bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Use of Morphology Discrimination, Sudden Onset, and Stability as Discriminating Algorithms in Single Chamber Cardioverter Defibrillators
Authors: BORIANI GIUSEPPE , OCCHETTA ERALDO , PISTIS GIANFRANCO , MENOZZI CARLO , JORFIDA MARCELLA , SERMASI SERGIO , PAGANI MASSIMO , GASPARINI GIANNI , MUSSO GIACOMO , DALL'ACQUA ALBERTO , BIFFI MAURO , BRANZI ANGELO
Published: July 2003

BORIANI, G., et al.: Combined Use of Morphology Discrimination, Sudden Onset, and Stability as Discriminating Algorithms in Single Chamber Cardioverter Defibrillators. Morphology Discrimination (MD) is a rhythm discriminator based on QRS morphology analysis that can be combined with other discriminators like Stability, with or without Sinus Interval History (SIH) and Sudden Onset. Thirty‐five patients implanted with a St. Jude Medical single chamber ICD were evaluated during exercise testing, during induced AF, and during follow‐up for 14 ± 5 months. At exercise testing (60 episodes detected) MD had a specificity (SP) of 96.7% and Sudden Onset a SP of 91.7%; during induced AF (25 episodes) both MD and Stability had a SP of 96.0%. The diagnostic performance on spontaneous arrhythmias was as follows: for ventricular tachycardia (126 episodes) a sensitivity (SE) of 94.4% for MD, 92.1% for Sudden Onset, 89.7% for Stability without SIH and 79.4% for Stability + SIH; for sinus tachycardia (44 episodes) a SP of 86.4% for MD, 97.7% for Sudden Onset, 2.3% for Stability and of 95.5% for Stability + SIH. For AF (165 cases) a SP of 67.9% for MD, 69.1% for Stability and 90.3% for Stability + SIH, 44.8% for Sudden Onset. Use of MD alone provided a SE of 94.4% and a SP of 71.4% for spontaneous arrhythmias and combined use of the discriminators in a “2 of 3” diagnostic logic implied a SP of 90.9% with maintenance of 96.0% of SE. In single chamber ICDs a wide range of SE/SP ratios may be obtained by use of multiple discriminators, but use of the algorithm in a 2 of 3 diagnostic logic may achieve a SP of 90.9% and a SE of 96.0%.
Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: A Case Report of Identical Twins with Heart Failure
Authors: INDIK JULIA H. , SMITH DAVID E. , SOBONYA RICHARD E. , MARCUS FRANK I.
Published: July 2003

INDIK, J.H., et al.: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: A Case Report of Identical Twins with Heart Failure.Arrhythmogenic right ventricular cardiomyopathy/dysplasia is characterized by the progressive replacement of myocardium by fatty or fibrofatty tissue. Presenting symptoms are generally related to ventricular arrhythmias, including sudden cardiac death. Heart failure due to right ventricular and sometimes left ventricular dysfunction is uncommon in the early stages of the disease, but is known to occur in advanced cases. This case report describes identical adolescent twins with presenting symptoms related predominantly to right heart failure.
A Case of Bad Timing: Inappropriate Implantable Cardioverter Defibrillator Therapy Due to a Critically Placed Premature Ventricular Contraction
Authors: HEALY EDWARD , NGARMUKOS TACHAPONG , ROSENTHAL LAWRENCE
Published: July 2003

HEALY, E., et al.: A Case of Bad Timing: Inappropriate Implantable Cardioverter Defibrillator Therapy Due to a Critically Placed Premature Ventricular Contraction. A 58‐year‐old man with an ischemic cardiomyopathy underwent ICD implantation after having an electrophysiological study positive for inducible, sustained monomorphic VT. Approximately 1 week later he experienced a shock. Inspection of stored electrograms revealed that a run of nonsustained VT had initiated his ICD to charge. The episode spontaneously terminated, yet the shock was still delivered during sinus rhythm. Further inspection revealed that a critically timed PVC during the “second look” interval resulted in delivered therapy. Thus, inappropriate ICD therapy can result from causes other than SVT, lead malfunction, or over sensing.
Pacemaker Reed Switch Behavior in 0.5, 1.5, and 3.0 Tesla Magnetic Resonance Imaging Units: Are Reed Switches Always Closed in Strong Magnetic Fields?
Authors: LUECHINGER ROGER , DURU FIRAT , ZEIJLEMAKER VOLKERT A. , SCHEIDEGGER MARKUS B. , BOESIGER PETER , CANDINAS RETO
Published: July 2003

LUECHINGER, R., et al.: Pacemaker Reed Switch Behavior in 0.5, 1.5, and 3.0 Tesla Magnetic Resonance Imaging Units: Are Reed Switches Always Closed in Strong Magnetic Fields? MRI is established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. The aim of this study was to investigate the state of a pacemaker reed switch in different orientations and positions in the main magnetic field of 0.5‐, 1.5‐, and 3.0‐T MRI scanners. Reed switches used in current pacemakers and ICDs were tested in 0.5‐, 1.5‐, and 3.0‐T MRI scanners. The closure of isolated reed switches was evaluated for different orientations and positions relative to the main magnetic field. The field strengths to close and open the reed switch and the orientation dependency of the closed state inside the main magnetic field were investigated. The measurements were repeated using two intact pacemakers to evaluate the potential influence of the other magnetic components, like the battery. If the reed switches were oriented parallel to the magnetic fields, they closed at 1.0 ± 0.2 mT and opened at 0.7 ± 0.2 mT. Two different reed switch behaviors were observed at different magnetic field strengths. In low magnetic fields (< 50 mT), the reed switches were closed. However, in high magnetic fields (> 200 mT), the reed switches opened in 50% of all tested orientations. No difference between the three scanners could be demonstrated. The reed switches showed the same behavior whether they were isolated or an integral part of the pacemakers. The reed switch in a pacemaker or an ICD does not necessarily remain closed in strong magnetic fields at 0.5, 1.5, or 3.0 T and the state of the reed switch may not be predictable with certainty in clinical situations.
Dual Chamber Pacing in Hypertrophic Cardiomyopathy: Long‐Term Effects on Diastolic Function
Authors: BETOCCHI SANDRO , ELLIOTT PERRY M. , BRIGUORI CARLO , VIRDEE MUNMOHAN , LOSI MARIA ANGELA , MATSUMURA YOSHIHISA , MIRANDA MARIANNA , MCKENNA WILLIAM J. , CHIARIELLO MASSIMO
Published: July 2003

