEININGHAUS DIRK , VOGT JÜRGEN , NEUZNER JÖRG
Published: July 2003

GRÖNEFELD, G.C., et al.: Morphology Discrimination: A Beat‐to‐Beat Algorithm for the Discrimination of Ventricular From Supraventricular Tachycardia by Implantable Cardioverter Defibrillators. Inappropriate therapy of SVTs by ICDs remains a major clinical problem despite enhanced detection criteria like “sudden onset” and “rate stability” in third‐generation devices. Electrogram morphology discrimination offers an additional approach to improve discrimination of supraventricular tachycardia (SVT) from ventricular tachycardia (VT). In a prospective, multicenter study, patients received an ICD with a beat‐to‐beat algorithm for morphological analysis of the intracardiac electrogram (Morphology Discrimination, MD). A nominal programming for standard enhancement criteria and morphology discrimination was required at implant. Electrogram storage of tachycardia episodes irrespective of delivery of therapy was used to assess sensitivity and specificity of the morphology algorithm alone and in combination with established detection criteria. During a 12 6 6‐month follow‐up, 886 episodes of device stored electrograms from 82 of 256 patients were evaluated. At nominal settings, the MD algorithm correctly identified 423 of 551 episodes as VT resulting in sensitivity of 77%. The classification of SVT was met in 239 of 335 episodes resulting in specificity of 71%. In combination with sudden onset, sensitivity increased to 99.5% at the expense of specificity (48%). In conclusion, SVT‐VT discrimination based on morphological analysis alone results in limited sensitivity and specificity. Programming the monitor mode allows individual assessment of the performance of this detection enhancement feature during clinical followup without compromising device safety. Only in patients with documented efficacy of morphology discrimination should this feature be subsequently activated.
Randomized Comparison of Efficacy of Cooled Tip Catheter Ablation of Atrial Flutter: Anatomic Versus Electrophysiological Complete Isthmus Block
Authors: MADRID ANTONIO H. , REBOLLO JOSE M. , DEL REY JOSE M. , GONZALO PEÑA , SOCAS ARPEL , ALVAREZ TEOFILO , RODRIGUEZ ANIBAL , CORREA CARLOS , CHÉRCOLES ANA , VÁZQUEZ CHARO , GARCIA‐COSIO MONICA , PALACIOS FERNANDO , MORO C.
Published: July 2003

MADRID, A.H., et al.: Randomized Comparison of Efficacy of Cooled Tip Catheter Ablation of Atrial Flutter: Anatomic Versus Electrophysiological Complete Isthmus Block. There is a subset of patients with failed ablation of the cavotricuspid isthmus (CTI) using standard catheters and with 10% of the patients having recurrences. The purpose of this study was to compare the cooled and standard ablation with regard to acute successful electrophysiological achievement of bidirectional isthmus block and the subacute anatomic characteristics of the lesions. This randomized, experimental study compares the effects of ablation on the isthmus using a cooled catheter with those of a standard ablation catheter in 16 pigs. In 12 animals, CTI block was achieved after ablation (8/8 cooled and 4/8 standard). In two animals, it was not possible to achieve complete isthmus block and two had persistent slow conduction (all four using the standard catheter). After 1 week, the animals were slaughtered. The size of the lesion was greater with the irrigated tip catheters. Transmural lesions were found in 14 animals. A complete line of anatomic isthmus block was not documented after the first line in six animals, four with the standard and two with the cooled catheter. A conduction block was never present across gaps ≥ 5 mm. In conclusion cooled catheters achieved a complete line of electrophysiological and anatomical block in a significantly higher percentage than the standard catheters.
Atrioventricular Interval Optimization and Exercise Tolerance
Authors: KHAIRY PAUL , TALAJIC MARIO , DOMINGUEZ MANUEL , TARDIF JEAN‐CLAUDE , JUNEAU MARTIN , LAVOIE LINDA , ROY DENIS , DUBUC MARC
Published: July 2003

KHAIRY, P., et al.: Atrioventricular Interval Optimization and Exercise Tolerance. Modern pacemakers offer many programming options regarding the AV interval including the ability to vary AV intervals depending on whether atrial activity is paced or spontaneous and to shorten AV intervals with increasing rates. To determine if optimization of these features improves exercise tolerance, 14 patients with intact sinus node function and AV block treated with dual chamber pacemakers were enrolled in a randomized double‐blind crossover trial. Doppler echocardiographic measurements of cardiac index and mitral flow were assessed over a range of programmable AV intervals at rest to determine each patient's optimal AV interval. Eleven patients completed serial graded exercise tests with spiroergometry after randomly programming the AV interval three ways in a crossover manner: fixed AV interval = 150 ms without rate adaptation (150/Fixed), fixed AV interval = 150 ms with rate adaptation (150/R), or optimized AV interval with rate adaptive AV interval shortening (optimized/R). Exercise capacity was determined by maximum oxygen uptake. Ten men and four women, age 64 ± 8 years, were enrolled. At rest, optimization of the AV interval improved the cardiac index by 21% (P < 0.001) and mitral flow by 13.4% (P < 0.001) when compared to least‐favorable AV intervals. During exercise, no differences in maximum heart rates were noted. Maximum oxygen uptake was increased in both groups with rate adaptive AV interval shortening when compared to fixed AV interval without rate adaptation: 13.9% (adjusted P < 0.04) and 14.6% (adjusted P < 0.02) in optimized/R and 150/R, respectively. No differences were noted between optimized/R and 150/R. In conclusion, rate adaptive AV interval shortening improved exercise tolerance independent of changes in heart rate. However, optimization of the AV interval with Doppler echocardiography at rest did not further improve exercise capacity.
QT Interval Prolongation and Torsades de Pointes Unmasked by Intracoronary Acetylcholine Administration
Authors: CHINUSHI MASAOMI , NAKAGAWA IWAO , HORI TOMOYUKI , YAMASHITA FUMIO , WASHIZUKA TAKASHI , AIZAWA YOSHIFUSA
Published: July 2003