BETOCCHI, S., et al.: Dual Chamber Pacing in Hypertrophic Cardiomyopathy: Long‐Term Effects on Diastolic Function. To assess the effects of chronic dual chamber pacing (DDD) on LV diastolic function in obstructive hypertrophic cardiomyopathy (HCM), 21 patients with obstructive HCM paced for refractory symptoms were studied at baseline and at 3 and 12 months. HCM patients were matched to 21 patients with obstructive HCM on conventional treatment. Left atrial fractional shortening was calculated by M‐mode echocardiography; this index reflects LV end‐diastolic pressure. LV outflow tract gradient decreased 65 ± 21% with DDD pacing and the NYHA class improved (P = 0.033). Left atrial fractional shortening worsened with DDD pacing (P < 0.001). Patients with abnormal baseline left atrial fractional shortening (< 16%) were older, had a higher NYHA class, and had more severe mitral regurgitation. In this subgroup, left atrial fractional shortening did not worsen with DDD pacing and the NYHA class improved more than in patients with normal left atrial fractional shortening (P = 0.033). In conclusion, chronic DDD pacing reduces obstruction but impairs diastolic function in HCM. In patients with normal diastolic function, the untoward effects of pacing on diastolic function are more evident than in patients with abnormal diastolic function at baseline. This suggests that DDD pacing might be beneficial in a subgroup of patients with obstructive HCM and abnormal diastolic function.
P Wave Signal‐Averaged Electrocardiography to Identify Risk for Atrial Fibrillation
Authors: DARBAR DAWOOD , JAHANGIR ARSHAD , HAMMILL STEPHEN C. , GERSH BERNARD J.
Published: July 2003

DARBAR, D., et al.: P Wave Signal‐Averaged Electrocardiography to Identify Risk for Atrial Fibrillation. AF is the most common sustained cardiac arrhythmia, and this prevalence is increasing. The impact of AF on morbidity and mortality is substantial, as are the socioeconomic consequences like higher health care costs, chronic disease management, and disabilities. Early recognition of patients at high risk for AF, combined with effective management, may help prevent AF from becoming chronic, helping to minimize potential health risks, costs, and other complications. P wave signal‐averaged electrocardiography (SAECG) has been shown to have a potential role in identifying patients at risk of developing paroxysmal AF and those likely to change from paroxysmal AF to chronic AF. The theoretical rationale of P wave SAECG in patients with AF is delay in the intraatrial and interatrial conduction. Intraatrial conduction delays can be seen on the surface electrocardiogram as P wave prolongation, which is more visible with averaging techniques and high resolution recording devices. Averaging followed by amplification after proper filtering of the electrical signal allows more precise measurements of duration and amplitude of the P wave. Data on reproducibility, filter settings, number of beats to be averaged, and definitions of the onset and offset depend on the system used, which can be QRS or, preferably, P wave triggered. A prolonged P wave duration is one of the best predictors of perioperative AF, but the role of P wave SAECG in the paroxysmal form is less well defined. Combining P wave duration with other predictors for AF improves the diagnostic value of P wave SAECG.
Usefulness of Orthostatic Self‐Training for the Prevention of Neurocardiogenic Syncope
Authors: ABE HARUHIKO , KONDO SHOICHI , KOHSHI KIYOTAKA , NAKASHIMA YASUHIDE
Published: July 2003

ABE H., et al.: Usefulness of Orthostatic Self‐Training for the Prevention of Neurocardiogenic Syncope. To clarify the effectiveness of an orthostatic self‐training program for the prevention of neurocardiogenic syncope, twenty‐four consecutive head‐up tilt induced syncopal patients (12 men, 12 women; mean age 34 ± 20 years) were treated with an orthostatic self‐training program. The syncope was induced by head‐up tilt testing (+ 80 degrees for 30 minutes) with or without the use of isoproterenol in all patients reproducibly. The hemodynamics during the syncope were of the cardioinhibitory type in 4, vasodepressor type in 7, and mixed type in 13 patients. The onset time of the tilt induced syncope was 16 ± 10 minutes after the upright position. The orthostatic self‐training included standing against a wall without moving twice a day every day for a planned duration of up to 30 minutes at home. The head‐up tilt response was reevaluated with the same protocol as the initial study after 22 ± 6 days based on the patient's daily recording of the self‐training, and the clinical effect of the training program performed only once a day at home was noted over a mean follow‐up of 9.5 ± 3.4 months (range 5–18 months). Tilt induced syncope after the self‐training was observed in 2 of 24 patients. However, spontaneous syncope was not observed in any of the patients during follow‐up. In conclusion, orthostatic self‐training significantly improved the symptoms in patients with neurocardiogenic syncope. Once a day training for up to 30 minutes was effective and easily accepted by the patients for the prevention of neurocardiogenic syncope.
Effects of Radiofrequency Pulses Delivered in the Vicinity of the Coronary Arteries: Implications for Nonsurgical Transthoracic Epicardial Catheter Ablation to Treat Ventricular Tachycardia
Authors: D'AVILA ANDRÉ , GUTIERREZ PAULO , SCANAVACCA MAURICIO , REDDY VIVEK , LUSTGARTEN DANIEL L. , SOSA EDUARDO , RAMIRES JOSÉ ANTONIO F.
Published: July 2003

D'AVILA, A., et al.: Effects of Radiofrequency Pulses Delivered in the Vicinity of the Coronary Arteries: Implications for Nonsurgical Transthoracic Epicardial Catheter Ablation to Treat Ventricular Tachy‐cardia. This study evaluates the effects of epicardial RF ablation on the coronary vessels in a canine model. Nonsurgical epicardial catheter ablation is a minimally invasive procedure that has proven to be efficacious for the treatment of VT. This approach is limited by concern regarding the potential adverse effects of RF ablation on the epicardial coronary arteries. After lateral thoracotomy, a multipolar linear ablation catheter was sewn adjacent to or crossing the LAD in nine mongrel dogs. Five of these dogs also had a standard 4‐mm tip ablation catheter sewn adjacent to the LAD. RF pulses were delivered using temperature control. Animals were sacrificed 14 days after ablation for histological analyses. Using the 4‐mm tip catheter, 22 consecutive single lesions of 2.67 ± 0.35 mm depth were studied. The only coronary arterial change seen was replacement of the media with extracellular matrix. Using the linear ablation catheter, 117 pulses were applied to generate 24 linear lesions (3.8 ± 1 mm depth). Replacement of the coronary arterial media with extracellular matrix proliferation was commonly seen, and severe hyperplasia occurred in one artery. Intravascular thrombosis occurred in six arteries. The internal perimeter of the vessel (0.78 ± 0.49 mm vs 1.79 ± 0.83 mm) was the only variable associated with severe arterial damage. The effects of RF ablation delivered adjacent to the LAD were limited to the media but when delivered above the artery, severe intimal hyperplasia and intravascular thrombosis may occur. Susceptibility to damage is inversely proportional to the vessel size.
Simultaneous Epicardial and Endocardial Mapping of a Left‐Sided Posteroseptal Accessory Pathway Associated with a Large Coronary Sinus Diverticulum: Successful Ablation by Transection of the Diverticulum's Neck
Authors: SAAD EDUARDO B. , MARROUCHE NASSIR F. , COLE CHRISTOPHER R. , NATALE ANDREA
Published: July 2003

SAAD, E.B., et al.: Simultaneous Epicardial and Endocardial Mapping of a Left‐Sided Posteroseptal Accessory Pathway Associated with a Large Coronary Sinus Diverticulum: Successful Ablation by Tran‐section of the Diverticulum's Neck. Transcutaneous pericardial instrumentation in a patient with a left‐sided posteroseptal accessory pathway associated with a large coronary sinus diverticulum was performed after three previous unsuccessful ablations. The earliest ventricular activation site was recorded epicardially using a catheter in the pericardial space, but energy delivery at this site was not possible due to high impedances. Intravascular linear lesions transecting the neck of the large coronary sinus diverticulum using the pericardial catheter as a target allowed successful radiofrequency catheter ablation of the accessory pathway. This case outlines potential problems with ablations in the pericardial space and provides an alternative solution that can spare patients from open surgical procedures.
P Wave Duration and Morphology Predict Atrial Fibrillation Recurrence in Patients with Sinus Node Dysfunction and Atrial‐Based Pacemaker
Authors: DE SISTI ANTONIO , LECLERCQ JEAN FRANÇOIS , STIUBEI MARCEL , FIORELLO PIERRE , HALIMI FRANCK , ATTUEL PATRICK
Published: July 2003

DE SISTI, A., et al.: P Wave Duration and Morphology Predict Atrial Fibrillation Recurrence in Patients with Sinus Node Dysfunction and Atrial‐Based Pacemaker. P wave duration and morphology have never been systematically evaluated as markers of AF in patients with a conventional indication to pacing. This study correlated sinus P wave duration and morphology and the incidence of AF in patients with sinus node dysfunction (SND), previous history of AF before implant, and atrial‐based pacemaker. Included were 140 patients (86 men, 54 women; mean age 71.8 ± 10.4 years) with recurrent paroxysmal AF and who received a DDD (128 patients) or AAI (12 patients) pacemaker for SND. Forty‐nine patients had structural heart disease. Sinus P wave duration and morphology was evaluated in leads II, III. Twenty‐two patients had an abnormal P wave morphology, diphasic (+/‐) in 5 and notched (+/+) in 17. The basic pacemaker rate was programmed between 60 and 70 beats/min. Rate responsive function was activated in 65 patients. During a follow‐up of 27.6 ± 17.8 months, AF was documented in 87 patients. Forty‐four patients developed permanent AF, following at least one episode of paroxysmal AF in 26 cases. Statistical analysis used Cox model regression. Univariate predictors of AF (P < 0.10) were drugs (mean: 2 ± 1.4) and DC shock before pacing (16/140 patients), P wave duration (mean 112.5 ± 24.6 ms), basic pacemaker rate (mean 68 ± 5 beats/min), and drugs in the follow‐up (mean 1.2 ± 0.94). Multivariate analysis showed that P wave duration (b = 0.013, s.e. = 0.004; P = 0.003), and drugs before pacing (b = 0.2; s.e.= 0.08; P < 0.01) resulted in a significant independent predictor of AF. Actuarial incidence of patients free of AF at 30 months was 35%: 56% in patients with a P wave < 120 ms, and 13% in those with P wave ≥ 120 ms (P < 0.01 by Score test). Univariate predictors of permanent AF were drugs and DC shock before pacing, left atrial size (mean 39 ± 6 mm), P wave duration, abnormal P wave morphology (22/140 patients), and drugs in the follow‐up. Multivariate analysis showed that P wave morphology was the most important predictor of permanent AF (b = ‐ 0.56, s.e.= 0.2; P = 0.008). Incidence of patients free of permanent AF at 30 months was 69%: 74% in patients with normal P wave, compared to 28% in the case of abnormal P wave morphology (P < 0.01). P wave duration and morphology are good markers of postpacing AF recurrence in patients with SND and an atrial‐based pacemaker. This observation suggests that intra‐ and interatrial conduction disturbances be extensively evaluated before implantation, and the indication for atrial resynchronization procedures be reevaluated.
Primary Radiofrequency Ablation for Incessant Idiopathic Ventricular Tachycardia
Authors: GUPTA ANOOP K. , KUMAR A.V. GANESH , LOKHANDWALA YASH Y. , VORA AMIT M. , MAHESHWARI ALOK , THAKUR RANJAN K.
Published: July 2003