CHINUSHI, M., et al.: QT Interval Prolongation and Torsades de Pointes Unmasked by Intracoronary Acetycholine Administration. Intracoronary acetylcholine administration, which was performed to exclude vasospasms, unmasked an abnormal QT interval prolongation and initiated torsades de pointes in a patient with normal QT interval at rest.
Two Cases of Bronchial Asthma After Treatment with Amiodarone
Authors: IMAMURA HIROSHI , KINOSHITA OSAMU , MARUYAMA KANA , IZAWA ATSUSHI , UCHIKAWA SHIN‐ICHIRO , KUMAZAKI SETSUO , TAKAHASHI WATARU , YOKOSEKI OSAMU , YAZAKI YOSHIKAZU , KOIZUMI TOMONOBU , KUBO KEISHI
Published: July 2003

IMAMURA H., et al.: Two Cases of Bronchial Asthma After Treatment with Amiodarone. Amiodarone is a highly effective antiarrhythmic agent for the prevention of life‐threatening arrhythmias. Two cases are described of patients who developed bronchial asthma after treatment with amiodarone. The bronchial asthma resolved after the dose of amiodarone was decreased in both patients. To our knowledge, an association between amiodarone and severe bronchial asthma has previously been reported only once in the medical literature. Physicians should note that amiodarone may cause bronchospasm in susceptible patients.
Surgical Treatment of Pacemaker Induced Left Innominate Vein Occlusion Using a Spiral Vein Graft
Authors: INOUE TAKEHIRO , OTAKI MASAKI , NAKAMOTO SUSUMU , ZANG ZHINEI , OKU HIDETAKA
Published: July 2003

INOUE, T., et al.: Surgical Treatment of Pacemaker Induced Left Innominate Vein Occlusion Using a Spiral Vein Graft. Superior vena cava syndrome due to transvenous pacing leads is an uncommon but potentially life‐threatening complication. This case involves a 54‐year‐old man who developed left innominate vein occlusion due to a pacemaker lead. This complication induced a progressive swelling on the left side of his face, neck, arm, and upper chest. The left innominate vein occlusion was surgically treated using a composite spiral saphenous vein graft. Postoperatively, the patient has received anticoagulation therapy with warfarin to prevent thrombosis and, thereby, the long‐term patency of the graft. He has undergone follow‐up on a regular outpatient basis without showing any recurrence of clinical symptoms.
Transient Complete Atrioventricular Block During Transcatheter Ablation of a Left Inferoparaseptal Anomalous Pathway in a Patient with a History of Previous Surgical Repair of Ventricular Septal Defect
Authors: D'ESTE DANIELE , ZERBO FRANCESCA , BERTAGLIA EMANUELE , MICHIELON GUIDO , GIACOMIN ALESSANDRO , PASCOTTO PIETRO
Published: July 2003

D'ESTE, D., et al.: Transient Complete Atrioventricular Block During Transcatheter Ablation of a Left Inferoparaseptal Anomalous Pathway in a Patient with a History of Previous Surgical Repair of Ventricular Septal Defect. This case describes a young woman with a manifest left inferoparaseptal accessory pathway and previous history of surgical repair of a defect of the ventricular inlet septum in whom a transient complete AV block occurred during radiofrequency ablation performed from the coronary sinus. The presence of a preexisting surgery related AV block unmasked by anomalous pathway ablation is the more reliable explanation for this case.
QT Prolongation Associated with Azithromycin/Amiodarone Combination
Authors: SAMARENDRA PADMARAJ , KUMARI SARITA , EVANS STEVEN J. , SACCHI TERRENCE J. , NAVARRO VICTOR
Published: July 2003

SAMARENDRA, P., et al.: QT Prolongation Associated with Azithromycin/ Amiodarone Combination. Administration of oral azithromycin, in addition to previously well‐tolerated long‐term amiodarone therapy, was associated with a marked prolongation of QT interval and increased QT dispersion, both substrates for life‐threatening ventricular tachyarrhythmia and torsades de pointes. This is a report of QT prolongation and increased QT dispersion associated with the use of azithromycin. The report assumes an added significance, in view of widespread empirical use of this antibiotic for the treatment of lower respiratory infections and belief of its safety in patients with cardiac diseases. Based on the authors' experience, they would like to emphasize that the combination of azithromycin with other drugs known to prolong QT or causing torsades de pointes be used with caution until the question of the proarrhythmic effect of azithromycin is resolved by further studies.
Absence of a Morning Peak in Ventricular Tachycardia and Fibrillation Events in Nonischemic Heart Disease: Analysis of Therapies by Implantable Cardioverter Defibrillators
Authors: TANEDA K. , AIZAWA Y. ,   THE JAPANESE ICD STUDY GROUP
Published: July 2003