GUPTA, A.K., et al.: Primary Radiofrequency Ablation for Incessant Idiopathic Ventricular Tachycardia. Fascicular VT and RVOT tachycardia are sometimes difficult to induce by programmed electrical stimulation (PES), despite pharmacologic provocation. In such instances, catheter mapping is hampered and efficacy of catheter ablation is difficult to judge. The study included nine patients who presented with incessant idiopathic VT and were directly taken to the electrophysiological laboratory for RF ablation. During the same period, elective ablation was performed on 108 patients with idiopathic VT. The success rate, procedural and fluoroscopy times number of energies, and the peak temperature were evaluated and compared. Of the nine patients, seven had incessant fascicular VT and two had RVOT tachycardia. The mean VT cycle length was 356 ± 32 ms and the earliest endocardial activation time during VT was 23.6 ± 6 ms relative to surface QRS complexes. A fascicular potential was not seen in three of the seven patients with fascicular VT. The mean procedural time was 71 ± 32 minutes and 144 ± 40 minutes (P = 0.023) while the fluoroscopy time was 14.6 ± 4.6 minutes and 30 ± 16 minutes (P < 0.001), respectively, in the primary ablation and elective groups. The total number of RF energies delivered was 2.0 ± 1.3 versus 7.4 ± 5.6 (P = 0.07), respectively. The significantly increased procedural time during elective ablation was largely due to time spent in fascicular VT induction. All patients in the primary ablation group were successfully ablated and none had a recurrence. Primary ablation is a safe and effective option in patients with incessant idiopathic VT. Moreover, in fascicular VT, it is superior to elective ablation in terms of success, fluoroscopy and procedural times.
Transesophageal Echocardiographic Evaluation of Tricuspid Valve Regurgitation During Pacemaker and Implantable Cardioverter Defibrillator Lead Extraction
Authors: ROEFFEL SIMONE , BRACKE FRANK , MEIJER ALBERT , VAN GELDER BERRY , VAN DANTZIG JAN MELLE , BOTMAN CEES JOOST , PEELS KATHINKA
Published: July 2003

ROEFFEL, S., et al.: Transesophageal Echocardiographic Evaluation of Tricuspid Valve Regurgitation During Pacemaker and Implantable Cardioverter Defibrillator Lead Extraction. Chronically implanted ventricular pacing and defibrillator (ICD) leads can adhere to the tricuspid valve. This study examined the effect of lead extraction, and laser sheath extraction in particular, on tricuspid valve regurgitation. Lead extraction was first tried with traction using limited force followed by a laser sheath if not successful. Tricuspid valve regurgitation before and after extraction was evaluated with transesophageal echocardiography and graded from 0 (none) to 4 (severe). A change in regurgitation was considered clinically relevant if it increased with two grades or more and resulted in at least grade 3 regurgitation. Fifty ventricular leads were extracted in 43 consecutive patients, including 14 ICD leads. In 20 patients (group I) leads were removed without a (laser) sheath crossing the tricuspid valve, in 23 patients (group II) leads were extracted with lasing across the valve. The mean time from implant was 43 ± 43 months and 99 ± 78 months, respectively, (P = 0.007). Tricuspid regurgitation increased in five (12%) patients. In group I only in one patient the laser failed proximal of the valve and forceful traction was subsequently used, and in group II this occurred in four (17%) patients. This difference did not reach statistical significance even excluding the patient from group I (P = 0.111). The increase of tricuspid regurgitation cautions against indiscriminate extraction of superfluous leads. There is a trend that when tools like a laser sheath are necessary the chance of tricuspid valve damage increases.
Chronic Threshold Testing of Implantable Cardioverter Defibrillators Does Not Increase Coagulation Activity or Platelet Activation
Authors: SMOLICH JOSEPH J. , YATES LYNETTE A. , MALAN ERICA , GAN T. ENG , HARPER RICHARD W. , ALISON JEFFREY F. , PEVERILL ROGER E.
Published: July 2003

SMOLICH, J.J., et al.: Chronic Threshold Testing of Implantable Cardioverter Defibrillators Does Not Increase Coagulation Activity or Platelet Activation. It is unknown if the brief periods of circulatory stasis occurring with induction of VF during DFT testing in patients with an ICD activate blood coagulation processes. To address this question, coagulation activity and platelet activation were measured in peripheral venous blood samples obtained from 12 patients undergoing DFT testing under general anesthesia, 3 (n = 11) or 6 months (n = 1) after ICD implantation for recurrent ventricular arrhythmias. Five patients were anticoagulated with warfarin and two to six episodes of VF (median five) were induced per patient. Blood samples were drawn at baseline, after each DFT test and on the following morning. Coagulation activity was assessed by measuring prothrombin fragment 1+2 (F1+2) (a marker of thrombin generation), soluble fibrin (a marker of fibrin production), and D‐dimer (a breakdown product of cross‐linked fibrin). Platelet activation was evaluated by measuring the expression P‐selectin on the platelet surface using flow cytometry. No significant changes in F1+2, soluble fibrin, D‐dimer, or P‐selectin expression occurred during DFT testing, or between baseline and morning after samples. Moreover, results were unaffected by warfarin. These findings suggest that chronic threshold testing of implantable cardioverter defibrillators is not associated with activation of blood coagulation processes.
What Is the Minimal Pacing Rate that Prevents Torsades de Pointes? Insights from Patients with Permanent Pacemakers
Authors: PINSKI SERGIO L. , EGUÍA LUIS E. , TROHMAN RICHARD G.
Published: July 2003

PINSKI, S.L., et al.: What is the Minimal Pacing Rate that Prevents Torsades de Pointes? Insights From Patients with Permanent Pacemakers. In the acquired long QT syndrome, torsades de pointes (TP) is invariably preceded by pauses or bradycardia. Thus, it has been proposed that out‐of‐hospital initiation of drugs that prolong repolarization should be safe in patients with permanent pacemakers. However, a minimal protective pacing rate has not been identified. The authors reviewed published reports of acquired TP in patients with permanent pacing. Those providing documentation of tachycardia onset and pacemaker programming were included in the analysis. Events occurring ≤ 1 month after AV nodal ablation were excluded. Eighteen cases were identified (age 74 ± 5; 10 women). QT prolonging drugs were present in 15 patients (quinidine 5, sotalol 3, disopyramide 3, amytriptiline, chloroquine, cisapride + haloperidol, and monopride + flecainide 1 each). Hypokalemia was present in eight patients. At the time of TP, the programmed lower rate was 63 ± 13 beats/min. However, the effective pacing rate was lower (55 ± 11 beats/min) due to invocation of pause‐promoting features (hysteresis [4 patients]; + PVARP extension on PVC [1 patient]) or ventricular oversensing (2 patients). No patient developed TP with an effective pacing rate > 70 beats/min. TP is possible in the presence of a functional permanent pacemaker. Programmed lower rates ≤ 70 beats/min are not protective. At programmed lower rates > 70 beats/min, TP may occur only when facilitated by programmable pause‐promoting features or oversensing. It remains to be seen if rate smoothing algorithms can prevent TP when the baseline rate is programmed ≤ 70 beats/min.
Fever Unmasking the Brugada Syndrome
Authors: PORRES JOSÉ MANUEL , BRUGADA JOSEP , URBISTONDO VICENTE , GARCÍA FRANCISCO , REVIEJO KARLOS , MARCO PILAR
Published: July 2003

PORRES, J.M., et al.: Fever Unmasking the Brugada Syndrome. This case report describes a 66‐year‐old woman with severe polymorphic ventricular tachycardia and syncope during a febrile state. The electrocardiogram revealed a right bundle branch block and pattern of elevated ST segment in the anterior and inferior leads similar to the Brugada syndrome. These electrocardiographic anomalies disappeared when the temperature returned to normal. The administration of procainamide reproduced the electrocardiographic changes. An electrophysiological study using two extrastimuli induced ventricular tachycardia. An automatic defibrillator was implanted.
Changing Trends in Pacemaker and Implantable Cardioverter Defibrillator Generator Advisories
Authors: MAISEL WILLIAM H. , STEVENSON WILLIAM G. , EPSTEIN LAURENCE M.
Published: July 2003

MAISEL, W.H., et al.: Changing Trends in Pacemaker and Implantable Cardioverter Defibrillator Generator Advisories. Pacemaker and implantable cardioverter defibrillator (ICD) generator recalls and safety alerts (advisories) occur frequently, affect many patients, and are increasing in number and rate. It is unknown if advances in device technology have been accompanied by changing patterns of device advisory type. Weekly FDA Enforcement Reports from January 1991 to December 2000 were analyzed to identify all advisories involving pacemaker and ICD generators. This article represents additional analysis of previously cited advisories and does not contain additional recalls or safety alerts over those that have been previously reported. The 29 advisories (affecting 159,061 devices) from the early 1990s (1991–1995) were compared to the 23 advisories (affecting 364,084 devices) from the late 1990s (1996–2000). While the annual number of device advisories did not change significantly, ICD advisories became more frequent and a three‐fold increase in the number of devices affected per advisory was observed. The number of devices affected by hardware advisories increased three‐fold, due primarily to a 700‐fold increase in electrical/circuitry abnormalities and a 20‐fold increase in potential battery/capacitor malfunctions. Other types of hardware abnormalities (defects in the device header, hermetic seal, etc.) became less common. The number of devices recalled due to firmware (computer programming) abnormalities more than doubled. The remarkable technological advances in pacemaker and ICD therapy have been accompanied by changing patterns of device advisory type. Accurate, timely physician and patient notification systems, and routine pacemaker and ICD patient follow‐up continue to be of paramount importance.
Radiofrequency Ablation of Cardiac Arrhythmias Using a Three‐Dimensional Real‐Time Position Management and Mapping System
Authors: SCHREIECK JÜRGEN , NDREPEPA GJIN , ZRENNER BERNHARD , SCHNEIDER MICHAEL A.E. , WEYERBROCK SONJA , DONG JUN , SCHMITT CLAUS
Published: July 2003