TANEDA, K., et al.: Absence of a Morning Peak in Ventricular Tachycardia and Fibrillation Events in Nonischemic Heart Disease: Analysis of Therapies by Implantable Cardioverter Defibrillators. A growing number of Japanese patients are being treated with ICDs. Efforts are warranted to minimize the rates of ICD shocks that cause discomfort and anxiety. The circadian distribution of ICD discharges was investigated in 80 patients (57 ± 10 years of age, 69 men) from ten Japanese medical centers. The underlying heart disease was ischemic in 27 versus nonischemic in 53 patients. All patients had refractory VT or VF, and received appropriate shocks confirmed by stored data retrieved from the memory of the ICD. In the analysis of 354 appropriate shocks delivered in the overall population, a morning peak in VT or VF episodes was observed. However, subgroup analyses of the circadian distribution of ICD shocks revealed that the morning peak in VT or VF episodes was confined to patients with ischemic heart disease and was blunted by treatment patients with β–adrenergic blockers. The absence of a morning peak in appropriate ICD shocks among patients with nonischemic heart disease remains unexplained and was unrelated to the use of β–adrenergic blockers. In conclusion, the circadian pattern of appropriate ICD discharges was related to the underlying heart disease. In patients with ischemic heart disease, recurrences of VT or VF peaked in the morning. In contrast, in patients without ischemic heart disease, the episodes of VT or VF were evenly distributed during waking hours. β–Adrenergic blockers appeared to blunt the morning peak in VT or VF among patients with ischemic heart disease.
Dual Chamber Pacemaker Therapy for Mid‐Cavity Obstructive Hypertrophic Cardiomyopathy
Authors: BEGLEY DAVID , MOHIDDIN SAIDI , FANANAPAZIR LAMEH
Published: July 2003

BEGLEY, D., et al.: Dual Chamber Pacemaker Therapy for Mid‐Cavity Obstructive Hypertrophic Cardiomyopathy. Intracavitary LV obstruction is an important determinant of clinical outcome in hypertrophic cardiomyopathy (HCM). In a minority of patients the obstruction is at the level of the papillary muscles. Mid‐cavity obstructive HCM may be associated with a distal LV aneurysm and a worse prognosis. It is often not amenable to standard cardiac surgery for LV outflow obstruction. The long‐term effects (mean follow‐up 4.8 ± 2.9 years) of dual chamber (DDD) pacemaker therapy in 14 patients with mid‐cavity obstructive HCM (mean age 34 ± 16 years, range 15–65 years) were studied. Patients were evaluated by cardiac catheterization at baseline and 6 months to 1 year after receiving DDD pacemakers off all drug therapy. Symptoms were improved in all patients and NYHA functional class reduced from 2.8 ± 0.1 to 1.9 ± 0.4 (P < 0.0005). Intracavitary LV pressure gradients was reduced significantly (43 ± 36 vs 84 ± 31 mmHg at baseline, P < 0.0005). There was a significant associated reduction in apical LV systolic pressure (152 ± 37 vs 188 ± 34 mmHg, P < 0.001). In addition, there was a trend towards increased exercise tolerance (445 ± 123 vs 396 ± 165). Cardiac output and LV filling pressures were unchanged. In conclusion, chronic DDD pacing results in significant symptomatic and hemodynamic improvement in this uncommon but important subset of patients with obstructive HCM in whom the role of cardiac surgery is less well defined compared with the more typical outflow tract location of LV obstruction.
Ablation of Incisional Atrial Tachycardias Using a Three‐Dimensional Nonfluoroscopic Mapping System
Authors: LEONELLI FABIO M. , TOMASSONI GERY , RICHEY MARK , NATALE ANDREA
Published: July 2003

LEONELLI, F.M., et al.: Ablation of Incisional Atrial Tachycardias Using a Three‐Dimensional Nonfluoroscopic Mapping System. Incisional atrial reentrant tachycardias are macroreentrant arrhythmias in which surgical scars or prosthetic material constitute one of the constraining barriers of the circuit. Accurate reconstruction based on fluoroscopy‐guided endocardial mapping of the reentrant circuit is often incomplete and time consuming explaining, at least in part, the modest long‐term results of this technique. Mapping and ablation of these arrhythmias using a three‐dimensional nonfluoroscopic mapping system that allows electroanatomic reconstruction of the reentrant circuit could help in identifying the ablation targets and improve long‐term outcome. The study included 20 patients (12 men, mean age 45 ± 18 years) with corrected congenital heart disease (4 patients), coronary artery bypass surgery (7 patients), mitral or aortic valve replacement or reconstruction (6 patients), valve replacement and coronary revascularization (2 patients), and mitral valve replacement with maze procedure for atrial fibrillation (1 patient). Endocardial mapping with this novel system was complemented by standard electrophysiological techniques used to identify a critical isthmus of conduction. Two or more nonconductive areas of atrial tissue or surgical prosthetic material delimiting a critical isthmus of conduction were identified in every patient. Radiofrequency linear applications spanning two to more boundaries successfully eliminated the tachycardia in every patient. At a follow‐up of 11.5 ± 5.1 months (range 17–5 months), two (10%) patients developed a new clinical arrhythmia. The remaining 18 had no recurrences off medical therapy. Mean fluoroscopy time was 45.7 ± 15.2 minutes for patients with a single scar and 89 ± 41.2 minutes in patients with two or more scars. In conclusions, this new nonfluoroscopic mapping system offers the opportunity to achieve a high rate of cure of complex macroreentrant atrial tachycardias by facilitating reconstruction of the macroreentrant circuit and its boundaries.
Accurate Linear Radiofrequency Lesions Guided by a Nonfluoroscopic Electroanatomic Mapping Method During Atrial Fibrillation
Authors: GEPSTEIN LIOR , WOLF TAMIR , HAYAM GAL , BEN‐HAIM SHLOMO A.
Published: July 2003

GEPSTEIN, L., et al.: Accurate Linear Radiofrequency Lesions Guided by a Nonfluoroscopic Electroanatomic Mapping Method During Atrial Fibrillation. Catheter‐based continuous linear lesions may become a curative procedure for AF. The accuracy of guiding the application of continuous RF lesions by a nonfluoroscopic mapping system (NFM) during AF in goats was tested. The NFM system (Carto) uses magnetic fields to determine, in real time, the location and orientation of a 7 Fr ablation catheter tip. AF was induced in nine goats by intravenous infusion of methacholine (3–4 μg⋅kg–1⋅min–1) and burst pacing. The three‐dimensional atrial geometry was reconstructed using the median location of the mapping catheter tip during 30 seconds when in contact with each endocardial site. Sequential RF energy (60 seconds in a temperature‐controlled mode [60°C]) was delivered along a predetermined path to create longitudinal lesions in both atria. Sites to which RF energy was applied were tagged on the NFM map, enabling the operator to accurately navigate the catheter tip to the adjacent sites. In all cases (n = 14) the location, shape, length, and continuity of the linear lesions on the electroanatomic maps highly correlated with the autopsy findings. Average line length on the reconstructed maps was 32.3 ± 4.1 mm, which highly correlated (r = 0.98, P<.001) with the lesions created in the pathological specimen (31.7 ± 3.9 mm). The NFM system can guide the application of RF linear lesions in a highly accurate manner during AF. Moreover, the ability to tag the ablation sites on the three‐dimensional maps together with real‐time monitoring of the ablation catheter tip location enables delivery of RF energy to create reproducible, continuous, longitudinal lesions without the use of fluoroscopy.
Initial Experience with an Active‐Fixation Defibrillation Electrode and the Presence of Nonphysiological Sensing
Authors: DOSHI RAHUL N. , GOODMAN JEFFREY , NAIK AJAY M. , SHIVKUMAR KALYANAM , CHEN PENG‐SHENG , PETER C. THOMAS
Published: July 2003

DOSHI, R.N., et al.: Initial Experience with an Active‐Fixation Defibrillation Electrode and the Presence of Nonphysiological Sensing. Nonphysiological sensing by a pacing and defibrillation electrode may result in inappropriate defibrillator discharges and/or inhibition of pacing. Active‐fixation electrodes may be more likely to sense diaphragmatic myopotentials because of the protrusion of the screw for fixation. In addition, the movement of the fixation screw in an integrated bipolar lead system could also result in inappropriate sensing. This may be increasingly important in patients who are pacemaker dependent because the dynamic range of the autogain feature of these devices is much more narrow. Five of 15 consecutive patients who received a CPI model 0154 or 0155 active‐fixation defibrillation electrode with an ICD system (CPI Ventak AV3DR model 1831 or CPI Ventak VR model 1774 defibrillator) are described. In 2 of the 15 patients, nonphysiological sensing appearing to be diaphragmatic myopotentials resulted in inappropriate defibrillator discharges. Both patients were pacemaker dependent. Changes in the sensitivity from nominal to less sensitive prevented inappropriate discharges. In one patient, discreet nonphysiological sensed events with the electrogram suggestive of ventricular activation was noted at the time of implantation. This was completely eliminated by redeployment of the active‐fixation lead in the interventricular septum. In two other patients, discreet nonphysiological sensed events resulted in intermittent inhibition of ventricular pacing after implantation. These were still seen in the least sensitive autogain mode for ventricular amplitude. These were not seen on subsequent interrogation 1 month after implantation. Increased awareness of nonphysiological sensing is recommended. The CPI 0154 and 0155 leads seem to be particularly prone to this abnormality. Particular attention should be made when deploying an active‐fixation screw for an integrated bipolar lead. This increased awareness is more important when a given individual is pacemaker dependent, which may warrant DFT testing in a least or less sensitive mode in these patients.
Complications Due to Abandoned Noninfected Pacemaker Leads
Authors: BÖHM ÁDÁM , PINTÉR ARNOLD , DURAY GÁBOR , LEHOCZKY DEZSÕ , DUDÁS GÁBOR , TOMCSÁNYI ISTVÁN , PRÉDA ISTVÁN
Published: July 2003