SCHREIECK, J., et al.: Radiofrequency Ablation of Cardiac Arrhythmias Using a Three‐Dimensional Real‐Time Position Management and Mapping System.. A recently developed three‐dimensional real‐time position management system (RPM) uses an ultrasound ranging technique that enables multiple distance measurements between two reference catheters and a mapping catheter each equipped with ultrasound transducers. In addition to three‐dimensional representation of the catheters and ablation sites it displays real‐time movements of catheters (including the tip and shaft). A recently released version of the system enables additional geometry reconstruction of the heart chamber and activation mapping. This study included 21 patients (mean age 59 ±14.5 years) referred for radiofrequency catheter ablation of various arrhythmias. Geometry was reconstructed by tracing the endocardial contour of the respective heart chambers. Global and local color coded activation maps were constructed to confirm the nature of arrhythmia and to guide ablation. Spontaneous or induced arrhythmias were typical atrial flutter (n = 8), atypical atrial flutter (n = 3), atrioventricular nodal reentrant tachycardia (n = 3), atrial tachycardia (n = 2), atrial fibrillation (n = 2), ventricular tachycardia (n = 2), and Wolff‐Parkinson‐White syndrome (n = 1). Geometry reconstruction and mapping of arrhythmias were possible in 20 of 21 patients. RPM‐guided radiofrequency ablation was successful in 19 (95%) of 20 patients. Due to difficulties in steering the RPM mapping/ablation catheter, in 6 (28%) successfully mapped patients, radiofrequency ablation was performed using another catheter. In one patient, the RPM‐guided map was inconclusive and in another patient, ablation failed due to multiple reentrant circuits. No complications were observed. In conclusion, the new RPM system enables geometry reconstruction and three‐dimensional positioning of the ablation catheters, reconstruction of the activation maps, marking of anatomic structures and reproducible tracking of multiple ablation sites. The system could be used to guide radiofrequency ablation of atrial and ventricular arrhythmias.
Spectral Analysis of Chronic Atrial Fibrillation and Its Relation to Minimal Defibrillation Energy
Authors: TAI CHING‐TAI , CHEN SHIH‐ANN , LIU ANN‐SHIN , YU WEN‐CHUNG , DING YU‐AN , CHANG MAU‐SONG , KAO TSAIR
Published: July 2003

TAI, C‐T., et al.: Spectral Analysis of Chronic Atrial Fibrillation and Its Relation to Minimal Defibrillation Energy. The average rate of fibrillatory activity may reflect the global activation pattern of AF. Electrical cardioversion is the most effective method of converting chronic AF to sinus rhythm. The aim of this study was to investigate the relation between the minimal defibrillation energy requirement and the dominant frequency of chronic AF. Twenty‐nine patients with chronic AF (mean duration 57.9 ± 7.7 months) underwent external electrical cardioversion. Before cardioversion, the frequency content of the 60‐second AF in ECG lead V1 was quantified using digital signal processing. After band‐pass filtering, QRST complexes were cancelled using a recursive least squares algorithm. The resulting fibrillatory baseline signal was subjected to fast Fourier transform and was displayed as a power spectrum. The dominant AF frequency was found to range from 4.9 to 8.7 Hz (mean 6.7 ± 0.9 Hz). Twenty‐six patients had successful conversion of AF to sinus rhythm without immediate recurrence. There was a positive correlation between the minimal defibrillation energy and the dominant frequency of chronic AF (ρ= 0.414, P = 0.035). Thus, power spectral analysis of AF using the surface ECG is feasible and may be useful in predicting the minimal shock energy required for successful cardioversion of chronic AF.
Electrocardiograms from the Turtle to the Elephant that Illustrate Interesting Physiological Phenomena
Authors: GEDDES L.A.
Published: July 2003

GEDDES, L.A. Electrocardiograms From the Turtle to the Elephant that Illustrate Interesting Physiological Phenomena. This article describes a collection of ECGs from many species obtained over the past 50 years. Presented are ECGs of species in which the pacemaker is a separate contractile chamber with its own action and recovery potentials. In such species, pacemaker atrial and AV block can be produced. Shortening of the atrial refractory period and the negative inotropic effect can be produced by vagal stimulation. The cardiac electrogram and stroke volume are recorded from the turtle heart. The ECG and respiration were recorded from the snake. ECG records were obtained from the anesthetized and decapitated housefly. ECG records of the rabbit show slowing when the nose encountered irritating vapors. Records from a dog with atrial fibrillation exhibit rhythmic fibrillation frequency changes correlated with respiration. In addition, in a morphinized dog with atrial fibrillation, impulses crossed the AV node only during inspiration. The ECGs of a cow and camel exhibit long P‐R intervals and biphasic P waves. Finally the elephant ECG shows a clear U wave following the T wave.
Right‐Sided Prepectoral Implantation of an Implantable Cardioverter Defibrillator in a Right Pneumonectomized Patient
Authors: AVRAMOVITCH NAOMI A. , MILITIANU ARIE , LEWIS BASIL S.
Published: July 2003

AVRAMOVITCH, N.A., et al.: Right‐Sided Prepectoral Implantation of an Implantable Cardioverter Defibrillator in a Right Pneumonectomized Patient. Right‐sided prepectoral implantation of an ICD is performed in unusual circumstances only, like in patients with abnormal venous drainage and preexisting left‐sided devices. This case report describes a 42‐year‐old man who had undergone previous right pneumonectomy and who required ICD implantation for symptomatic inducible nonsuppressable hemodynamically unstable ventricular tachycardia. To avoid the small but real possibility of inadvertent iatrogenic left‐sided pneumothorax in a patient with previous right pneumonectomy, a dual chamber ICD with an active can was implanted in the right prepectoral position.
Radiofrequency Catheter Ablation of an Incessant Ventricular Tachycardia Following Valve Surgery
Authors: LEWALTER THORSTEN , JUNG WERNER , PREUSSE CLAUS J. , LICKFETT LARS , WOLPERT CHRISTIAN , YANG ALEXANDER , WELZ ARMIN , LÜDERITZ BERNDT
Published: July 2003

LEWALTER, T., et al.: Radiofrequency Catheter Ablation of an Incessant Ventricular Tachycardia Following Valve Surgery. Sustained monomorphic ventricular tachycardia (VT) after valve surgery represents a clinical entity with different tachycardia mechanisms. This case report describes an incessant VT after tricuspid and aortic valve replacement that did not respond to antiarrhythmic drug treatment. The tachycardia exhibited VA block and a right bundle branch block pattern with left‐axis deviation, suggesting ventricular excitation via the left posterior fascicle. The electrophysiological study was limited by the prosthetic tricuspid and aortic valve replacement, therefore a transseptal approach was necessary to obtain access to the ventricular myocardium. Radiofrequency catheter ablation was performed in the proximal left bundle or distal His region with termination of the incessant VT followed by complete AV block. After pacemaker implantation using a transvenous right atrial and an epicardial ventricular lead, no VT reoccurrence could be documented.
Clinical Study of the Laser Sheath for Lead Extraction: The Total Experience in the United States
Authors: BYRD CHARLES L. , WILKOFF BRUCE L. , LOVE CHARLES J. , SELLERS T. DUNCAN , REISER CHRISTOPHER
Published: July 2003