BÖHM, Á., et al.: Complications Due to Abandoned Noninfected Pacemaker Leads. Noninfected unwanted pacemaker leads are usually abandoned since the reported complication rate related to them is low. We followed 60 patients with noninfected retained leads, and complication was observed in 12 (20%) of them. Lead migration occurred in 5 patients, skin erosion in 3 patients, venous thrombosis in 2 patients, and muscle stimulation in 2 patients. Management of the complications was a surgical procedure in seven patients, including two cases of open heart surgery, while chronic medical treatment was necessary in the other five patients. The results of this study suggest that complications due to noninfected abandoned leads may not be as rare as it was previously thought and may present a significant morbidity and cost burden. With the lead extraction technique available, the issue of the removal of all unwanted pacemaker leads should be addressed.
Pacemapping of the Triangle of Koch: A Simple Method to Reduce the Risk of Atrioventricular Block During Radiofrequency Ablation of Atrioventricular Node Reentrant Tachycardia
Authors: DELISE PIETRO , BONSO ALDO , CORO LEONARDO , FANTINEL MAURO , GASPARINI GIANNI , THEMISTOCLAKIS SAKIS , MANTOVAN ROBERTO
Published: July 2003

DELISE, P., et al.: Pacemapping of the Triangle of Koch: A Simple Method to Reduce the Risk of Atrioventricular Block During Radiofrequency Ablation of Atrioventricular Node Reentrant Tachycardia. Slow pathway ablation in common AVNRT can be complicated by total AV block. When radiofrequency energy is delivered to the posterior aspect of the triangle of Koch, total AV block may be the consequence of the absence of anterograde conduction along the fast pathway or of inadvertent damage to a fast pathway abnormally located close to the slow pathway. To localize the anterogradely conducting fast pathway, the triangle of Koch was pacemapped in 72 patients who underwent the ablation of common AVNRT. In all cases, before ablation the St‐H interval was calculated by stimulating the anteroseptal (AS), mid‐septal (MS), and posteroseptal (PS) aspect of the triangle of Koch at a rate slightly faster than the sinus rate. In all patients, common AVNRT was induced. In 64 (89%) of 72 patients (group A) the shortest St‐H interval was recorded on stimulating the AS region. In six (8%) patients (group B) the shortest St‐H interval was recorded on stimulating the MS region. Finally, in two (3%) patients (group C) the shortest St‐H interval was recorded stimulating in the PS region. In group C, AH interval, calculated on stimulating in the AS region, was significantly longer than in patients of groups A and B (200 ± 99 ms vs 64 ± 18 and 62 ± 3, respectively). In group A, on stimulating in the AS, MS, and PS regions, the AH interval remained costant in all patients. In contrast, in groups B and C on stimulation in the MS and PS regions, AH interval shortened (in group B from 56 ± 8 to 27 ± 37 and 37 ± 14, respectively; in group C from 200 ± 99 to 170 ± 100 and to 137 ± 109, respectively). In groups A and B, a posteroseptal slow pathway, and in group C, an anteroseptal retrograde fast pathway were succesfully ablated without AV block. Pacemapping of the traingle of Koch can help to recognize patients in whom the anterograde conducting fast pathway is abnormally located far from the anteroseptal region or in whom anterograde conduction of the fast pathway is absent. In these cases the risk of AV block can be reduced by performing slow pathway ablation in a site sufficiently far form the site of the anterograde fast pathway or ablating the retrogradely conducting fast pathway.
Electrogram Width Parameter Analysis in Implantable Cardioverter Defibrillators: Influence of Body Position and Electrode Configuration
Authors: FAVALE STEFANO , NACCI FRIDA , GALATI ANTONIO , ACCOGLI MICHELE , DE GIORGI VITO , GRECO MARIA ROSARIA , NASTASI MAURIZIO , PIERFELICE OSVALDO , ROSSI SIMONA , GARGARO ALESSIO
Published: July 2003

FAVALE, S., et al.: Electrogram Width Parameter Analysis in Implantable Cardioverter Defibrillators: Influence of Body Position and Electrode Configuration. The “EGM width criterion” is a discrimination algorithm that was available in the last generation ICDs. It improved ventricular tachycardia detection by withholding inappropriate therapy deliveries in the presence of narrow QRS tachycardias. The accuracy of the algorithm depends on the optimal settings of the intracardiac EGM source, the “slew thresholds,” and the “width threshold.” The possible dependence of these parameters on body position may affect the detection efficacy. Whether these effects can be minimized by a proper choice of the electrode configuration used for signal analysis is still to be investigated. This study aimed to evaluate the stability of the slew threshold and width threshold obtained in the supine and orthostatic positions detected by the tip‐to‐ventricular coil and can‐to‐ventricular coil electrode configurations. Their time dependence was also evaluated at the 6‐month follow‐up. Fifty‐eight patients who were recipients of an ICD (model Medtronic 7223cx and 7227cx) were included in the study. Changing from supine to orthostatic position caused a marked variation of slew and width thresholds (21.0 ± 13.9 V/s and 10.1 ± 9.6 ms, respectively) in 36% of patients with tip‐to‐ventricular coil and in 44% of patients with can‐to‐defibrillating coil (the mean slew threshold variation was in this case 17.6 ± 15.8 V/s, while the mean width threshold variation was 18.8 ± 21.0 ms). Width threshold variation was statistically significant (P < 0.02) with the latter electrode configuration. Slew thresholds settings changed between the 1‐ and 6‐month follow‐ups in the 75% of patients with can‐to‐defibrillating coil configuration and in 50% with tip‐to‐defibrillating coil. These time related variations were significantly larger with the tip‐to‐defibrillating coil configuration (P < 0.01). In conclusion, EGM width parameters may change between supine and orthostatic position and over time with tip to‐defibrillating coil configuration and can‐to‐defibrillating coil configuration. The former configuration was less sensitive to body position changes, but more sensitive to time related variations. These findings may be useful for optimal programming of the EGM width criterion, but if parameter programming based on these results can improve the discrimination specificity still needs to be investigated.
Radiofrequency Catheter Ablation with the Split‐Tip Electrode in the Temperature‐Controlled Mode
Authors: ANTZ MATTHIAS , OTOMO KENICHIRO , NAKAGAWA HIROSHI , YAMANASHI WILLIAM S. , JACKMAN WARREN M. , KUCK KARL‐HEINZ
Published: July 2003

ANTZ, M., et al.: Radiofrequency Catheter Ablation with the Split‐Tip Electrode in the Temperature‐Controlled Mode. The 7 Fr “split‐tip electrode” (2.5‐mm tip electrode divided longitudinally into four electrodes with an adjacent 2‐mm ring electrode) improves mapping resolution due to its small recording electrodes and narrow interelectrode distances (0.1 mm). The purpose of this study was to examine the temperature‐controlled ablation properties of this electrode. In seven anesthetized dogs, the thigh muscles were exposed and superfused with canine blood. A split‐tip catheter electrode (with a thermocouple in each of the five electrodes) and a conventional 4‐mm catheter electrode were positioned at constant pressure perpendicular or parallel to the surface of the thigh muscle. Impedance measured between each split electrode and a skin patch correlated with the degree of contact with blood and tissue. In the parallel catheter to tissue orientation, split electrodes not in contact with tissue had a low impedance (mean 210–224 Ω), and the split electrode almost entirely in contact with tissue had the highest impedance (380 ± 56 Ω). In the perpendicular catheter to tissue orientation all split electrodes had a similar impedance (mean 279–286 Ω). A total of 75 radiofrequency (RF) lesions were produced in the temperature‐controlled mode with the 4‐mm electrode (target 60°C) or the split‐tip electrode (power limited by the hottest electrode reaching 70°C) with current delivered to all five electrodes simultaneously, or only to electrodes in contact with tissue. Lesion depth was not significantly different between electrodes in the parallel orientation (5.2 ± 0.9 vs 5.1 ± 1.4 vs 5.3 ± 1.1 mm), but significantly deeper with the conventional 4‐mm tip electrode in the perpendicular orientation (6.7 ± 1.2 vs 5.3 ± 1.3 vs 5.6 ± 0.9 mm, P < 0.05). This was due to higher power delivered to the conventional 4‐mm electrode (27 ± 9 vs 17 ± 7 vs 15 ± 7 W, P < 0.05) because convective cooling by the blood flow was less effective for the split‐tip electrode due to a reduced heat conduction across the interelectrode space from the hottest electrode to cooler areas of the group of five electrodes (mean temperature difference between the hottest split electrodes and the ring electrode: 24°C). Electrode cooling or heat conduction was not effected by the elimination of current delivery to noncontact electrodes. Steam pops occurred in 36% of applications with the conventional 4‐mm electrode in the perpendicular orientation but never with the split‐tip electrode in spite of the higher target temperature. Measurement of impedance from the split electrodes allow the determination of electrode tissue contact and RF lesions produced with the split‐tip electrode in the temperature‐controlled mode using a target of 70°C were of reasonable size and not associated with steam pops.
Amplified Effects of d,l‐Sotalol in Canine Dilated Cardiomyopathy
Authors: CHUGH SUMEET S. , JOHNSON SUSAN B. , PACKER DOUGLAS L.
Published: July 2003

CHUGH, S.S., et al.: Amplified Effects of d,l‐Sotalol in Canine Dilated Cardiomyopathy. Despite the presence of well‐described cardiac repolarization abnormalities in heart failure, d,l‐sotalol effects on cardiac repolarization have not been evaluated in animal models of CHF. The authors hypothesized that the d,l‐sotalol effects on cardiac repolarization are altered in canine dilated cardiomyopathy when compared to controls. Effects of d,l‐sotalol were compared in seven dogs with tachycardia induced cardiomyopathy (CHF) and six control animals. In an open‐chest model, contact monophasic action potential recordings were obtained from RV and LV endocardium/epicardium during and after two doses of d,l‐sotalol (1 mg/kg and 3 mg/kg, each over 20 minutes). Effects of d,l‐sotalol on action potential duration at 90% repolarization (APD90) were examined at pacing cycle lengths of 300–1,000 ms. Plasma d,l‐sotalol levels were measured at baseline, 10, and 40 minutes following each dose. Prolongation of APD90 by d,l‐sotalol, was significantly exaggerated in CHF animals versus controls (P < 0.05, ANOVA). These differences were magnified at slow heart rates (P < 0.05, ANOVA). There were no significant differences in plasma d,l‐sotalol levels between the two groups. Effects of d,l‐sotalol on cardiac repolarization are exaggerated in CHF without significant alterations in plasma drug levels. While using d,l‐sotalol in heart failure, independent additional effects due to ventricular electrical remodeling may be a consideration.
Pacemaker‐Mediated Tachycardia in a Biventricular Pacing System
Authors: VAN GELDER BERRY M. , BRACKE FRANK A. , MEIJER ALBERT
Published: July 2003