BYRD, C.L., et al.: Clinical Study of the Laser Sheath for Lead Extraction: The Total Experience in the United States. The laser sheath uses optical fibers, delivering pulsed ultraviolet excimer laser light, to vaporize fibrotic tissue binding intravenous cardiac leads to the vein or heart wall during lead extraction from the implant vein. The total investigational experience with laser sheaths is reported. During the period from October 1995 to December 1999, 2,561 pacing and defibrillator leads were treated in 1,684 patients at 89 sites in the United States with three sizes of laser sheath. Endpoints were complete removal of the lead, partial removal (leaving the tip behind), or failure (abandoning the lead, onset of complications, change to transfemoral or transatrial approach). Minimal follow‐up at 30 days was recorded. Of the leads, 90% were completely removed, 3% were partially removed, and the balance were failures. Major perioperative complications (tamponade, hemothorax, pulmonary embolism, lead migration, and death) were observed in 1.9% of patients with in hospital death in 13 (0.8%). Minor complications were seen in an additional 1.4% of patients. Multivariate analysis showed that implant duration was the only preoperative independent predictor of failure; female sex was the only multivariate predictor of complications. Success and complications were not dependent on laser sheath size. At follow‐up, various extraction related complications were observed in 2% of patients. The learning curve showed a trend toward fewer complications with experience. Lead extraction with the laser sheath can be safely practiced with high success rates. Success is independent of laser sheath size. Major complications can be expected in < 2% of patients, and occur more often during an investigator's early experience.
Postpacemaker Implant Pericarditis: Incidence and Outcomes with Active‐Fixation Leads
Authors: SIVAKUMARAN SOORI , IRWIN MARLEEN E. , GULAMHUSEIN SAJAD S. , SENARATNE MANOHARA P.J.
Published: July 2003

SIVAKUMARAN, S., et al.: Postpacemaker Implant Pericarditis: Incidence and Outcomes with Active Fixation Leads. Pericarditis has been noted as a potential complication of pacemaker implantation. This study evaluated the risk of developing pericarditis following pacemaker implantation with active‐fixation atrial leads. Included were 1,021 consecutive patients (mean age 73.4 ± 0.4 years, range 16–101 years; 45.2% women) undergoing new pacemaker system implantation between 1991 and 1999 who were reviewed for the complication of pericarditis. The incidence and outcomes of postimplantation pericarditis in patients receiving active‐fixation atrial leads were compared to those not receiving these leads. Of 79 patients who received active‐fixation atrial leads, 4 (5%) developed pericarditis postpacemaker implantation. Of 942 patients with passive‐fixation atrial leads or no atrial lead (i.e., a ventricular lead only), none developed pericarditis postoperatively (P < 0.001). Of patients receiving active‐fixation ventricular leads only (n = 97), none developed pericarditis. No complications were apparent at the time of implantation in patients who developed pericarditis. Pleuritic chest pain developed between 1 and 28 hours postoperatively. Three patients had pericardial rubs without clinical or echocardiographic evidence of tamponade. They were treated conservatively with acetylsalicylic acid or ibuprofen and their symptoms resolved without sequelae in 1–8 days. One patient (without pericardial rub) died due to cardiac tamponade on postoperative day 6. Postmortem examination revealed hemorrhagic pericarditis with no gross evidence of lead perforation. Pericarditis complicates pacemaker implantation in significantly more patients who receive active‐fixation atrial leads. It may be precipitated by perforation of the atrial lead screw through the thin atrial wall. Patients developing postoperative pericarditis should be followed closely due to the risk of cardiac tamponade.
Suppression of Concealed Pulmonary Vein Bigeminy by Atrial Pacing in a Patient with Paroxysmal Atrial Fibrillation
Authors: REITHMANN CHRISTOPHER , HAHNEFELD ANTON , STEINBECK GERHARD , HOFFMANN ELLEN
Published: July 2003

REITHMANN, C., et al.: Suppression of Concealed Pulmonary Vein Bigeminy by Atrial Pacing in a Patient with Paroxysmal Atrial Fibrillation. Concealed pulmonary vein bigeminy, as a pair of a pulmonary vein spike potential within a fragmented far‐field atrial electrogram and a premature ectopic pulmonary vein spike potential with exit block, was continuously recorded in a patient with paroxysmal AF. Atrial pacing suppressed the breakthrough from the left atrium to the pulmonary vein, thus preventing the conducted and the premature ectopic pulmonary vein potentials. Atrial pacing induced conduction block between the left atrium and the arrhythmogenic pulmonary vein might be a possible explanation for the prevention of paroxysmal AF by atrial pacing.
Estimation of bacterial risk in extending the shelf life of PLT concentrates from 5 to 7 days
Authors: Lee C.K. , Ho P.L. , Lee K.Y. , Cheng W.W. , Chan N.K. , Tsoi W.C. , Lin C.K.
Published: July 2003

BACKGROUND: The use of bacterial culture to prevent bacterial contamination of blood components has renewed interest for extending the shelf life of PLT concentrates to 7 days after collection.

STUDY DESIGN AND METHODS: This study was therefore conducted to determine the residual risk of bacterial contamination in PLT concentrates at the end of 5 and 7 days after collection in a center where all PLT concentrates are routinely screened by taking samples on Day 2 for culture. PLT units with no growth after 48 hours were sampled a second time on Day 5 or Day 7 after collection, followed by inoculation into aerobic culture bottles. The inoculated bottles were then monitored for up to 7 days at 35°C in an automatic monitoring and detection system.