VAN GELDER, B.M., et al.; Pacemaker‐Mediated Tachycardia in a Biventricular Pacing System. A 63‐year‐old man with chronic atrial fibrillation and heart failure had a biventricular pacing system implanted. The pulse generator was a standard DDDR pacemaker, using the atrial channel for the right ventricular lead and the ventricular channel for the left ventricular lead. During final adjustment of the pacing parameters, a pacemaker tachycardia triggered by T wave oversensing from the right ventricular lead was recorded.
Electrical Storm Due to Amiodarone Induced Thyrotoxicosis in a Young Adult with Dilated Cardiomyopathy: Thyroidectomy as the Treatment of Choice
Authors: MARKETOU MARIA E. , SIMANTIRAKIS EMMANUEL N. , MANIOS EMMANUEL G. , VARDAS PANOS E.
Published: July 2003

MARKETOU, M.E., et al.: Electrical Storm Due to Amiodarone Induced Thyrotoxicosis in a Young Adult with Dilated Cardiomyopathy: Thyroidectomy as the Treatment of Choice. For a patient with idiopathic dilated cardiomyopathy, an implantable defibrillator, and amiodarone induced thyrotoxicosis associated with ventricular fibrillation storm. Medical therapy was ineffective. Thyroidectomy resulted in immediate control of the arrhythmia and permitted reinitiation of amiodarone. At 18‐month follow‐up, the patient remained euthyroid on amiodarone and ventricular arrhythmia free.
Recurrent Pericardial Chest Pain: A Case of Late Right Ventricular Perforation After Implantation of a Transvenous Active‐Fixation ICD Lead
Authors: KAUTZNER JOSEF , BYTEŠNÍK JAN
Published: July 2003

KAUTZNER, J., et al.: Recurrent Pericardial Chest Pain: A Case of Late Right Ventricular Perforation After Implantation of a Transvenous Active‐Fixation ICD Lead. A 36‐year‐old woman with a history of recurrent syncopal episodes presumably due to ventricular tachyarrhythmia in mitral valve prolapse underwent implantation of a transvenous ICD system. During a 23‐month follow‐up, she developed recurrent pericardial chest pain with pericardial friction rub. The first episode of chest pain occurred without any detectable change in pacing or sensing parameters. The second episode was associated with an increase in pacing threshold and drop in intracardiac signal amplitude. Right ventricular perforation was suspected fluoroscopically and confirmed by right ventriculography. This case report emphasizes the key steps in the diagnosis of this rare complication of an ICD implantation.
Atypical Atrial Flutter Involving the Isthmus Between the Right Pulmonary Veins and Fossa Ovalis
Authors: TAI CHING‐TAI , LIN YUNG‐KUO , CHEN SHIH‐ANN
Published: July 2003

TAI, C.‐T., et al.: Atypical Atrial Flutter Involving the Isthmus Between the Right Pulmonary Veins and Fossa Ovalis. Typical atrial flutter, counterclockwise or clockwise movement around the tricuspid annulus, has been well studied. However, the reentrant circuits in atypical atrial flutter are not well defined. A patient without a prior history of cardiac surgery who presented with incessant atypical atrial flutter is described. Activation mapping demonstrated a circular movement around the fossa ovalis in the interatrial septum. Entrainment mapping demonstrated a protected isthmus between the right pulmonary veins and the fossa ovalis. Radiofrequency ablation of this isthmus terminated atrial flutter without recurrence during the follow‐up period.
Automatically Optimizing Pacing Output: An Excellent Idea, But with Potentially Lethal Pitfalls
Authors: SURI RANJIT , HARTHORNE J. WARREN , GALVIN JOSEPH
Published: July 2003

SURI, R., et al.: Automatically Optimizing Pacing Output: An Excellent Idea, But with Potentially Lethal Pitfalls. AutoCapture (AC) and Ventricular Capture Management (VCM) are pacing algorithms that attempt to automatically optimize pacing output, providing consistent capture and enhancing device longevity. This report describes potentially serious consequences from use of these algorithms. In one pacemaker dependent patient, AC malfunction led to failure of ventricular capture. This was fixed with a software correction. The potential seriousness of AC malfunction leads to the recommendation that this software be downloaded into all susceptible pacemakers. In a second patient, VCM malfunction resulted in unnecessary high output pacing. Our experience illustrates the need for postmarketing surveillance when embracing newer technology.
The Effect of Ablation Electrode Length and Catheter Tip to Endocardial Orientation on Radiofrequency Lesion Size in the Canine Right Atrium
Authors: CHAN RODRIGO C. , JOHNSON SUSAN B. , SEWARD JAMES B. , PACKER DOUGLAS L.
Published: July 2003