RESULTS: During a 16‐month study period, a total of 6020 PLT concentrates were tested 5 days (Group A, n=3010) and 7 days (Group B, n=3010) after collection. Four units in each group (0.133%) were found to be contaminated. In 6 units, bacteria were seen on direct Gram stain. In addition, 5 of the associated RBC units grew the same organisms on culture. The organisms include three coagulase‐negative staphylococci and five Propionibacterium acnes. The positive rate of routine short‐term bacterial culture was 0.035 percent during the same study period.

CONCLUSION: Despite routine short‐term bacterial culture, a significant risk of bacterial contamination remains at 5 and 7 days after collection. For now, the shelf life of PLT concentrates should remain 5 days.
Biologic activity of RANTES in apheresis PLT concentrates and its involvement in nonhemolytic transfusion reactions
Authors: Wakamoto Shinobu , Fujihara Mitsuhiro , Kuzuma Kazuhiro , Sato Shinichiro , Kato Toshiaki , Naohara Tohru , Kasai Masaharu , Sawada Ken‐ichi , Kobayashi Ryoji , Kudoh Tooru , Ikebuchi Kenji , Azuma Hiroshi , Ikeda Hisami
Published: July 2003

BACKGROUND: RANTES, one of the PLT‐derived biologic response modifiers, accumulates in PLT concentrates (PCs) during storage and may play a causative role in nonhemolytic transfusion reactions (NHTRs) after PC transfusion.

STUDY DESIGN AND METHODS: To investigate the association of RANTES with NHTRs, the biologic activity of RANTES in the supernatant of stored PC at the intravascular concentration expected after PC transfusion was assessed by examining chemotaxis and histamine release in human basophils. In addition, the levels of RANTES in PCs involved in NHTRs were compared with those in PCs causing no transfusion reactions.

RESULTS: The supernatant of PC diluted to contain 1 nM RANTES significantly increased the migration of and release of histamine from basophils. Neutralizing antibody to RANTES suppressed the PC‐triggered migration, but not histamine release. The levels of RANTES in PCs involved in NHTRs after PC transfusion were comparable to those in PCs that did not cause any transfusion reactions.

CONCLUSION: RANTES that accumulated in PCs during storage was biologically active in a basophil chemotaxis assay at the intravascular concentration expected after PC transfusion. However, the NHTRs after PC transfusion were not simply related to the RANTES level in PCs.
ABO mismatch increases transplant‐related morbidity and mortality in patients given nonmyeloablative allogeneic HPC transplantation
Authors: Worel Nina , Kalhs Peter , Keil Felix , Prinz Erika , Moser Karin , Schulenburg Axel , Mitterbauer Margit , Mannhalter Christine , Mayr Wolfgang R. , Schwarzinger Ilse , Höcker Paul , Lechner Klaus , Greinix Hildegard T.
Published: July 2003

BACKGROUND: ABO mismatch has not been thought to affect the outcome of patients undergoing myeloablative conditioning and allogeneic HPC transplantation. Data on transplant‐related complications after ABO‐mismatched transplantation after nonmyeloablative conditioning are limited.

STUDY DESIGN AND METHODS: Therefore, 40 patients were analyzed after nonmyeloablative conditioning with regard to ABO compatibility. Eleven received a minor and bidirectional and 8 a major ABO‐mismatched graft.

RESULTS: Four patients had evidence of hemolysis during engraftment, being lethal in one, and three developed pure RBC aplasia. Six patients in the ABO‐mismatched group developed thrombotic microangiopathy, and three of them died. ABO‐identical and ABO‐mismatched patients had a similar incidence of GVHD. Viral infections occurred in both groups in equal shares. Patients with an ABO‐mismatch had to be rehospitalized until Day 100 for a median of 19 days versus 0 days in the identical group (p < 0.05). Overall survival was 60 and 57 percent in the ABO‐identical and ABO‐mismatch groups, respectively. The probability of transplant‐related mortality was 0 versus 28 percent in the identical group compared to patients with an ABO mismatch (p < 0.05). The probability of relapse or progression was 76 versus 25 percent in the ABO‐identical group compared to the ABO‐mismatched group, respectively.

CONCLUSION: Significantly more patients with ABO mismatch showed transplant‐associated complications and died as a result of transplant‐related causes.
Effect of WBC reduction and storage temperature on PLTs frozen with 6 percent DMSO for as long as 3 years
Authors: Valeri C. Robert , Srey Rithy , Lane Joseph P. , Ragno Gina
Published: July 2003

BACKGROUND: PLTs frozen with 6 percent DMSO can be stored at −80°C for 2 years, while those frozen with 5 percent DMSO at −150°C can be stored for at least 3 years. The more rapid deterioration seen in PLTs frozen at −80°C may be due to the presence of granulocytes. The effects of storage temperature and WBC reduction on PLTs frozen with DMSO and the breakage of the PVC plastic bags stored at −80 and −135°C were assessed.

STUDY DESIGN AND METHODS: Apheresed PLT‐rich plasma (PRP) was either divided into two equal volumes where one volume was WBC‐reduced and the other volume was not or filtered or not and then divided into two equal volumes. PLTs frozen with 6 percent DMSO were stored in PVC plastic bags at either −80 or −135°C for as long as 3 years.

RESULTS: After 2 years of storage at −80°C, the PLTs exhibited satisfactory freeze‐thaw‐wash values regardless of whether or not they were WBC‐reduced, but after 2 to 3 years of storage at −80°C, the PLTs had significantly reduced freeze‐thaw‐wash values. Freeze‐thaw‐wash values were not reduced in PLTs stored at −135°C for up to 3 years.

CONCLUSIONS: WBC reduction did not improve freeze‐thaw‐wash recovery values in PLTs stored at −80 or −135°C for up to 3 years, but reducing the storage temperature from −80 to −135°C did. Breakage of PVC plastic bags stored at −135°C was excessive.