CHAN, R.C., et al.: The Effect of Ablation Electrode Length and Catheter Tip to Endocardial Orientation on Radiofrequency Lesion Size in the Canine Right Atrium. Although the determinants of radiofrequency lesion size have been characterized in vitro and in ventricular tissue in situ, the effects of catheter tip length and endocardial surface orientation on lesion generation in atrial tissue have not been studied. Therefore, the dimensions of radiofrequency lesions produced with 4‐, 6‐, 8‐, 10‐, and 12‐mm distal electrode lengths were characterized in 26 closed‐chested dogs. The impact of parallel versus perpendicular catheter tip/endocardial surface orientation, established by biplane fluoroscopy and/or intracardiac echocardiography, on lesion dimensions was also assessed. Radiofrequency voltage was titrated to maintain a steady catheter tip temperature of 75°C for 60 seconds. With a perpendicular catheter tip/tissue orientation, the lesion area increased from 29 ± 7 mm2 with a 4‐mm tip to 42 ± 12 mm2 with the 10‐mm tip, but decreased to 29 ± 8 mm2 with ablation via a 12‐mm tip. With a parallel distal tip/endocardial surface orientation, lesion areas were significantly greater: 54 ± 22 mm2 with a 4‐mm tip, 96 ± 28 mm2 with a 10‐ mm tip and 68 ± 24 mm2 with a 12‐mm tip (all P < 0.001 vs perpendicular orientation). Lesion lengths and apparent volumes were larger with parallel, compared to perpendicular tip/tissue orientations, although lesion depth was independent of catheter tip length with both catheter tip/tissue orientations. Electrode edge effects were not observed with any tip length. Direct visualization using intracardiac ultrasound guidance was subjectively helpful in insuring an appropriate catheter tip/tissue interface needed to maximize lesion size. Although atrial lesion size is critically dependent on catheter tip length, it is more influenced by the catheter orientation to the endocardial surface. This information may also be helpful in designing electrode arrays for the creation of continuous linear lesions for the elimination of complex atrial tachyarrhythmias.
Fiberoptic Balloon Catheter Ablation of Pulmonary Vein Ostia in Pigs Using Photonic Energy Delivery with Diode Laser
Authors: LEMERY ROBERT , VEINOT JOHN P. , TANG ANTHONY S.L. , GREEN MARTIN , FARR NORMAN , BAXTER LINCOLN , MCINTYRE JON , SINOFSKY ED
Published: July 2003

LEMERY, R., et al.: Fiberoptic Balloon Catheter Ablation of Pulmonary Vein Ostia in Pigs Using Photonic Energy Delivery with Diode Laser. Circumferential lesions to the pulmonary vein (PV) ostia to cause conduction block at the junction of the PV and left atrium could offer a new approach during catheter ablation of patients with paroxysmal (focal) atrial fibrillation. Diode laser can deliver energy through diffusing or ring fiber tips. In three pigs weighing between 60 and 65 kg, transseptal puncture was performed and a fiberoptic balloon catheter with a collapsed profile of 10 Fr was advanced through a sheath under fluoroscopic guidance to the ostium of the right and left PVs. The balloon was inflated with a 3‐cc mixture of D2O (deuterium oxide) and contrast to deliver circumferential lesions with a 15‐mm diameter × 3‐mm ring width of light. Applications consisted of 3.2 to 3.8 W/cm for 120 seconds; the animals were sacrificed 3 hours after ablation for pathological examination. Photonic energy was delivered successfully to the ostium of five of the five targeted PVs, and was well tolerated hemodynamically in each animal without ectopy. Gross inspection revealed endocardial lesions at the ostium of four of five PVs, confined to the atrium in each and circumferential in three of five PVs. Microscopically, transmural coagulation necrosis of the atrium was present at the ostium of three of five PVs, and extended into the myocardial sleeves of two PVs. Photonic energy delivery using a fiberoptic balloon catheter can create circumferential lesions to the PV ostia, suggesting that this new form of energy delivery may be therapeutically advantageous for pulmonary vein ablation with need to pursue chronic studies.
Predicting the Outcome of Patients with Unexplained Syncope Undergoing Prolonged Monitoring
Authors: KRAHN ANDREW D. , KLEIN GEORGE J. , FITZPATRICK ADAM , SEIDL KARLHEINZ , ZAIDI AMIR , SKANES ALLAN , YEE RAYMOND
Published: July 2003

KRAHN, A. D., et al.: Predicting the Outcome of Patients with Unexplained Syncope Undergoing Prolonged Monitoring. Patients with unexplained syncope are often considered candidates for prolonged monitoring or empiric pacing when noninvasive and invasive investigations fail to provide a diagnosis. Identifying the outcome of patients undergoing prolonged monitoring that would ultimately benefit from empiric pacing may permit a cost‐effective approach to resolution of syncope. Two hundred and six patients (age 57 ± 18 years, 57% male) underwent prolonged monitoring with an implanted loop recorder for syncope of unknown origin. The median number of previous syncopal episodes was four (mean 29 ± 133). Prior tilt testing was performed in 63% of patients, and electrophysiological testing in 46%. Symptoms recurred during follow‐up in 142 patients (69%). Recurrence was associated with bradycardia leading to pacemaker implantation in 35 patients (17.0%), tachycardia in 12 (5.8%), sinus rhythm in 63 (30.6%), neurally mediated syncope based on rhythm and clinical assessment in 22 (11%), and failed activation in 10 (5%). Logistic regression analysis of baseline variables found that age was the only independent variable that predicted the need for pacing, associated with a 3% increase in risk per advancing year of age (odds ratio 1.027, P = 0.026). Despite this finding, no age group could be identified in which the likelihood of requiring pacing exceeded 30%. Logistic regression also found that patients with structural heart disease were less likely to experience recurrent symptoms during monitoring (49% vs 78%, P = 0.001) and that advancing age was associated with earlier recurrence of symptoms (P = 0.01). The etiology of recurrent syncope is diverse and cannot be predicted by baseline clinical variables. Empiric pacing appears to have little role in the management of this patient population.